ProAgri Zambia 49 by ProAgri

ProAg Agri ri technology for the farmer

Crops flourish under the United Fertilizers range

Z a m b i a No 49

Free

Stock farmers benefit from Novatek

EVERY KERNEL COUNTS

Advanced panel

FREE! with

internet control.*

Agrico centre pivots are supported Order new Agrico centre by theamanufacturer through:pivot with a Premium control panel• Crane and get an upgrade. trucks for service • Own branches as well as agents • Trained irrigation designers • Irrigation technicians

• Unmatched guarantee • Optional internet control with 24/7 helpline

*Free subscription included for the first 24 months. Contact: Hanré Wiese | +26 0 973 170 557 | +26 0 211 845 874 Alfred Andrag | +27 82 824 1214 | sales@agrico.co.za

More than 100 years’ service

Cover

Letter from the Editor

Falcon distributes one of the world’s most famous and popular implement brands, Amazone. Their fertiliser spreaders, sprayers and tillage equipment with their innovative German technology opens new horizons for famers. You may get better acquainted with their products on page 2.

ne of the most demanded Zambian export products is crocodile skin. Crocodile skin became even more popular after the ZCFA (Zambian Crocodile Farmer’s Association) improved the breeding and feeding practices over the past four years. The industry now complies with world standards to meet the requirements of their very particular clients like Hermes and Louis Vuitton Moët Hennessy, who manufacture high-end footwear, wallets, handbags and garments – a market estimated to be worth more than US$100 million per year. But these improvements came with a huge price tag, because it disrupted the crocodile hide industry significantly. To make matters worse, just when the crocodile farmers were back on their feet, government slapped an export duty of 10% on the export of crocodile skins… This duty will make Zambian crocodile skins uncompetitive in the global market. Still, it wasn’t even announced during the 2019/2020 budget speech and neither was there any consultation beforehand. To make matters worse, farmers had to pay the duty up front, which had to come out of their limited operational capital. On one stage, US$1,3 million of stock was stuck in cold storage facilities before the duties could

Content

be paid, while the subsequent harvests were causing a huge bottle neck. Farmers already paid more than US$350 000 that was not budgeted for. Farming operations were severely hampered. Two farms already terminated operations, and many more are the on the brink of closing down. 600 jobs in rural areas are on the line should this industry collapse. The ZCFA has entered talks with the ministry to nullify this unwelcome surprise. Government hasn’t budged yet, despite having been informed that regulations regarding crocodile skins got confused with the general regulations of skins and hides. The Minister of Finance was recently invited to one of the crocodile farms to experience the industry and to get engaged in discussions. Let’s hope 2020 will revolve into a better year for our crocodile farmers who exported 44 000 skins in 2015, 31 685 skins in 2018 and about 22 000 skins in 2019… This month, Novatek and United Fertilizers share some very useful product and educational information with us. We also offer six very informative articles for you to enjoy. Farm smartly! Du Preez de Villiers dupreez@proagri.co.za

Useful tips from Novatek: Aspects to consider when moving dairy cows

Create the perfect environment for your dairy cattle: Part 6

12.

The operation and application of medium and big square balers: Part 5

16.

Irrigation made easy: Part 2

20.

Fertigate for soil health and profit: Part 7

23.

United Fertilizers: Give your plants all they need to grow

24.

Turn your crops into condiments and seasonings: Part 3

30.

Water wise farmers build earth dams: Part 2

ProAgri Zambia 49

ProAgri technology for the farmer

Z a m b i a

Nangwenya House No. 7352 Nangwenya Road Rhodespark +26 (0)97-769-9786 www.proagri.co.za Copyright © 2019. All rights r eserved. No m aterial, text or p hotographs may be r eproduced, copied or in any other way t ransmitted without the written consent of the publisher. O pinions expressed are not n ecessarily those of the publisher or of the e ditor. We recognise all trademarks and logos as the sole property of their r espective o wners. ProAgri shall not be liable for any errors or for any actions in reliance thereon.

ProAgri Zambia Editor Du Preez de Villiers > +27 82-598-7329 dupreez@proagri.co.za Reporters Annemarie Bremner > +27 82-320-3642 annemarie@proagri.co.za Benine Ackermann > +27 73-105-6938 benine@proagri.co.za Jaco Cilliers > +27 71-893-6477 jaco@proagri.co.za Senior Production Manager: Zainab Pandor > +26 (0)97-769-9786 zainab@proagri.co.za Marketing Manager Diane Grobler > +27 82-555-6866 diane@proagri.co.za Marketing Xander Pieterse > +27 79-524-0934 xander@proagri.co.za Johan Swartz > +27 71-599-9417 johan@proagri.co.za Tiny Smith > +27 82-698-3353 tiny@proagri.co.za Anelda Strauss > +27 74-424-0055 anelda@proagri.co.za Gerhard Potgieter > +27 74-694-4422 gerhard@proagri.co.za Creative Manager Christiaan Joubert > christiaan@proagri.co.za Enquiries Engela Botha > +27 12-803-0782 engela@proagri.co.za Accounts Ronel Schluter > +27 12-803-0782 accounts@proagri.co.za Business Manager George Grobler

WHAT TO EXPECT 18500+ attendees

GROWING KNOWLEDGE FOR FUTURE FARMERS

7+ international pavilions

220+ exhibitors

70 000 sqm of exhibition space

50 training workshops

AGRITECH EXPO ZAMBIA IS ONE OF THE LARGEST OUTDOOR FARMING TECHNOLOGY EXHIBITIONS IN THE SOUTHERN AFRICAN REGION.

2â&#x20AC;&#x201C;4

Presented by

26 live crop trials

Organised by

April 2020 GART Research Centre, Chisamba, Zambia

HURRY SPACES LIMITED. CALL OUR TEAM TODAY: Liam Beckett, Sales Director | +27 79 281 7865 | liam@agritech-expo.com Jerome Dyson, Sales Manager | +27 81 586 1005 | jerome@agritech-expo.com

www.agritech-expo.com

ProAgri Zambia 49

Useful tips from Novatek: Aspects to consider when moving dairy cows by Wiehan Visagie

ave you ever wondered how many friends your dairy cow can make? Is it even possible, you may think. According to the latest research, a cow is more than capable of forming new relationships. As part of their investigation of biosecurity on a farm, the University of Minnesota College of Veterinary Medicine studied the behaviour of dairy cows. They found that cows react differently when placed in different herd sizes. Every time a cow was moved from one group to another or from an old farm to a new farm, the cow reacted differently. Cows placed in small herds struggled to adapt; their condition scores were poor, they produced less milk, and it took them longer to regain a good level of immunity. However, cows placed in bigger herds almost never struggled. These cows

produced adequate amounts of milk, they hardly ever got sick and during challenging times they retained their body condition scores. The researchers then recommended that a cow should be moved to groups larger than 20 animals, because cows released into smaller groups showed negative behavioural patterns. The competition factor is higher in smaller groups; there is more stress and the cows' dry matter intake (DMI) was reduced. The decrease in DMI has serious consequences; for example, a dry cow that eats less struggles in the transition phase. Additionally, it appears that a cow can identify with up to 20 animals but struggles to “make friends” as the group grows larger. This limited identification can be counterproductive. Larger groups of cows prevent the new cow from being suppressed, and the adap-

tation period runs more smoothly. In groups larger than 20, no hierarchy can be identified, so these cows do not experience much social stress when they are moved. The effect on biosecurity Many factors can affect a farm's biosecurity, especially when we move a cow from one farm to another. Apart from the socialisation aspect related to herd numbers, the following factors must also be considered: Origin and number of animals introduced: As far as is practicable, keep a herd closed. If it is necessary to add animals, use as few sources as possible and limit the number of animals. Check the health status of the animals introduced to prevent the spread of common communicable diseases. And remember a cow's propensity for forming counterproductive friendships in small groups! Location and layout of the farm: Predetermine onsite pathways, and move animals on a route that reduces exposure to disease and avoids possible sources of infectious disease. Water supply sources: Water supplies used for drinking, bathing and cleaning can transmit pathogens to or from animals. Water can be contaminated with waste products such as manure – from wild birds, rodents or native mammals, for example – posing a risk to both animals and staff. Clean water is a non-negotiable requirement for a healthy herd. Food supply sources: Feed inputs include dry feed (concentrates, hay, grains and seeds) and wet feed (silage, brewer's grain, Japanese radish and pasture). Feed can carry pathogens and can be contaminated by the raw materials used during production or even when the feed is transported. You may contact Wiehan Visagie at wiehan.visagie@novatek.co.zm or Marné Visagie at nutritionist@ novatek.co.zm for any information on feeding and feeds.

ProAgri Zambia 49

Create the perfect environment for your dairy cattle

Part 6: Influence of unfavourable environmental conditions Eksteen Lindeque and Petrus Britz (Pr. Eng.)

he occurrence of wet, muddy conditions and accumulation of manure, do not only make the production of hygienic milk difficult, but also contribute to mastitis, hoof and leg problems, and reproduction and respiratory problems. Muddy conditions Although it stands to reason that a cow will soil her udder and teats while lying down in the mud, the spread of manure and mud to her udder resulting from her movements, may not be that obvious. Abe (1999) carried out a study to determine how impurities spread to a cowâ&#x20AC;&#x2122;s udder from her legs and tail as a result of her movement. This study proves that a cow carries impurities by means of her natural leg movements to many areas of her udder when she steps in mud or deep manure. These include areas not usually noticed in dairy situations. Good sanitation, or a docked tail, is two possible solutions for keeping a 6

Muddy conditions have a detrimental effect on a cowâ&#x20AC;&#x2122;s hooves. Photo: geography.org.uk.

ProAgri Zambia 49

NERIA’S INVESTMENTS LTD LEADERS IN AGRO COMMODITY TRADING THE MOST AFFORDABLE P R I C E S O F CO M P O U N D D A N D U R E A I N T H E CO U N T R Y

Saturnia House, Opp. Ndeke Hotel Longacre’s Tel: +260 211 244 505/6

E-mail: info@neriainvestments.com

www.neriainvestments.com

ITI

C EX

ProAgri Zambia 49

in the air significantly. Ammonia gas is released from fresh manure and the further aerobic breakdown of manure and urine, while a large quantity of CO2 is produced daily by the breathing of animals and the breakdown (rotting) of manure. The resistance of animals against pathogens can be decreased by the inhaling of gases such as carbon dioxide, ammonia and methane. Fodder intake and, consequentially, production can also be influenced adversely. Daily cleaning of manure alleys and good ventilation is therefore essential. Sainsbury, according to Engelbrecht (1991), alleges that the threshold values of ammonia gas and CO2 in the air of intensive housing units, are given as 50 and 500 parts per million respectively. It seems, though, that animals can endure considerably higher concentrations of these gases for short periods. A docked tail. cow clean. Many people feel that the tail is necessary for controlling flies, but other alternatives exist, as the tail is a feeding source for flies. Improved housing, a docked tail or the clipping of the tail can be considered to prevent contamination of the udder. Dirty legs contaminate the bedding with bacteria found in manure and mud. Although the growth of bacteria will depend on the bedding, it will grow and create a greater risk of mastitis infection. Corrals, roads, grazing, shed entrances and walking surfaces, as well as bedding, must be kept clean and dry. High-flow areas such as fodder and water troughs must especially be kept spotless. If soil conditions are

very poor, the areas must be fenced and, under very severe circumstances, the cows must be kept inside. Dairy procedures must be adapted to muddy conditions. The udder must not be summarily washed with hot water. This will spread the mud to the teats. Many farmers waste money to keep udders clean and dry under unfavourable conditions. A better option is to rather address sanitary problems, as good sanitation leads to higher quality milk and fewer cases of mastitis.

Disease control The prevention and control of diseases are of the utmost importance for success in a dairy enterprise. To prevent diseases in a dairy herd, the dairy cattle must be well fed and the herd, farmstead and grazing must be kept clean. Especially note the health of animals introduced into the herd. If the dairy herd is well fed, the cattle will have better resistance to diseases. Although there are a great many diseases that can affect dairy cows, only the two most important ones are discussed, namely mastitis and hoof and foot injuries.

Accumulation of manure An accumulation of manure in the manure alleys of intensive housing units can increase the concentration of ammonia (NH3) and carbon dioxide (CO2)

Mastitis. Photo: Nadis.org.uk.

Accumulating manure produces gasses like CO2, methane and ammonia which are toxic and pose a severe threat when it gets out of hand. Photo: Pixabay. 8

Mastitis The word mastitis simply means â&#x20AC;&#x2DC;inflammation of the udderâ&#x20AC;&#x2122; and is usually caused by infection of the udder by bacteria. Mastitis can be described as acute, sub-acute or chronic, depending on the intensity and duration. The exceptions are cases caused by environmental pathogens.

ProAgri Zambia 49

Bulk milk SCC

Percentage loss

Interpretation

< 300 000

0 to 2,5

Minimal mastitis: Effective control

300 000 - 500 000

2,5 to 7,5

Mastitis infection possible

500 000 - 800 000

7,5 to 15

Mastitis infection present

> 800 000

15 to 25

Mastitis problem in herd

Table 1: Somatic cell count (SCC) of bulk milk as an indication of loss in milk production and the effectiveness of mastitis control in the herd. Clinical mastitis Clinical mastitis is easily detectable in the abnormal appearance in the stripping jug. It will also be visible in the reddish colour, heat and swelling of the udder, accompanied by pain. Sub-clinical mastitis Sub-clinical mastitis is easiest diagnosed in the laboratory. The udder looks normal but the somatic count is higher and bacteria are usually present. Mastitis is comparable with an iceberg. The clinical cases are the visual parts of the iceberg, while the sub-clinical cases are those parts of the iceberg which are underwater and invisible.

Somatic cells Somatic cells are white blood cells, which are part of the body’s defence against bacteria and invasive microorganisms. These cells are always present in the bloodstream and in the milk, but their numbers increase visibly when infection is present. A cow should have a somatic cell count of less than 100 000/ml. Older cows should have a somatic cell count of less than 250 000/ml, but it can be as high as 500 000/ml. Normal physiological deviations occur during the lactating period. The somatic cell count (SCC) of bulk milk is a good indication of milk quality, milk loss and the effectiveness of mas-

titis control in the herd, as indicated in Table 1. Hoof and foot injuries There are four main factors that can lead to lameness or that can react upon each other to cause clinical signs of lameness, namely: • Hereditary factors (mass and composition) • Feeding factors (proteins, vitamins, minerals and poisonous substances) • Infection factors (bacteria and viruses) • Environmental factors (climate and housing) The foot and the hoof are the areas most affected by lameness problems, with 80% of the injuries taking place in this area. The remaining 20% of injuries associated with lameness is spread over the entire body and limbs. It is associated with the joints and ligaments and is mainly attributed to trauma. Most lameness problems begin with hypertrophy (overgrowth) of the hoof. It usually occurs in cattle on high levels of concentrate fodder. Hypertrophy also causes the opening between the

Hypertrophy of a cow's hooves can lead to disease and lameness. Photo: tbasine.wordpress.com. ProAgri Zambia 49

A cowâ&#x20AC;&#x2122;s hooves are her mode of transport. They should be kept in a running condition. Photo: agritrimhoofcare.com.

in feeding habits. Increased histamine levels in the blood cause the inflammation of the sensitive hoof tissue. High levels of concentrate feeding, silage rich in non-protein nitrogen or high levels of rumen-catabolic protein can lead to an excess production of ammonia in the rumen. The problem can be solved by correcting the imbalance in the total ration and by ensuring that sufficient fibre is available. The clinical injury of botulism is ulceration of the soles. These ulcers usually develop on the weight-carrying hoof and inflammation can easily set in. This can lead to serious, deep-rooted infection of the foot. Implementation of a health programme The following general health programme can be implemented to prevent the occurrence of diseases and the spreading of infectious diseases and to control parasites:

Take care not to over-trim a cow's hooves. Photo: agritrimhoofcare.com.

claws to cicatrise (grow together), with the result that the dirt is caught in them. This can lead to infection of the skin between the claws (foot-rot). Decaying of the soft heel is also aggravated by hypertrophy, because a cow with extremely long hooves is inclined to walk on her heels. This increases decaying of this sensitive area. Softening of the hooves during lengthy wet conditions causes the hooves to have less resistance and are therefore made more susceptible to injuries and infection. In extremely wet conditions, or when animals are compelled to stand in wet muck, sole ulcers can develop. Under such conditions foot baths can relieve the condition. Bovine Para botulism is a more complex problem and has its origins 10

Wet conditions can soften a cow's hooves which can lead to infection and ulcers. Photo: agritrimhoofcare.com.

ProAgri Zambia 49

•

• • •

Gestating cows must get enough exercise, preferably by letting them graze on adequately fenced grazing where sufficient shade and water are available. Ensure that premises and corrals are well drained and kept as dry as possible to prevent breeding places for foot rot and parasites. For the same reason, fence off grazing where mud holes and puddles are present. Drainage from adjacent farms must preferably be diverted and communal fences that allow direct contact between cattle must be avoided. Do not visit farms where contagious diseases occur, as shoes, clothing and vehicles transmit the organisms. Fodder must not be purchased from such contaminated farms. Fodder bags must not be re-used. Rented grazing areas where cattle spend the winter must be avoided. Use grazing where no cattle grazed for a year or grazing that has been ploughed. Follow a healthy feeding programme to avoid ketosis, milk fever and nutritional diseases. Avoid injuries by keeping wire, nails and loose metal objects away from cows. Avoid heifers’ first time calving problems by feeding them generously and only breed when the

Use your common sense to identify potential hazards.

• • •

heifer is large enough for a bull that breeds calves that are small at birth. Keep sick or infected animals away from others and obtain the services of a veterinarian. Early diagnosis is the key to quick treatment and recovery. Isolate all new additions from shows or auctions to the herd for a period of three weeks.

Next month we shall look at the planning of a dairy. Published with acknowledgement to the ARC Agricultural Engineering for the use of their manuals. Visit www.arc.agric.za for more information.

NoseRi NoseRing®

• Wean with ease • No stress Wean with ease | No stress | Next to the mother • Next to the mothe

Whole Concepts cc PO Box 1806, Vryburg,8600, Sout

NoseRing® is available at Livestock Services, Lusaka – Pamodzi Highway, off Nangwenya Road, Showgrounds; Tel: 0211-254497 / 254024; E-mail: admin@livestock.co.zm

Tel: +27 Cell: +27 E-mail: judy@ Tel: +27 (0)53 927 4999 www. Cell: +27 (0)82 459 9451 judy@nosering.co.za

www.nosering.co.za ProAgri Zambia 49

The operation and application of medium and big square balers Part 5: Field operation

by GJ Stoltz (Reg Eng Tech)

ProAgri Zambia 49

his month we move into the field where the hay is cut and already dried, to start with the baling operation. Baling can begin when the windrows are ready. Bale the driest hay first. The baler should move in the same direction that the rake had gone, because this helps the pick-up teeth to reach under the windrow and pick up the hay in a “head-first” position. Lower the pick-up before engaging the baler-drive clutch. Bring the engine up to the recommended speed before starting to pick up hay. Drive in a low gear for a short time to make sure that the baler is functioning properly. When starting with an empty bale chamber, the first few bales will be light and their length irregular. The productivity of a baler depends on crop characteristics, ground conditions, condition of the tractor and baler and the judgement of the operator. Do not overcrowd the baler. If the feeding mechanism is properly adjusted and still cannot handle the incoming hay, the baler is being crowded beyond its capacity and serious damage may result. Reduce the ground speed, but maintain the recommended PTO speed for proper baler operation. Always run the tractor’s engine fast enough to maintain a proper baler operating speed. When turning on the headlands, disengage the tractor’s PTO to avoid excessive vibration.

require no corrective action. If broken bales must be rebaled in the field, the original wires or twines must be removed and the hay spread out so that it can be picked up again. Do not hand feed broken bales into the baler because it is very dangerous and somebody can lose an arm in the process. Pick-up adjustments: Adjust the pick-up of the baler until a clean pick-up from the stubble is achieved.

Picture 4: A pick-up gauge wheel helps the pick-up to follow the ground contour properly.

Picture 3: A clean pick-up from the stubble must be achieved. Normally the teeth are set to operate just below the top of the stubble, but not low enough to hit the ground. If the pick-up’s teeth strike the ground, they may bend backward and when recoiling they will shatter leaves and mix dirt with the hay (see Picture 3 and Figure 1). A pick-up gauge wheel is available for some balers that prevents such problems and helps the pick-up to follow the ground contour (see Picture 4).

Feed rake adjustments: Most balers have feeder teeth to move hay from the auger into the bale chamber. Some balers don’t have augers and use only their feed rakes to feed the hay from the feeder compartment into the bale chamber. The rake’s movement must be such that uniform bales are produced. If the feed rake is improperly adjusted, more hay will be packed onto one side of the bale than the other. This usually results in one wire, or twine, being pulled tighter than the other and causes “banana” bales, which are very unstable (see Picture 5).

Do not overcrowd a baler.

Picture 5: The feeder teeth on the feed rake must be properly adjusted to produce uniform bales.

Keep the twine and wire tying mechanisms as well as the plunger safety stop clean from chaff. Accumulation of chaff on the bale measuring trip device results in long and untied bales. Field adjustments When a malfunction occurs, always analyse the situation before taking action. For example, a baler may occasionally miss tying a bale. Unless a true malfunction pattern is established, the condition may be only temporary and

Figure 1: The pick-up height must be such that the teeth operate just below the top of the stubble.

ProAgri Zambia 49

If the feeder teeth on the feed rake are set to their longest stroke and material is still not going far enough into the bale chamber, the baler is probably being underfed and the land speed must be increased or the windrows must be combined. Always consult the operator’s manual when adjusting the feeder teeth. The feeder teeth on some balers are called the “packer cross-feeding system” and the plunger is called the “ram” (see Figure 2).

bale tension control is available for some balers and can provide on-the-go control of the bale weight (see Picture 6). Bale density may be further increased by installing hay resistors in the bale chamber, especially when baling fluffy hay or very light windrows. Hay resistors slow the passage of material through the bale chamber and prevent it from bouncing back between plunger strokes. They are very helpful when baling straw (see Figure 3).

Figure 2: A top view of a square baler with a “packer cross-feeding system”. Note the two crankshafts driving the two sets of teeth.

chamber get wet with rain, the material will expand and cause problems when restarting the baler. Bales that are too tight or too heavy put excessive strain on the baler and can break parts, twine and wire. Hay bales normally weigh between 22 kg and 25 kg. Measuring wheel A measuring wheel with prongs, projecting into the forming bale, rotates as the compressed hay moves to the back of the bale chamber. After the wheel has turned a certain distance, the tying mechanism is tripped and the needles take the twine, or wire, to the knotters to complete the tying of the bale. Irregular-length bales come from inconsistent hay density. Make the density more consistent by increasing the land speed, increasing the size of the windrow or tightening the bale tension cranks.

Picture 7: Testing the twine and hay density

Bale weight Bale weight is effected by the size of the windrows, moisture content and the quality of the hay. Since these factors may vary from hour to hour, or from windrow to windrow, the bale weight should be checked regularly during the operation. To regulate bale weight, change the tension on the bale chamber by adjusting the two tension cranks at the rear of the chamber. This pulls the upper and lower tension bars together and restricts the hay passage through the bale chamber. Hydraulic

Figure 3: The wedge-shaped resistors slow the passage of the hay through the bale chamber.

Picture 6: Adjusting the two tension cranks at the rear of the bale chamber. 14

The resistors must be removed when baling normal hay again to avoid unnecessary strain on the baler caused by the extra resistance. The tension cranks must be released at the end of each day’s operation to relieve the tension springs and to reduce the possibility of bales sticking in the bale chamber. If bales left in the bale

Flywheel shear bolt The shear bolt on the flywheel will shear if the plunger is blocked. After the blockage is cleared up, replace the shear bolt with a new one. Use only shear bolts recommended by the manufacturer. Do not replace a shear bolt with a standard bolt. Bolts that are too soft will shear unnecessarily and waste time. Bolts that are too hard may not shear when needed and will not provide protection. If the needles are in the bale case when the bolt shears, return the needles to the “home” position by hand before starting the baler. Before starting the baler, the flywheel must be turned by hand through a complete plunger cycle to make sure all components are functioning properly and no obstructions are blocking the operation.

We thank the ARC Agricultural Engineering in South Africa who made the information on square balers available to the readers of ProAgri Zambia. Next month we shall look at baler attachments. Visit www.arc.agric.za for more information.

ProAgri Zambia 49

Irrigation made easy Part 2: What happens with water, air and nutrients? by Kevin Scott

What happens with water?

lant available water is stored in the soil. Water that can be reached by the roots is sucked up by the plant. 16

A plant sends down roots to find water in the soil profile and suck it up. The soil must, however, still contain air to allow the roots to breathe. The plant can only draw up water that is close to a living and active root and then only when the plant doesnâ&#x20AC;&#x2122;t need to suck hard to try to pull water away from a particle of soil.

The soil acts like a sponge, holding water and then releasing it under (suction) pressure. Plant roots suck water directly from this sponage-like reservoir.

ProAgri Zambia 49

What happens with air?

The air that plants breathe in is the same as the air that animals breathe out. The plant needs to take carbondioxide from the air. The plant then breathes out air that is rich in oxygen, which is needed by animals.

An animal makes use of the oxygen in the air and breathes out air that is rich in carbon-dioxide. Both life forms will die without sufficient air.

A plant uses the air that animals breathe out, together with energy derived from sunlight to make sugars and starches, releasing oxygen back into the atmosphere. An animal uses sugars and starches, together with oxygen to release energy to power the body, releasing carbondioxide back into the atmosphere. Both plants and animals use air to process the water and food that they need to grow.

Plant available water can be derived from a number of different sources including rain, irrigation and groundwater. ProAgri Zambia 49

ProAgri Zambia 49

An animal breathes air into its lungs. The air is then carried by the blood to the rest of the body

An animal will die without air.

Each part of the plant breathes in air. What happens with nutrients? The plant draws its food from the soil together with water. Most nutrients tend to move in the soil together with water. If too much irrigation water is applied and water flows downwards to below the root zone, nutrients will also be washed down, out of reach of the roots.

Air is not transported within the plant and each part of the plant that doesnâ&#x20AC;&#x2122;t get enough air will die. As water moves down through the soil it will force out air. For a short time, the saturated wetting front has no air. Soils particles attract and hold some water and the rest drains away downward. As water drains away, air flows back into the spaces between soil particles.

Nutrients Soil, water and air Soil and water

Dry soil

The plant needs to be able to feed from the soil. With too little water in the soil, this cannot happen. Too much water will wash nutrients away from the roots. A water balance is needed.

If too much water is applied, or if drainage does not take place, plant roots will not get air and will suffocate and die. Plant roots need to breathe.

ProAgri Zambia 49

Next month we shall look at the distribution of water. Published with acknowledgement to the ARC Agricultural Engineering for the use of their manuals. Visit www.arc.agric.za for more information.

Photo: mainepublic.org.

Fertigate for soil health and profit Part 7: Electronic control, safety measures and injection of fertiliser solutions Frikkie Koegelenberg Pr Eng and Gert Conradie Pr Eng

pH-control It is important to regulate the pH of the irrigation water (between 5,6 and 6,2) to ensure the effective application of the fertiliser. The injection of fertilisers is also inclined to change the pH of the irrigation water and it might be necessary to adjust the pH. This can be done by adding an acid or alkali (depending on the pH) to the irrigation water.

lectronic control of injectors for fertigation can be done by monitoring of electrical conductivity (EC) and pH. Electronic control of injectors ensures that a higher measure of accuracy is possible, as these types of systems can be fully automated. Sophisticated equipment is usually used, resulting in high costs. Singular and dual control is possible. Singular control is done where injection takes place from one tank and dual control when injection from two tanks. With dual control, the fertiliser is injected from two tanks and the injection thereof is therefore also proportional. Electronic conductivity control Electric conductivity (EC) is the measurement of the total dissolved salts in the irrigation water. The conduction is an indication of the irrigation water’s natural salt content and composition of the fertiliser mixture. The EC is measured in milli-siemens per metre (mS/m) or mg/l. EC × 0,8 = g/l (concentration of elements). Electronic control of fertigation can be done by using an EC sensor and control equipment (controller, relays, motorised valve, et cetera). The set-up consists of an EC sensor in the irrigation pipeline, a short distance after the fertiliser is applied in the pipeline by the fertiliser pump. This ensures thorough blending between fertiliser mixture and irrigation water before it arrives at the sensors. 20

Mounted and portable EC sensor and control equipment. Photos: hannainst.com An electronic controller then uses this sign from the EC sensor to open and close a motorised valve by means of a valve driver. This ensures that the correct fertiliser concentrate is always applied from the injection pump to keep the EC of the water and therefore also the concentration of the elements at the required level. EC-control can also be applied where the fertiliser is applied simultaneously with two pumps. Each valve can have its own valve driver, or one can be shared with mechanical arms between the valves (See Figure 1).

Safety measures The following safety measures must always be followed carefully: • Use the most suitable storage tanks for the specific application. The specific gravity (SG) of the liquid that the tank can handle, is very important. Always install a manual valve directly after the tank’s outlet so that injectors can be serviced. • Build a bunker wall around the storage tanks. This bunker wall must be able to hold at least 120% of the content that the largest tank can hold for a period of 72 hours. The tank must preferably be placed on a concrete slab, under a shade net or roof. Secure the tanks to the concrete slab with cables. Provision must be made for emptying of the tank, when necessary. • Always use eye protection and wear an acid protective overall with PVC gloves when using fertilisers.

ProAgri Zambia 49

Figure 1: The ideal fertigation set-up.

Injection of fertiliser solutions The optimal utilisation of a fertigation system does not only mean the use of dependable equipment, but also the accurate calculation of the correct injection rate. The calibration of the injectors after installation must also be done to ensure that the injection pump complies with the manufacturer’s specifications under field conditions. Each set-up will differ and factory conditions will never be found in the field. Injection pumps must be accurate within at least 1%. The following steps are proposed to determine the required injection rate of the injection pump: • Calculate the target area where fertigation will be applied or the number of plants to be served by the irrigation system. • Obtain the recommendation of a fertiliser consultant on the quantity of fertiliser mixture to be applied per hectare or per plant or per m3 irrigation. • Obtain the applicable information on the specific type of fertiliser mixture to be used, for example concentration and composition. • Calculate the total quantity of the fertiliser mixture to be applied (per hectare or per m3 irrigation water).

A safe fertigation storage and control room. Photo: dynatrade.co.za.

Automatic fertigation control systems can take the headache out of the calculations needed. Photo: indiamart.com. •

• •

Provide a shower and eyewash bottles at storage sites as well as at the injection points for use during emergency situations. Obtain the applicable directions for use from the supplier, especially for the mixing of fertilisers to be used. Always prevent back-flow of fertilisers to the water source, overflow of fertilisers from storage tanks, injection of fertilisers into empty irrigation lines and the use of fertilisers which are incompatible. Make provision that equipment can be rinsed with clean water after each use. Mark pipe networks with different colour paints, for example for fertiliser mixtures from tank A, B for clean water. Also refer to the applicable regulatory colour codes for pipelines.

Automatic injection of fertilisers ensures precicion farming. Photo: climatecontrolinc.com.

ProAgri Zambia 49

•

Determine the duration of the injection (depending on the irrigation system’s standing time and application rate, time required for the fertiliser solution to move from the injection point to the last emitter, the quantity of fertiliser mixture to be injected and the movability of the fertiliser mixture in the soil). Determine the injection rate of the injection pump with the aid of the following equation:

•

IT =

Ok x A KxT

(1)

IT = injection rate of the fertiliser mixture (ℓ/min) Ok = amount of fertiliser to be injected (kg/ha) A = area (ha) K = required injection concentration of the solution (kg/ ℓ) T = injection duration (min)

•

The injection rate will be determined by the maximum capacity of the available injection pump or the flow rate of the irrigation system. The minimum injection rate is usually 10% of the maximum value and must not be exceeded (Wilson, 1996). Calibrate the injection pump according to the injection rate as calculated. For calibration of the injection rate, a stopwatch and measuring jug is required. The measuring jug must be clearly and precisely marked in millimetres and must be large enough to hold enough of the fertiliser mixture for five minutes of injection. The measuring jug can then be filled with liquid and the time to suck a specific volume of the liquid from the measuring jug, or the quantity of liquid that is sucked from the measuring jug in a specific time, is measured with the stopwatch. The method of sucking from an open measuring jug is preferred over the method where liquid is pumped into a container, because the back pressure in the container can influence the reading.

Measuring jug. We thank the ARC Agricultural Engineering in South Africa who made the information on fertigation available to the readers of ProAgri Zambia. Next month we shall discuss examples of the calculation of injection rates. Visit www.arc.agric.za for more information.

ProAgri Zambia 49

United Fertilizers Company:

Give your plants all they need to grow healthy and be productive

the preparation of concentrated stock solutions and for further injection into irrigation systems. This potassium fertiliser is chloride free, contains 46,2% K 2O and 13,7% nitrogen in nitric form. Urea micro prills is another Uralchem high-tech product from their watersoluble line. It is a modified urea with a very fine granulometric composition, completely soluble in water. It can be

From left to right: Solar potassium nitrate, Solar calcium nitrate, Solar MAP, Solar universal NPK micro. applied through drip irrigation or onto the leaves. Urea micro prills can also be effectively used for preparation of water-soluble fertiliser mixtures, characterised by outstanding physical properties such as high homogeneity, non-caking and non-flaking.

Plants require different compositions of nutrients at different growth stages. The Solar NPK Micro family aggregates three major types of ready-to-use, 100% water-soluble NPK mixtures with micronutrients (ME) for foliar application: i) high phosphorus (for example Start 13:40:13+ME) to be used at the beginning of the vegetation period to support and stimulate the

ProAgri Zambia 49

Aqua Drop represents the line of high purity water-soluble NPK mixtures. These are based on potassium chloride as a source of potassium, instead of more expensive potassium nitrate, which makes Aqua Drop a cost-effective alternative to above-mentioned fertilisers. The range of NPK grades is created to provide crops with optimum mineral nutrition at every growth stage. However, due to the chloride content, the application of Aqua Drop is limited to open-field drip-irrigation systems and chloride tolerant crops.

Drip Kali.

Urea micro prills.

It is crucial to provide crops with calcium, especially in high-output soilless and soil-based growing systems. Calcium is barely redistributed between different plant organs, but plays a vital role in stress resistance of plants, influences the quality of fruits and significantly extends their shelf life. Calcium deficiency leads to well-known physiological plant disorders, such as blossom-end rot and fruit curling. Calcium nitrate is the only source of readily available calcium for crops. Uralchemâ&#x20AC;&#x2122;s Concentrated Grade contains 25% more calcium than any other competing product, making it unique and perfect for use in irrigation systems. Phosphorus availability is critical during the root system formation stage, but is also required throughout the growing period. With monoammonium phosphate (MAP 12:61), crops simultaneously source two readily available nutrients: nitrogen (12% by weight) and phosphorus (61% by weight). MAP 12:61 can be tank mixed, foliar-applied, or mixed with other fertilisers. Worth noting is that it should not be blended with fertilisers containing calcium or magnesium. Potassium is required during the entire vegetation period to maintain a water balance in the plant, to enhance nitrogen uptake, to redistribute nutrients, to ensure assimilation among plant organs and finally to increase yield and plant quality. Therefore, potassium nitrate is irreplaceable in

Aqua drop.

ll the nutrients your crops need to produce a healthy and abundant harvest are available in the complete range of products offered by United Fertilizers Company Ltd (UFCL), the trading arm of two Russian fertiliser manufacturers, Uralkali and Uralchem. This article briefly describes why you should use different water-soluble fertilisers with various irrigation systems.

establishment of the root system, ii) balanced (for example Universal 18:18:18+3MgO+ME) to correct plant nutrition and soften the negative impact of various possible stresses, iii) high potassium (for example Final 15:7:30+3MgO+ME) to be used at the reproductive stage to improve output and quality of produce, by helping crops to translocate nutrients and assimilate from one organ to the other.

DripKali is a potassium chloride (MOP), commonly used in fertigation for a variety of crops. It is the most concentrated source of potassium among potash fertilisers. It contains 62% K2O, compared to the 50% K2O in potassium sulphate and 46% K2O in potassium nitrate. Besides, MOP is compatible with all types of water-soluble fertilisers and can be safely used in irrigation systems. For more information visit the United Fertilizers website at ufertilizers.com or send an e-mail to M.Poltoradnev@ufertilizers.com 23

Turn your crops into condiments and seasonings Part 3: Mango Achar by Theresa Siebert

ProAgri Zambia 49

Mango achar. Photo: alishacooking.com

reen mangoes with premature soft seeds are suitable for achar or oil pickles. Achar is very popular with a large part of the Southern African population. It is eaten with maize porridge or bread as a substitute for meat and also serves as an aromatic flavouring with other foods. Owing to its high oil content, achar has a high nutritional value. The oil used is either mustard or ginger oil. Cured green mango slices are drained, mixed with spices and oil and filled into suitable containers and sealed. Extra oil is added on top to prevent air entry. High acid mangoes (5 to 6%) were found to produce the best quality achar. Harvesting of mangoes Harvesting is the manual or mechanical removal of a food product from its natural source or parent plant. The fruit is harvested in a mature, but unripe stage, and allowed to ripen for a few days for fresh consumption or processing.

ProAgri Zambia 49

Industrial sorting of mangoes.

Unripe mangoes.

Cleaning and washing Cleaning removes undesirable elements, removes impurities, damaged and shrunken or broken fruit and involves removal of material adhering to the surface of fruit. The fruit is washed in water-baths with brushes (large containers filled with potable water). The water must be changed regularly to minimise the chance of any contamination, and a detergent can be added, if required. Trimming, sorting and inspection Unwanted or unfit parts of the fruit are deliberately removed and only the best suitable raw materials are selected for manufacturing the value-added end product. Inspection is employed to ensure that the products adhere to the minimum predetermined quality attributes required for further processing and eventual end-use. 26

Inspection of the products is the most labour intensive practice. The quality of the product and adherence to pre-set quality standards (colour, shape and size) must be controlled with careful inspection. The fruits should be full size, immature, with incomplete seed formation, free from diseases, scars, mechanical damage, bruises, insect damage and latex staining.

Manual inspection and sorting of mangoes.

ProAgri Zambia 49

Green mangoes Harvesting Cleaning & washing Trimming, sorting & inspection Washing (Peeling) Cutting Blending (Selected spices, salts and acids are added) Packaging & storage Fermentation

Mangoes are washed with a chlorine solution. Photo: mangomaango.com.

Re-packaging (Mustard or ginger oil is added) Achar Process description for mango achar. Washing The fruit is finally washed with a chlorinated water spray (20 to 60 ppm active chlorine). Peeling of mangoes (optional) Mangoes are traditionally not peeled for achar, but can be peeled by hand with special knives or peelers if required. Cutting The flesh is quartered and cut into broad slices on a cutting board. Uniformity of size and shape is attractive in preserves and ensures even salt and spice penetration.

Peeled and cut pieces of green mango. Green mangoes don't have to be peeled to make achar. Photo: wikimedia.org.

Mango tree.

Uniformly cut pieces of green mango. Photo: wikimedia.org. ProAgri Zambia 49

Nothing Stands Still in Your Business

The seasons stop for no one and with a generator set from FG Wilson, neither do you. FG Wilson offer a complete range of robust and reliable self-contained diesel generator sets from 6.8 â&#x20AC;&#x201C; 2,500 kVA which are easy to operate and require a minimum of installation work. Our dealers can help you choose a generator set which will give you years of service, install it for you and ensure that you have all the service and support you need.

To find out more, visit www.fgwilson.com or contact sales@kva.co.za

Blending of other ingredients Blending is a means of dispensing additional components or ingredients uniformly into an existing food system. The selected spice mixture (for example, 15 to 19% salt and a spice mix of 5 to 10%), preservatives permitted by legislation and citric acid permitted by legislation are mixed with the chopped mangoes. Packaging Packaging is defined as the containment of a food product in a protective barrier that prepares goods for transport, distribution, storage, retailing and end-use. The mango-spice mixture is packed into suitable containers that can be sealed hermetically. Storage / fermentation Fermentation is the breakdown of organic molecules under anaerobic conditions (absence of oxygen) by microorganisms such as yeast and bacteria. The packaged mangoes are stored for up to three months in a cool, dry place to allow for fermentation to take place.

Re-packing The achar must be re-packed after fermentation in smaller containers â&#x20AC;&#x201C; suitable for individual use. Coloured oil (mustard or ginger oil) is added to the achar, to cover the product completely and prevent air entry. Labelling of fruit preserves The containers are labelled and coded so that the product contains all the nec-

essary information. Products must be correctly labelled according to the requirements set out in the labelling and advertising regulations of the country. Legislation for fruit products The fruit processor should be familiar with and adhere to the laws and regulations that are applicable to the products manufactured to ensure the safe and legal marketing of a product.

Next month we shall look at peach chutney. Published with acknowledgement to the ARC Agricultural Engineering for the use of their manuals. Visit www.arc.agric.za for more information.

Mango achar in packaging for retail and individual use.

Mango achar, ready to enjoy. Photo: happyshappy.com.

ProAgri Zambia 49

LITERATURE SOURCES 1. Arthley, D. & Ashurts, P.R. (eds) 1996. Fruit Processing. London: Blackie Academic & Professional. 2. Fellows, P. 1997. Traditional foods: Processing for profit. London: Intermediate Technology Publications, Ltd. 3. Holdsworth, S.D. 1983. The preservation of fruit and vegetable food products. London: MacMillan Press. 4. Kader, A.A., et al. 1985. Postharvest technology of horticultural crops. Cooperative Extension University of California. 5. Mallett, C.P. 1994. Frozen Food Technology. London: Chapman & Hall. 6. Nagy, S., Chen, A.S. & Shaw, P.E. (eds) 1993. Fruit Juice Processing Technology. Auburndale, Florida: AgScience, Inc. 7. Raiken, M.D.; Kill, R.C. & Baker, C. (eds). 1998. Food Industries Manual, 24th ed. New York: Chapman & Hall. 8. Shaw, P.E., Chan, H.T. & Nagy, S. (eds) 1998. Tropical and Subtropical Fruits. Auburndale, Florida: AgScience, Inc. 9. Singh, L.B. 1968. The Mango. London: Leonard Hill: 10. South Africa - Agricultural Products Standards Act (No 119 of 1990) and regulations. Pretoria: Government Printers 11. South African - Foodstuffs, Cosmetics and Disinfectant Act (no 54 of 1972) and regulations. Johannesburg: Lex Patria 12. Woodroof, J.G. & Luh, B.S. 1986. Commercial fruit processing. 2nd ed. Connecticut: AVI Publishing co.

by Jan van Heerden, M.Eng Tec

Water wise farmers build earth dams Part 2: Building cost and natural losses of stored water

ams can be expensive to build and therefore a farmer should do his calculations and planning very carefully to prevent those hidden costs from rising out of control. Water seepage can also be a huge unplanned expense, but it can be reduced to a minimum through proper planning. We thank the ARC Agricultural Engineering in South Africa for making their manual on earth dams building available to the readers of ProAgri Zambia. The building cost of a storage dam is a function of: • The required preparation of the site. • The quantity of building material 30

• •

• • • •

needed, that is soil, pipes, cement, sand, quarry stone, et cetera. The availability of the building materials and the transport distance. Working with soils with long hauling distances increase difficulty and the cost of an earth dam considerably. The quality of the foundation and the necessary preparation thereof. The spillway as required by the design. Outlet pipe as required, namely type, diameter and length with valves and necessary cut-off walls. Fencing of structure, if necessary.

Hidden costs like fencing can easily increase the cost of your dam way above budget.

ProAgri Zambia 49

Natural losses of stored water Seepage Seepage usually occurs in two ways, namely through the basin of the dam or through the wall. This is as a result of permeable formations that the dam basin consists of or faults in the structure itself. To prevent seepage through the wall or foundation, provision must be made in the design to ensure a denser structure. In the case of an earth dam, the foundation and topsoil must be of a reasonably dense type; where this is not the case, the construction of a pit wall, clay core or a clay blanket must be considered. A certain measure of seepage occurs in most dam basins. The amount of seepage is difficult to determine. If there is fine silt in the run-off water, the deposit of the silt in the basin will reduce the seepage. If the basin of the dam is very permeable, a blanket of clay can be placed over the entire basin, which will be described in a future article. It is therefore preferable that the building ground and the dam basin be dense or compacted economically where the storage of water is a prerequisite. Evaporation The average gross evaporation figure for Southern Africa from a free water surface is approximately 2 m per year. It varies from approximately 1,2 m per year in the south and east to about 3 m per year in the dry, warm regions. Preference is therefore given to dam sites which are relatively deep and have small surface areas.

Evaporation must be considered when designing a dam. Photo: Makal, Pixabay.

ProAgri Zambia 49

Silting of dams When muddy water flows into a dam basin, the larger and heavier sediments tend to settle first, but the finer material in suspension moves toward the dam wall. Earth dams with exceptional long walls and side spillways must not be designed in regions where the run-off water contains a high percentage of sediments, because delta forming takes place. The lifespan of such a dam is extremely limited. After silting, it will eventually fail and cause flooding. In the choice of an earth dam with a side spillway, the catchment area must be well covered with vegetation and if fields are present, it must be mechanically and biologically protected against erosion.

Silting of a dam. Photo: educalingo.com.

Catchment areas and run-off Annual run-off The amount of run-off, regarding flood peaks as well as the average annual run-off, is in a certain direct relation with the size of the catchment area. Other factors, such as annual rainfall, intensities and seasonal distribution of rainfall, vegetation, topography, mother rock, type and depth of the soil and water use in the catchment area, each play particular roles in determining the run-off, regarding both the average annual run-off and the run-off flood peaks. Various hydrological models exist that use the above factors to determine run-off intensities, average annual run-offs, flood sizes and the catchment water delivery potential. The models each have specific application ranges and are used by specialists. Methods that can be used for first order approximations exist for small catchment areas. Examples of flood approximation models are: Unit hydrograph, SCS, Rational, and Roberts. The ACRU-model of the University of KwaZulu-Natal in South Africa is a computer-supported model that not only calculates run-off, but also handles dam balances, and risk analysis. 31

obtained from the relative department beforehand. In the case of large dams, an environmental impact assessment might be required.

Annual run-off is influenced by factors like topography, rainfall and vegetation.

An indication of a few hydrological models, with an indication of catchment area size applications is given in Table 1.

Table 2 provides the quantity of water that can normally be expected annually in the different rainfall regions from a catchment area of one km². These results are only averages based on the average values regarding factors such as rainfall, topography, vegetation, soil depth and infiltration.

Hydrological model

Catchment area size (km2)

SCS

Roberts

< 15

Rainfall region (mm/yr)

300

Rational

10 - 2 000

Percentage run-off (%)

2,5

Unit hydrograph

10 - 2 000

Run-off (m3/km2)

7 500

Table 1: Hydrological models with catchment area sizes

Permanent flow This is water from consistent fountains or streams. The volume can usually be determined by means of some or other simple method of stream measurement. Temporary run-off This is the run-off that persists during rain showers up to a few days after the showers and it is difficult to determine the extent thereof.

Temporary run-off after a rain shower. Photo: Hans Braxmeier, Pixabay.

400

500

600

800

1 000

9,5

12 000

30 000

57 000 112 000

220 000

Table 2: Average annual run-off

Regarding annual run-off, the following two distinctions can be made:

Does your dam comply with your local water acts? Photo: Hans Braxmeier, Pixabay.

Run-off flood peaks There are various methods according to which the flood peak can be determined, namely: • By using the rational formula for catchment area of one km² and smaller. • By using the Department of Water Affairs and Forestry’s method of calculating run-off flood peaks. Various sources for the calculation of run-off flood peaks are available. Storage capacity of dam basin and run-off A healthy relation must exist between the size of the catchment area and the storage capacity of the dam basin. If the catchment area is small and the storage capacity of the dam basin is large, there is a slight chance that the dam will fill up. Such a design is uneconomical and the flood plain downstream is deprived of run-off water, which is extremely essential for the biological maintenance thereof. If the catchment area is relatively large and the storage capacity of the dam basin is small, a large, expensive spillway will be required. It is therefore recommended that the maximum storage capacity of a farm dam must normally not be more than half of the expected annual run-off. Apart from the practical implications that the capacity of storage dams may have, it may not exceed the regulations of the country’s water act and the necessary authorisation must be

The danger potential The proposed dam’s potential as source of danger for life, private and public property and installations, such as roads, rail and buildings. must be considered thoroughly. The danger potential will influence the design and cost of construction to a large extent. The dam safety legislation of your country must be consulted and adhered to. Extremely small dams must be designed to allow a peak flood to flow safely, which can occur every ten years. Larger dams with a low danger potential, is designed for a 20 to 30 year frequency. Larger or more expensive dams with a greater danger potential are designed for a 50 to 100 year frequency. Dam safety legislation Dam safety legislation attempts to have dams comply with certain safety conditions and thereby prevent potential loss of life and damage to infrastructure. The South African law is taken as an example. Background In 1984, Article 94 regarding “Safety of dams” was included in the Water Act. It is also known as the Water Amendment Act, 1984 and was published in Government Gazette no. 9339. Regulations originating from this amendment act came into force in 1986 and contains the conditions which must be complied with regarding classification, design, building, registration, putting into com

ProAgri Zambia 49

A large dam should be designed for a 50 to 100 year peak flow. Photo: tunfux, Pixabay.

Size class (H = Maximum wall height in metres)

Threat potential Slight (PLL = 0 and PEL: Minimal)

Significant (0 < PLL ≤ 10 or PEL: Significant)

High (PLL > 10 or PEL: Great

Small (5 < H < 12)

Category I

Category II

Medium (12 ≤ H < 30)

Category II

Category III

Great (H ≥ 30)

Category III

Table 3: Dam safety risk groupings

mission, operation, maintenance and abandoning of a dam with safety risks. Different conditions are set regarding dams of different sizes and danger potential. Definitions and requirements The following three definitions are given as part of the regulations, namely: • A “dam” is defined as any structure in which water can be stored. • A “dam with a danger risk” is defined as a dam with a storage potential of more than 50 000 cubic metres and a vertical wall height (H), measured on the downstream side of the wall, of more than 5 m. Any dam that does not comply with the above description can be declared as a dam with a safety risk if the minister is of the opinion that such a structure is a threat to human life or public safety. • An “approved professional engineer” is defined as a professional that has been approved by the minister after consultation with the Engineering Council (ECSA) for the purposes of this series. Requirements originating from this Act include the following: • An owner of a dam that was built before the coming into force of the Act has to register the dam within 120 days. • An owner of a dam that is completed after the coming into force of the Act has to register the dam within 120 days after it is able to store or discharge water. • An owner of a dam must comply with all the regulations in accordance with this article, regarding design, building, putting into commission, changing, enlarging or usage of the dam.

Consult your water department before you start building a dam in a river or stream. Photo: Cipo13, Pixabay. Dam classification Each dam with a safety risk must be classified by the Director-General as a Category I, II, or III dam according to the size (maximum wall height) and the potential threat thereof. For this purpose, the threat potential is defined as an indication of the Potential Loss of Life (PLL) and Potential Economic Loss (PEL) that the failing of a dam can lead to. The separate consideration of the PLL and PEL for the resultant highest level is used. Table 3 summarises the category grouping of dams with a safety risk. The maximum wall height (H) is the height measured from the bottom of the river or stream to the crown of the

ProAgri Zambia 49

wall. The measurement is done on the downstream side. Before the commencement of any construction of a new dam or the changing of an existing dam, the local Water Affairs office must be contacted for the acquisition of the necessary application forms and permits. Next month we shall look at design essentials. Published with acknowledgement to the ARC Agricultural Engineering for the use of their manuals. Visit www.arc.agric.za for more information. 33

ProAgri Zambia 49

HERBICIDES

INSECTICIDES

FUNGICIDES

VETERINARY PRODUCTS

AFRICAN AGROVET ZAMBIA LIMITED +260 969 914 558 +260 972 904 505

admin@africanagrovetz.com info@zcvcl.org

Plot no. 1694, Lumumba Road, Lusaka, Zambia

A MEMBER OF CROPLIFE ZAMBIA

ProAgri Zambia 49

http://www.gib.co.za/dev/

Speed. Empathy. Agility

Your family is our Biggest Priority

Agriculture Insurance We believe farming is the most important thing in our economy. We also believe your farm produce and equipment should be protected at all costs. Let BlackGOLD cover you while you continue feeding our country. CONTACT US: INSURANCE PRODUCTS

Lusaka Add: Suite 211 Foxdale Court 609 Zambezi Road, Post: P.O Box 32232 Lusaka Zambia, Tel: +260 211 847 145 email: info@blackgold.co.zm or grace@blackgold.co.zm Copperbelt Add: Kitwe: Lyness House Unit 1&2 Freedom Avenue Park, 793 Kitwe, Zambia

Property/Assets Insurance, Agriculture, Liability Insurance, Bonds, Money Insurance, Goods in Transit Insurance, Group Life, Fidelity Guarantee, Travel Insurance.

Imtec Sales Agricultural implements

Bearings: Industrial, agricultural & automotive

Tractor parts & agricultural equipment

Power transmission parts

Workshop tools

Fasteners

COPPER BELT

LUSAKA

CENTRAL PROVINCE

SOUTHERN PROVINCE

Tel: +260 212 511 242 Cell: +260 979 773 830 alves@imtec.co.zm

Tel: +260 211 235 383 / 221 085 Cell: +260 978 217 217 imtec@zamnet.zm

Tel: +260 215 362 040 Cell: +260 964 355 746 anitraptors@gmail.com

Tel: +260 213 225 030 Cell: +260 978 777 919 greensolutions.sales@gmail.com

Johnsonâ&#x20AC;&#x2122;s Arcade, Corner of Zaona Avenue & 16th Street, Luanshya

Plot 1663, Panganani Road, Lusaka P.O Box CH 310220

Raptor R us Plot 12/13, Buteko Avenue, Mkushi

Green Solutions Ltd. P.O Box 630 358, Choma

ProAgri Zambia 49

Distributors of Dekalb maize seed DKC 80-33 DKC 90-89 DKC 80-53 DK777

Tamanga Early maturing Ngao - Ngao Medium maturing - Shoma Medium maturing

Farmers Barn Ltd. Tel: +260 211 225 352 Cell: +260 977 518 635 Farmersbarn_ltd@hotmail.com

ProAgri Zambia 49

Address Plot 51, Chiparamba Road, Lusaka, Zambia

Mumba Road branch +260 975 386 240 Mumba Road, next to Uniturtle, Lusaka

ProAgri Zambia 49

TUTAFIX (Emamectin Benzoate + Indoxacarb) controls TutaAbsoluta in tomatoes, eggplants, Irish potatoes and Diamond-back moths in cabbages and many other sucking and chewing insects in various vegetables and fruit trees.

FA R MER S AF RICA ( Z AM BIA) LTD FACTORY OUTLET FOR VETENARY PRODUCTS & AGRICULTURAL INPUTS

PLOT No. 396A/67/D/1 Makeni, P.O. Box 34902, Lusaka - Zambia Cell: +260 966 500 096 / +260 966 500 032, E-mail: sales@farmersafrica.com / farmersafrica01@gmail.com

Fert Seed & Grain Ltd Being a full time farmer is not easy. We pay close attention to our inputs, because we know that the quality of your inputs, like seed, chemicals and Superfert fertiliser, determines the size of your bumper harvest. Ask any good farmer and theyâ&#x20AC;&#x2122;ll tell you The Formula for Success.

The Farmerâ&#x20AC;&#x2122;s best Fertiliser. Our focus is on the manufacturing and distribution of fertiliser as well as commodities trading. Contact us:

+260 977 416 459 | +260 977 845 877 | +260 969 169 563 | +260 979 761 797 Gabriel.chipeta@fsgzambia.co.zm | Daniel.Maimbo@fsgzambia.co.zm | amin.edhi@fsgzambia.co.zm

ProAgri Zambia 49

NEW BEGINNINGS, START YOUR NEXT CHAPTER WITH US OPENING IN MKUSHI

SOON

• Property Management • Property Rentals • Property Buying • Property Selling Agency Unit 114,Foxdale Court - Phase 2. Plot 609, P.O Box 32232 Lusaka - Zambia (C) 260 977 230 228 (O) 260 211 295 740 (E) lusungu.kayela@seeff.com

Unit 1 & 2, Park 793, Lyness House, Freedom Avenue, Kitwe - Zambia (C) 260 979 459 259 (O) 260 954 848 900 (E) mwila.mulundika@seeff.com

a UNITURTLE enterprise... Cell: 0974 990928 / 0973 142990 Fax: 0211287528/0211 287611 Email: infolime@uniturtle.com

Chivuna, Mazabuka Tel: 03 233069

Plot 12913, Mumbwa Road Tel: 286057 / 286064 / 286258

Also available: Stock Feed lime & Stock Feed Grit

Lime Your Fields, Get Better Yields

Get better Yields: Using Turtle Agri-Lime! FOR EACH TON OF FERTILISER, THE SOIL NEEDS ONE TON OF LIME

ProAgri Zambia 49

Cheapest licks throughout the year

Stone and feed salt

Stone salt blocks ±60 kg each Course feed salt 50 kg bags

Orders must be sent via e-mail:

hentiesoutwerke@gmail.com Bulk stock available. Load and weight trucks free. Payments can be made via internet banking or with cash Free loading from, 7:30 to 17:00, Monday to Friday

Henties Soutwerke Suppliers of course, natural, unwashed sea salt as feed salt (50kg bags) stone salt blocks, 60kg each Client must order via e-mail at least 3 days before the pick-up date

Manie: 081:213-8828 of Izak: 081-338-0862

N akonde

ESSE Clearing ltd A g r i c u lt u r e ’ s a g e n t for a g r i c u lt u r e ’ s n e e d s Ndo la

Imp

Lusaka

EXp Katima Kazungula

C h ir u ndu Livingstone Vic Falls bo r der ESSEC Ltd

HEAD OFFICE

ESSE Cl e ari ng L t d

+260 977 849 697 / +260 213 3 2 2 5 5 3 i nfo@essecl ea ri ng.com

www.esseclearing.com 42

ProAgri Zambia 49

Zambian Pig Genetics is the distributor of Topigs Norsvin genetics in central Africa. Built on our global research, innovation and absolute commitment to integrity and biosecurity, our close partnership approach means your farm benefits directly from our experience, energy and passion. The only SPF pig herd in Zambia, which means we supply pigs that are free of diseases such as mycoplasma and APP.

THE TRUSTED COMPANY THAT'S A BREED APART.

TN Tempo boar (AI only)

TN 60 sow

• • • • •

• Excellent mothering characteristics • Large uniformed litters • Performs well in challenging environments • Great temperament

Natural resistance to Circovirus High born alive Strong uniform pigs Excellent growth & feed conversion Good temperament

TN Natural Service boar • Tough robust boar for any farm

GENETICS | TECHNOLOGY | SERVICE +260 762 589 884 | +260 972 788 521 | sales@zpgzambia.com

ProAgri Zambia 49

www.topigsnorsvin.co.za

For all your farming Taxes and Accounting HLB is here for you! HLB Mkushi Branch. Contact us today on +260 955 336 060 | Email: shuko@hlb.co.zm | lillian@hlb.co.zm | info@hlb.co.zm

THE GLOBAL ADVISORY AND ACCOUNTING NETWORK

+27 +27

ProAgri Zambia 49

We sell the full range of Kymco ATVs including: MXU150, MXU250, MXU270, MXU450, MXU700

We sell a full range of Yamaha and Lifan motorcycles including: XTZ125, AG125, AG200, TW200, YZ125, DT125, DT175, YBR125, LF125GY

We sell Kymco’s SIDE x SIDE ATV’s including: UXV450 & UXV700

We sell an extensive range of Yamaha power products including engines, generators, pumps and lawnmowers

We sell the full range of Yamaha Marine motors including: F25, F40, F60, F70, F100, F115, F130, F150, F200 and more

+260 973 584 778 / +260 964 584 778 / info@bestofbikes.com www.bestofbikes.com

ProAgri Zambia 49

Get your copy of ProAgri at one of these outlets Z a m b i a

Dairy Association of Zambia

ProAgri Zambia 49

A FIRST FOR SOUTH AFRICA!!!

KUDOS FOR BONNOX’S NEW 3METRE FENCE.

WOW! Kudus can’t clear THIS fence!

2.44m

1.8m

1.2m

AVOID POOR IMITATIONS AND BUY DIRECTLY FROM THE ONLY BONNOX FACTORY, SITUATED IN SUNDERLAND RIDGE, CENTURION ONLY A BONNOX INVOICE SERVES AS A CERTIFICATE OF AUTHENTICITY.

zane@bonnox.co.za • gerda@bonnox.co.za • linda@bonnox.co.za

www.bonnox.co.za • 012 666 8717 +27 (0)12 666 8717

ProAgri Zambia 49

www.reinke.com Patrick Ellis 50

+27 (0)31 350 4525

patrickellis@reinke.com ProAgri Zambia 49