Caring for the earth today, we guarantee life and our future.
And the Lord God took mankind and put him into the Garden of Eden to tend it and keep it.
The Lord God took the man and put him into the garden of Eden to tend and keep it.
S t u d y m o d u l e f o r C o m m u n i t y A g r i c u l t u r a l P r o m o t e r s
CARING FOR THE EARTH TODAY GUARANTEES LIFE AND OUR FUTURE
Environmental Management and Development Program
CEPAD Council of Evangelical Churches for Denominational Alliance Managua, Nicaragua, March 2009 (Translated to English in 2016)
Series of modules Developing local skills: by taking care of the earth today, we guarantee life and our
future.
CEPAD,
First
Council
edition. of
Managua-Nicaragua:
Evangelical
Churches
for
Denominational Alliance, March, 2009. 131 pages Translated to English for this edition by Episcopal Relief & Development in 2015-16
© Council of Evangelical Churches for Denominational Alliance (CEPAD) Co-author:
Denis Francisco García Ocampo
Design and layout
Carlos A. Silva Mejía
Editing
Yemila Exteny
Printing:
Impresiones Universales, Managua
Print run:
200 copies
All rights reserved The full or partial content of this reproduction module is not allowed without prior written authorization of the institution. Managua, Nicaragua, March 2009
Presentation
Introduction In celebration of 36 years of proclaiming the kingdom of God, called to serve through the ministry of CEPAD, we want to deliver to the Nicaraguan people this series of study modules "Developing local skills", which represents the systematic and validated experience with a pastoral and community base with which CEPAD worked during the period 2004 to 2008. This module is aimed towards Community Agricultural Promoters (CAP) as part of the community structure of CEPAD; but also to all producers interested in the conservation and utilization of the environment and the production of pollutionfree food. In five units of study, in a clear and simple manner, necessary information is presented about: the establishment of soil and water conservation projects, integrated pest management, crop diversification, production of fertilizer and commercialization and marketing. All this is for the purpose of orientating and supporting producers in the management of the agricultural production cycle in order to improve their land, make more efficient use of resources, and produce food for healthy families. With this module expect promoters to learn to use the techniques of how to care and protect soil and water conservation structures, thereby improving agricultural production and contributing to the sharing of these techniques with producers from their community. They will learn to make rational use of natural resources, ensure sufficient quality and quantity of food for families and a healthy environment for the community. The module is the result of five years of hard work on the plots of 79 CAP(s) in areas of Managua, Carazo, Matagalpa, Jinotega and Nueva Guinea, Nicaragua.
The Editorial Team
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FIRST UNIT ESTABLISHMENT AND MAINTENANCE OF PROJECTS SOIL AND WATER CONSERVATION
Working to transform our farms and orchards GENESIS 1:1-11 In the beginning when God created the heavens and the earth, the earth was a formless void and darkness covered the face of the deep, while a wind from Gods wept over the face of the waters. Then God said, “Let there be light”; and there was light. And God saw that the light was good; and God separated the light from the darkness. God called the light Day, and the darkness he called Night. And there was evening and there was morning, the first day. And God said, “Let there be a dome in the midst of the waters, and let it separate the waters from the waters.” So God made the dome and separated the waters that were under the dome from the waters that were above the dome. And it was so. God called the dome Sky. And there was evening and there was morning, the second day. And God said, “Let the waters under the sky be gathered together into one place, and let the dry land appear.” And it was so. God called the dry land Earth, and the waters that were gathered together he called Seas. And God saw that it was good. Then God said, “Let the earth put forth vegetation: plants yielding seed, and fruit trees of every kind on earth that bear fruit with the seed in it.” And it was so.
CEPAD-Environmental Management and Development
I. The Field Survey. Our soils are ill-treated and exhausted like the body of a patient; we have to know how ill our soil is that we may cure it. To do this, you must know and apply some techniques for the management of erosion in cultivated hillsides. First and foremost is to make a practical study of soil in our fields, to know what kind of soil and how much fertile land there is and what kind of measures we must take to improve it. A. Study the plot The type and amount of weeds, the slope, and the color of the earth are indicators of the health of the soil of the plot. However, to thoroughly understand the plot, one needs to take soil samples and analyze them. B. Select 3 locations. To understand the soil, choose at least 3 well-separated places within the plot, chosen for visible differences in slope, vegetation, and soil appearance.
Tool List. For soil sampling, you need: • 1 spade or shovel • 1 pickaxe • 1 tape measure or one meter
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C. Making terrain profiles A profile is a vertical cut in the soil that is performed to determine the depth of the surface layer, which is the fertile layer of the soil, that carries life inside it. For this, it’s necessary to dig a hole of 12 inches deep and at least 12 inches wide. D. Observe the soil profile The changing of the colors mark the boundaries of the different layers that make up your soil. This measures the depth of each layer of the soil and the moisture therein. The first layer is the fertile soil where the roots of the crops will grow and absorb nutrition. In lower ground the area around a river can have a single layer profile because the topsoil is more than 12 inches. Conversely, at the top of very steep ground, badly damaged by erosion, the topsoil will be very thin. What is the texture of soil? Soil can be of three types: Clay, Sand or Silt. In each soil, in every place, the type changes. And that change in texture is noticeable to the naked eye or just by touching the ground. Each type of soil has its own texture. The soil texture varies in its ability to hold water, its resistance to erosion, its ease to work with, and its fertileness and in the end, productiveness. For discovering the texture of the soil there is a simple method that we will explain.
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E. Making earth figurines A one inch thick slice of earth is cut from the fertile topsoil profile. Crumble the slice until it comes apart like flour. Grab a handful of the earth and add a little water to it. Knead the slice with the hands, trying to form a snake shape from the soil.
F. Analyze the results of the figurines • If a ball couldn’t be formed with the soil or the earth snake breaks easily, the soil has lots of sand. It's sandy. • If the snake can be formed into a donut then the soil has a lot of clay. It’s clayey. • If the snake can be stretched and stay together then the soil has the three elements in almost equal measure. The soil is loamy.
G. Count the creatures in the soil
Creatures such as earthworms, grubs, beetles, ants and others are almost invisible, work for free, dig kilometers of tunnels and produce fertilizer from buried materials they eat. With a digging tool remove one square meter from three places where samples were already taken and count the number of each type of creature that is found.
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What does the texture analysis reveal?
What does the soil profile reveal?
• If your soil is sandy, it is easy to work with, but functions as a colander. Water and nutrients drain quickly away from the roots. We will have to incorporate large amounts of organic material such as compost.
With loamy soil you will observe the following: We will have a profile that shows a moist soil, with many creatures and a deep topsoil. With poor soil we will find erosion, dry topsoil, without much life or fertility, caused by errant handling of the soil. It is good that there is life, moisture, and fertility in the topsoil and we will need to protect the area with soil conservation works and enrich it with compost.
• If your soil is clayey or silty it is heavy and will be difficult to cultivate. You will also have to add lots of organic matter to aerate and enrich it. • Loamy soil is the very best
for agriculture.
II. How to protect and conserve our soil? To conserve the soil it will have to be protected against erosion caused by rain.
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EROSION: Is the damage caused by rain to cultivated soil. The raindrops hit the ground, fill it with water and close off the roots from oxygen.
In addition to erosion by water, there is also erosion by wind, when the wind carries fine pieces of earth away - this happens mainly when it is dry, causing great loss of topsoil annually. But that we will not cover in this module.
[-When the soil is hard and closed, the water can no longer infiltrate, it stays on the top and takes away the fertile soil, the crops, the nutrients... - The water forms bigger canals each time, until it is no longer possible even to plant. -‘And all my work’ ]
On steep or broken terrain where the land is cultivated, erosion is stronger. This is because the water runs faster.
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How to conserve soil? The first thing to do is ensure that the land you are cultivating is level. Level means that there can be no sloping, neither to one side nor the other.
Construction and use of the "A" level
A level is found easily in the field and is a simple and inexpensive apparatus that you can make and use yourself. These devices are called “levels� and one of these devices is the "A" LEVEL.
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An “A” level is so called because of its “A” shape and its use in agriculture. To make an “A” LEVEL we need a few materials ... Now how do we start?
Three wooden sticks one of 1 meter and two of 2 meters - nails, hammer, a rope two meters long and a heavy stone.
A. FOLLOW THESE STEPS STEP ONE: setting the level:
2m 1m
STEP TWO: Suspend the rope
Lay out the 2m long sticks next to each other. v Mark each stick at the halfway point, or 1 meter. v The two long poles are attached at their ends. They are left in an open V-shape. v The horizontal ruler connects the two sticks at a height of 1 meter. That is, in the center, thereby being in the form of an A. For this reason it is called an “A” level. v
and the stone like this:
STEP THREE: Put the right leg of the “A level” on a stone and on the horizontal stick mark the point X where the stone touches it. Mark with an X the point where the lower tip of the left leg was on the ground. STEP FOUR: Give the level a half turn. The left leg is now on the stone and the right leg on the X made on the ground. The pendulum will go to the other end of the horizontal ruler, there again make a mark of evenness. 14
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STEP FIVE: The level now has two dashes made on the horizontal ruler. The center point between the two dashes on the horizontal ruler is called zero point.
When the stone falls on the "point O" it means that both legs are at the same level. The “A” level, or “agrolevel”, is ready to be used. That was so EASY so let's use it! The agrolevel is used in many countries with great success; it is an inexpensive and accurate tool for use in soil conservation in agriculture. With the "A" level, or agrolevel, level lines can be made in the field. These are called “Contour Lines". Contours – because the land we are farming is not level, and with contours we can trace the level ground
These contour lines serve as guides for plowing and seeding, and to tell us where to build soil conservation works. Aha!.... And... how do you use the AGRO LEVEL?
Calm down Juan! Continue reading the next page.
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B. HOW TO USE THE AGRO LEVEL 1. Up on the field, where the water starts running and forms small canals, the first stake is placed. It is preferable to place it near a road or fence where the plot ends. 2. On one side of this first stick place one leg of the “A” level (you can place a machete or other tool instead of putting stakes). 3. Without moving the leg that is next to the stake, move only the other leg to search for the point that is level with the first stake. 4. When the rope falls to mark "0" get a second stake and put it next to that leg of the level. 5. Now place the level next to the stake which was just placed and move the other leg of the level to the next level point, place a stake there and continue like that until you reach the border of the plot. When the rope falls opposite mark "0" there is no difference in the height of the legs of the “A” level. The two legs of the agrolevel are ... LEVEL. Thus place a row of stakes to the other edge of the plot. C. SOME SPECIFIC CASES a. When trees are in the plot
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-
When you have trees on the plot it is important to conserve them, they are also
protecting the soil with their roots and they give wood and fruit. - You can put the level to one side of the tree, and trace the level curve. Ultimately, you can use the tree as part of the row of stakes. - Later you can go to the other side of the tree, to finish the other part.
b. Tracing the stakes on uneven ground When the terrain is very rough, the tracing of the stakes in the plot can get like this ...
When it is like this one cannot plow with oxen or do works of conservation. In the corners the water would gather and start to run. You have to make corrections!
This is done by moving some of the stakes; some to a higher level and others to a lower level. Now that you have already defined the contour to your plot, the next step is to see if you have to build erosion control works or whether it is 17
CEPAD-Environmental Management and Development
sufficient to cultivate following the contour, which follows the stakes.
But how I can know if I need control works or not? It’s easy to find out! þ When you have drawn up the first turn on your plot, find the steepest part of it and walk down until your eyes reach more or less the level of the first corner. If where you stand is at the end of your parcel then that will be sufficient to cultivate that level without control works. ü Most agricultural land has a slope that will require control works. ü To make a second contour, walk down the slope, until your line of site is even with the first contour. Mark the second contour there. Continue and repeat this step for each contour until you reach the end of the plot.
Continue working friend until you have staked out all the contours you need for the plot! ! ! þ We may also measure the slope or sloping terrain with the "A" level. With a tape measure, we measure the horizontal rod of the agrolevel on each side of the central line "O”, in centimeters, marking it with a pencil. When we put the AGROLEVEL on sloping ground the rope with the stone falls to either side of the center line 18
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"0" on the scale. Now we can tell how many centimeters the slope is from level. The agrolevel measures up to two meters because that is the distance between the legs. The center “0� has one meter to the left side and one meter to the right. So when the rope hangs down to the centimeters marked, that indicates the height difference on the ground per meter, which is the percentage of the slope. D. Measuring the slope in the field. To measure the slope in the plot, we first seek the steepest part of the plot and on this slope we take steps with the agrolevel in a single straight line from the highest point to the lowest point.
Read the centimeters of slope with every step and keep track of them. Add up the centimeters of slope accumulated at every step: 10 + 15 + 13 + 12 + 20 = 70 This result is divided by the number of steps taken: 5. 70 / 5 = 14.
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The average slope of the plot is 14%. The following table tells us the distance between the works:
When the land has a slope of: Less than 4% Around 4% Around 5% 6% 7% 8% 10% 15% 20% More than 20%
The land where we grow can vary widely: it can be flat, it can be very rough.
always
The distance between the works should be: 25 meters 22 meters 19 meters 18 meters 16 meters 15 meters 12.5 meters 12 meters 11 meters 9 meters
REMEMBER... always measure the slope and the distance between the works on the steepest part of the plot.
Knowing the amount of slope will tell us if we can plow and plant or if we have to build works. In the following pages we will show you different works, from which you can choose the most suitable.
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In any parcel, whether rough or not, and when there are works and soil conservation, you should always PLOUGH AND SOW ALONG THE LEVEL. Plowing along the level. The plow shapes the ground into furrows and ridges across the slope. Water no longer runs, it gathers at the level and this infiltrates into the ground.
Ridging crops helps even more. You must ridge the crops after every heavy rain, renewing the washed-away ridges.
Plow starting at the top, along a row of stakes until roughly midway between the rows. Then you plow starting at the bottom toward the part already plowed towards the middle. The part in the center will be shorter. In this way plow between all staked contours. All of the preparation of the earth can be done without worrying about the level, only the last step before planting or before the first rains should be at level, and before any farming done during the rainy season. But with rough terrain it is not enough to cultivate along the LEVEL.
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In rough, broken or thin soil it is not enough to use ridges to stop water running. Of course you have to cultivate along the level, but besides that, it is necessary to construct works to have barriers against water flow. III. Building structures for soil and water conservation 1. Physical works in the field Now that we have prepared contours, we will build control works i.e. ditches or terraces, following the slope of the plot, to better take advantage of rains, since a one meter long trench catches 1 barrel of rainwater. Depending on the texture and moisture of the soil, a person can construct from 20-40 meters of trench per day. A. THE TRENCH Depending on the percentage of slope in the plot, you have to dig either trenches or terraces. If the slope is between 10 and 40% it is enough to build trenches. a. Staking out the trench. The bottom of the trench should be about 30 centimeters wide so that, starting from the stakes of the contour, some stakes can be placed 30 centimeters above the contour level. If you do not have a tape measure, you can measure with a meter long stick. b. Digging the trench Dig up to about 30 cms of depth, dumping the earth on the underside. 30 cms are measured at the bottom of trench, using the meter stick. 22
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c. Measure and stake out the slope below The banks of the trench, i.e., the inclined edges also known as bevels, do not measure the same from top to bottom, the top is wider than the bottom. The width of the lower bank measures the same 30 cm as the depth of the trench. See diagram below for a trench in steep or flat terrain.
d. Measure and stake the bank above The bank above varies its width according to the slope. The greater the slope the greater the width, the less inclined it will be. e. Cutting the banks - Measured and staked out, the 2 banks are given a regular slope down to the stake at the bottom of the trench, like a canoe. The dug-up earth can also be put on the side below the trench. f. Build regulators After each 8 meters of trench, it is recommended to build a water regulator: that is a short wall like a small dam, half the height of the trench, that is, 15 centimeters high.
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g. Function of the Regulator. These little walls help to better distribute water along the trench, since the currents are not equal throughout the plot. In certain parts of the trench, water could spill over while others would remain relatively dry. Thus, rainwater is filtered more evenly, and this benefits the entire crop. B. THE TERRACE. If the slope exceeds 40 or 45%, a trench would not be enough to stop the currents. Think of terracing if the slope exceeds 50%. In this case it is more advisable to devote your land to fruit plants because it is not good for grain. a. The stakes. Starting from the contour line, place 1 stake on the upper bank to a depth of 1/2 meter to mark the bottom of the terrace and another at 1 meter from the latter, to mark the slope of the terrace. b. Remove the topsoil. The fertile layer of the soil is removed, until a harder, rocky or muddy layer is left. Put this good fertile soil aside while the terrace is made. c. Dig the terrace You start by digging the first half meter, making a vertical cut and putting the dug-out earth below in order to gain ground on the slope. Remember to give it a slight slope back to the flat part of the terrace to retain the water. After cut out the bank, as was done with the trench. 24
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d. Put the topsoil back where it was. Once the terrace is finished, put back the topsoil that was removed before, since you will need it to plant crops on your terrace. Use of the terrace: Terracing is not a luxury, in steep terrain; if you don’t want to plant above and harvest below it is the only way to retain your fertile soil. Seeds must be planted in the flat part of the terrace, leaving a border of 30 inches against the wall, so that the water flows. C. CONTOUR PLOWING Another measure to protect your works and decrease erosion is contour plowing, i.e., following the contour lines. For that, the plowman should plow the first 4 rows along the trench above and then 4 rows along the bottom. And so on, until the furrows come together in the middle. 2. Establishment of live and dead barriers A. Live barriers It is not enough to build ditches or terraces. The crops must be protected to prevent the currents from carrying them away or burying them. For that, we must protect the plot from above, by planting a row of some crops, trees or grasses. In the lower border, tubers such as the cassava can be sowed. a. Live barriers with Leucaena plants. To protect the canals, ditches and terraces, implement hedgerows, using plants such as leucaena, planted in dense rows, following the contour lines. These reduce water velocity, and block the wind and will act as a filter which retains the ground that travels with the water. To accomplish this put foliage and debris or crop stubble up 25
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to the tree barrier and this protection will allow the formation of terraces. These plants can be sowed directly, or transplanted, placing from 5 to 7 plants for every stake. The weeds or scrubs should be cleaned 3 to 4 times per year and are sowed 8 inches from the rim of the ditch. The living barrier should be pruned in the first year once, then every 25 months pruned to 12-16 inches of height, with a sharp machete, cut in the shape of a bevel. Foliage the first year is placed in the top part of the barrier, in the following years it is used for animal feed or firewood. The Gliricidia sepium tree is also used to protect the irrigation ditches and terraces, equal to the leucaena in planting and in its management and use, the difference in planting is that it can be planted by cuttings, but it is more advisable to transplant. b. Live barrier of Pigeon Pea This legume serves to protect the ditches, reduce water velocity and wind. There are two varieties of pigeon pea, one that lasts 2-4 years, and another 6-9 months. The latter is red. The planting is 2-3 seeds together, 10 to 20 feet apart. The area is cleaned twice to ensure its growth, and is seeded 8 inches from the top edge of the terrace. Maintenance in the first year is to prune them to 1 or 1.5 feet high, after two years prune them to be no thicker than a pencil. Cut branches that have seeds, so that these produce new plants and with more
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harvests, residue from branches or foliage can be left at the base of the living barrier to better protect the soil. c. Live Vetiver barrier Dense, thick rows of vetiver grass is used to protect the upper edge of the canals; this improves water infiltration into the soil, reduces water velocity and filters the soil that travels with the water. Vetiver grass is a perennial plant, resistant to pests and drought. After planting vetiver grass you will need 2-3 years to form a dense barrier. Dig up a live plant, cut the root to a length of 4 inches and the foliage to 6-8 inches, plant 2-3 together, 4-6 inches apart at the beginning of winter. In the first 2-3 years you must clear out the weeds, replant in the spaces where sowing failed (for the stalks that bend down and make contact with the ground regrow one more plant) and conserve moisture. Prune the foliage to a height of 12-20 inches twice a year, so that the barrier becomes denser and filters the soil better. d. Live barrier with Pineapple Dense rows are used to protect soil and the water conservation structures. On gentle slopes they are often used to protect the tops of irrigation ditches. They are planted at the end of the dry season or early rainy season, at a distance of 8-12 inches between plants. They need 4-6 annual cleanings. To make them more effective they should be planted in 3-4 rows, and to avoid water damaging the plants in the first year, a small trench above the planting is dug with a hoe.
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e. Live Napier grass barrier. It is sown in dense rows, for protection of soil and water conservation works. When used for irrigation ditches it is planted 8 inches from the top edge of the ditch and on the terrace also 6 inches from the top edge. The Napier grass guarantees good filtration of the soil as it forms a strong clump and is a perennial plant with a height of 1.5-3 stalks. For planting, cut off vegetative material of 3-6 months of age. To obtain stems, choose the center portion of the stalk, eliminating the bottom part because it is ripe and the end is very tender. To plant, two stems are used, with 2- 4 knots, in an inclined form of 10-15 inches for each plant, with buds out and a knot out of the ground. You can also plant them lying flat, splicing the two stems and covering with soil. Clean the area at the start, until the barrier is well-established. B. Dead barriers You can make a dead stone barrier or a mixture of dead barrier with fruit such as pineapple, papaya or citrus. Thus, each year, you will have fewer rocks and more earth in cultivated parts, which will facilitate the work of the soil. a. Dead barriers of stones. These are stone walls set along contour lines. For best performance, they could be combined with other techniques and protections, with barriers of trees, napier, pineapple, or vertiver grass among others. These will protect the lower and upper edges, reducing the speed and capturing soil sediments. These can be combined with other 28
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techniques to improve the soil, in this case the use of legumes and organic fertilizers. When working with oxen, the dead stone barriers must be at least 3 meters apart. These should be given maintenance whenever the accumulated soil behind the barrier reaches the top edge of the barrier. If necessary, increase its height. To profit from this, you can sow the upper or lower side with squash, cucumber, sweet potato, or passion fruit. 40 man-days are necessary to construct this barrier, but for maintenance only 4 man-days. b. Dead barriers of crop residues If the arrangement of crop residue around the contour line isn’t enough, combine it with other techniques. Use the residue barrier as a reinforcement to the upper base of the live wall. Its function, in addition to reducing the speed of the flow of water, is to retain soil while enriching it. These should be repeated every year, in contrast to the stone barrier, which is one time only. When working with oxen, this type of barrier must have a distance between each wall of at least 8 meters. In addition to being used with live barriers, this can be combined with contour planting and tillage. With coffee, you can use weeds as a debris barrier. Maintaining this barrier is simple and can be very beneficial. However, at critical points, runoff from terraces can force you to rebuild them every year and to have to check them after every heavy rain.
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c. Drainage ditches. These allow water to drain into ditches, without damaging the soil. To optimize their use they must be used in combination with ridges, live barriers and other techniques. It is recommended that you seed the top side of the ditch with live plants, so that the soil can be filtered and water can pass without damage. The ditches should be cleaned once or twice a year, depending on the amount of soil entering the channel. The amount of water can be reduced by establishing live barriers on the upper edge of the trench so that soil can be filtered and water can pass more easily. The material remaining in the trench can be mixed with organic material in the ditch in the dry season, thus giving use of the ditch as a compost heap. e. Level trenches, level drainage ditches The main function is to hold water, improve water infiltration into the trench, contribute to the improvement of the soil, and is to be combined with live, dead or other barriers. You can work with oxen or horses. In this structure semi-perennial (i.e. papayas) and annual crops (i.e. grains, vegetables) should be grown in the bottom of the trench, to take advantage of the moisture.
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In the dry season, the banks above the ditch must be protected by live barriers, and establish separators in the ditch every 8 meters, to maintain water distribution in the field. The ditches should be cleaned 1-2 times a year- the rest of the maintenance equal to the previous structures. f. Fruit-tree terraces. Small platforms, round, semicircular, or square. 1-2 meters wide, with fruit trees planted in staggered rows. Level the soil surface with your hand, and then make a hole to put the plant in, and then press down again with the hands. With a slight lean against the slope, this works well with live and dead barriers, and takes advantage of the moisture at the bottom. They also fertilize, and prevent erosion in the area of cultivation. These structures are established on the level curves and can be grown with 200-250 fruit trees per system (at 7x7m spacing) or 780-950 banana trees per system (at 3.5 x 3.5m spacing). For maintenance, a live coverage of legumes or grasses on the banks and a living wall on the lower edge of the terrace is planted. The slope is corrected every year: in dry lands using crop residue on the terrace to retain moisture is recommended, while it is recommended to start the rainy season reviewing the lateral drainage (water outlet). For this you need 15 man-days, 3 man-days for maintenance. g. Stone dikes. These are stone structures with a wide base for retaining water. They are constructed in a crescent shape 31
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in the eroded area, and the size and distance between the dikes depends on the depth and slope of the eroded portion. The function of these dikes is to slowly decrease the velocity of water, and to prevent soil from being carried away with the water. In the future you may remove the ditches, achieving terraces where you can establish your crops in nutrient rich, fertile areas. With these structures we achieve improved water retention and filtration, contributing to the management and protection of water sources. These structures should be established at the top of the slope and the distance between each depends on the depth and slope of the trenches. When these ditches are not deep they can be at the level of the plot, but when they are deep they should be filled up with soil to the level of the dike. The base of the wall should be well buried 12 inches deep and about 3ft wide, smaller stones are arranged at the base and the largest at the top. At the bottom of the wall surface, stones are placed as a ramp, which protects the wall from falling water, and this prevents it from eroding. The width should be in proportion to the height of the wall. For maintenance we should be seeing whether the dike is filling with each rain shower and, if so, then we must raise the wall of the dam with stones and other local materials. Having recovered the area, we can use the plot for growing plants with dense, deep fibrous roots. If the water currents are well-controlled 32
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you can plant fruit crops, plantains, sugarcane, taro, cassava and cocoyam. h. Dikes with living tree stakes. These are built with tree stakes, in the form of a crescent, in the ditch, and the measurements and distances between the dikes will be based on the depth and slope of the eroded part. The role and benefits are the same as those that stone dikes provide. Wood is used where there are no stones. Stakes are aligned across the width of the ditch- they should be lower in the center of the channel than in the banks. At the bottom of the water outlet stones are placed to cushion the fall of the water, so the dike is not eroded. The stakes should be attached together well and tied with wire or rope under their tips.
The growth of the living stakes must be monitored and they should be pruned from time to time so that the water can pass freely. These dike stakes can be made of fast growing tree or plant species such as Bamboo, Gliricidia Sepium, Bursera simaruba (gumbo-limbo), Ficus insipida , agave striata, Pachira quinata (Pochote) or Erythrina fusca (the leguminous flowering tree Helequeme). For maintenance we must monitor the level of filling of the dam, reinforce it and establish vegetation on the banks of the ditches, using short plants, with thick roots. We can also cultivate Napier grass, or 33
CEPAD-Environmental Management and Development
other grasses and we should strengthen the upper base of the dikes with Napier grass. To conserve and make the most of these structures, do not forget that when establishing our crops, we can also use contour planting, which is merely preparing the soil, planting, and caring for the crops, following the contour line. To perform these tasks remember to begin at the ends of each contour line and conclude at the center of the strip. We can also implement zero tillage. This involves direct seeding into the soil without plowing before depositing the seed and other products; this planting is done with a handspike in our areas, following the contour line. Other measures to protect your works and decrease erosion are contour plowing, or following along contour lines. For that, the plowman should plow the first 4 rows along the trench above and then 4 rows along the bottom, and so on until the grooves come together in the middle Another is minimum tillage. This is to remove soil only where we are going to plant, in the furrows. Seeds are planted in exactly the same manner in the same row year after year. 34
First unit– Establishment
This system increases soil fertility, maintains moisture, protects the soil from erosion and allows cultivation in poor soils while saving labor, supplies and expenses. This removes the need to plow the whole field while keeping our land and capturing the small amount of rain that falls in the winter. IV. Maintenance of conservation projects Remember that our works are not complete unless we protect the barriers above them to achieve full coverage of the furrows. However well-constructed the ditches and terraces are we will have to spend some time and work every year to clean, dig them up and rebuild the stone barriers or simply increase their height as they fill with soil. Without barriers, the ditch fills quickly with soil and loses its ability to collect water. Without barriers and without cleaning the drainage ditches do not work; they fill, the furrows break down and erosion occurs. Without cover the furrows are exposed to the weather. The rains wear them down and dry weather crumbles them. To protect drainage ditches live barriers are established. Where there are plentiful stones, build a stone barrier. And if time allows and there is nothing to sow, cut the weeds more often, leaving them at a height to function as a retaining strip. 35
CEPAD-Environmental Management and Development
For our work to be well preserved and durable we have to proceed with the following steps. a. Monitor - If the ditches drain well. - If there is much soil washed into the canal. - If the furrows have no breakages. - If the barriers are working. - If there are eroded trenches. b. Repairs Fill in well any breakages in the furrows. Clean the drainage ditch well and return topsoil to the plot. Replant where there is little protection. If the area remains weak then reinforce it with crop residue or cut weeds. c. Care Avoid that the canals, ditches, dikes, barriers and borders are: • Used for grazing. • Burned. • Applied with herbicides. d. Maintenance Clean ditches. The borders and barriers are trimmed regularly. The canals and borders get all the cut material.
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First unit– Establishment
Live barriers must be pruned, with cuttings and pruning’s deposited above the row of stakes. Stone barriers are increased gradually by filling with trapped soil. Upon completion of this training you will have the basic tools for retrieving, improving and caring for your land, in order to produce more efficiently. You'll take advantage of available water better and be able to retain the rainwater that falls on your land. In addition, the richest part of this learning experience will come upon sharing this experience and knowledge with fellow producers in your community.
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