Subscription form

aQUaCUlTURE: MaINTaINING oxYGEN lEVElS 18

In designing the aeration system for a fish farm we need to calculate the total aeration volume required and the delivery depth. With this information we then assess the most appropriate tool for the job. Let’s look at the chart above differently to compare 3 unique design requirements of 10, 50 and 1 000m3/hr. In the case of the 10m3/hr requirement it is clear that the least expensive option is the ACQ7 (2 units) or ACQ12 air pumps, both in terms of capital cost and kW consumption. When the need climbs to 50m3/hr the S4M blower is the most cost effective, but, although the capital cost is far higher, the air pumps are more energy efficient in this case. By the time we get to commercial scale applications as demonstrated by the 1 000m3/hr graph the blowers are far more cost effective and generally more power efficient too.

Thus we conclude that in a small installation an air pump is probably going to be the most appropriate, but by the time the usage exceeds about 20m3/hr, it becomes more efficient to purchase and operate blowers. By: Leslie Ter Morshuizen, Aquaculture Africa

DRaPENET – ITS SUCCESS oN PoME FRUIT FaRMS 16 PICkING UNDER DRAPENET

There are two methods of picking apples and pears under DrapeNet ; one is to throw a lane’s net across the next lane and picking under the ‘roof’ and the other, by creeping in under each tree’s DrapeNet to pick. The first option offers the advantage of a faster harvesting process, but nonetheless, with experienced farm assistants, trees and fruit are not hurt.

FUTURE PROSPECTS

Denné Strydom is confident that his farm of 312 hectares will be completely covered with DrapeNet within three years. There is only about 90ha of orchard still to be covered. He is outspoken about the fact that his farm’s success rely on his shade net structures but all new orchards are and in future will be covered with DrapeNet . “We just cannot obtain the results we already experienced without covering our orchards,” Denné concluded. By JS

Granny Smith apples freshly picked.

Subscribe now!

Electronic subscription for 6 bi-monthly issues is R 350.00 (ZAR) annually

For online subscription e-mail your details as indicated on the form to

magazine@axxess.co.za

with your subscription deposit details

ucf Undercover

farming

MaY/JUNE 2021 I VolUME 18 No 3 I  I R45.00 per issue For more information contact Suzannne Oosthuizen (+27) (0) 82 832 1604 or e-mail suzanne@axxess.co.za NAME:

SURNAME:

ADDRESS:

CODE:

CONTACT NUMBER:

Account Name: Nufarmer Pty Ltd t/a Undercover Farming Bank: First National Bank, kolonnade Branch Code: 25 10 37 Account No: 62007699806