PHOTO: VAN REENEN FARMING
PHOTO: VAN REENEN FARMING
PHOTO: VAN REENEN FARMING
SOIL MANAGEMENT ▶▶▶
Not afraid to experiment with cover crops
C BY ARTHUR GRAY
over crops are catalysts in soil regen- eration as they increase soil cover, helping to minimise wind and water erosion. In addition, they increase
water infiltration into the soil while at the same time reducing evaporation. Cover crops regulate the soil surface temperature margin- ally, by increasing soil temperature in the cool- er months and reducing it in the warm months. All this makes it more pleasant for the essential microbes, insects and earthworms to want to stay and regenerate while maintaining a healthy fertile and productive soil. An enthusiastic member of the KwaZulu Natal No-Till Club, J.P. van Reenen, farms in the Berg- ville District, South Africa. “I modified my John Deere planter with an APV seeder unit origi- nally. I relocated the fertiliser coulters (dou- ble-disc openers) to an extra toolbar. I’m quite happy with how this is working. In the begin- ning I started with three inter-rows, but the trash was too much for this to handle, it kept clogging up. Now it plants 16 rows. The rear depth wheels also act as press wheels, but I think I will add a little chain behind the
Moisture availability is important. Deciding on a suitable soil regeneration or maintenance strategy – especially in the summer rainfall regions of Africa – needs to be given a great deal of thought and planning, should you want to adopt and succeed with a winter cover crop regime. No-Till enthusiast J. P. van Reenen talks about his experiences.
coulters to help cover the seed. When I origi- nally checked the price of proprietary units, the cost was prohibitive, especially as we were just testing theories, so I decided to use available parts to construct our own unit.”
Timing is critical “Last year I left the cover crop in a bit too long, where the cattle where grazing. Sprayed it off a bit late and, with no rain, lost a lot of mois- ture. Timing is critical and heavily dependent on when the rain comes. When the following maize germinated, the areas which had had the cover crop showed signs of moisture short- age. Because of this a lot of people are talking negatively about cover crops, but you can’t change your farming system because of one bad year.”
J.P. van Reenen plants 2 rows in-between maize, basically a stooling rye mix. Accord- ing to him, the stooling rye has worked the best.
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Cover regulates the soil surface temperature marginally, by increasing soil temperature in the cooler months and reducing it in the warm months.
▶ FUTURE FARMING | 24 May 2019
Biggest factor are input costs Looking at farming 3 years ago, Mr van Reenen realised that the biggest factors are input costs, chemical input costs in particular. “My aim in the next five years is to try to get totally away from these high inputs. I know that some farm- ers locally are up to about 300kg nitrogen (N) on their irrigated maize, I’ve been at about 220kg N. This year I’m on about 160/170kg N. And walking the lands, now that the maize is tasselling, I haven’t picked up any nitrogen defi- ciency. These lands have had two leguminous crops before on the irrigated lands. Soy beans and then peas in the beans. In the next few years I want to see if I can cut down on fertiliser.” “This year, on all my plant mixes I looked at what I would have spent, rand/hectare on fer- tiliser; this would have been about R1,800/ha (€ 110.86/ha), that would be for nitrogen (N), phosphorus (P) and potassium (K). But it’s not only those elements that matter. I understand that there are in fact about 74 different ele- ments and nutrients, but we only rely on three, and think that is going to sort everything out.” “When I looked at my soil samples, I found they were all short of manganese, zinc, boron, sul- phur and other trace elements. So I took my po- tassium chloride out to avoid putting chlorine in the soil, and went to potassium sulphate, MAP (mono ammonium phosphate), manga- nese sulphate, copper sulphate, boron and zinc sulphate. I made a mixture for that same R1,800, which ends up at about 10kg N, 22kg P and 22kg K. Most people will say that’s not enough, but I’ve been doing it for the past two years and I’m still getting good results. And my soil sam- ples where I’m doing the cover crops are good.”
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