It is winter in South Africa and the temperature outside is certainly confirming the calendar. Thepast few years we complained that the winters were too warm, now we complain that it is too cold! Human nature, I guess.
We have recently finished harvesting our maize. The yields were very good, which is amazing considering how poorly the season started. We had an incredibly dry spring and only managed to plant in December, which is about a month too late.
Unfortunately, we could only harvest later than normal which meant that some of the crop lodged. We experience strong winter winds which took their toll on some of the fields. A good crop nonetheless.
At the end of the season I always like to look at the yields and reflect as to why a particular field did well or not. There are two correlations that I can draw.
First, crop rotation. Generally, maize after soya did better than maize after maize. The first is an easy fix, the second not so much. There was a correlation between yield and soil organic matter content. Not only was this evident between fields, but also vividly apparent on the combine’s yield map.
Unfortunately, soil organic matter is not something that can be bought in a bag. The only way to improve organic matter is through management. Firstly, don’t reduce what you have. That is, don’t till the soil, as tillage introduces oxygen which the microbes use to digest carbon, releasing carbon dioxide.
Second, aim to have a green leaf photosynthesising for as many months of the year as possible. That leaf uses energy from the sun to lock up carbon dioxide from the atmosphere to produce organic carbon, releasing oxygen.
Another problem with our strong winter winds is fire. At this time of the year we spend a lot of time and effort burning firebreaks. As you could imagine, one runaway fire would undo years of organic build-up in a field. I know that many UK farmers hanker after the days when they could burn their residues, but here I would do almost anything to stop a fire.
Bruce Shepherd farms in KwaZulu-Natal, South Africa. He plants 500ha of rain-fed summer crops across 3,000ha. He also runs 2,600 weaner oxen on pastures, finishing them in a feedlot with maize grown on the farm.