Thinning the crop

Removing one in three maize plants shortly after emergence will give you a higher yield.

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When you planted your maize, you placed three seeds together directly above the fertiliser. Many experts say two seeds is enough, but a good, full, even stand is essential for a high yield. With the difficulties caused by weather, pests and other factors, it’s tough to achieve this by planting only two.

The difference between a 90% to 100% population and a 60% to 70% population can translate to a yield difference of up to 3t/ha. So the extra investment is certainly worth the payback. Young maize plants can be thinned down to two per hole, or station, two to three weeks after emergence. If you try thinning before the plants are 10 days old, they’ll break off above the roots and grow again.

Roots and all
To reduce the population to two plants per station, remove the weakest looking ones by pulling them out with their roots.
If only one plant has emerged at a station, leave three plants on either of the stations next to it. If there are no plants, leave three on both sides to bring the population back to an average of two plants per station.

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Leaving three plants in every station will give a total plant population that is too high, and the extra competition for moisture and nutrients will reduce the yield. The one exception In a dry year, this could even result in total crop failure. In a wet year, lodging (stalk bending due to ‘overgrowth’) could occur. Planting three seeds per station is a safety measure.

The exception to this is if you plant a 4-series, or short-stature cultivar, such as SC401 or SC403. Then you can leave three plants per station. The temptation to leave three plants is very strong for beginners, because removing one seems like a waste. It is advisable to follow the rule and trust more experienced growers.

Foundations for Farming (FFF) is an NGO based in Zimbabwe that teaches conservation agriculture practices to farmers, based on Christian principles. FFF provided the information for this article. Visit