By Saintly Ngwenya
Yield is the proportion of harvested crops to the land used. In a given piece of land, the yield may vary from farmer to farmer due to a number of factors like pest and disease management, soil fertility management, moisture control, time of planting just to name a few. A lot of farmers have mastered on most of these factors but are still experiencing lower yields. The main challenge could be their plant population.
Plant population is the total sum of plants on a given unit area of land. Plant population is affected by how the plants are arranged in the field, seed viability and maintenance of optimum populations. For farmers to attain higher yields, they have to do everything possible to ensure correct populations from planting to yielding. These populations may differ with type of crop, varieties soil type and location of the farmer.
The farmer therefore has to know the standard optimum population for each crop and variety they are growing. Too high populations cause unnecessary completion among plants for nutrients, water and sunlight resulting in crops failing to reach maturity. Too low populations cause excessive consumption of nutrients and underutilisation of land resulting in low yields.
Therefore, optimum plant populations are ideal for proper land utilisation, nutrient consumption and easy management. This is the secret to attainment of higher yields in any given land. Below are optimum plant populations for several crops. These assist farmers in planning on the amount of seed to buy and yield estimation.
| Crop | Minimum plants/ha | Maximum plants/ha |
| Maize | 36 000 | 60 000 |
| Sorghum | 200 000 | 250 000 |
| Soyabeans | 200 000 | 550 000 |
| Groundnuts | 222 000 | 570 000 |
| Sugar beans | 300 000 | 400 000 |
| Cow peas | 60 000 | 120 000 |
These are just basic guidelines for those farmers targeting grain yield. For those who harvest the forage for stock feed the maximum plant populations given above may be exceeded and still get desired results. For more information on how to maintain plant populations for other crops to ensure higher yields, follow our discussions on all of our vaMudhumeni platforms.