By Prossy Nandudu and Joshua Kato
Beans thrive best in a warm climate of optimum growing temperature range of 200C to 28oC with a minimum of 15oC and a maximum of 32oC. Temperatures above 32oC and below 15oC will cause poor pod set resulting in yield loss. Bean production is more successful in areas where rainfall is moderate to light during the latter part of growing season. Beans are adapted to a wide range of soils as long as the soils are reasonably fertile, well drained and free of conditions such as saline. An optimum soil pH of 5.8 to 6.5 is ideal for beans production.
It is essential to assess soil health before any soil management operations are implemented. Constraints such as soil acidity and soil nutrient deficiency can lead to significant reductions of crop yields. The soil PH and nutrients levels can be determined by conventional soil analysis in addition to observation methods of crops growing in the field.
Soil testing is an essential crop management decision-making tool that enables one to:
-Determine acidity and alkalinity levels (soil PH);
-Identify any soil nutrient deficiencies;
-Estimate optimum fertilizer requirements for target yields;
-Estimate the optimum cost of fertilizer needed and the returns
In the field, a soil testing kit can be used or soil samples can be taken to a recommended laboratory for further analysis.
Land preparation involves; bush clearing, removal of tree stamps and termite mounds, and ploughing. Beans require a fine seedbed for uniform and proper growth of roots to absorb the available water and soil nutrients. Well prepared seedbed reduces on the number of weeding times.
The timing of land preparation is extremely important. Land preparation should begin either at the end of the harvesting period or at least 3 weeks (21 days) before planting to allow breakdown of organic fine seedbed. Where the field has a known history of bean pests such as pod borers, bean fly and beetles, complement ploughing with harrowing to kill the surviving eggs, pupae and adult pests.
If the site is very bushy, first clear land by slashing down all plant parts and leave them on the ground, or plough in the plant residues using appropriate equipment. This will help soil to conserve moisture; improve the water retention capacity, water-infiltration capacity and increase soil fertility.
Source of Quality Seeds
High yield begins with good quality seed. It is therefore important to select well developed, mature, uniform seed of sound vigour. Farmers should always buy seed from certified seed companies or use Quality Declared Seeds usually produced by farmer groups (Community Seed Multipliers).