Sugar bean production


AS farmers get ready for the 2021/2022 summer cropping season, it is imperative to note that farming is a rewarding venture if the appropriate crop is planted in the right regions at the right time with the right inputs.

One crop for farmers to consider this cropping season is sugar beans. 

Sugar beans have a very huge market as they are consumed by every household and large institutions such as boarding schools and prisons. 

Sugar beans are an annual crop which thrives in warm climates and grows optimally at temperatures between 18 and 24 Celcius. 

According to Windmill, the maximum temperature during flowering should not exceed 30 Celsius. 

“High temperatures during the flowering stage leads to abscission of flowers and poor pod set, resulting in yield loss,” read part of the guidelines on sugar bean production by Windmill. 

“Day temperatures below 20 Celcius will delay maturity and cause empty or immature pods.” 

Windmill said sugar beans should be cultivated under rain-fed conditions, which record a minimum of 400 to 500 millimeters rainfall during the rain season. However, an annual rainfall total of 600 to 650 mm is considered ideal.

According to Windmill, sugar beans should be planted in warm soil. 

“Beans grow well in soils with a depth of at least 90 cm, which have no nutrient deficiencies and are well drained. Sandy loam, sandy clay loam, or clay loam with clay content of between 15 and 35 percent is suitable. With sandy soils, problems of low fertility or nematode damage may occur.” 

Windmill said seedbed preparation for planting of dry beans follows the same pattern as that for any crop planted in the spring. 

“The seedbed must be deep, level and firm as this ensures better surface contact between the seed and the soil, increasing the absorption of moisture. A level seedbed also facilitates planting to a uniform depth.

Planting dates in Zimbabwe range from October to mid-January in areas where frost occurs. In frost-free areas, March and April are the best for planting beans.” 

For spacings and plant population, Windmill said, the inter-row spacing for all types of beans under commercial production 900 mm because dry beans are usually cultivated in rotation with maize. 

“For early maturing cultivars, especially those with determinate growth habit, a row spacing of 750 mm is recommended in the case of mechanisation. Planting depth is determined by the soil texture and its moisture content. 

Generally the seeds are placed 2,5 to 5 cm below the soil surface.”

Windmill said it is recommended that sugar beans be planted on soils which had been well fertilised previously. 

Additional fertilisers are said to be more efficient when there is already some degree of fertility. 

The Windmill-recommended basal fertiliser is Windmill’s Compound D (7:14:7).

For top dressing ammonium nitrate is recommended.

Irrigation offers the potential for increasing yields and enabling production in otherwise unsuitable soils. 

Sprinkler irrigation has been described as ideal for sugar beans.

“The sprinkler irrigation system used is determined by the size and shape of the lands, as well as available labour and capital. In areas where water is unrestricted (not merely supplementary irrigation), the soil should be wet to field capacity.

Irrigation scheduling is essential for optimum yield per unit of water.” 

Windmill said the critical moisture-sensitive growth stages were flowering and early pod set. 

Irrigation cycles must be scheduled correctly, as excessive moisture can create conditions conducive to root rot and sclerotinia. 

Moisture stress can also aggravate some root rots such as fusarium oxysporum. 

Efficient weed control is a pre-requisite for high sugar bean yields. 

Sugar beans compete poorly with weeds as they are slow-growing plants and do not easily overshadow weeds. 

Early control is extremely important because the root system of the plant develops at this stage and some weeds secrete chemical substances which inhibit plant growth. 

At a later stage, weeds hamper harvesting and threshing processes and adversely affect the quality of the crop.

“Mechanical weed control should begin during seedbed preparation and be repeated with a tiller between the rows when necessary up to the flowering stage,” said Windmill. 

“Care should be taken that implements do not damage the crop by using row spacings which permit easy access and taking care that roots are not damaged. Cultivation between the rows is also advantageous because it loosens the soil and improves aeration and water penetration. 

Integrated pest management, using all suitable control measures is recommended.”


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