The third-year SUA student in Agriculture Johnson Mwakyusa assesses the effect of mulching materials on the growth of Okra cultivars in Morogoro in his research project for the completion of his bachelor studies. Mulches are helpful tools to conserve soil moisture which is one of the requirements for higher yields. Due to the high cost of plastic mulch, organic alternatives are a necessity for many small-scale farmers. Through his attendance in the Workshop for Participatory Research Design (WPRD), which takes place every year and is organized by SAT, Johnson learned about this challenge and wanted to make a contribution through his research.
Specific objectives of his study include the assessment of the effect of organic mulches on growth, yield and soil moisture conservation as well as the ability for weed control. Using two different types of Okra seeds (Pusa sawani and Clemson spineless), the set-up covers two times three replications with four plots each. The used treatments are rice husks, dry mango leaves, dry thatch grass and a control plot. Collected data include soil moisture and germination percentage, plant height, weed emergence, number of pods per plant and okra yield per hectare among others.
In Mid-June 2016, Johnson was undertaking data collection and was getting first results on the effectiveness of the different mulches. His recommendations for small-scale farmers vary depending on the main aims that one pursues. For increased yields for example, rice husks have the biggest impact. Rice husks also have the highest ability in conserving soil moisture, while dry mango leaves perform worst in this regard, not considering the control plot. As well, dry mango leaves are best to improve nutrients in the soil as they decompose fast. But this also means that they have to be replenished frequently. Nevertheless, Johnson observed that these also attract a lot of insects, including termites, which especially cause problems to cereal crops. Dry thatch grasses on the other hand perform best when it comes to air circulation and are second best in conserving soil moisture and in controlling weed emergence. Finally, among the two different Okra seeds, the Pusa sawani variety was observed to perform better when it comes to first flowering, first mature pods and also pod length.
These results have led Johnson to recommending different mulching-materials depending on the specific needs of the farmers. Organic mulches have many benefits but in order to optimize their application, one has to consider the main aim and then choose carefully.