Dry season Vegetable production with Cover Crop Integration

The Conservation Agriculture (CA) approach in dry season Vegetables starts with the establishment of the cover crop Mucuna pruriens var. (Cream Mucuna) during the rainy season from July to November, here in 2021. Its aggressive and climbing growth will then be terminated either manually by herbicide or cutlass, or with a tractor drawn crimper, which breaks the stamps and presses the biomass flat to the ground for its subsequent use as mulch.

Picture 1 and 2: Cream Mucuna produces enormous amount of biomass. The aggressive character controls weeds, by climbing and pulling them down. Below the thick cover it is always moist. November 2021, Sissala (East Kong).

Into this mulch the vegetable seedlings are transplanted at the beginning of the dry season, here cabbage in December 2021.

Picture 3: Cabbage in Cream Mucuna mulch in Sissala East (Kong), 23.02.2022

What are the benefits using this approach, with a cover crop before dry season vegetable production?

• Beside nitrogen fixation, Cream Mucuna takes up phosphorus from deeper soil levels and makes it available for vegetable nutrition during decomposition. Fertilizer application to the vegetable can be reduced by one third.
• Tap and lateral root system loosen the soil and break compacted hard pans, what increases the water storage capacity and makes ploughing redundant.
• The mulch layer suppresses weed germination for several months and minimizes evaporation. Savings are made from pumping, labour) and weed control (labour, herbicide).
• Erosion control (water, wind) during rainy and dry season.
• Positive phytosanitary effects especially for soil borne diseases like nematodes, allow a return to sensitive crops like tomatoes.

Picture 4: Nodules - small nitrogen power plants, are a symbiosis between legume roots and soil bacteria (rhizobia), here on Cream Mucuna. November 2021, Sissala East (Kong).

The CA sequence of Cream Mucuna before dry season vegetable production can be repeated yearly, especially for soil rejuvenation purposes when dealing with depleted soils or severe nematode infestation. Seeds of Cream Mucuna can easily be multiplied at free corners or low-rate soils of the farm.

Kristin Bothe, GIZ-AgriBiz MOAP NW, 26.05.2022