Abstract

In many parts of Malawi, including Balaka district in Southern Malawi, are prone to erratic rains with poor soil productivity and famer practices. A research and outreach project was initiated in October 2015 to establish learning centres (LCs) of groundnut: maize rotations as an entry point to diversify nutrition and income base of smallholder farmers, while building up on soil fertility for increased resilience to production under climatic variation. Some 132 plots of groundnut were established in 2015/2016 in four sections of Ulongwe Extension Planning Area (EPA) in Balaka district. Of these, 44 fields were sampled for yield, biomass, plant stand and soils data. In the second season of 2016/2017, a maize fertilizer response trial (five rates of NP2O5K2O; 0, 23:21:0+4S, 46:21:0+4S, 69:21:0+4S, and 92:21:0+4S) was super-imposed in plots where farmers incorporated groundnut residues, in comparison with continuous maize from adjacent own field. In the first season, rainfall was below average and erratic, with 10-day dry spells recorded in two of four recording stations. The soils were generally poor, with test values below threshold for many variables including organic matter, nitrogen and phosphorus. Groundnut average yields and standard deviation were 754 (±186) kg/ha, respectively. Plant stands were poor, with up to 24% of the 46 LCs attaining ≤50% of targeted plant stand of 8.88 plants m-2.  Poor plant stand is suggested as a major contributor to low yields. Results from the 2016/2017 fertilizer response trials showed linear response of maize to fertilizer application. Yields ranged from an average of 1.47 t/ha without fertilizer application to 4.0 t/ha at 92:21:0+4S. It is concluded that the poor soil fertility, low field plant densities, and dry spells are the main causes of low yields. Gross margins were positive for groundnut yield of 1,000 kg/ha and fertilizer rates on maize of 46:23:0+4S and above.

Key words: Groundnut-maize rotation, nitrogen response, drought spells.