Effects of intercropping systems and the application of Tundulu Rock phosphate on groundnut grain yield in Central Malawi

Abstract

Low soil fertility remains a major constraint in agricultural production in Malawi. Legumes hold the
promise of being a cheap alternative to improve soil fertility owing to their ability of fixing atmospheric
nitrogen (N2). Growing two leguminous crops on a piece of land at the same time and applying
phosphorus (P) may increase N2 fixation while at the same time realizing high grain yield from the
legumes. A study therefore, was conducted to investigate the effect on nitrogen fixation and grain yield
in a groundnut/pigeon pea intercrop, groundnut/maize intercrop treated with an indigenous rock
phosphate (TRP) and groundnut treated TRP. Researcher designed but farmer managed trials involving
eight farmers were mounted on farm. Treatments were laid out in a randomized complete block design.
The results indicated an apparent significant (P<0.05) groundnut grain yield reduction in the
groundnut/pigeon pea intercrop (1,163 kg ha-1) and groundnut/maize intercrop (910 kg ha-1) below the
groundnut sole crop (1,644 kg ha-1) and the groundnut that was treated with the TRP (1,518 kg ha-1).
However, both intercrops showed yield advantage (total LER >1.0) compared with the monoculture on
equal land area. The application of the TRP appeared not to have affected the grain yield.