Effects of Fallowing and Nitrogen Application on Striga Infestation, Soil Fertility and Maize Performance

Abstract

Striga possesses an ominous obstacle to the African continent that is struggling with food security as it affects the livelihood of more than 300 million people. The control of Striga has proved exceptionally difficult. Two fallows, namely natural fallow (NF) and A. histrix fallow (AF) were maintained in 2012, such that the field was divided into two parts and each part was further divided into three replicates. Each part was separated from one another by a strip of 2 m width and the fallow factor was randomly assigned to each part which constituted the main plot. In 2013, the inorganic N fertilizer levels (0, 60, 90 and 120 kg ha-1) were applied to the fallow plots and assigned to the sub-plot. These treatments were laid out in a split plot arrangement fitted to a randomized complete block design with three replicates. The two fallows significantly (P < 0.05) reduced Striga infestation similar to application of N at 60 – 120 kg N ha-1. The two fallows significantly (P< 0.05) increased SOC. Only natural fallow significantly (P<0.05) increased the STN by 36 %. Maize grain yield after natural fallow (1527 kg ha-1) was not significantly (P>0.05) different from that after A. histrix (1943 kg ha-1). Inorganic N application had highly significant (P<0.05) effect on grain yield. Lowest grain yield of 1253 kg ha-1 was obtained without inorganic N application, which was significantly different from those fertilized with inorganic N. Inorganic N fertilizer rate of 60 kg ha-1 seems to be optimum for maize. The Nitrogen Fertilizer Replacement Value of A. histrix was low, 13 kg N ha-1. The effect of both fallows on grain yield was due mainly to increased SOC content.