Authors : A.T. Omokanye, F.M. Kelleher and A. McInnes
Abstract: Crop residue yield and quality in five Cropping Systems (CSs) comprising cereal-legume, cereal-cereal (CS4) and cereal-bare fallow (CS5) rotations, together with three rates of N fertilizer application on maize and barley were investigated over two consecutive 12 months cropping phases. Cereal-legume CSs were Winter field pea green manure-Summer maize (CS1), lucerne fodder bank intercropped with Winter barley and Summer maize (CS2) and Winter field pea for grain-Summer maize intercropped with cowpea (CS3). N rates were 0, 60 and 120 kg N ha-1 on maize and 0, 40 and 80 kg N ha-1 on barley. Inclusion of legumes in CSs generally increased maize stover yield and quality relative to those without legumes. The exception was CS2, in which stover DM yields were limited by competition with the lucerne in the system. Mean stover DM yield ranged from 5.3-9.5 and 6.4-7.1 ton ha-1 in phases 1 and 2, respectively and was consistently higher for CS1 in both phases. In general, stover quality benefits from legume inclusion were higher Crude Protein (CP), K, Mg and Ca contents. Mean stover DM yield, N content and N yield all increased with increasing N rate in both maize crop phases. Cowpea residue DM yields from CS3 increased with N application to intercropped maize but only up to 60 kg N ha-1 in phase 1. Significant CSxN rate interactions were only observed for barley straw yield in phase 2 where greater response to applied N was observed in CS4 than in CS2. Compared to the N control, mean straw yield in phase 1 increased by 88 and 169% for the N40 and N80 application rates, respectively. In CS3, field pea residue DM yield and N content increased with increasing N application to the preceding maize crop. Forage DM yield from lucerne in the barley-lucerne intercrop (CS2) increased with N application to barley up to 80 kg N ha-1.
A.T. Omokanye, F.M. Kelleher and A. McInnes, 2013. Crop Residues for Mulch, Feed Yield and Quality as Influenced by Low-Input Maize-Based Cropping Systems and N Fertilizer. Agricultural Journal, 8: 222-231.