Crop management factors influencing yield and quality of crop residues

Abstract

In the semi-arid tropics, over two-third’s of the world’s people depend on agriculture within which livestock play a major role in building rural livelihoods. Crop residues (fodder/stover) are important feed resources for ruminants. This review was undertaken with the objective of improving understanding of the role of various crop management factors in affecting the productivity and quality of crop residues. Variability in productivity and quality of residues can be of both genetic and non-genetic origin. Recommended agronomic practices vary according to crop and cultivar and can release the maximum genetic potential determining quantity and quality of residues. Planting method and planting rate recommendations should be followed to maximise productivity. Although low density planting improved fodder quality, fodder yield declined. Time of sowing affected fodder yield in most of the crops, but fodder quality was not generally affected. It was common to observe that application of nitrogen (up to 120 kg ha −1) in cereals and application of phosphorus (up to 60 kg ha −1) in legumes improved the green and dry fodder yields, as well as crude protein (CP), crude fibre (CF) and other quality parameters. Inoculation of cereal seed with nitrogen fixing bacteria such as Azotobacter and seed of pulses with phosphate solubilising bacteria has been reported to decrease fertiliser needs and improve the CP and in vitro dry matter digestibility (IVDMD) of fodder. Irrigating at more frequent intervals by splitting the same quantity of irrigation water into smaller irrigations and at critical stages improved dry matter and CP yields. Hand weeding resulted in better weed control efficiency and stover yield than application of herbicides. However, application of herbicides resulted in the greatest benefit:cost ratio. Manual harvesting resulted in lower losses than mechanical harvesting, and may affect quality depending on the extent of loss of different fodder components. Drought stress yielded more digestible organic matter due to increases in the proportion of leaves compared to stems. Saline conditions affected seed germination and crop yields. Several methods are suggested to counteract the effects of salinity. Intercropping of cereals with legumes improved fodder nutritional quality (mostly protein content). In almost all crops, a positive association was found between fodder and grain yield indicating simultaneous improvement in both characters. In most cases, fodder yield and digestibility were positively correlated and showed positive association with plant height, leaf number and the number of tillers per plant, but there were limits and variation among crops. The ICRISAT–ILRI partnership experiments were conducted with a diverse set of sorghum and pearl millet cultivars at ICRISAT, India. Planting density levels in both crops did not influence forage quality although some fodder yield traits were affected. A significant interaction of genotype with planting density was observed for grain and fodder yield in sorghum and grain yield and harvest index in pearl millet. Adherence to recommended crop management practices can potentially facilitate the release of the maximum genetic potential determining quality and yield parameters for improved animal production.