Annual legume species as green manure/cover crops in low-input farming systems of Nepal

Abstract

Models, which predict the duration between sowing and reproductive maturity, are used to examine the suitability of cover legumes for use in farming systems of the mid-hills region of Nepal. The National Agricultural Research Council hill research institutes at Hattiban, Lumle, and Pakhribas were selected for study. In addition, the temperature regimes of a typical span of elevations (600-2,400 m) were constructed to examine the range of environmental variability associated with cropping in this region. Models predicting rates of crop development were used to determine the feasibility of six legume cover species to reach maturity prior to the sowing period for the principal summer cereal crops. Model outputs indicate substantial variability in maturity dates resulting from genotype, site, elevation, and sowing date effects. Vicia faba, Vicia villosa ssp. dasycarpa, and Lupinus mutabilis grown as autumn-sown crops across most of the mid-hills would be feasible where early sowing is possible. More caution would be needed if Vicia sativa or Trifolium resupinatum were chosen because they are only likely to mature early enough to permit unhindered summer cereal sowing at lower elevations