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

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