Kd. Sharma et al., Study on the performance of contour vegetative barriers in an arid region using numerical models, AGR WATER M, 41(1), 1999, pp. 41-56
The purpose of the study was to evaluate and derive the optimum spacing of
contour vegetative barriers (CVB) of locally adapted, drought resistant pla
nt species as soil and water conservation measures for rainfed crop-fields
in an arid region. Adapted perennial grasses performed the best and formed
effective barriers against soil erosion. Runoff volume and specific peak di
scharge were reduced by 28 to 97% and 22 to 96%, respectively using CVB wit
h negligible soil loss. The resultant increase in soil moisture storage inc
reased pearl millet crop yield by 35%. Hydrologic processes with respect to
crop response for digitally generated CVB layouts were simulated using the
distributed numerical models SWAMREG (rainfall-runoff) and SWACROP (moistu
re storage-plant transpiration-crop yield), and a personal computer-based g
eographic information system (GIS) for designing optimum CVB spacing. Input
s needed for these models are soil hydraulic parameters, daily meteorologic
al data, and crop characteristics. Simulated outputs were validated with th
e observed runoff soil moisture storage and pearl millet yield data. At an
optimum simulated vertical spacing of CVB between 0.5 and 0.6 m, 24% reduct
ion in runoff resulted in better moisture regime and crop yield improvement
by 70% over control. (C) 1999 Elsevier Science B.V. All rights reserved.