|Author:||Adhikari, R. N. ; Selvi, V.|
|Book Group Author:||NA|
An experiment was conducted during 1988/89-1991/92 in Karnataka, India, on sorghum cv. SPV-86 to predict crop yield from evapotranspiration using a simple logarithmic model. The total crop yield and maximum expected yield were considered for data analysis. The crop coefficient determined for various phenological stages of sorghum crop from sowing to harvest varied from 0.26 at initial stage to a maximum of 0.71 at development stage when there was full attainment of ground cover and it was again decreased to a minimum of 0.16 at harvesting stage. The water use efficiency varied from 6.46 to 9.16 kg ha-1 mm-1 with an average of 7.6 kg ha-1 mm-1. To predict crop yield from evapotranspiration, the maximum potential crop yield was assumed. The potential yield under no water stress during crop period was assumes as 5000 kg/ha. The results showed that the observed yield was very close to the predicted yield. The effect of water stress on the growth and yield of any crop depends on its species and variety, and magnitude of the water deficit. A simple linear relationship was developed between rain runoff and evapotranspiration, rain runoff and crop coefficient. Rain and runoff widely varied yearly during the rabi season (September to first week of February). The correlation coefficient was more than 0.90 in all the cases suggesting the validity of these equations for operational use. During the crop period, water availability through rain and irrigation was much less than the actual water used by the crop. The excess water used by the crop was contributed from the moisture stored in the soil profile. Normally, the sowing period in the region was the second week of September to the first week of October, soil moisture after sowing was used as evaporation and transpiration. The soil moisture used (SM) was computed by water budgeting considering drainage as negligible. In the years of good rain or when irrigation was applied, the SM used was less and vice versa when water availability was poor during crop period. The SM used by the crop ranged from 106 to 155 mm with an average of 130 mm.
|Pages:||164 - 166|
|Journal:||Indian Journal of Soil Conservation|
crop yield, evapotranspiration, mathematical models, plantwater relations, prediction, water use efficiency, India, Karnataka,Sorghum bicolor, South Asia, Asia, Developing Countries, Commonwealth ofNations, India, Sorghum, Poaceae, Cyperales, monocotyledons,angiosperms, Spermatophyta, plants, eukaryotes, Mysore, Field Crops(FF005) (New March 2000), Plant Physiology and Biochemistry (FF060),Plant Water Relations (FF062), Plant Production (FF100), Mathematics andStatistics (ZZ100)