Hydrophysical characteristics of a sandy loam soil under bed planted maize (Zea mays)

A field experiment was conducted for two years on sandy loam soil for maize (Zea mays L.) cultivation on beds. An index called least limiting water range (LLWR) was computed to compare hydrophysical characteristics of soil under bed planted maize with those under conventionally flat planted maize. Among all four parameters of LLWR, soil water content at field capacity (fc) and wilting point (q(pwp)) did not change much, whereas soil water content at 10% aeration porosity (q(ap)) reduced significantly and soil water content at 2MPa soil strength (q(2MPa)) increased appreciably with increase in bulk density (BD). It was further observed that available water retention capacity (AWRC) did not vary appreciably with BD, whereas LLWR decreased with increase in BD, which indicated that LLWR was a true indicator of soil structural condition. Again, lower water stress period was obtained under bed as compared to conventional planting system. Field saturated hydraulic conductivity at 10 cm soil depth was 3 times of its value of 0.36 cm/hr under conventional planting. Root length density was also more in upper 45 cm in beds due to porous soil environment. These results thus indicated that bed-planting system is superior to conventional planting as it had wider LLWR indicating better water availability and improved soil structural conditions which led to enhanced root growth, and higher maize yield. The above study also confirmed that LLWR could be used as a tool for assessing the suitability of a given soil management practices in improving soil productivity.