Comparative Value of Different Legumes in Soil and Water Conservation

The leguminous plants have long been known to possess high nitrogen content and add to the fertility of the soil. In his classical monograph on green manuring, Sorney (1916) has recorded the highest nitrogen value in the Phaseolus species of plants among all the legumes examined for green manuring. Desai (1935) found the best effect of nzoong (Phaseolus radiatus), followed by soybean (Glycine max.), guar (Cyamopsis psoraliodes) and then groundnut (Arachis hypogea) on the subsequent yield of cotton in Sind. Mukerjee & Agarwal (1950) have summarised the entire information on green manuring research done in India upto 1940 wherein the use of sunn (Crotalaria juncea), dhaincha Sesbania aculeata) and cowpea (Vigna catjang) for green manu- ring the common Kharif and rabi crops has been well established. Reliable information on the value of nwong as a green manure crop was obtained in Uttar Pradesh by Singh and Agarwal (1953 ) who recorded a definite superiority of moong T—l over sunn and guar for the green manuring of wheat crop. Gupta and Agarwal (1961) reported that moong T-1 when grown far grain and green manuring over a period of years increased as much humus and nitrogen status of the soil as did sunn for green manur- ing alone although the beneficial effect in both the cases was signicant only at 5 per cent level. Singh (1961) has compared the relativo nitrogen and phosphorous content of the various legumes and found cowpea to have the highest nitrogen content followed by moong, sanai, wd (Phaseolus mungo) and guar. The phosphorous content of naoong compared favourably with sunn and cowpea. A compre- hensive bibliography on the subject of green manuring has been compiled by Agarwal & Gupta (1961); The role of various legumes as a cover crop for reducing run off and erosion and conserving soil moisture has however been very little studied. Kibe (1958) recorded the effect of some legumes in reducing run off and erosion suited to southern penninsular India. The present study has been directed to gather information on this important aspect of the leguminous crops suited to the alluvial tracts of Uttar Pradesh.