Water and Energy Abstracts

The Bundelkhand region (23° 10′ - 26° 3′ N and 78° 20′ - 81° 40′ E) having a geographical area of 7.04 m ha in Central India is characterized with undulating terrain, scare vegetation cover, hostile climate, lack of irrigation facilities and unfavourable edaphic conditions. The crop yield potential is low and the resource-poor farmers of this region cannot afford much investment on costly chemical fertilizer oriented modern agriculture for increasing crop yield. Sunnhemp (Crotolaria juncea L.) is an excellent green manuring crop, which improves the fertility status of the soil besides reducing runoff and soil loss. Field experiments were conducted during 1994–95 to 1998–99 in 3 adjacent fields with red soil and different average soil depths viz., shallow (0–30 cm), medium (0–60 cm) and deep (0–90 cm or more) to compare green manuring versus no green manuring situations on the succeeding wheat crop. Maximum green as well as dry bio-mass was added under deep soil (21.0 t ha⁻¹ green and 5.3 t ha⁻¹ dry bio-mass), intermediate under medium depth soil (18.4 t ha⁻¹ green and 4.7 t ha⁻¹ dry bio-mass) and minimum (15.9 t ha⁻¹ green and 4.0 t ha⁻¹ dry bio-mass) under shallow soil. Similar trend was also recorded for nutrient addition by green manuring under different soil depths, Maximum amount of N, P and K was added by green manuring crop under deep soil (58.4 kg N, 4.2 kg P and 63.4kg K ha⁻¹), intermediate for medium depth soil (43.7 kg N, 3.3 kg P and 51.9 kg K ha⁻¹) and minimum under shallow soil (34.2 kg N, 2.8 kg P and 40.4 kg K ha⁻¹). The growth, yield, yield attributes and water use efficiency of succeeding wheat crop was significantly influenced by soil depths as well as green manuring. The highest grain yield of 23.4 q ha⁻¹ was recorded under deep soil followed by medium depth (17.2 q ha⁻¹) and shallow soil (11.5q ha⁻¹). The extent of increase in grain yield of wheat under shallow, medium and deep soil due to green manuring was 39, 40 and 30 per cent over no green manuring, respectively. The straw yield also followed the trend of grain yield. The present study suggested that the productivity of red soils of Bundelkhand in Central India could be increased considerably by green manuring in a sustainable manner.