INFLUENCE OF RICE (ORYZA-SATIVA) CULTIVATION METHOD AND CROPPING SYSTEM ON NUTRIENT STATUS OF SOIL AND PRODUCTIVITY IN VERTISOLS

A field experiment was conducted during 1990-91 and 1991-92 to find ou t the influence of cultivation method of rice (Oryza sativa L.) and ri ce-based cropping systems on nutrient status of soil and total product ivity of the system in Vertisols. The methods of rice cultivation such as direct sowing dry seed in dry seed-bed, direct sowing of sprouted seed on puddled wet soil and transplanting did not influence significa ntly the available nutrient status of the soil. Growing pigeonpea or r edgram [Cajanus cajan (L.) Millsp.] in winter season (rabi) increased the soil-organic matter and the N and P status of the soil. It led to higher rice -equivalent yield in rice-redgram sequence (6314 kg/ha) du ring succeeding year in comparison with that of rice-sorghum [Sorghum bicolor (L.) Moench]. But rice-safflower (Carthamus tinctorius I,.) se quence recorded the overall best result in terms of rice-equivalent yi eld. Final nutrient status of the soil indicated that rice-pigeonpea s equence gives higher content of soil-organic carbon and the available N and P, whereas K and Zn availability declines in rice-sorghum and ri ce-safflower sequences.