Effect of nutrient management on nutrient uptake and changes in soil fertility in maize (Zea mays)-wheat (Triticum aestivm) cropping system

Abstract

A long-term experiment initiated in 1983 was selected during 1997-99 to study cumulative impact of organic sources (FYM, rice straw and green karanj leaves) substituting inorganic fertilizers in recommended fertilizer dose (RFD) once each by 25% and 50 % during rainy season (kharif, in maize (Zea mays L.)-wheat (Tn'ticum aestivum L. emend. Fiori & Paol.) cropping system. All the organic sources were instrumental in improving pH and aggregation of soils. Only rice straw in its higher substitution (50%) could induce significant improvement in bulk density and water-holding capacity of soils but a constant trend of improvement was there under application of all the sources. All the 3 sources both in their higher and lower substitutions enriched the soils in organic car- bon contents. Farmyard manure (FYM) and green karanj leaves in their higher substitution improved NPK levels of soils. Rice straw at this level (50% substitution) could bring about significant improvement only in available K content of soils. At lower level of substitution (25%) green manuring with karanj leaves induced higher available P and K in soils, but FYM at the level could bring about significant improvement only in available P level. Appli- cation of rice straw at this level of substitution (25%) could not alter status of any of the NPK significantly. Substi- tution of inorganic fertilizers by FYM either at higher (50%) or lower (25%) level was helpful in increasing grain yield and uptake of NPK.