Nitrogen Fractions and their Relatioships under Sorghum Sunflower Cropping Sequence in a Typic Haplustert

A field experiment on fixed plot was conducted on nitrogen fractions under sorghum-sunflower cropping sequence by using organic and inorganic fertilizer treatments at Marathwada Agricultural University, Parbhani during 2001-2002. The doses based on soil test framed in 1997 which were found to be optimum for sorghum (80:40:40 kg N, P and K ha^-1) and for sunflower (60:40:30 kg N, P and K ha^-1).The results of these studies revealed that all nitrogen fractions like total hydrolysable nitrogen, amino acid nitrogen, organic ammonium nitrogen, acid insoluble nitrogen and total nitrogen were increased significantly in all treatment combination. The combined application of organics + inorganic fertilizers caused significant increase in available nutrients status of the soil. The relationship with availability and soil properties exhibited significantly negative correlation with soil pH and significant positive correlation with organic carbon and CaCO₃ of soil.