Soil properties in rice-based cropping systems as influenced by fertigation levels in the eastern plains of Bihar

An experiment at Bihar agricultural college, Sabour Bhagalpur was carried out in split plot design with three fertigation levels of nitrogen in main plots (nitrogen @ 20, 40 and 60 kg ha-1 in rice with irrigation @ 200, 300 and 400 mm in post rice crops) and six rice-based cropping systems as subplot treatments (rice followed by either durum wheat, barley, linseed, chickpea, lentil, lathyrus) on the on-going experiment initiated from 2014. The findings of the research after four years of continuous fertigation and cropping systems practice was that they had no significant change in the soil properties such as pH, EC and bulk density at all the different soil depths considered (0-15 cm, 15-30 cm and 30-45 cm). Soil carbon content was increased with increasing nitrogen levels. The concentrations of available nitrogen, phosphorus and potassium were found to be vary among all the levels of fertigation as well as cropping systems and there was reduction in content with move to the lower soil depths. The higher values for all soil parameters were observed under nitrogen level of @ 60 kg ha-1 in rice through fertigation followed by 400 mm irrigation in post-rice crop compared to other levels of fertigation and cropping systems. Finally, it can be concluded that fertigation and cropping systems had non-significant on soil properties even after four cropping cycles; however, there was slight increment in organic carbon status of soil.