Some Nutrients Availability in Rice Soil under Utilization of Organic and Inorganic Fertilizers

Abstract

A field experiment was conducted at the Experimental Farm of Sakha Agricultural Research Station; Kafr El-Sheikh, throughout the summer season of 2017 and 2018 to examine the nutrients status in rice soils under the utilization of organic and inorganic fertilizers. Egyptian hybrid rice one (EHR1) variety was used. The experiment was laid out in a split-plot design with four replications, where main plots were assigned to NPK fertilizer treatment and sub-plots were allocated to organic material treatments. The NPK fertilizer’s treatments were full dose, 2/3, 1/3 of NPK recommended doses and control (without any mineral fertilizers application). The recommended doses of NPK are 165 kg N ha-1, 36 kg P2O5 ha-1 and 58 kg K2O ha-1. The organic material treatments were control (without any organic materials application), rice straw compost, farm yard manure, chopped rice straw and mixture of chopped rice straw and farm yard manure (1:1). The application rate of the organic materials was 7 tons ha-1 for each treatment. The studied characteristics were the available ammonium (ppm), nitrate (ppm), phosphorus (ppm), potassium (ppm), zinc (ppm) as well as grain yield (t ha-1). Soil samples were collected at 30, 45 and 60 days after transplanting (DAT) and after rice harvest during the two study seasons. The available nutrients in soil tended to increase as NPK fertilizer levels increased and by the application of organic materials. Available NH4 markedly increased after flooding reached its high peak at 30 DAT and then declined to the minimum values at harvest. The high peak of NO3 was observed at 30 DAT, then started to decline afterward and reached its minimum values at harvest. The highest amount of available K was obtained at 45 DAT and then decreased continuously with crop growth, reaching the lowest values at harvest time. Current data reveal that the maximum available Zn was found at 30 DAT. The application of a full recommended dose of NPK mineral fertilizer combined with compost or farm yard manure and compost alone produced the highest values of grain yield.