Effects of Manure Application on Nutrient Uptake in Two Rice Varieties and Some Post-harvest Soil Chemical Properties

Organic manures, as suitable alternatives to chemical fertilizers, supply plant nutrients and contribute to the sustainability of agricultural ecosystems. It is the objective of this study to investigate the effects of applying organic fertilizers of different sources and levels on paddy soil chemical properties. The experiment was conducted in a randomized complete block design with three replications at the research farm of Rice Research Institute of Iran at Rasht during the two farming years of 2018 and 2019. The experimental variables included poultry (2.5, 5, and 10 t/ha), cow (5, 10, and 20 t/ha), and sheep (10, 20 and 40 t/ha) manures. The results obtained revealed that, compared to the control treatment, application of 40 t/ha of sheep manure led to an increase of 0.41 dS/m in EC and enhancements of 0.14% and 3% in N and OC, respectively, while application of 20 t/ha of cow manure increased available P and K in soil by 8.6 and 173.2 mg/kg, respectively. Also, application of 20 t/ha of cow manure led to the highest grain nitrogen of 48.6 kg/ha, phosphorus uptake of 33.1 kg/ha, and straw potassium uptake of 78 kg/ha in the Gilaneh variety while the Hashemi variety exhibited its highest grain nitrogen of 44.9 kg/ha, phosphorus uptake of 29.6 kg/ha), and straw potassium of 75.9 kg/ha under the same treatment. Thus, application of 20 t/ha of cow manure may be recommended as a superior treatment for it showed soil fertility improvement and paddy yield compensation of 80% in the Hashemi and Gilaneh rice varieties when compared with the treatment using chemical fertilizers.