Effect of nutrient omission on rice yield in a wetland double rice cropping system

Long term crop cultivation affects the soil indigenous nutrient supply which is the basis of sustainable nutrient management. The field experiment was conducted during 2015-2019 to study the effects of nutrient omission on rice yield and soil inherent nutrient supply capacity in a rice -fallow- rice cropping system under wetland condition. The experiment received seven treatments [Control, recommended dose of NPKSZn fertilizer, (-N)PKSZn, N(-P)KSZn, NP(-K)SZn, NPK(-S)Zn and NPKS(-Zn)] in a randomized complete block design with three replications. The highest yield reduction was found with the omission of N in each rice crop illustrating that N was the most deficient nutrient in the soil. After three cropping years, omission of P and K significantly reduced the rice grain yield indicating that although initially the soil could supply these nutrients, they should be added to soil for continuous rice cultivation. However, no significant yield reduction was observed due to Zn omission, while the results of S omission was inconsistent. The contribution of soil to rice yield varied with crop growing seasons and was higher in Aman season (67%) compared to Boro season (43%). The recommended fertilizer dose sustained the rice yield during the study period. However, after five years of rice cropping soil available P and K content reduced from its initial content even in the recommended fertilizer treatment. Therefore, our study suggests that in long term crop cultivation the fertilizer dose should be updated regularly to maintain sustainable yield and soil health.

Automated summary

Long term crop cultivation affects soil nutrient supply, highlighting the need for regular fertilizer dose updates to maintain sustainable yield and soil health.