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Potassium nutrient response in the rice-wheat cropping system in different agro-ecozones of Nepal

Most of the soils of Nepal had a higher potassium (K, expressed as K(2)O) level inherently. Later in 1976, the Government of Nepal has recommended K fertilizer rate at 30 kg K(2)O ha(-1) in rice-wheat cropping systems. However, those crops began showing K deficiency symptoms in recent decades, which...

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Detalles Bibliográficos
Autores principales: Ojha, Roshan Babu, Shrestha, Shova, Khadka, Yajna Gajadhar, Panday, Dinesh
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7971854/
https://www.ncbi.nlm.nih.gov/pubmed/33735327
http://dx.doi.org/10.1371/journal.pone.0248837
Descripción
Sumario:Most of the soils of Nepal had a higher potassium (K, expressed as K(2)O) level inherently. Later in 1976, the Government of Nepal has recommended K fertilizer rate at 30 kg K(2)O ha(-1) in rice-wheat cropping systems. However, those crops began showing K deficiency symptoms in recent decades, which could be due to a large portion of soils with depleted K level or the insufficient input of K fertilizer for crop production. This study explored a limitation of K nutrient in the crops by establishing field trials from 2009–2014 at three agro-ecozones i.e., inner-Terai (2009–2010), high-Hills (2011–2012), and Terai (2012–2014) in Nepal. Seven rates of K fertilizer at 0, 15, 30, 45, 60, 75, and 90 kg K(2)O ha(-1) were replicated four times in a randomized complete block design, where crop yields and yield-attributing parameters of rice-wheat cropping system were recorded. Results revealed that an increase in K rates from 45 to 75 kg K(2)O ha(-1) under inner-Terai and Terai conditions and 45 to 60 kg ha(-1) under high-Hills conditions produced significantly higher grain yields compared to the recommended K dose. Economically, the optimum rate of K fertilizer should not exceed 68 kg K(2)O ha(-1) for rice in all agro-ecozones, or 73 kg K(2)O ha(-1) for wheat in inner-Terai and 60 kg K(2)O ha(-1) for wheat in high-Hills and Terai. Our findings suggest to increase potassium application in between 1.5 to 2.5 times of the current K fertilizer rate in rice-wheat cropping system of Nepal that need to be tested further in different locations and crop varieties.