To determine the coefficients of c1 and c in Mitscherlich-Bray equation, critical level and fertilizer recommendation for potassium (K) as by Mitscherlich-Bray (MB) equation, an experiment in a randomized complete block design of 5 treatments and 3 replications was carried out in 12 irrigated wheat (Triticum aestivum L.) fields in Sarpol-e-Zohab region during the 2007-08 growing season. The treatments included T1 = Farmer's conventional fertilization practice= NP); T2 = control (all the nutrients included except K);
T3 = T2 + 100 kg ha-1 muriate of potash (MOP); T4 = T2 + 200 kg ha-1 MOP and T5 = T2 + 300 kg ha-1 MOP in three stages of: preplanting, tillering, and stalk bearing. Following harvest, grain yield was determined, and MB Equation's coefficients for K calculated. The value of c1 coefficient for the 11 wheat fields was found as 0.0020. Potassium critical level was 115 mg kg-1 for 85% of the maximum yield under non-subsidized, i.e., free market fertilizer prices condition. However, under existing subsidized fertilizer prices, potassium critical level achieved for 95% of maximum yield was 180 mg kg-1. Therefore, based on the information obtained, the managers of soil test laboratories will have a suitable tool in predicting the farmers' relative yields and economic return on wheat with each incremental increase in K-fertilizer application just only by analyzing the available K in the soils. There is need for such information also for other regions and for other different field crops.
Abdolahi, A., Malakouti, M. J., & Ghaderi, J. (2011). Potassium Fertilizer Recommendations through Determination of Mitscherlich-Bray Equation Coefficients for Irrigated Wheat. Iranian Journal of Soil and Water Research, 42(1), 121-128.
MLA
Ali Abdolahi; Mohammad Jafar Malakouti; Jalal Ghaderi. "Potassium Fertilizer Recommendations through Determination of Mitscherlich-Bray Equation Coefficients for Irrigated Wheat". Iranian Journal of Soil and Water Research, 42, 1, 2011, 121-128.
HARVARD
Abdolahi, A., Malakouti, M. J., Ghaderi, J. (2011). 'Potassium Fertilizer Recommendations through Determination of Mitscherlich-Bray Equation Coefficients for Irrigated Wheat', Iranian Journal of Soil and Water Research, 42(1), pp. 121-128.
VANCOUVER
Abdolahi, A., Malakouti, M. J., Ghaderi, J. Potassium Fertilizer Recommendations through Determination of Mitscherlich-Bray Equation Coefficients for Irrigated Wheat. Iranian Journal of Soil and Water Research, 2011; 42(1): 121-128.
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