Calibration of optimum nitrogen rate for sweet potato production based on soil organic matter [Philippines]
1987
Forio, A.F. | Pascual, P.P. | Escalada, R.G. (Visayas State Coll. of Agriculture, Baybay, Leyte (Philippines). Philippine Root Crop Research and Training Center)
Nitrogen level studies were conducted in 10 upland areas having different organic matter contents to quantify the optimum N requirement of each area. Root yield of sweet potato responded more to added N in soil with lower organic matter content than in soil with higher organic matter content. No response was observed in soil with low organic matter content with ideal pH (6.05) required the highest N application. Regression/correlation analysis between quantified optimum N rate and soil organic matter revealed that soil organic matter content cannot be used as sole basis for N fertilization. Also, amount of N fertilizer must be based both on soil organic matter and on a pH factor. The formulated multiple regression equation was: Y=91.6-10.2X1-38.9X3 (R to the second power=0.75) where: Y=optimum N requirement, X1= % soil organic and X3=deviation from ideal pH (6.05) for sweet potato.
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Эту запись предоставил University of the Philippines at Los Baños