Crop Response to Different Soil Fertility Levels in a 5 by 5 by 5 by 2 Factorial Experiment: II. Peanuts1
- W. K. Robertson,
- C. E. Hutton and
- W. D. Hanson2
Four years' data are reported from a 5 by 5 by 5 by 2 experiment in which nitrogen, phosphorus, potassium and lime respectively, were the variables. The experiment was conducted on Red Bay fine sandy loam in west Florida.
No response to nitrogen was obtained.
There was a negative response to potash every year when more than 15 pounds of K2O per acre as potassium chloride were applied. The level of exchangeable potassium in the soil did not seem to be responsible for the negative response. Ninety pounds of exchangeable potassium per acre was adequate for maximum yields. The lack of response to potassium may have been associated either with the application of the fertilizer potassium in the peanut row or with increasing rates of phosphorus applied as superphosphate. Since high rates of phosphorus are necessary for maximum yields of other crops grown in rotation with peanuts, excess potassium, equivalent to that removed by the peanuts, probably should be applied to the other crops in the rotation.
There was a significant yield response to phosphorus every year. When the soil was adequate limed, maximum yields were obtained when the soil contained 45 pounds per acre of P2O5 extractable with 0.002N H2SO4 buffered at pH 3 with (NH4)2SO4 or 110 pounds per acre of P2O5 extractable with 0.03 N NH4F in 0.1 N HCl; 10 of extractant to 1 of soil.
Calcium gave significant yield responses three out of four years. Three tons per acre of dolomitic lime were better than one. One ton per acre of lime raised the pH from 5.3 to 5.6 and the exchangeable calcium from 300 to 500 pounds per acre of Ca approximately. When 3 tons per acre of lime were applied, the pH was 6.2 and the exchangeable Ca 850 pounds per acre.
Phosphorus interacted with lime. Less fertilizer phosphorus was necessary to give maximum yields on limed than unlimed soil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © .