Effect of N, P, and S Fertilizers on Alfalfa Grown on Three Soil Types in Northeastern Saskatchewan. I. Yield and Soil Tests1
- W. F. Nuttall2
Experiments were conducted on three soil types to determine the effect of N, P, and S fertilizers on herbage yield of alfalfa (Medicago media Pers.) and on nutrients in soils over extended periods of time. Rates of 10,45, and 67 kg N ha−1 were applied in combination with 0,22, and 45 kg S ha−1 in the spring of each year. Twenty kilograms of P ha−1 was applied with these treatments. A control with no fertilizer yielded an average of 2.15 Mg ha−1 per cut Waitville loam (Wv 1, Typic Cryoboralf). An additional treatment (22 N, 0 P, and 26 S kg ha−1) yielded 3.01 Mg ha−1 per cut (avg. 10 cuts) which was the most economical treatment on Wv 1. Response to S fertilizer was significant on Wv 1, but only significant in 1 year on Whitefox fine sandy loam (Wf fsl, Typic Cryoboralf) which was Initially slightly lower in 0.01 M CaCl2 soluble-S [18.4 vs. 16.5 S mg (4 kg)−1 soil]. Contrary to expectation, yield responses to S as much as 0.76 Mg ha−1 of herbage were obtained in 2 years on Melfort silty clay (M sic, Typic Cryoboroll), a soil initially containing a very high amount of So4-S 146 mg (4 kg)−1 soil]. Results indicated that soils need to be tested every 4 to 5 years to provide a basis for adjusting S fertilizer rates. Regression analyses revealed that N significantly increased yield per cut on Wv 1 and Wf fsl soils and that S increased yield on Wv 1, averaged over 5 years. Becanse an expected response to S was not obtained on one site, tissue analyses should be investigated further as a method for determining availability of S.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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