The Correlation of Soil Tests with Yield Response and Uptake of Phosphorus by Barley

This study has stemmed from the results of a number of fertilizer experiments conducted by Carson et al. (12, 31) with spring wheat on Chestnut soils in the North Western part of South Dakota. Results of experiments with phosphorus conducted on non-fallowed land during the years 1961 through 1964 showed that added phosphorus produced a higher percentage yield increase on soils having a low phosphorus produced soil tests as determined by modified Bray No. 1 method (11) than on soils with high P. On the other hand, the yield increases from added phosphorus on fallowed land have not been as related with soil tests as on non-fallowed land. A greater yield increase was obtained from added phosphorus on soils with a high P soil test than a medium soil test. The purpose of this study was to examine some of the soil test methods and relate them to yield response and phosphorus uptake by plants on chestnut soils. For uptake of phosphorus studies, the quick uptake method proposed by Stanford and DeMent (34) was used. The method as proposed does not fully take care of moisture control problems. It was hoped, therefore, that by using the moisture control apparatus proposed by Waugh and Corey (40) for quick uptake studies, it would be possible to fully maintain uniform moisture in the soils during the growth period of the plants and thus increase the precision of the experiment