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An effective water extraction method for the determination of plant-available soil phosphorus
SummaryA new variant of the water-extraction method for the assessment of soil phosphorus availability to the plant was recently developed by Van der Paauw and Sissingh. The correlation between theExpand
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Calibration of soil test methods for the determination of phosphate and potash status
SummaryThe practical value of soil analyses depends to a large extent on the accuracy of the calibration of the tests under field conditions. Examples are given to illustrate the procedure followedExpand
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Periodic fluctuations of soil fertility, crop yields and of responses to fertilization effected by alternating periods of low or high rainfall
SummaryThe phenomenon of cyclic fluctuation of factors is common in meteorological literature.More or less cyclic alternations of periods of different rainfall appear to be especially evident fromExpand
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Residual effect of nitrogen fertilizer on succeeding crops in a moderate marine climate
Residual effects of fertilizers have been observed frequently; those of phosphorus may last several years. Though the soluble nitrogen in a humid climate is subject to vigorous leaching, recentExpand
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Critical remarks concerning the validity of the mitscherlich effect law
SummaryA criticism is made of the evaluation of the Mitscherlich Effect Law on the basis of more than 27000 field experiments with graded amounts of fertilizers by Mitscherlich and Gericke.Expand
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Factors controlling the efficiency of rock phosphates for potatoes and rye on humic sandy soils
The results obtained in experiments and in farming with rock phosphate applied to any given crop on acid humic sandy soils are very variable. These variations are mainly due to relatively smallExpand
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Die Leistungen des Hämoglobins beim Regenwurm
ZusammenfassungZusammenfassend können wir sagen, daß unsere Untersuchungen die Meinung von Bea Schwarz bestätigt haben, daß die Bedeutung des Hb für den Stoffwechsel des Regenwurms nicht gegeben istExpand
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Effect of winter rainfall on the amount of nitrogen available to crops
The importance of winter rainfall for the availability of nitrogen to the crop in the following season has already been recognised in earlier work. R u s s e l l 11 compared the need for nitrogen ofExpand
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