Studies in crop variation: V. The relation between yield and soil nutrients
Studies in crop variation: V. The relation between yield and soil nutrients
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作物变异研究：五、产量与土壤养分的关系
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0.6
通讯作者：
Bhai Balmukand
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作者：
Bhai Balmukand
对植物生长与环境因素关系的研究已导致许多研究致力于阐述通用公式，这些公式表达了实验植物或作物对所提供的营养量的定量反应。对于单一营养素的变化，只有许多不同的数学表达式才能准确地描述这些事实，而这些事实通常是通过实验来确定的;然而，如果这些公式所涉及的参数或常数在实验之间改变其值，那么这些公式的实用价值就会受到很大的损害。相反，如果我们能得到一个具有普遍性质的公式，它不仅能令人满意地表示对单个因素变化的响应，而且能令人满意地表示对两个或多个不同因素同时变化的响应，那么我们有理由相信，这样的公式的参数将不依赖于实验的偶然或非必要条件，而是能够直接解释为物理量。我们已经证明，阻力公式确实与几个双因素试验的数据相吻合，从三种马铃薯作物中测定的三个α值的一致性，以及在一个有粪肥和无粪肥的地块上的k值的差异与预期从10吨粪肥中可获得的钾肥的一致性，表明这种预期到目前为止是合理的。阻力公式的参数能够直接和明确的物理解释;对于每种营养素，有两个常数;一个代表所考虑的营养素对有关作物的重要性，并且可以预期在作物与作物之间以及在品种与品种之间是不同的，并且因此提供品种之间的肥料需求的直接比较，而第二个代表未施肥土壤中可利用的养分量。
The study of the relation of plant-growth to environmental factors has led to much research directed to the elaboration of General Formulae expressing the quantitative response of the experimental plant or crop to the quantity of the nutrients with which it is supplied. For variations of a single nutrient only many different mathematical expressions will serve to describe the facts to the accuracy with which these are usually ascertained by experiment; the practical value of such formulae is, however, much impaired if the parameters or constants which they involve change their value from experiment to experiment. If, on the contrary, we can obtain formulae of a general character which represents satisfactorily not only the response to variation of a single factor, but the response to simultaneous variation of two or more different factors, then we have reason to believe that the parameters of such formulae will not depend upon the casual or non-essential conditions of the experiment, but will be capable of direct interpretation as physical quantities. We have shown that the Resistance Formula does fit the data of several two-factor experiments and the agreement of the three values of an determined from the three potato crops as well as the agreement of the difference in the values of k on a dunged and undunged plot with the potash expected to be available from the ten tons of dung shows that this expectation is so far justified. The parameters of the Resistance Formula are capable of a direct and definite physical interpretation; for each nutrient there are two constants; one represents the importance of the nutrient considered to the crop concerned, and may be expected to vary from crop to crop and from variety to variety, and so to afford a direct comparison between varieties of their manurial needs, while the second represents the amount of nutrient available in the unmanured soil.