The Conservative Concern

Hopkins, Vincent C.

doi:10.5840/thought19563112

Cited by 1 publication

(1 citation statement)

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“…We may look forward to further experiments w i th this interesting phosphatic material and to the effects that it might have on the microbial population of soils as well as the curious ability of plants being able to tolerate this chemical compound which has such an extreme toxicity for animals. Hopkins (59) has reviewed the latest developments pertaining to the use of phosphine as a phosphatic fertilizer as of 1956. The reviewers have not been able to discover further reference to this subject.…”

Section: Phosphorusmentioning

confidence: 99%

The Macronutrient Elements

Broyer¹,

Stout²

1959

Annu. Rev. Plant. Physiol.

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The term "macronutrient" is recent, having come into popular usage since the general acceptance of the term "micronutrient." Therefore, the term "macronutrient element" suggests· one of the nine elements needed by plants in larger quantity, namely: nitrogen, phosphorus, sulfur, calcium, magnesium, potassium, carbon, hydrogen, and oxygen. However, only the first six which can be supplied conveniently as fertilizers are ordinarily con sidered among the macronutrients. In plant physiology, the understanding associated with "nutrient elements" is distinctively separate from the general sense of energy-containing foods. Thus, in speaking of "nutrient elements," the implications are always of the simple mineral constituents necessary for the growth and development of the living plant.A large and expanding need for the macronutrient elements in contem porary agriculture encourages most of the research effort directed toward them. For the same reason, many other specialists besides plant physiol ogists maintain similar interests in the macronutrients.A continuing live interest in the chemical elements required for plant growth stems, of course, from the activities of agriculture in providing our "daily bread." The time has long since passed when agriculture can supply food to the more advanced countries of the world by the simple methods of tradition. As agriculture accommodates more and more into the methods of industrialization, it depends increasingly upon other industrial activities.Agriculture has now become the most sophisticated of all the arts in adapting things of the natural world to the uses of human society. It calls upon every facet of contemporary science to help in meeting the common problem. It enlists industry to provide the continually increasing require ments for machinery and for additional supplies of water, fertilizers, and toxins to fight the unrelenting war against insects, nematodes, and diseases of plants or animals. Macronutrient elements appear clearly as subjects of ex ceptional importance if for no other reason than their sheer bulk, which has to be moved to suitable geographic regions for economical plant production.It is very rare when the chemical elements needed for maximal plant growth are supplied adequately by soils. Enormous tonnages of calcium, magnesium, potassium, nitrogen, phosphorus, and sulfur are mined, proc-1

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Section: Phosphorusmentioning

confidence: 99%