Showing papers in "Advances in Agronomy in 1954"

Potassium in Plant Nutrition

Abstract: Publisher Summary It is often difficult to assign specific roles to potassium within closely related physiological processes as unlike nitrogen, phosphorus, calcium, and magnesium, the potassium ion does not enter into permanent organic combinations in plants, but exists as soluble inorganic and organic salts. However, potassium is essential for various metabolic activities of living cells. A lack of sufficient potassium for normal growth causes disturbances in one or more vital plant processes resulting in the appearance of visual symptoms of disorder. By comparing certain constituents and properties of plants starved for potassium with those of normal plants, much insight has been gained regarding the influence of potassium on the physiology of plants. Potassium affects the synthesis of simple sugars and starch, translocation of carbohydrates, reduction of nitrates and synthesis of proteins, and helps in normal cell division. Potassium plays a role in the maintenance of turgor in plant cells as well as in the formation of oils and in the enhancement of disease resistance.

New Concepts of Management of Corn Belt Soils

Abstract: Publisher Summary This chapter examines the objectives underlying the new tillage and cultural practices being tested for cultivated crops in the Midwest. It also evaluates the concepts on which these objectives are based. In specific, the new tillage implements and management practices being tested in the Midwest represent a philosophy in land use and a philosophy of maximum crop production per acre of land with a minimum of soil deterioration. The philosophy is based on the concepts that high production is good for the soil, minimum tillage promotes soil tilth and conserves soil organic matter, high fertility promotes high yields and lessens the losses of soil humus, large amounts of decomposable organic matter in the soil are essential to good soil tilth and good soil physical conditions, and cover in the form of both living and trash mulches is good protection against all forms of erosion. The philosophy of maximum production with minimum soil deterioration is dependent on the assumption that adequate supplies of commercial fertilizers are available for implementation.

Requirement and Availability of Soil Water

Abstract: Publisher Summary This chapter describes the broad aspects of water requirement, the consumptive use of water in plant growth, total use of water on the farm, and the availability of water as related to the nature and distribution of plant roots and to moisture stress in the soil In planning for irrigation it often becomes essential to know about the quantity of water consumed in growing a crop and the efficiency with which water can be applied Such information is not only necessary in planning for large irrigated projects, but is also needed in planning individual farm systems or layout and in improving irrigation practices It is noted that consumptive use varies with soil moisture level The higher the average soil moisture level, the higher the value for consumptive use The effect of soil moisture levels on the efficiency of water use by plants are conditioned by the influence of moisture levels on crop growth

Seed-Flax Improvement

Abstract: Publisher Summary The flax plant essentially produces two valuable products, flaxseed and fiber. Seed-flax or linseed types are grown principally for their seed. Fiber-flax types, on the other hand, are grown for the high-quality fibers from which linen yarn is spun. In specific, flaxseed has excellent keeping qualities when stored in a relatively dry state. In context to grain respiration and under aerobic conditions, respiration involves the oxidation of organic constituents of the seed, particularly carbohydrates and fats, with the formation of carbon dioxide and water as the ultimate end products. The total respiration of a particular lot of grain free from insects can arise from the biological processes of the seeds themselves and of the microorganisms that are invariably present on the surface of grain and under the seed coat. The rates at which chemical changes occur in stored grain are largely determined by the moisture content, the storage temperature, the oxygen supply, and the degree of soundness of the grain.

A Pattern for International Collaboration in Agriculture

Abstract: Publisher Summary This chapter highlights foreign technical aid programs should be established only after a clearly demonstrated interest and enthusiasm is noticed on the part of the recipient government and the individuals most directly concerned. A thorough preliminary survey of agricultural potentialities, local personnel resources, and economic possibilities result in the conclusion that a useful operation can be initiated. The staff members assigned to foreign technical aid programs should be selected with extreme care and chosen on the basis of qualities of leadership, character, and personality in addition to unquestioned attainment in their special fields of agricultural science. It is observed that in any agricultural improvement program it is often desirable to begin with those problems which are of major significance to the population of the country concerned, and these should be selected in agreement with the appropriate persons in the country. Projects should be strategically located, started on a modest scale in an effort to minimize errors, and permitted to grow only as rapidly as accomplishment dictates.

Progress in Range Improvement

Abstract: Publisher Summary This chapter presents developments in the field of range management, emphasizing its importance, and showing progress of research. Management of ranges or pastures refers to the manner in which livestock is handled on grazing lands. In specific, it can be defined as the science and art of planning and directing range use so as to obtain maximum livestock production consistent with conservation of range resources. It is observed that proper range management assumes many specific aspects. It includes adequate development and wise use of improved range lands. It also requires revegetation of depleted areas, establishment of sown or reseeded pastures, and construction of adequate facilities for retaining, spreading, and impounding water. It provides control of troublesome plant, insect, and animal pests and fire. Range management requires appropriate attention to all phases of animal husbandry, including the best class of livestock during proper seasons and the integrated use of growing and harvested feeds as well as minerals and other supplements.

Crop Adaptation and Climate

Abstract: Publisher Summary Crop adaptation essentially refers to the relationships between the principal environmental factors and the growth response of crop plants. Largely ecological in character, this branch of plant science can be considered a synthesis of important elements of geography, physiology, genetics, meteorology, and agronomy. It is noted that because of its direct relationship to food production, the adaptation of crops is of vital concern to all. High on the list of important relationships are those dealing with the climatic elements, precipitation, temperature, and light, as they relate to the adaptation of old varieties of crops and to the development of new ones. This chapter reviews the contributions to the development of principles on which these relationships are based.

Technological Aspects of Trace Element Usage

Abstract: Publisher Summary The essentiality of trace elements for optimum growth and yield of plants is well established The metallurgical industry has recovered trace element metals from the ores and converted them into salts suitable for agricultural purposes It is necessary to develop special processes for the removal of such toxic elements namely arsenic, selenium, and tellurium The use of trace element salts has become very economical because of the large-scale production of trace element salts In using trace element salts for correcting deficiencies, the acid radicals should be taken into consideration Neutral salts, usually basic sulfates, are found highly suitable for direct foliage treatment, since they are compatible with most insecticidal and fungicidal materials A standard formula for trace element mixtures with major fertilizers is developed with the idea of furnishing nutrient elements in a balanced ratio The fertilizer industry is called upon to provide forms of trace element salts suited for meeting deficiencies