Humidity, agricultural applications

All of the many biological transfer processes combine to determine a net surface resistance to transfer. Empirical relationships can be used to infer stomatal resistance from data on photosynthetically active radiation, water stress, temperature, atmospheric humidity and carbon dioxide levels. The resulting net surface resistance has been coupled with mathematical descriptions of aerodynamic and boundary-layer resistances in a "big leaf" model derived on the basis of agricultural and forest meteorology literature (4). At present, the big-leaf model is relatively coarse, permitting application only to areas dominated by maize, soybeans, grass, deciduous trees, and conifers. 

Insecticides are the pesticides most commonly known by the public. Insects are not only a nuisance in everyday life they pose a real danger to man, animals, crops, and the environment in general. In agriculture, insecticides are used widely to control insects in fruits, vegetables, rice, and other cereals. Other application areas are on farm animals, animal housing, and to control insects that are vectors of diseases. Mosquitoes (for malaria) and tsetse flies (for sleeping sickness) are just two examples. Control of these insects is a never-ending task, especially in hot and humid countries. 

The Ca content of soils varies widely, ordinarily ranging from about 0.07 to 3.60%. Calcium is contained in a number of soil minerals including dolomite, calcite, Ca feldspars, apatite, amphiboles and many others. Coarse-tex-tured soils in humid regions, particularly those formed from rocks low in Ca minerals, are generally low in Ca. In spite of this, Ca deficiencies in crops do not appear to be of widespread occurrence, although a number of other factors affect nutrition in low base status soils. Fertilizers are not generally manufactured specifically to provide Ca as a plant nutrient, since this element is economically supplied by periodic applications of agricultural lime, as discussed subsequently. 

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