Demand for Agricultural Products and Plant Nutrients

Soil nutrients removed in farm products must be-re-plenished or the soil becomes impoverished of those nutrients, and plant growth and production from succeeding crops is decreased. From the very beginning of sedentary agriculture, farmers have recognized the basic problem of nutrient depletion. On all continents slash 

Agriculture is commonly perceived to have functioned well before World War 11 without commercial fertilizers however, this was not the case. Farming was inefficient because large segments of the population had to be involved to produce enough food the systems were not 

If soils are to be cultivated for crop production, other conditions must be present that are conducive to plant growth, i.e., a favorable climate, adequate water and rooting depth, absence of excessive flooding or seawater intrusions, favorable terrain, and sufficient cultivat-able area. AraUe or cultivatable land, therefore, consists of only about 24% of the earth s land surface. Another 27% is suitable only for grazing, and 47% of the earth s land surface will not support any agricultural activity [3], 

In a natural state, the availability of nutrients in soils depends on the nutrient contents of the parent materials (the rocks or naturally imported materials) and on processes that degrade the minerak to make the nutrients available to plants, recycle nutrients between the soil and vegetation, and remove them from the soil-plant system. The processes that form s , particularly weathering of rocks to smaller particles, break down the mineral structures thereby, their contained nutrients are released to soil solution and made available for plant 

Productivity of soils is quite different from soil fertility. If a soil is to be productive for crop production, it must have a suitable climate, sufficient but not excessive water-supplying ability, and available plant nutrients for crop growth. A droughty soil may be fertile (contain nutrients) but not productive however, it could become productive 

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