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A maize crop yielding 6–9 tonnes of grain per hectare (2.5 acres) requires 31–50 kilograms (68–110 lb) of phosphate fertilizer to be applied; soybean crops require about half, 20–25 kg per hectare. [21] Yara International is the world's largest producer of nitrogen-based fertilizers. [22]
A 15-ton crop of onions uses up to 19 lb of sulfur and 4 tons of alfalfa uses 15 lb per acre. Sulfur abundance varies with depth. In a sample of soils in Ohio, United States, the sulfur abundance varied with depths, 0–6 inches, 6–12 inches, 12–18 inches, 18–24 inches in the amounts: 1056, 830, 686, 528 lb per acre respectively. [98]
The N value in NPK labels represents actual percentage of nitrogen element by weight, so it does not need to be converted. So, for example, an 18−51−20 fertilizer contains by weight 18% elemental nitrogen, 0.436 × 51 = 22% elemental phosphorus, and; 0.83 × 20 = 17% elemental potassium.
In agriculture, the yield is a measurement of the amount of a crop grown, or product such as wool, meat or milk produced, per unit area of land. The seed ratio is another way of calculating yields. Innovations, such as the use of fertilizer, the creation of better farming tools, new methods of farming and improved crop varieties, have improved ...
Nitrogen and potassium are also needed in substantial amounts. For this reason these three elements are always identified on a commercial fertilizer analysis. For example, a 10-10-15 fertilizer has 10 percent nitrogen, 10 percent available phosphorus (P 2 O 5) and 15 percent water-soluble potassium (K 2 O). Sulfur is the fourth element that may ...
Food production per capita since 1961 Grain silos Rice plantation in Thailand Cambodians planting rice, 2004. Agricultural productivity is measured as the ratio of agricultural outputs to inputs. [1] While individual products are usually measured by weight, which is known as crop yield, varying products make measuring overall agricultural ...
Micronutrients are present in plant tissue in quantities measured in parts per million, ranging from 0.1 [3] to 200 ppm, or less than 0.02% dry weight. [4] Most soil conditions across the world can provide plants adapted to that climate and soil with sufficient nutrition for a complete life cycle, without the addition of nutrients as fertilizer.
Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces. [1] Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the surrounding soil water. [2]