Pertanyaan

The Effects of Acids Soil Soils with a pH of less than 7.0 are acids. The lower the pH, the more acids the soil. When soil pH falls below 5.5, plant growtg is affected. Drop fields decrease, reducing productivity. Soils provide water and nutrients for plant growthand development. Essential plant nutrients included phosphorus, nitrogen, potassium, and sulfur. Plants require other elements such as molybdenum, in smaller quantities. Some elements e.g. alluminium and manganese, are toxic to plants. Nutrients become available to plants when they are dissolved in water. Plants are not able to take up phosphorus, nitrate, potassium, and sulfate lions in solution. The solubility of nutrients changes with pH In acids soils, (low pH), molybdenum become less soluble and aluminium becomes more soluble. Therefore, plant growtg may be affected by either a deficiency of molybdenum or too much aluminium. Both drop and pasture plants are affected by acids soils. There may be a range of symptomps. Crops and pastures may be poorly established resulting in patchy an uneven growtg. Plant leaves may go yellow and die at the tips. The root system of the plant may be stunted. Drop may field less. Plant vary in their sensitivity to low pH. Canola and lucerne are very sensitive to acids soils so they do not grow well. Lupins and triticale are tolerant to soils of low pH so they still perform well. Land can become unproductive if acids soil is left untreated. Incorporating lime into the soil raises the pH. Therefore, living soil can reverse the effects of acids soil on plants and return a haddock to productivity. "Therefore, plant growth may be affected by either a deficiency of molybdenum or too much aluminium." (Paragraph 4) The underlined word is closest in meaning to .....