OBJECTIVE FORESTRY

Detailed explanation-1: -Nutrients are lost when the pH of the soil changes due to the use of acidic or basic fertilizers. Extreme pH values result in a deficiency of nutrients in the soil. Very low pH decreases the availability of trace elements while very high pH decreases the presence of major elements in the soil.

Detailed explanation-2: -In all agricultural systems, nutrients are removed over time in harvested products, such as grain. Off-site losses of nutrients can also occur through soil erosion, runoff, leaching and burning of crop residues.

Detailed explanation-3: -Processes affecting food nutrient content. A variety of things can happen during the growing, harvesting, storage and preparing of food that can affect its nutritional content. Processes that expose foods to high levels of heat, light or oxygen cause the greatest nutrient loss.

Detailed explanation-4: -Losing topsoil to erosion contributes to a loss of inherent soil fertility levels of nitrogen, P, K, and thus to a decline in potential crop yield. The addition of manure and fertilizer can supply needed crop nutrients and help offset some loss of inherent fertility caused by soil erosion.

Detailed explanation-5: -Soil degradation describes what happens when the quality of soil declines and diminishes its capacity to support animals and plants. Soil can lose certain physical, chemical or biological qualities that underpin the web of life within it. Soil erosion is a part of soil degradation.