NUTRIENT MANAGEMENT

Soil’s productive capacity depends on the nutrient content that is available to the crop. Natural amendments to soil have been used for centuries: ash, manure, crop residue, and seaweed. However, the most productive balance of nutrients often was not achieved.

Even if the optimum amount of one nutrient is met, other nutrients may be in excess supply and leach into the environment. Improvements in chemical fertilizer technologies have enhanced farmers’ ability to increase production in developed and developing countries alike.  

Increased fertilizer use accounted for one-third of the growth in world cereal production in the 1970s and 1980s. Among developing regions, per-hectare fertilizer consumption increased most rapidly in land-scarce areas (such as in Asia) and most slowly in Africa.

Excess fertilizer components that were transported to the environment caused concern and led to research on better nutrient management practices. Knowledge about soil chemistry and structure was used to design systems to sustain the productivity of the soil while reducing nutrient losses to the environment.

Technologies to test soil and plant tissue nutrient content have been improved to give farmers timely information that can be used in making decisions.

Several nutrient management practices have been designed to help farmers manage fertilizer use more efficiently while obtaining desired crop yields:-

N-Testing– Soil and plant tissue nitrogen tests used to estimate the residual nitrogen available for plant use in determining fertilizer needs.

Split Nitrogen Applications– The application of half or less of the required amount of nitrogen for crop production at or before planting, with the remainder applied after emergence.

Nitrogen inhibitors can also be used to release nitrates later in the growing season to meet plant nutrient needs.

Micro nutrients– Applied to the field either alone or mixed in bulk blended fertilizer, micro nutrients are essential to plant nutrition but are needed in relatively small amounts.

Legumes in Rotation– Nitrogen-fixing crops (soybeans or alfalfa) are grown in rotation with other crops to improve soil fertility.

Manure– Animal wastes are applied to the field as a source of nutrient replacement.

Root Zone Application– There are several fertilizer application methods that ensure that the nutrients are readily accessible to the plant.

Banded, side-dressed, and injected applications are used in contrast to broadcast methods.

Chemigation is used in conjunction with irrigation.