Choose fertilizer varieties that can supply all the necessary nutrients of the crop in a balanced and synchronized manner.
The fertilizer varieties selected in the nutrient management system must ensure that all necessary nutrients can be supplied in an effective and balanced manner according to the needs of the crop throughout the growing season. When selecting fertilizer varieties (including organic fertilizer), the possibility of nutrient loss, the interaction and coexistence of different nutrients, the potential sensitivity of the crop to the fertilizer, and the non-nutrient elements contained in the fertilizer risks of. Reasonable fertilizer varieties are determined by crops, climate and soil properties, available fertilizer products, economic benefits, and fertilizer application methods.
The scientific principles to be followed when choosing a reasonable fertilizer variety include:
● Supply effective nutrients of crops.
The nutrients supplied should be water-soluble and directly usable by crops, or be easily converted into effective forms in the soil.
● Matches the physical and chemical properties of the soil.
For example, avoid applying nitrate nitrogen fertilizer in flooded soil or applying urea to high pH soil without applying urease inhibitor. Some fertilizers acidify the soil, so they can only be applied to alkaline soils, or together with lime.
● Pay attention to the interaction between different nutrient elements or fertilizer varieties.
For example, phosphorus-zinc interaction, nitrogen can improve the effectiveness of phosphorus, and the supplementary effect of chemical fertilizer on organic fertilizer.
●Pay attention to the compatibility of the mixture.
Some different fertilizer varieties or products will absorb water and accumulate when mixed together, resulting in component separation and cannot be uniformly applied to these mixed fertilizers. Similarly, granular fertilizers should avoid segregation between different products. Some liquid fertilizers will salt out at low temperatures, or chemically react with other components to form colloids or precipitates.
● Pay attention to the sensitivity of crops to certain nutrients.
Most fertilizers contain an accompanying ion that is beneficial, harmful, or neutral to certain crops. For example, the chloride ion combined with potassium ion in potassium chloride is beneficial to the growth of corn, but it can also adversely affect the quality of certain fruits and vegetables.
● Control the effects of non-nutritive elements.
For example, raw materials used in the production of fertilizers may contain some non-nutritive trace metal elements. The application amount of these elements should be kept within safe limits.