Water-soluble fertilizer is actually formula fertilizer. According to different crops, different soils and different water quality, different formulas are prepared to meet the nutritional needs of crops to the greatest extent, improve the utilization rate of fertilizers and reduce waste. Therefore, the formula is the key to distinguish the quality of water-soluble fertilizer. Look at the ratio of nitrogen, phosphorus and potassium. For example, the commonly used high-potassium formula, according to the nutritional requirements of general crops at fruit-setting stage, the ratio of nitrogen: phosphorus: potassium is controlled at 2: 1: 4, and the effect will be very different with different ratios. You can look at the products with good performance on the market, such as the water-soluble fertilizer of the old stationmaster of Mantianxing and the water-soluble fertilizer of Haifa Poly, which all follow this ratio. Then see if trace elements are incomplete and the proportion is reasonable. A good water-soluble fertilizer must contain all six trace elements and have a scientific proportion, because there is a problem of antagonism and synergy among various nutrient elements, not the high content of one or more elements, but the scientific and reasonable proportion. There are many water-soluble fertilizers with high content of individual trace elements such as boron and iron in the domestic market, but the effect is not good and the absorption and utilization rate is not high.
Second, look at the content.
Good water-soluble fertilizers use industrial and even food-grade raw materials. For example, Israel's Lamla special fertilizer has a high purity and will not add any filler, so the content is relatively high. 65,438+000% of the nutrients can be absorbed and utilized by crops, and the contents of nitrogen, phosphorus and potassium can generally reach 60% or even higher. Other fertilizers with poor water solubility are generally low in content. Every time the content is less, the cost is different, and the price of fertilizer is also different. At the same time, low-content water-soluble fertilizers have lower requirements on raw materials and production technology, and generally use agricultural-grade raw materials, which contain more impurities and fillers. These impurities and fillers not only have no benefit to soil and crops, but also cause damage to the environment.
Third, look at water solubility.
Plants have no teeth and can't eat fertilizer, so they can only drink fertilizer. Therefore, only fertilizers that are completely soluble in water can be absorbed and utilized by crops. To identify the water solubility of water-soluble fertilizer, we only need to dissolve the fertilizer in clear water to see if the solution is clear and transparent. If the color of fertilizer is the same as that of water, the water solubility will be very good. If the solution is turbid or even precipitated, the water solubility is poor, so it can't be used in drip irrigation system, and fertilizer will be wasted more.
Fourth, the smell.
Crops like eating delicious food as much as people, and fertilizer crops with pungent smell or other odors don't like it. Therefore, the quality of water-soluble fertilizer can be identified by smell. Good water-soluble fertilizers are made of high-purity raw materials, and have no taste or weak fragrance. However, the odorous fertilizer either contains hormones or contains too many harmful substances. This fertilizer takes effect quickly, but it is not beneficial to the disease resistance and sustainable yield and quality of crops.
Fifth, make a comparison.
After the preliminary screening of water-soluble fertilizer by the above simple methods, the field comparison is carried out, and the water-soluble fertilizer is determined by the actual application effect. A good fertilizer will not take effect too soon, because nutrients have a process of absorption and transformation. A good water-soluble fertilizer will have obvious differences in plant growth, crop quality, crop yield and disease resistance after being used for two or three times. The more times it is used, the greater the difference.