for a long time, in the concept of many farmers, the more fertilizer is applied, the faster the crops will grow and the better the harvest will be. in fact, it is not. sometimes it will backfire. excessive use of chemical fertilizers can also cause a lot of harm. beijing aohe soil test today with you to specifically analyze the role of a large number of elements of nitrogen, phosphorus and potassium fertilizer and excessive use will produce what harm.
the function and harm of nitrogen
1. the role of nitrogen
the plant is short of nitrogen, the color of green is light, the color of old leaves at the base is yellow, and brown after drying! small fruit, less fruit, hard peel, must be fruit trees lack of nitrogen! that is, it can make up chlorophyll and nucleotide!
role of nitrogen: nitrogen fertilizer is a kind of chemical fertilizer required in agricultural production, which plays an important role in improving crop yield and quality of agricultural products. it is the component of amino acid, protein and chlorophyll, which plays a decisive role in photosynthesis. nitrogen can also help crop colonization. application of nitrogen fertilizer can not only improve the yield of agricultural products, but also improve the quality of agricultural products.
2. harm of excessive nitrogen: hindering crop growth and producing toxic nitrite
nitrogen fertilizer is a kind of chemical fertilizer needed in agricultural production. it plays an important role in improving crop yield and quality of agricultural products. however, if the supply is too much, the crops will become green and late maturing, and the growth period will be prolonged. the main performance is that the cell wall is thin, the plant is soft, and vulnerable to mechanical damage (lodging) and diseases (such as barley brown rust, wheat scab, rice brown spot).
the function and harm of phosphorus
1. the role of phosphorus
the lack of phosphorus in crops is very troublesome. the plants are dark green, and red and purple also appear. after drying, the color is green and dark, and the stem node is also thin and short! the color of the base leaves turns yellow, the flowering time is a few days later, and the seeds become small and not full!
the role of phosphorus: it can not only increase the yield of crops, but also improve the quality of crops. it can accelerate the growth of cereal crops, promote the large and full grains, promote the flowering and fruiting of vegetables, fruits, cotton and other fruit trees, and improve the fruit bearing rate; increase the sugar content of fruits and sugarcane, and also increase the oil content of rapeseed.
phosphorus is an important component of plant nucleus. it plays an important role in cell division, differentiation and development of plant organs and tissues, especially flowering and fruiting. it is an indispensable element in physiological and metabolic activities of plants. phosphorus is mainly concentrated in the seeds of plants, and the seeds store more phosphorus, which is conducive to the healthy growth of seedlings at the initial stage. phosphorus also has a good effect on improving the resistance to insecticides, cold resistance and drought resistance of plants. phosphorus also promoted root development, especially lateral root and fine root.
2. the harm of excessive phosphorus: causing the soil sulfur deficient crops to lose green and yellow
the application of common superphosphate can not only provide phosphorus nutrition for crops, but also make crops obtain sulfur nutrition. however, because of its low phosphorus content and many by-products, the heavy superphosphate is commonly used in production. there are no impurities such as calcium sulfate in ssp, so that the content of phosphorus is greatly increased and becomes a high concentration phosphate fertilizer. therefore, the problem of sulfur deficiency will occur naturally in the application of ssp all year round.
the harm of potassium
1. the role of potassium
to make up for the lack of potassium in crops, the edges of leaves turn yellow at first, the edges of leaves burn seriously, and the veins of dicotyledons lose green, and the nutrient transport can not keep up. organic compounds do not participate in the cell liquid ionic, multiple enzyme activator, the role of the metabolic process is strong!
function: application of potassium fertilizer can promote photosynthesis of crops, promote crop fruiting, improve cold resistance and disease resistance of crops, so as to improve agricultural yield. potassium exists in plants in the form of free potassium ions, which can promote the metabolism of carbohydrate and nitrogen, control and regulate the activities of various mineral nutrients, activate the activities of various enzymes, control the transportation of nutrients and water, and maintain the internal pressure of cells to prevent plant wilting.
2. potassium excess: affecting crop growth and destroying soil structure
potash fertilizer is a kind of potassium fertilizer for plant growth. proper application of potassium fertilizer can make grain plump, increase potato and potato tuber root, increase sugar content of fruit, increase tiller of gramineous crops such as rice and wheat, and make plant stem and root robust, not easy to lodging, and enhance drought resistance, cold resistance and disease resistance. although potassium fertilizer has many benefits, the more it is used, the better it is
① the results showed that the absorption of magnesium and calcium by crops decreased, and many diseases such as "rotten heart disease" of leafy vegetables and "bitter pox disease" of apple were caused;
② it hinders the growth of crops and causes lodging and other symptoms;
③ the results showed that the harmful metals and pathogens in some plots exceeded the standard, destroyed the nutrient structure and balance in the soil, and led to the deterioration of soil properties and water pollution;
④ it will reduce the production of crops, seriously weaken the production capacity of crops and reduce the yield.