as the saying goes:
the people take food as their heaven and the earth as their foundation.
without soil, we have no food.
without the health of soil, there is no healthy food;
without the health of food, there will be no healthy body for us.
without a healthy body, no matter how much wealth you have, it's only a zero!!!
1. the data shows that the utilization rate of chemical fertilizer in china is not high. the utilization rate of nitrogen fertilizer in the current season is only 35%, while that in greenhouse is as low as 10%.
according to the information of the food and agriculture organization of the united nations, from 1980 to 2002, china's fertilizer use increased by 61%, while its food production increased by only 31%.
the low utilization rate of fertilizer has always been a problem in china's agricultural fertilization. lu rukun and other researchers found that the utilization rate of agricultural phosphate fertilizer in china was only 10% - 25%.
zhu zhaoliang, academician of the soil research institute of the chinese academy of sciences, pointed out that the amount of chemical fertilizer used in china is 55 times that 40 years ago. the author's estimate is that we need to consume 1 jin of fertilizer for every 9 jin of grain we produce.
if the ration of grain per person is calculated as 30 jin / month, then each person consumes 40 jin of fertilizer every year because of the production of grain. therefore, we have to "eat" chemical fertilizer. we, especially our descendants, have grown up by "eating" chemical fertilizer.
2. as a catalyst of agricultural production, chemical fertilizer and pesticide not only bring high yield to crops, but also bring some negative effects to agriculture.
the agricultural products produced by invisible soil pollution have been put on people's table, such as "melon is not sweet, vegetable is not fragrant, fruit is tasteless, toxic cowpea" and other issues in front of people!
therefore, it is imperative to solve the problem of soil pollution. compared with visible pollution such as water blackening and sky graying, soil pollution has certain concealment. because of this, soil pollution has been ignored for many years.
3. excessive application of chemical fertilizer leads to hardening of soil, aggravation of acidification and serious salinization, and leads to extremely low utilization rate of fertilizer, pollution of groundwater, poor growth of crops, degradation of quality and low efficiency.
therefore, the ministry of agriculture of the people's republic of china has put forward the goal of zero growth of fertilizer application under the condition of no reduction of crop yield.
three hazards of excessive application of chemical fertilizer
i. weakening crop production capacity
like people, eating too much is not only bad for growth,
and it's not good for your health. according to professor zhang fosuo, head of the national expert group on soil testing and formula fertilization and dean of the school of resources and environment of china agricultural university, there are two main results of the damage caused by excessive fertilization to crops: one is prone to lodging, once lodging occurs, it will inevitably lead to the reduction of grain production; the other is prone to diseases and insect pests, and excessive application of nitrogen fertilizer will weaken the plant's resistance to diseases and insect pests, and make it vulnerable to diseases and insect pests infection.
ii. increase environmental pollution
the direct consequence of the decrease of fertilizer utilization efficiency is the pollution of farmland environment. since 1994, experts from agricultural university of china have surveyed more than 600 sites in 20 counties in beijing, shandong, shaanxi and other places. the results show that 20% of the groundwater nitrate content in the intensive high-fertilizer areas in the north exceeds the national limit standard of nitrate content in drinking water (89 mg / l of nitrate content), 45% of the groundwater nitrate content exceeds the drinking water in the major developed countries relevant limit indicators. in addition, the chemical fertilizer contains heavy metals, acid roots and other substances, and its impact on the environment is multifaceted.
iii. waste a lot of scarce resources
4. long term application of chemical fertilizer is easy to cause damage to soil structure and physical and chemical properties
(1) increase heavy metals and toxic elements in soil
the main heavy metals causing pollution are zn, cu, co and cr. the results show that the long-term application of chemical fertilizer will lead to the enrichment of heavy metal elements in acid soil, slightly acid soil and calcareous soil. for example, long-term application of ammonium nitrate, ammonium phosphate and compound fertilizer can make the content of as in soil reach 50-60 mg / kg.
(2) increase soil acid
long term application of chemical fertilizer accelerates soil acidification. on the one hand, it is related to the nitration of nitrogen in soil to produce nitrate. first, ammonium is transformed into nitrite, then nitrite is transformed into nitrate, forming h , leading to soil acidification. on the other hand, some physiological acid fertilizers, such as calcium phosphate, ammonium sulfate and ammonium chloride, increase h in the soil after the plant absorbs nutrient ions in the fertilizer. the acidification of many cultivated soil is related to the long-term application of physiological fertilizer. at the same time, the long-term application of kcl can make the neutral soil with low buffer capacity become acid gradually due to the physiological acid effect caused by crop selective absorption.
(3) lead to soil nutrient imbalance
from the aspects of soil nutrient balance and sustainable utilization, it can be clearly seen that the high concentration of chemical fertilizer not only brings about the improvement of economic benefits, but also brings about new problems, that is, the use of a large number of high concentration fertilizers increases crop yield, and also increases the depletion of trace elements in the soil.
(4) damage to soil structure
a large amount of nitrogen fertilizer, especially a large amount of ammonium fertilizer, is used for a long time. after ammonium ion enters into the soil, hydrogen ion is released in the process of nitrification, which makes the soil acidify gradually. the ammonium ion can replace the calcium ion which plays a role of binding on the soil colloidal particles, causing the dispersion of soil particles, thus destroying the soil aggregate structure, causing serious hardening of the soil, and ultimately losing the value of agricultural cultivation.
(5) in view of the above phenomena, some scholars think that chemical fertilizer can improve the fertility of cultivated land in a short time, but the unreasonable use in a long time will cause adverse effects on the health of the land. according to this, some people turn fertilizer into "land opium". the farmers are addicted to it, and the cultivated land will also be addicted to it. but after the cultivated land degenerates, its high productivity will be difficult to maintain. just like that, people can get nutrition from blood vessels, but they can't do it for a long time. a lot of nutrition must be mainly absorbed by the stomach and intestines. for cultivated land, rich organic fertilizer is the key. plants must take advantage of soil microorganisms and soil animals to absorb the mineral elements they need, instead of "running blood vessels" frequently.
cctv: banning the sale of chemical fertilizers and pesticides has been implemented, and china's agriculture is facing a major transformation
of course, banning the use of chemical fertilizers and pesticides is not suitable for china's agricultural market, but the less chemical fertilizer is undoubtedly the direction of agricultural development in the future, so how should we deal with the harm of excessive chemical fertilizer at present.
1. in the field of crop fertilization, we should change the traditional way of fertilization from blind fertilization to optimized formula fertilization.
2. to strengthen and improve the technical measures in the formula fertilization. in the process of formula fertilization, it is necessary to enrich and improve the fertilization parameters, such as nutrient absorption per unit yield, nutrient utilization rate of soil, fertilizer utilization rate, etc., which are also changing with the change of production conditions. on the basis of the original test of soil and plant nutrient demand, new environmental condition analysis projects (such as water quality, content of harmful substances in soil, fertilizer and pesticide pollution, etc.) are added continuously enrich and improve the fertilization parameters and optimize the formula fertilization.
3. increase the proportion of organic fertilizer in formula fertilization. organic fertilizer has the characteristics of complete nutrient, long fertilizer effect and no pollution. high efficiency organic fertilizer can increase the content of soil organic matter, improve the ability of soil water storage and fertilizer conservation, improve the physical and chemical properties and aggregate structure of soil, and improve the quality of agricultural products.
4. the utilization of micro fertilizer and bio fertilizer should be increased. micro fertilizer can balance the nutrients needed by crops, while bio fertilizer can secrete physiological active substances through the microorganisms contained in itself, which can fix nitrogen, remove phosphorus, remove potassium and decompose other micro nutrients in the soil, improve the utilization rate of chemical fertilizer and organic fertilizer, improve the physical and chemical properties of the soil, enable the soil to supply various nutrients for crops, promote crop growth, improve crop yield and products at the same time, it can decompose the harmful chemicals in the soil and kill the harmful bacteria, reduce the residue of chemical fertilizer and pesticide and harmful bacteria.
5. we should coordinate the relationship between a large number of elements and trace elements. in formula fertilization, people often pay attention to the use of nitrogen, phosphorus, potassium and other elements, but ignore the application of microelement fertilizer. adding microelements or spraying microelements growth agent and compound biological growth agent can balance the supply of nutrients, promote the rapid transformation of nutrients in the plant and reduce the accumulation of harmful substances. it is a good way to promote the disease resistance, disease prevention, increase the yield and improve the quality of crops!