At all the time, the farmland soil is an essential resource for human livelihood. 7% of arable land in the world affordable to feed 22% of the world population, which means that visible protection of arable land is the most important task. However, due to soil erosion, the decay of salinization and swamping, soil fertility and soil pollution and acidification, soil degradation with a total area of approximately 4.6 million hectares every year in China, accounting for 40% of the total land area of the country. The survey by Integrated Ministry of agriculture and the Ministry of environmental protection shows that the overall quality of cultivated land reflect 40% degradation, 30% poor, 20% pollution state. The quality of cultivated land is worrying, arable land almost fall, soil health protection is imminent.
In many aspects, the main problems of farmland soil are acidification, salinization, heavy metal pollution, element imbalance, loss of organic matter and etc.
It is understood that acidification is an important aspect of soil weathering process. The reasons of soil acidification are mainly caused precipitation and concentration of leaching result in huge loss of calcium, magnesium, potassium and other alkali base. In addition, the lack of traditional agricultural measures lead to the farmland soil nutrient imbalances and applied containing ammonium nitrogen fertilizer for a long time. These reasons leading to soil acidification, soil organic matter content decreased, buffering capacity decreased. If not timely remedy, it will make a lot of nutrients in soil by leaching, the soil becomes barren, clay, soil compaction, soil fertility decline, the crop will inhibit the root growth and the formation of Rhizopus rot dead roots no white Gentu, aluminum in the soil is released from the steady states, guide induced by aluminum elements gathered, root aluminum poisoning, death withered plants, crops and aquatic organisms, quality decline, and severe acidification also inhibits some soil microbial breeding, hindering nitrogen fixing bacteria, bacteria and actinomycete bacteria breeding, intensified soil borne diseases.
In addition, heavy metal pollution is also a major problem in the soil. Nowadays, the pollution of crops need to raise awareness on the south arsenic and the north arsenic. The main sources of heavy metal pollution of wet and dry atmospheric deposition (dust, precipitation), agricultural materials irrational use, solid waste, sewage and irrigation water heavy metal band, and it brings immeasurable risks. For instance, it will not only weaken and inhibit soil nitrification and ammonification bacteria activity, affecting the supply of nitrogen, but also it cause plants physiological function disorder and malnutrition, reducing the crop quality, effect on soil microbial activity. Through the food chain bioaccumulation, resulting in biomagnification. At present, the soil heavy metal pollution caused by frequent food safety incidents.
All the farmland soil has life, regarding the problems which require to use the improvement method on time. Improving the physical environment, soil texture, structure, porosity, moisture and temperature, crop nutrient, add organic nutrients , inorganic minerals and other ingredients. Moreover, upgrade storage capacity, improve the chemical environment, regulate acid-base degree and soil salt content, improve cation adsorption and exchange performance, control the content of toxic substances. Soil conditioning agents are needed to improve the physical, chemical and biological properties of the soil.
Soil regulator is the main function of soil improvement medicine. Soil conditioner reflected in improved soil structure, get rid of compaction and increase its permeability, adjust the soil pH and reduce the harm of saline and alkaline of the soil, supply soil nutrition, improve fertilizer utilization rate and promoting the high crop yield, quality, improve soil moisture status, inhibit harmful bacteria, remediation of contaminated soils. The soil conditioner can be divided into seven types, such as natural mineral, agricultural waste, organic fertilizer, urban and domestic waste, industrial by-products, biomass and artificial polymers. In recent years, soil conditioner industry in the active trend, the constant introduction of new materials, new technology, new products, but development also encountered a corresponding problems. Such as the considerable potential pollution risk, bring the possibility of secondary pollution, quality control system is imperfect, incomplete evaluation system, the evaluation mechanism is not in place, the product technical level is not high, process quality is not stable. At the present, market perception of soil conditioner is still in the fuzzy stage. The future product promotion level still needs to be improved. And also many problems of soil conditioner industry need to improve.
A good understanding of the role of soil conditioner can help soil to the healthy development stage as soon as possible. Amount of cultivated land in China are deficient and the quality unsatisfied is the biggest obstacle to restrict the agricultural production. Soil conditioning is one of the important measures to improve the quality of cultivated land. Thus, current situation of cultivated land provides market for the development of soil conditioner. With increasingly awareness of countries of cultivated land quality and safety, food safety and agricultural products quality, the prospects for the development of the soil conditioner will be in a good trend.
But it is worth to notice that soil repair also needs a relatively long process because it’s unlike the compound fertilizer use soon after production and income, generally require years to appear, the development of soil conditioner to strengthen the source control, heavy metals, hazardous substances must meet the requirements of the relevant standards of the state, shall not choose may farmland pollution raw materials as soil conditioners. And, to make full use of cheap natural resources, development locally, nearest application; to find the soil problem in principle. When the soil acid damage, alkali injury, salinity, fertilizer harm or materials within soil not coordinated to produce symptoms appear, it can be use soil conditioner to strengthen the tracking and evaluation, effect and harm for long-term quantitative monitoring.
In fact, today, soil conditioner industry in agricultural development has rapidly progress. Specifically, mineral source, source of organic and chemical source three soil conditioners in 2013 with an annual capacity of only 101 million tons, but now it has reached 274 million tons, which growth nearly two times less than two years. Until April 2015, the number of soil conditioner products registered totally 75. Good effects, low price, good ecological environment conditions, multifunctional composite soil conditioner are the future development directions. For fertilizer production enterprises, how to combination of fertilizer and soil conditioner to promote need to be take into considered in the future.