Considering the "limited" thinking of water-soluble fertilizers

The integration of water and fertilizer technology has been widely promoted in China due to its outstanding advantages of “work-saving, water-saving, fertilizer-saving, pesticide-saving, high-efficiency, environmental protection, high-yield, and high-quality”. The National Development Plan for Modern Agriculture (2011-2015) issued by the State Council will promote the application of water and fertilizer integration technologies as an important task for strengthening agricultural science and technology support. In the spring of 2013, the General Office of the Ministry of Agriculture issued the “Water and Fertilizer Integration Technical Guiding Opinions”. It is required that by 2015, the total area for the promotion of water and fertilizer integration technology should reach 80 million mu or more, and the newly promoted area should be more than 50 million mu, achieving more than 50% water saving. , Fertilizer 30%, grain crops increase production by 20%, and economic crops increase by more than 600 yuan per mu. With the popularization of water and fertilizer integration technology, water-soluble fertilizers for the supporting products of this technology have also ushered in the spring of development.

With the release of policies, the market potential of water soluble fertilizers has gradually emerged. However, some aspects of the water-soluble fertilizer industry have not been straightened out. For example, unreasonable standards, misunderstandings, and biased policies have limited the rapid development of water-soluble fertilizers. Recently, Professor Zhang Chenglin, Director of Crop Nutrition and Fertilization Research Department of South China Agricultural University, combed out some important problems and misunderstandings in the development of the water-soluble fertilizer industry, and proposed that the healthy development of the water-soluble fertilizer industry needs various cooperation and support.

Misunderstanding: The concept of “a chlorine crop” shields the fertilizer

Professor Zhang Chenglin believes that there are many misunderstandings in the development of water soluble fertilizer industry. “The misconception and understanding of chlorine-containing fertilizers has limited the application of these raw materials and delayed the development of the industry.” Zhang Chenglin Yan Zheng pointed out that many crops such as potatoes, grapes, oranges, sugarcane, alfalfa, watermelon and berries are considered It is a so-called "crop crop", which is caused by mistakes in translation. Chlorine sensitive crop was translated as "a chlorine-inhibiting crop" and Boron sensitive crop was translated as a "boron-sensitive crop." The same sentence, the translation is completely different.

Zhang Chenglin said, "The Xinhua Dictionary tells us that 'bogey' means 'prohibit, taboo, avoid.' The literal meaning of the 'chlorinated crop' is that crops cannot contain chlorine and cannot use chlorine-containing fertilizers. This is completely wrong. According to the basic theory of plant nutrition, chlorine is an essential trace element of plants and is an element of osmotic adjustment of cells. From the standpoint of the content in plants, chlorine has reached the level of medium to large elements. At such high levels, the crop normally grows. Therefore, there is no "crop crop" in nature. Potassium chloride is used in various crops in Israel's fields. Only crops grown in the greenhouse generally use cesium or potassium. The reason is not that chlorine is a toxic problem. The main concern is the salt damage caused by chlorine. In Daejeon, there is water rinsing, so I don't have to worry about the chlorine salt problem.

In fact, various chemical fertilizers are sources of salt damage in over-application or unbalanced applications. It is not only chlorine that causes salt. So the correct name should be "chlorine-sensitive crops." The meaning of the word “sensitive” is “prudent use”, meaning that unreasonable use may have a negative effect, and attention must be paid to correct usage. This does not mean that this element is harmful to crops and must be prohibited from being used.

Chlorine-containing fertilizers have outstanding advantages, such as fast dissolution, full water solubility, low price, and easy elution of chlorine. If this misconception can be corrected, chlorine-containing fertilizers can be used as basic raw materials for water-soluble fertilizers. It can be said that the problem of chlorine is a prominent issue that plagues the water-soluble fertilizer industry. Chlorine is currently in a state of "demonization." Many dealers and farmers talk about chlorine change. Zhang Chenglin told reporters that experts such as Mao Zhiji and Li Jiakang proposed the concept of “crop soil chlorine capacity” instead of the absolute “chlorinated chlorine” and “hi chloride” in the past 20 years. "The best way to judge whether a soil can be fertilized with chlorine is to determine the saturated solution conductivity and chlorine content of the soil. Then use the crop to determine the amount, rather than just consider the fertilizer containing no chlorine." Unfortunately, this A scientific opinion has not been applied in practice.

As a water-soluble fertilizer researcher, Zhang Chenglin explained the selection criteria for high-quality raw materials for water-soluble fertilizers. "To develop water-soluble fertilizers, potassium chloride is an important basic raw material. In fact, potassium chloride is widely used in the water-soluble fertilizer raw materials in developed countries." In low-concentration liquid fertilizers, ammonium chloride can also be used. Nitrogen source. Although agricultural potassium is a good source of potassium, it is not suitable for water-soluble fertilizer formulations due to its slow dissolution. The water-soluble **potassium is expensive and increases formulation costs. In areas where irrigation water hardness is high, the application of **potassium using a drip irrigation system may result in precipitation of **calcium, leading to clogging of the dripper.

“China’s misunderstanding of chlorine-containing fertilizers has led companies to produce large quantities of potassium-based compound fertilizers. This spring, **potassium is becoming a torreya, and prices are soaring that it is difficult to obtain a single supply. In fact, many crops and regions There is no need to use **potassium or kalium-type compound fertilizers at all.” The consequences of doing so are the waste of resources and the increase in the burden on growers. Excessive application of potassium may lead to soil acidification.

The confusion of management: delaying the development of the industry

At the management stage, it is faced with the mistaken definition of water soluble fertilizer. Zhang Chenglin believes that the water-soluble fertilizers currently being discussed cannot refer to water-soluble fertilizers such as urea and hydrazine (these fertilizers already have standards). In fact, they are talking about “water-soluble compound fertilizers.” If this name is called, it can be Differentiating water-soluble compound fertilizers from common compound fertilizers can also include various nutrient elements. Usually a large number of elements generally only refers to nitrogen, phosphorus, and potassium, but the current standard (NY1107-2010) requires trace elements to reach 0.2% to 3.0% or medium-sized elements to reach 1%, which is inconsistent with the name of "a large number of elements in water-soluble fertilizers."

“I think that in the current situation in China, water-soluble fertilizers mainly refer to 'water-soluble compound fertilizers' so that calcium and magnesium* trace elements can be included. Water-soluble compound fertilizers are only part of the compound fertilizers, which emphasizes The solubility and dissolution rate of fertilizers can be defined by the index of insoluble matter in water, it is clear that the finer the irrigation, the less water insolubles in the fertilizer, but the specific water insoluble content is appropriate It is difficult to give a specific value in relation to irrigation mode, filtration method, fertilizer pre-treatment mode, planting area, and automation degree. It is best to give this task to the user or the company and let them according to the actual situation and market. It is necessary to produce fertilizers with different water-insoluble content.

Water-soluble fertilizers are currently registered at the National Fertilizer Quality Supervision and Inspection Center. The registration of water-soluble fertilizers is much more complex than compound fertilizers, and it takes 3 years to get an official registration certificate. The "frustration" of registration has also seriously affected the development of water-soluble fertilizers in China. Zhang Chenglin believes that "water-soluble compound fertilizers" are a kind of compound fertilizers, rather than special fertilizers, and they should be registered as compound fertilizers. In order to meet the standards, some companies suffer from the stringent requirements of the current water-soluble fertilizer standards, and helplessly granulate the water-soluble fertilizers and take the path of water-soluble compound fertilizers.

If it is acknowledged that "water-soluble compound fertilizers" are part of compound fertilizers, registration procedures will be greatly simplified. Exemption from field fertilizer trials, toxicity tests, renewal of registration and other links will save companies time and money for registration.

The scientific nature of the standard influences the authority and normativeness of the standard. Zhang Chenglin pointed out: "The industry standards need to be improved." Taking the macroelement water-soluble fertilizer standard as an example, its nutrient content of 500 g/L or more is difficult to achieve for liquid water-soluble fertilizer products. Liquid fertilizers have to overcome the environmental conditions' impact on their stability, such as crystallization, flocculation, delamination, agglomeration, flatulence, etc., and have high technical requirements. For liquid fertilizers, the higher the N, P and K total nutrient contents, the smaller the room for the proportion of nitrogen, phosphorus and potassium elements to be adjusted. "If you want to produce 500g/L of liquid fertilizer products, then there are only a few nitrogen, phosphorus, potassium ratios, making the space for the regulatory formula very limited, and severely limiting the development of multi-functional liquid fertilizers. Zhang Chenglin suggested that foreign liquids should be consulted." In the water-soluble fertilizer industry standard, the total NPK content of almost all liquid liquid fertilizers is less than 30%, which is about 400g/L.The nutrient content of suspended fertilizers is relatively high, ranging from 400-600g/L. The standard of fertilizer is not modified, and the development of liquid fertilizer in China is hopeless.

In solid water-soluble fertilizer products, the sum of a large number of elements is specified to be greater than 50%, and only high-content products can be produced. The standard of compound fertilizers stipulates three ranges of low, medium and high concentrations. Why can the water-soluble compound fertilizers fail to produce low-to-medium content products? In fact, the market needs a variety of nutrient content of water-soluble fertilizer products.

It is more widely concerned that the industry standards are too restrictive for heavy metals and toxic elements, which is not conducive to the development of water-soluble fertilizers.

In NY1110-2010, the heavy metal limits are too stringent, and there are limitations on the selection of raw materials. Many water-soluble fertilizer materials need to use feed-grade or food-grade specifications to meet the heavy metal limit standards, making raw material costs substantially higher, and even raw materials that meet the standards cannot be found. In particular, phosphate fertilizer raw materials. The national standard (GB/T 23349-2009) of "ecological indicators of arsenic, cadmium, lead, chromium, and mercury in fertilizers" released in 2009 is quite reasonable. Unfortunately, the national standard is not used in the registration of water-soluble fertilizer but the industry standard is adopted. . The proportion of water-soluble fertilizers is currently very small. It is unfair to apply such stringent heavy metal limit requirements to single-phase water-soluble fertilizers and adopt other standards or requirements for other fertilizers.

Water-soluble fertilizers are mainly blended and do not require granulation. Most of liquid fertilizers use liquid raw materials and are more energy-efficient and environmentally friendly. They should be encouraged and supported by policies. More crucially, there is a policy bias in fertilizer management. Organic fertilizers and granular compound fertilizers can enjoy subsidies or benefits such as transportation, taxation, and energy, while water-soluble compound fertilizers do not. At the same time, the government can subsidize irrigation equipment, but the supporting water-soluble fertilizer is not subsidized. Since the water-soluble fertilizer is used for diluting water, it greatly promotes the absorption of nutrients, and the fertilizer utilization rate is obviously higher than that of the granular fertilizer applied. It should enjoy subsidies and even more subsidies. Unreasonable standards and subsidy policies are important factors limiting the development of water-soluble fertilizers in China.