Is it okay not to use chemical fertilizer? Can organic fertilizer replace chemical fertilizer in the end? An experiment that lasted 30 years found the answer.

Is it possible to produce crops without chemical fertilizer? Can organic fertilizer replace chemical fertilizer in the end? How to replace it? How to apply fertilizer scientifically can not only achieve high yield and high quality, but also minimize environmental pressure? These hot topics that the industry has been exploring for a long time have found scientific conclusions and answers at the long-term experiment on reducing fertilizer application and increasing efficiency of chemical fertilizers and the demonstration of new fertilizers held in Dezhou, Shandong Province.

You can't do without fertilizer, even if you use too much fertilizer.

A few days ago, the reporter walked into the Yucheng Experimental Base of the Chinese Academy of Agricultural Sciences, which was founded in the 1960s. It has done long-term positioning experiments on different fertilization systems of organic fertilizer and chemical fertilizer for more than 30 years. Because of its complete design and long duration, it is praised by foreign experts as "unique in the world". Years of persistent experiments also make the results more convincing.

The reporter saw that the experimental base was divided into a number of fields with the same area, which were treated with no fertilization, major chemical fertilizer, major organic fertilizer, organic and inorganic fertilizer, high amount of chemical fertilizer, and high amount of organic fertilizer respectively. Wheat shows an obviously different scene in these fields with different fertilization treatments.

In the non-fertilizer control field, the wheat grew sparsely and dwarfed, which formed a strong contrast with the surrounding fields. "in this piece of land that has been completely free of fertilizer for many years, the yield per mu can reach no more than 200 to 300 jin, while the yield per mu can reach more than 600 kilograms. There is a big difference. If no fertilizer is applied that year, the yield will be reduced by half immediately." Zhao Bingqiang, a researcher at the Institute of Agricultural Resources and Agricultural regionalization of the Chinese Academy of Agricultural Sciences, who is in charge of the project.

You can't do without fertilizer, even if you use too much fertilizer. Many years of experiments at the base show that the output is not higher when the amount of chemical fertilizer is doubled, but the risk to the environment is greatly increased. Zhao Bingqiang pointed out that although long-term excessive application of chemical fertilizer or organic fertilizer can ensure crop high yield, high quality and soil fertility, fertilizer loss is serious, and environmental problems are prominent: the soil nitrate content of double application of chemical fertilizer is 800 mg / kg, that is, 16 times the threshold; the soil nitrate content of double application of organic fertilizer is higher than that of constant chemical fertilizer, especially the environmental risk of excessive accumulation of soil phosphorus in the long-term application of large amount of organic fertilizer.

The combination of chemical fertilizer and organic fertilizer has an excellent effect of learning from each other's strong points to make up for their weaknesses.

So, is it better to use organic fertilizer than chemical fertilizer? Long-term experiments have given a clear answer to this-in terms of environmental risk, under the condition of equal nitrogen input, the environmental problem of organic fertilizer is significantly smaller than that of chemical fertilizer. For example, the ammonia volatilization of farmland treated with organic fertilizer is 94% less than that of chemical fertilizer, and the accumulation of nitrate in soil is only 1 / 6 of that of chemical fertilizer treatment.

Organic fertilizer can improve soil fertility and soil structure, but it also has its disadvantages. Zhao Bingqiang said that the nitrogen supply capacity of organic fertilizer is weak, 100% of the application of organic fertilizer, crops are not easy to obtain high yield and high quality in the short term. For example, the seasonal nitrogen supply of cow dung winter wheat is only equal to that of chemical fertilizer, so under the condition of equal nitrogen input, the yield-increasing effect of organic fertilizer is lower than that of chemical fertilizer at the initial stage. After about 12-15 years, the yield-increasing effect of organic fertilizer on winter wheat can reach the same level of chemical fertilizer, and the yield-increasing effect of organic fertilizer on summer corn will not be equal to that of chemical fertilizer after 5 years. "there are also problems with the use of too much organic fertilizer. Although the environmental risk of nitrogen is small, the environmental risk of phosphorus is high. Our important conclusion is that the combined application of half chemical fertilizer and half organic fertilizer in Huang-Huai-Hai winter wheat-summer corn farmland can not only ensure high yield and high quality, but also fertilize the soil. it can also greatly reduce environmental risks such as ammonia volatilization and soil nitrate accumulation in farmland. "

"the data from the 30-year positioning trial clearly answer a series of major scientific questions such as reducing fertilization and increasing efficiency." Chen Mengshan, secretary of the party group of the Chinese Academy of Agricultural Sciences, said that scientific fertilization has three purposes: first, to achieve high yield and high efficiency; second, to ensure sustainable soil use; and third, to achieve green development and control environmental pollution. A very important measure is to combine Chinese traditional farming civilization with modern scientific fertilization, and to combine chemical fertilizer with organic fertilizer. Europe and the United States and other developed countries have achieved a sustained increase in crop production under the condition of zero or negative growth in the amount of chemical fertilizer, and an important way is to strengthen the utilization of organic fertilizer resources. China is rich in organic fertilizer resources, and the scientific research achievements of Dezhou Experimental Station have given us an important inspiration. The scientific application of chemical fertilizer and organic fertilizer has explored a way to achieve high yield and high quality, improve soil and protect the environment.

In order to lose weight, we must first improve the efficiency of new fertilizers to show their skills.

In order to reduce the application of chemical fertilizer and increase the yield of agriculture, in addition to using organic fertilizer instead of chemical fertilizer, it is also an important way to improve the utilization rate of fertilizer through new fertilizer.

In an improved variety breeding wheat field of Dedi planting Professional Cooperative located in Dezhou Economic Development Zone, the reporter saw that a large area of wheat is tall and straight, strong and growing gratifying, and this is also a demonstration field of value-added fertilizer and green production increase for Dezhou Denong seed Co., Ltd. "there is nothing wrong with this year's output!" Zhang Wenguo, technical director of the cooperative, said that last year, the yield of wheat per mu reached 700 kg, while corn became the grain king of Dezhou with an output of more than 960 kg. To have such a high yield, in addition to relying on its own advantages of improved varieties, the application of new products of value-added fertilizers plays an important role.

"using new fertilizers such as zinc humic acid compound fertilizer, zinc humic acid ammonium phosphate, zinc humic acid urea and other new fertilizers developed by the New Fertilizer Innovation team of the Chinese Academy of Agricultural Sciences, wheat has developed roots, strong growth stamina, less diseases, reduced fertilizer costs, and increased output by 10%." Zhang Wenguo said.

New varieties with high yield, new products of value-added fertilizers, integration of water and fertilizer, new sowing techniques, prevention and control of diseases, insect pests and weeds. With the integration of these green yield-increasing technologies, the Dezhou Experimental Station of the Chinese Academy of Agricultural Sciences and the Dezhou Municipal Bureau of Agriculture have cooperated since 2008 to carry out a large-scale green high-yield demonstration of winter wheat-summer corn in Dezhou, increasing the utilization rate of chemical fertilizer by 8% and reducing application by 10%. The yield of winter wheat per mu is more than 700kg, the yield of summer corn is more than 800kg per mu, and the annual grain yield per mu is more than 1500 kg. In recent years, most of the wheat and corn grain kings in Dezhou come from the high-yield demonstration fields of the green yield-increasing model carried out by both sides.

Zhao Bingqiang told reporters that the new fertilizer represented by black urea is effective and cost-effective. If the cost per ton is increased by only a few dozen yuan, it can increase the benefit of nearly 2000 yuan. The effect of 40 kg of black urea is equivalent to that of 50 kg of ordinary urea, and the same amount increases by 10%, which is easy for ordinary people to accept, which is also the reason why value-added fertilizers are so hot today.

"if you want to reduce the amount of chemical fertilizer, you must first improve its efficiency." Chen Mengshan said that our new fertilizer innovation team has worked with the Texas Experimental Station for ten years to establish a new concept of carrier efficiency fertilizer production, and the research and development of new and efficient fertilizers is a convenient way to solve environmental contradictions and achieve green production.

It is understood that in recent years, the New Fertilizer Engineering and Technology Center of Dezhou Experimental Station has developed more than 20 new fertilizer products, authorized 29 invention patents, and transformed and industrialized the achievements in more than 30 large fertilizer enterprises. At present, the production capacity of value-added fertilizers has exceeded 10 million tons, with an output of more than 5 million tons, popularizing 150 million mu, increasing grain production by 4.5 billion kilograms, and increasing benefits by 6.3 billion yuan.