Grassland agriculture is a new position for the construction of ecological civilization

China is in a great transition period from agricultural civilization to industrial civilization, and the problem of ecological environment has become one of the prominent problems restricting economic development and affecting social harmony and stability. In 2015, the No. 1 document of the Central Committee proposed to promote the coordinated development of the ternary planting structure of grain, cash crops and forage, which pointed out the way for the sustainable development of agriculture in China in the future. Grassland agricultural system is a modern agricultural system that meets the food structure of modern people, gives consideration to both ecology and production, and can develop sustainably. The development of grassland agriculture is a new position for China to build ecological civilization, which is of great significance to ensure China's ecological security and promote the sustainable development of agriculture.

First of all, China's grass industry has entered a new period of historical opportunity. Grassland has many functions, such as regulating climate, conserving water sources, conserving soil and water, preventing wind and fixing sand, improving ecological environment, improving the quality of human settlements, promoting the harmonious development of urban and rural areas and so on. The study shows that when the vegetation coverage increases to more than 50%, the surface wind erosion and water erosion will be significantly reduced. The development of artificial recommendation in agricultural areas and northern agro-pastoral ecotone, especially the planting of perennial grazing grasses such as alfalfa and Elymus, can not only obtain a large amount of high-quality forage, but also increase ground cover in winter and spring. It can significantly reduce wind speed, reduce wind erosion and improve the ecological environment.

Secondly, the development of grassland agriculture is conducive to the protection of grassland ecology. With the increase of population and the improvement of dietary structure in China, the demand for animal products, especially beef and mutton, continues to increase, and as far as the current situation of natural resources in China is concerned, it is difficult to meet this demand by relying entirely on natural grassland and rural straw resources. It is estimated that planting 1 mu of artificial forage land with high quality and high yield is equivalent to the yield of 10-30 mu of natural grassland grass. If we can make use of 10% of the high-quality land with suitable conditions in our country and establish intensive artificial grassland, we can produce more than 300 million tons of forage grass every year, which is equivalent to 1% of the biological output of 1.8 billion mu of cultivated land in our country, which is equivalent to 450 million mu of new "ploughed land". Through the construction of artificial grassland, not only the problem of insufficient forage can be solved, but also the pressure of carrying livestock in natural grassland will be greatly alleviated.

Third, for a long time, China's agriculture has implemented the dual planting structure of grain and cash crops, resulting in soil degradation and consolidation caused by excessive use of chemical fertilizers and pesticides. The development of grassland agriculture, the introduction of grass into the field and grass field rotation, and the introduction of forage grass, especially leguminous forage, into the crop rotation system can effectively improve soil, improve soil fertility and reduce the use of nitrogen fertilizer. Feeding livestock with forage grass can also really raise the land and speed up the recuperation of cultivated land and soil ecological restoration. The net increment of soil nitrogen in alfalfa fields planted for 1 year, 2 years and 3 years was 83 kg, 115 kg and 124 kg per hectare, respectively. Alfalfa planted for 5 years could achieve high yield of 3-5 years.

Grassland agriculture contains the output of multiple production layers, and it is an optimized ecological circular agricultural production mode. Through the combination of planting and cultivation, extending the industrial chain and developing circular economy, the grass industry and agriculture are coupled to form a multi-level modern comprehensive agricultural system. Therefore, as an advanced and ecological mode of production, grassland agriculture is bound to make an important contribution to the construction of ecological civilization in China.

(the writer is a professor of China Agricultural University and secretary-general of China Grass Association.)