How can agricultural production be fully cycled?

Currently, China's agriculture is facing an important juncture of adjusting its industrial structure. How should the crop-livestock structure and the grain-feed structure be optimized? How should farmland use and protection be coordinated? The reporter interviewed Wang Yingchun, an expert at the Institute of Agricultural Resources and Regional Planning of the Chinese Academy of Agricultural Sciences, on this topic.

Reporter: How can crop farming and livestock farming be organically linked?

Wang Yingchun: The structural allocation of crop farming and livestock farming is the basic framework of the agricultural industrial structure, and optimizing the crop-livestock structure is an important task in transforming the agricultural development model. At present, the multi-sector allocation ratio in China's agriculture, with farming and animal husbandry as the main body, is unreasonable; the output value ratio of farming, forestry, animal husbandry and fisheries is about 13:1:8:2, whereas the agricultural and livestock structure in the United States is roughly balanced, with the ratio of crop farming to animal husbandry at about 1:1. Because China has long suffered from an imbalance between crop farming and livestock farming, resource utilization has not formed a chain, and as the quantity of agricultural product output has continued to increase, agricultural waste has surged accordingly. The manure and sewage from large-scale livestock farms in the south cannot be absorbed on site, causing non-point source pollution; in Northeast China, after the corn harvest, straw cannot be fully utilized as a resource, and burning has become a disaster.

It can be said that the faster isolated industries develop, the greater the potential threat to the ecological environment. Once a problem arises in a certain link of a certain industry, the regional environment is affected. Therefore, to solve the balance between developing production and protecting ecology at the source, and to develop agricultural production guided by ecological construction, it is necessary to apply the way of thinking of traditional Chinese medicine that “to treat the symptoms, first treat the root cause,” promote circular agriculture models of crop farming and livestock farming, build a circular agriculture system, turn waste into resources, make resources generate benefits, ease the pressure on resources, ecology and the environment, and increase agricultural returns.

Some regions of China already have typical circular agriculture models of crop farming and livestock farming, such as “pig-biogas-fruit” and “rice-fish symbiosis,” which fully utilize agricultural natural resources and biological resources, improve resource utilization efficiency and production benefits, and control waste emissions. Therefore, all regions should base themselves on resource and environmental characteristics, industrial foundations and crop-livestock habits, take economical resource utilization, cleaner production processes and resource-based waste utilization as the main line, fully utilize the characteristics of agricultural organisms, scientifically arrange crop planting and livestock species, and build inter-industry circular chains and ecological circular agriculture systems at different levels.

Reporter: How can farmland use and farmland protection be effectively combined?

Wang Yingchun: Crop rotation is the basic means of maintaining ever-renewed soil fertility, and it is also the essence of China's thousands of years of traditional agricultural planting methods. A reasonable crop rotation system, fallow, and intercropping, mixed cropping and relay intercropping multi-cropping models can achieve the combination of using and nourishing the land, and can also achieve “storing grain in the soil.”

However, with the rapid development of agriculture, the improvement of agricultural technology levels and the drive of economic benefits, regional single-variety planting structures have become increasingly common, and continuous cropping areas have continued to expand. For example, in recent years, Northeast China has planted corn over large areas year after year, while the planting area of the former dominant crop soybean has continued to shrink, breaking the original corn—soybean rotation balance. In 2013, the corn planting area in the three Northeast provinces already exceeded 160 million mu, 3.6 times that of soybean. While large amounts of corn were transported out of the black soil, the role of soybean nitrogen fixation in fertilizing the soil was ignored, causing problems such as the decline of soil organic matter and the degradation of black soil, for which a huge ecological price must be paid. At the same time, the single product brought by single-variety planting not only increases the inventory pressure of a single variety, but also increases market risk.

Planting models for restoring soil fertility must proceed from the long term and ensure the quantity, quality and ecological security of farmland resources. Therefore, the focus should be on promoting corn/soybean rotation in Northeast China, promoting corn/peanut intercropping and relay intercropping in the Huang-Huai-Hai region, promoting double-cropping rice—green manure or rice—rapeseed planting in the middle and lower reaches of the Yangtze River, promoting corn/soybean intercropping and relay intercropping in Southwest China, and promoting corn/potato rotation in Northwest China.

Reporter: How can the structure of staple grain and feed grain be balanced?

Wang Yingchun: In recent years, animal husbandry has developed rapidly, among which grass-fed animal husbandry has grown most significantly. From 1990 to 2013, pork output grew at an average annual rate of 4.0%, while beef and mutton output grew at average annual rates of 8.0% and 6.2%, and the share of beef and mutton in meat output rose from 8.1% to 12.7%. At present, China's imports of corn and soybean meal have surged, the supply-demand gap for feed grain has widened, and the insufficient supply of feed grain has aggravated the threat to national food security. If the internal structure of agriculture is not adjusted in a timely manner and grass-fed animal husbandry is not accelerated, a situation will inevitably arise in which livestock and poultry compete with people for grain.

The foundation for developing grass-fed animal husbandry lies in forage grass. With the coordinated development of “grain, cash crops, grass and livestock” as the main line, the variety structure and layout changes within crop production and within animal husbandry should be adjusted to form an agricultural structure that gives consideration to both grain and forage. Replacing part of feed grain with high-quality forage grass not only helps ensure people's staple grain needs, but also promotes the development of the grass industry, enhances the production capacity of dairy cows and beef cattle and mutton sheep, increases the supply of grass-fed livestock products and ensures the quality and safety of grass-fed livestock products.