Why can an area with nine years of drought out of ten achieve bumper harvests year after year?
"The land is still the same land, but with full-film technology it is completely different, no need to look at the heavens' mood anymore." In the fields of Malian Village, Xiangquan Town, Dingxi City, Gansu, farmer Su Shangren's face was covered with smiles, the corn was growing well, almost as tall as a person, and the thick leaves reflected the sunlight.
Malian Village has long been trapped by water, "a bowl of oil cannot be exchanged for a bowl of water," and in the past it was "plant a slope and harvest a basket." Su Shangren sighed: "I really never imagined that now every household's per-mu yield can reach 1300 jin!"
Gansu lacks water; dryland accounts for 70% of the province's cultivated land area, and nearly 80% of the rural population lives in arid and semi-arid areas. Especially in the central and eastern parts, the per capita water resource volume is only 6% of the national average.
However, the promotion of dryland farming technology has completely changed the situation here. The basic reality of "nine years of drought out of ten" has not changed, but Gansu's grain production has achieved bumper harvests year after year, remaining stable above 10 million tons for 5 consecutive years.
1. The "full-film" technology forced into existence
Preserving soil moisture, collecting rainwater and keeping warmth, increasing grain output by more than 30%, promoted on more than 15 million mu in 8 years
Su Shangren's family has 10 mu of land. In the past, small droughts caused small disasters and big droughts caused big disasters. "'There is soil but no water'; in bad years, it could not even supply the family's rations."
How to change the situation of relying on the weather became the number one problem for Gansu's agricultural science and technology personnel.
In the 1980s, some places in Gansu began trying plastic film planting technology. "At first it was half-film mulching. When a major drought came, it did not preserve water; under the sun, the corn leaves under the film instead twisted up like rope." Su Shangren said.
Several generations of agricultural technicians kept researching and tackling key problems, developing from "half-film" to "full-film," and then combining it with ridge-furrow sowing. Gansu people independently explored the "full-film double-ridge furrow sowing" dryland farming technology and promoted it across the province in 2007.
Yang Qifeng, deputy director of the Gansu Provincial Department of Agriculture and Animal Husbandry, who led the main research and development of the technology, introduced that the principle of full-film double-ridge furrow sowing technology is simple: use autumn rain in spring. After the rainy season, large and small double ridges are formed in the field, crops are sown in the furrows, and plastic film is used to completely cover the cultivated land, reducing evaporation and preserving soil moisture.
This technology can not only preserve soil moisture and collect rainwater, but also increase light and temperature. It can raise the precipitation utilization rate from 40%-50% to more than 70%; grain output per millimeter of precipitation increases from less than 1 kg to 2.5 kg.
Promoting new technology was not easy. The masses saw that it was still film mulching and were strongly resistant. The government increased subsidies and arranged special funds for demonstration and promotion. Looking at the heavy corn cobs, everyone was eager to try, plowing, forming ridges, laying plastic film, rotating crops where needed, and trial planting where needed.
Su Shangren became the first person in the village to "eat the crab." Starting in 2008, he changed wheat to film-mulched corn and potatoes. Corn yield per mu reached 1800 jin, and annual income was more than 30,000 yuan.
Now, Su Shangren has also become a local expert. He "revealed" to reporters: "White film is laid in corn fields, and black plastic film is laid in potato fields, because potatoes like cool conditions, and the soil temperature under black film is 1 degree lower, which is beneficial to their growth."
The planting structure changed, and the farming method changed. Malian Village achieved village-wide poverty alleviation in 2014. Cao Xin, a village-stationed cadre, said: "Now every household in the village uses plastic film, not only for planting corn and potatoes; some farmers are also trying film-mulched cultivation of medicinal herbs."
Practice has proved that this technology has low input and high output and can increase grain output by more than 30%. By 2015, Gansu Province had completed 15.26 million mu of full-film double-ridge furrow sowing area, covering 10 cities and prefectures and 50 counties and districts in the central and eastern dryland farming areas, with 1.7834 million beneficiary farming households. Today, the dryland farming area has become a new "major grain-producing area," fundamentally changing the face of Gansu Province's dryland farming areas.
Not only in Gansu, from full-film corn to full-film potato, and then to full-film wheat, this technology has driven agriculture in the arid areas of the northwest into the era of "full-film technology."
2. Standardized technology has its particular requirements
Procedures have rules to follow, agricultural machinery is combined with agronomy, and ecological environment is emphasized according to local conditions
In a region with severe soil erosion like Gansu, will developing agriculture affect the ecology? Focusing on the long term, dryland farming technology must continuously move toward standardization and normalization.
Drought-resistant technology is based on ecology and adapted to local conditions, making good use of "water from the sky" and preserving "soil water." Yang Qifeng introduced that Gansu Province is adjusting and optimizing the industrial layout so that the natural precipitation period and crop water demand period are highly consistent. Based on factors such as altitude and accumulated temperature, the advantageous areas for full-film double-ridge furrow sowing corn, potato and wheat were determined. Areas with annual precipitation of 250-450 mm mainly use autumn film mulching, while areas with annual precipitation greater than 450 mm mainly use top-ridge film mulching. The proportion of autumn film mulching area increased to 56%, basically covering suitable areas.
In order to promote the technology in place, agricultural technicians at all levels went deep into the front line, and technical personnel stayed at points to cover villages and households, ensuring training reached every household.
Li Wenjun, a farmer from Lishan Village, Liuliang Township, Zhuanglang County, spoke about drought-resistant technology with great familiarity: "The technical procedures are written clearly. Only when soil moisture content reaches more than 15% can corn germinate. The width of large and small ridges and planting density also have particular requirements."
Combining agricultural machinery with agronomy further improves the effect of drought resistance and yield increase. "Using machinery for film mulching, 3 mu of land is finished in half an hour, while with manual labor, 3 laborers can only do 1 mu in a day." Li Wenjun said that the most important thing is that mechanical film mulching is as flat as a mirror. The full-film double-ridge furrow sowing technology requires large ridges 70 cm wide and 10 cm high, and small ridges 40 cm wide and 15 cm high, which is difficult to standardize manually.
Today, the Zhuanglang County dryland farming machinery service team is active on the terraced fields, skillfully plowing, mulching and harvesting for farmers by machinery. The county's agricultural production mechanization rate has reached more than 40%. Across Gansu Province, more than 2,560 specialized agricultural machinery service organizations have been supported and cultivated. Through the integrated use of agricultural machinery and tools, the level of mechanization in dryland farming has been improved, and the area of mechanical ridge formation and film mulching has reached 9.38 million mu.
Integrated drought-resistant technology has continuously matured, achieving a win-win of ensuring grain and protecting ecology. Through comprehensive small-watershed management, Zhuanglang County has built one million mu of terraced fields, turning the former "three-loss fields" into "three-preservation fields." At present, the county's forest land area has reached 640,000 mu. By the end of 2015, more than 800 square kilometers of soil erosion had been cumulatively controlled, with a control rate of 75.5%, achieving green income growth.
3. Directly facing "white pollution"
Issuing local mandatory standards, turning old film from waste into treasure, recovery rate reaching 78%
Full-film double-ridge furrow sowing technology solved the water problem, but new problems appeared. The most prominent was "white pollution"; a large amount of residual plastic film brought hidden worries to cultivated land.
"We cannot ignore ecology for today's bumper harvest. If the problem of soil 'white pollution' is not solved well, agriculture is destined to be unsustainable." Yang Qifeng said that Gansu Province took the lead in the country in issuing regulations on the recovery and utilization of waste agricultural film, prohibiting the production and use of agricultural plastic film with a thickness of less than 0.008 mm, prohibiting the use of agricultural film with a weather-resistant period greater than 12 months, and promulgating local mandatory standards.
"Government + market" governs "white pollution." Following the idea of "government support, market operation, and circular utilization," the province arranges 20 million yuan in special funds each year to support the construction of a group of recovery and processing enterprises with advanced processes. At the same time, it adds rural waste film recovery points, formulates a trade-in policy, and increases enthusiasm for plastic film recovery.
Huachi County explored turning "white garbage" into treasure, processing it into plastic pellets and making plastic buckets, plastic basins, plastic tables and chairs, etc. This year Huachi County recovered 11 million tons of plastic film, achieving economic benefits of more than 8 million yuan. Ai Sanhong, head of the plastic film recovery station in Shanzhuang Township, introduced that in townships with concentrated corn planting, the county agriculture and animal husbandry bureau is responsible for setting up recovery stations. Farmers transport recovered plastic film to the recovery station, exchange it by weight for new film, and then sell the old plastic film to the county's plastic processing enterprises. The more waste film farmers bring, the more new film they can take back, which gives them enthusiasm.
Yu Yanwen, a farmer from Shangwan Village, Shanzhuang Township, dug out all the old plastic film piled at the edge of the field at the beginning of the year and sent away more than 20 tons of waste plastic film. At an exchange ratio of 13 jin for 1 jin, he exchanged it for new plastic film, saving a lot of money on film mulching this spring.
At present, the province has established more than 2,000 township- and village-level waste agricultural film recovery stations, initially forming a market-based recovery and utilization mechanism. In 2015, the province's waste agricultural film recovery rate reached 78%.
New technologies are being continuously applied. Yang Qifeng introduced that the high-light-efficiency, long-life and environmentally friendly plastic film currently developed in cooperation with enterprises has initially achieved "one film mulching, continuous use for three years." The province is also carrying out pilot projects for degradable plastic film in Guanghe, Liangzhou and other places, and this autumn will demonstrate the use of degradable plastic film in 15 counties and districts.