New no-till, straw-mulching sowing technology for summer soybeans after wheat harvest successfully developed by Chinese experts
It is the "three summer" season, and farmers are busy rushing to harvest wheat, but how to recycle the wheat straw after the harvest remains a problem that troubles farmers.
However, in Yongqiao District, Suzhou City, Anhui Province, Li Qingwu, head of the Huaihe Grain Industry Consortium, and his cooperative members seem particularly relaxed this year: "We've almost finished harvesting the wheat in our fields, and in another week we can sow soybeans. Recycling wheat straw is not a problem at all for us."
Li Qingwu's ease is not without reason. This year, 1,200 mu of the consortium's land is participating in the technical demonstration of the National Soybean Industry Technology System. With the breakthrough made by Chinese agricultural experts in mechanized no-till, straw-mulching technology for summer soybeans after wheat harvest in the Huang-Huai-Hai region, the wheat straw recycling and disposal problem that has long troubled them will be completely solved.
Wheat straw disposal methods are diverse
but each has its pros and cons
"Returning straw to the field benefits the country and the people"; "Burning straw is prohibited; violators will be fined 2,000 yuan and detained for 15 days." On June 11, as the reporter drove through the rural fields of Suzhou City, red banners hung on both sides of the roads could be seen everywhere.
"Now the state explicitly prohibits burning straw, but after harvesting the wheat, we farmers must hurry to plant the next crop. With burning no longer allowed, we really don't know how to deal with it." Cai Jian, a staff member of the Suzhou City Agriculture Committee, told the reporter that the ban on straw burning is not welcomed by local farmers. To prevent farmers from burning straw, local village and township officials are stationed in the villages to supervise without interruption, but the effect is not ideal.
Straw is rich in organic matter, nitrogen, phosphorus, potassium and trace elements. Practice has proved that using straw return can effectively increase soil organic matter content, improve soil structure and build up soil fertility. Straw has so many benefits, so why are farmers unwilling to return it to the field? Why would they rather burn it all?
"On one hand, they need to keep up with the farming season, and burning is the fastest and easiest; on the other hand, the technology for recycling and returning straw to the field is not yet simple and mature enough." Wu Cunxiang, an expert with the National Soybean Industry Technology System and a researcher at the Institute of Crop Sciences of the Chinese Academy of Agricultural Sciences, told the reporter that at present there are mainly four ways to deal with wheat straw: first, manual clearing, which is time-consuming and laborious with high labor costs; second, mechanical baling, but it requires space for safe stacking; third, straw burning, which can eliminate a certain amount of soil-borne disease but seriously pollutes the environment; fourth, crushing and returning to the field, but this has high mechanical requirements and needs high-horsepower mechanical rotary tillers to crush the straw, and if the crushing is not clean enough, manual picking is still required.
"Not all straw is suitable for direct return to the field, and direct straw return involves many steps and can also cause disease. The key is still to be scientific, considering both the method and the crop." Han Tianfu, chief scientist of the National Soybean Industry Technology System and a researcher at the Institute of Crop Sciences of the Chinese Academy of Agricultural Sciences, added that the Huang-Huai-Hai region is one of China's main soybean producing areas, and farmers mostly plant soybeans after wheat harvest. If wheat straw is crushed and rotary-tilled into the soil, it will not only affect the sowing quality of soybeans, but also easily lead to problems such as moisture loss, straw decomposition competing with soybeans for nitrogen, and aggravated disease.
Scientific utilization focuses on the word "mulch"
As early as 2007, experts with the National Soybean Industry Technology System began thinking about the problem of wheat straw recycling. "Through long-term comparative research, we found a scientific way to return straw to the field, and ultimately decided to focus on the word 'mulch'." According to Han Tianfu, after 8 years of effort, the experts proposed a straw-mulch cultivation technology model for summer soybeans after wheat harvest, successfully developed a prototype machine, and formed a highly simplified no-till, straw-mulching precision sowing technology system for wheat stubble that organically combines agricultural machinery, agronomy and matching varieties.
On June 11, the reporter saw in Li Qingwu's demonstration field that a tractor was pulling a no-till, straw-mulching precision seeder rapidly advancing across the harvested wheat field. As the machine moved forward, it pulled up the 30 cm high wheat stubble by the roots, with all the straw and part of the stubble pulled out laterally to the left. After the machine passed, several straight sowing strips were left in the field. When the machine turned back to sow the next row, the previously pulled-up wheat stubble had already been crushed and evenly covered over the sowing strip just made.
"You may not know that with just one pass, the machine has already completed multiple operation steps, including lateral straw clearing, lateral deep fertilization, precision sowing, closed weeding and straw mulching." Chen Haitao, an expert with the National Soybean Industry Technology System and a professor at Northeast Agricultural University, told the reporter that the no-till, straw-mulching precision sowing technology for summer soybeans after wheat harvest mainly solves the problems of difficult wheat stubble and straw disposal and poor soybean sowing efficiency. Relying on this set of machinery, both problems can be smoothly solved.
Under Chen Haitao's guidance, the reporter pushed aside the soil clods covered with wheat straw and dug down 8 cm, where the soybean seeds were found, with each seed spaced the same distance apart, about 8-10 cm. "After the wheat straw is crushed, it is directly covered on the field. For soybeans, it is like a quilt for the season, which can save water and preserve soil moisture; and for wheat, the next crop after soybeans, the wheat straw has already decomposed and can fully serve as fertilizer for the next season. This gives full play to the role of wheat straw and achieves scientific return to the field. And precision mechanical dibbling also helps soybeans emerge early and grow into strong, uniform seedlings." Chen Haitao explained.
"After mechanical wheat harvest, the stubble is high, and the straw is scattered in the field, seriously affecting the sowing quality of soybeans. But now, with just one machine, we farmers can do it completely effortlessly. Not only can we recycle the wheat straw well, but we can also plant soybeans well. It is really too convenient." Wang Bingyin of the Suzhou City Academy of Agricultural Sciences, who was visiting the mechanical operation in the demonstration field, said with heartfelt emotion.
Soybean yield increases by 20 kg per mu; technology promotion is of great significance
Ji Yongmin, a farmer in Suixi County, began using this new technology model last year. He calculated an account for the reporter: "Adopting this technology helped me solve the problems of seedlings and labor, and after the soybeans are planted, basically no further management is needed. Last year, my soybean yield increased by 40 kg per mu, and I also saved 7-10 labor days. The seedlings emerge early, uniformly, evenly and strongly, and later there is no need to thin or space the seedlings."
Starting in 2012, this technology was recommended by the Ministry of Agriculture as a main promotion technology and was comprehensively demonstrated and promoted in major summer soybean producing areas such as Henan, Shandong, Hebei, Jiangsu and Anhui. According to estimates, covering the field with wheat straw not only saves the amount of pesticides and fertilizers used per mu, but also increases soybean yield, with an average increase of 15-20 kg per mu and a benefit increase of 70-140 yuan. In 2013, at the Xinxiang Experimental Base of the Chinese Academy of Agricultural Sciences, the soybean variety XA12938 planted with this new technology even set a record of 311.2 kg.