Rice mechanized hill-drop direct seeding technology rises rapidly in Shanghai
Editor's note: At present, Shanghai's rice planting area reaches more than 1.4 million mu. When Shanghai first introduced rice mechanized hill-drop direct seeding technology in 2012, only a few hundred mu were promoted. Several years have passed, and this year the citywide promoted area has grown to 370,800 mu. Why has this technology been able to rise rapidly in Shanghai? Compared with manual broadcasting and machine transplanting, what exactly are the advantages of this technology? What risks does it have? How should it be promoted to give full play to its effectiveness? In response, reporters conducted an in-depth investigation in the suburbs of Shanghai.
1. Saves labor, lowers costs, highly efficient, precise and controllable
At the mention of rice mechanized hill-drop direct seeding, Zhu Liudong, a farmer from Dongjing Town, Songshan District, Shanghai, gives a thumbs-up: “This new rice planting technology not only eliminates the rice seedling-raising step, saves labor and lowers costs, but also gives rice better aeration and light penetration during planting, stronger lodging resistance, and a somewhat higher 1000-grain weight.”
Rice planting in Shanghai has a tradition of direct seeding, and in the past it was mostly manual broadcasting. “However, due to changes in the rural labor structure in recent years, there are fewer and fewer experienced older farmers, and broadcasting technology is no longer as mature as it once was.” Zhu Min, head of the Shanghai Agricultural Machinery Appraisal and Extension Station, told reporters, “In addition, manual broadcasting makes it hard to achieve uniformity, crop seedling establishment is clearly disordered, and the risks of rice sheath blight, rice planthoppers and other pests and diseases are increasing day by day. Therefore, mechanized direct seeding has broad demand in Shanghai as a replacement for manual broadcasting.”
Compared with manual broadcasting, the primary advantage of rice mechanized hill-drop direct seeding lies in its high efficiency, which suits Shanghai's moderate-scale operations dominated by family farms. “Family farms are generally 100 to 200 mu in area. The rice hill-drop direct seeders we are now promoting have an operating efficiency above 8 mu/hour, so all seeding work can be completed in just two days, and the seedlings emerge neatly and in order, which facilitates later field management.” Zhu Min said.
Especially since the promotion of the rice-wheat two-crop rotation system and the ban on straw burning with straw return to the field, the advantage of the rice hill-drop direct seeder's precision and controllability has become even more prominent. “The mechanical operation has the functions of ditching, ridging, leveling and pressing the stubble, and seeding. Rice seeds are sown in the seeding furrows at set distances, and the furrows on both sides of the seeding furrow can serve to drain and store water. This suits rice planting after straw return to the field, because seeds from manual broadcasting easily remain on the surface layer of the returned straw, which not only greatly reduces the germination rate, but also leads to shallow rooting and easy lodging.” Zhu Min explained, “In addition, after the seeds are ‘punched’ into the hills, water management and precise fertilization must follow in step, and the rice has good aeration and light penetration, deep rooting, and strong lodging resistance. Mechanical hill-drop direct seeding saves about 0.5~1 kg of seed per mu compared with manual broadcasting, and increases yield by more than 5% per mu compared with manual broadcasting. Last year, a high-yield demonstration plot reached a yield of 802 kg per mu.”
Another major advantage of rice mechanized hill-drop direct seeding is low cost. Zhao Zhipeng of the Science Popularization and Publicity Section of the Shanghai Agricultural Science and Technology Service Center feels this deeply: “The machine transplanting popular now requires raising seedlings 18~20 days in advance, going through many steps such as taking soil, crushing soil, seeding, darkening, transporting, and raising seedlings, and finally the seedling trays must also be transported to the field. None of these steps can do without manual labor. By adopting mechanized hill-drop direct seeding, the labor cost saved alone has won recognition from more and more farmers in Shanghai's suburbs.”
Zhang Ping, head of the Agricultural Machinery Service Station of Dongjing Town, Songjiang District, Shanghai, told reporters that each operation of a rice hill-drop direct seeder requires about 1.5 workers, while machine transplanting, due to steps such as transporting and installing seedling trays, requires 6~7 workers for a single operation. In terms of yield, rice mechanized hill-drop direct seeding is higher than manual broadcasting and comparable to machine transplanting in yield per mu, but the current cost of machine transplanting is about 150 yuan per mu, while hill-drop direct seeding requires only more than 30 yuan.
In addition, seedling trays have relatively high requirements for substrate soil, which must be about 15 cm of mature soil from the field surface and must not contain impurities such as bricks and stones. “But for Shanghai, soil resources are indeed very tight. It can be said that the shortage of seedling-raising soil has largely restricted the further promotion of machine transplanting.” Chen Yong, head of the Agricultural Machinery Management Office of Songjiang District, Shanghai, believes that rice mechanized hill-drop direct seeding is highly efficient, eliminates the seedling-raising step, and avoids the constraint of tight soil-taking resources. Today, when rural labor prices are getting more and more expensive and the comparative benefits of rice planting are declining day by day, this technology's ability to save labor means greatly reducing production costs. It is precisely because of the comprehensive advantages it shows in reducing costs and increasing efficiency in rice production that this technology has been able to spread rapidly in Shanghai's suburbs.
2. Advantages and risks coexist, with relatively high technical requirements
Although rice mechanized hill-drop direct seeding technology is good, its technical requirements in practical application are relatively high, and improper operation can cause certain risks. “To promote rice mechanized hill-drop direct seeding technology, three major difficulties must be overcome: land preparation, weed control, and seed.” Shen Caibiao, head of the Agricultural Machinery Technology Extension Station of Pudong New Area, Shanghai, said.
The “three passes” Shen Caibiao mentioned vividly express the three major risks of this technology. First, the risk of tillage and land preparation. If the land is not levelly prepared and drainage is poor, water will accumulate in low-lying areas and drown the seeds, affecting seeding uniformity and germination rate.
Second, the risk of weed control. Unlike machine transplanting, which operates in flooded fields, fields using rice mechanized hill-drop direct seeding technology have no standing water on the surface, so weeds easily grow at the same time as rice, and once they break out they are extremely difficult to control. In addition, uneven fields can also affect the progress of mechanized operations.
Third, the risk of seed soaking and sprouting. The use of rice mechanized hill-drop direct seeding technology requires the seed surface to reach a certain degree of dryness and to maintain a certain sprout length. If the sprouting technique is improper, it will reduce the emergence rate and lead to uneven seedling establishment. In addition, the time gap between agricultural machinery operations and seed soaking and sprouting should be coordinated well, otherwise there may be situations where “the machine waits for the field” or “the field waits for the machine.”
It can be seen that if the technology is not applied properly, it can also cause rice yield reductions. In fact, to reduce weed damage, the use of rice mechanized hill-drop direct seeding technology requires herbicides, generally applied three times: after puddling and harrowing the field, 3~5 days after mechanical seeding, and at the three-leaf stage. Therefore, compared with machine transplanting, it generally uses one more herbicide application, and compared with machine transplanting the amount of herbicide used is greater and the technical requirements are more difficult.
“In addition, the promotion of rice mechanized hill-drop direct seeding technology must also take regional ecological conditions into account. It is not that it can be promoted anywhere; special attention must be paid to the temperature and light resources of the promotion area.” Zhu Min believes that at present, viewed nationwide, especially in rice-producing areas north of the Yangtze River, machine transplanting is still the most scientific and advanced rice planting technology because accumulated temperature is insufficient. Even in Shanghai, machine transplanting and mechanized hill-drop direct seeding each have advantages and disadvantages, and farmers' understanding of the two is not unified.
3. Adapt to local conditions, demonstrate agricultural machinery and agronomy integration
What kind of rice planting technology to adopt ultimately depends on adapting to local conditions. “For example, hybrid rice is more suitable for machine transplanting, while conventional rice is more suitable for hill-drop direct seeding.” Sun Linjun, general manager of Shanghai Star Modern Agricultural Machinery Co., Ltd., proposed, “The choice of equipment and technology must be comprehensively considered according to specific factors such as crop variety, natural conditions, and social benefits.”
“Rice mechanized hill-drop direct seeding technology cannot be mechanically copied and forcibly pushed; plans must be formulated according to the actual conditions of each district and county. At the same time, demonstration guidance should be carried out step by step in the order of first experimenting, then demonstrating, and finally promoting.” Zhu Min gave an example, “For example, Baoshan and Minhang districts in Shanghai are close to the central urban area, so promoting machine transplanting is more appropriate. On the one hand, there is a large area of hybrid japonica rice, which suits machine transplanting; on the other hand, adopting machine transplanting can appropriately reduce the amount of herbicide used, which is conducive to developing ecological agriculture. For urban agriculture, in addition to economic benefits, attention must also be paid to the ecological benefits of agriculture. Especially in near-suburban areas, preventing agricultural non-point source pollution and protecting the urban ecological environment should be placed in an important position.”
The rapid rise of rice mechanized hill-drop direct seeding technology in Shanghai in recent years is due not only to the advantages of the technology itself, but also to the promotion method integrating machinery and agronomy. “From the very beginning of researching and promoting the plan, the agricultural machinery and agronomy departments must both get involved. If it becomes two separate skins, each singing its own tune, it is very easy to cause risks such as weed damage and yield reduction.” Zhu Min told reporters, “In all districts and counties where promotion and application results are relatively good, the biggest feature is the deep integration of agricultural machinery and agronomy, and risks have been effectively controlled.”
The ultimate users and beneficiaries of hill-drop direct seeding technology are farmers, so strengthening training for farmers is crucial. “Training should pay attention to two points: first, simple and easy to understand; second, integration of machinery and agronomy.” Shen Caibiao explained, “For example, we summarized the precautions for technology application as the ‘six precisions’: carefully selected crop rotation slots, precisely calculated sowing dates, finely prepared land, precisely sprouted seeds, precisely controlled weeds, and precisely measured seeding.”
In addition, the government's subsidy policy is also a good remedy for the promotion of this technology. It is understood that a hill-drop direct seeder in Shanghai costs about 100,000 yuan. After the government's agricultural machinery purchase subsidy, farmers need only about 20,000 yuan to buy one machine. At present, Shanghai's operating subsidy for hill-drop direct seeders is generally about 30 yuan per mu, while machine transplanting is subsidized at 80~100 yuan. “It can be said that the promotion of rice mechanized hill-drop direct seeding technology is a win-win-win matter for the government, farmers, and machine operators. On the premise of unchanged yield, the government's fiscal subsidy expenditure is reduced, grain farmers' production costs and labor intensity are lowered, and machine operators' income increases by expanding operation services.” Zhu Min said.
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What are the rice planting methods?
Rice planting methods are generally divided into direct seeding, transplanting, and seedling throwing.
Direct seeding includes water direct seeding and dry direct seeding.
Transplanting includes manual transplanting and mechanical transplanting. Seedling throwing includes no-tillage (minimum-tillage) rice seedling throwing, young seedling throwing, paper-tube seedling throwing, plastic pot tray seedling throwing, and trayless dry-raised seedling throwing.
What is rice direct seeding?
Rice direct seeding is a sowing method in which seeds are sown directly in the field without the process of raising seedlings and transplanting. In addition to being divided into water direct seeding and dry direct seeding, it can also be divided into hill sowing, broadcasting, and drilling.
Hill sowing, also called spot sowing, refers to digging holes in the soil at certain intervals and sowing seeds in them, which can effectively ensure the plant spacing and density of sowing.
Broadcasting is sowing seeds evenly in the soil. The broadcasting method is fast and saves time, but the seeds are not easily distributed evenly and the amount of seed used is relatively large. This method has been used for a long time, and many areas still use it for sowing today.
Drilling is sowing seeds into the soil layer in rows at a certain spacing. In this method, the sowing depth of the seeds is relatively consistent and the seed distribution is relatively even. In recent years, this sowing method has gradually replaced broadcasting in many places, and its current scope of application is also relatively wide.