Connotation and Cultivation Techniques of New Triple Cropping Wheat/Jade/Bean Model in Dryland _ Dryland Wheat Varieties

The 14 provinces, municipalities and autonomous regions in the south are the main agricultural production areas in China, especially in the southwest. The hilly and mountainous areas have a large proportion of dry land and a high degree of multiple cropping, which is a typical dry farming and multiple cropping agricultural area in the south of China. For a long time, wheat/jade/potato, oil-jade/potato, sugarcane/sweet potato, etc. have been planted twice a year and three times a year in the dry land in southwest China, with an annual planting area of 53.7 million mu. In recent years, with the improvement of farmers' living standards and their diet structure, the production status of sweet potato has gradually changed from the main grain type to the miscellaneous grain type. In addition, there are some problems in planting, harvesting and handling, such as high labor intensity, difficult storage and low efficiency, which can not meet the needs of farmers under the new situation of modern agricultural development, and the production area has gradually shrunk. In order to meet the requirements of farmers for new production technology and increase agricultural income and efficiency in the new era, Sichuan Agricultural University, on the basis of summing up the shortcomings of the "wheat/jade/potato" model, cooperated with Sichuan Agricultural Technology Extension Station and formed a new model of high-efficiency ecological multiple cropping in dry land-"wheat/jade/bean". After nearly 1 years of research, demonstration and popularization, this model has initially formed a comprehensive supporting cultivation technology system of "wheat/jade/bean", including seed treatment technology, variety sowing date adjustment technology, chemical control technology, group configuration technology and agricultural machinery and agronomy supporting technology. From 27 to 28, it was listed by the Ministry of Agriculture as the main technology in the main producing areas of superior agricultural products (soybeans), and it was listed by Sichuan Province as the new technology widely used in Document No.1, the eight new water-saving agricultural technologies and technologies in Sichuan Province, and the main technology in the 3 Project. In 27, the planting area reached 2.613 million mu, with an average yield of 138.2kg； per mu. In 28, the planting area reached 3.5 million mu, with an average yield of 118.3kg. Since the demonstration and popularization of this technology in Sichuan Province in 23, it has developed very rapidly, and its area has increased year by year, which is deeply loved by the people. It has played a very important role in increasing local grain production and farmers' income, and is becoming a new practical technology to promote the development of modern agriculture in the multi-cropping areas in southern China.

I. the connotation of "wheat/jade/bean" model

The new triple cropping wheat/jade/bean model in dry land is a multi-cropping system with soybean instead of sweet potato in "wheat/jade/potato" model under the conditions of integrating no-tillage, straw mulching and direct seeding of crops. Its multiple cropping method is as follows As a new dryland planting model integrating drought resistance and disaster reduction, land use and cultivation, conservation tillage and light cultivation, this model embodies the connotation of developing high-quality, high-yield, efficient, ecological and sustainable agriculture, promotes the optimization and adjustment of planting structure, and is an important technical measure to increase production and income of dryland agriculture.

the "wheat/jade/bean" model has the technical characteristics of "five changes, four reductions, three increases, two benefits and one promotion". Five changes: changing sweet potato into soybean, intercropping, spring sowing into summer sowing, sparse planting into dense planting, furrowing and ridging into no-tillage straw mulching; Four reductions: reducing material input, reducing labor intensity, reducing soil erosion and reducing environmental pollution; Three increases: strengthening drought resistance, increasing annual output and increasing farmers' income; Two benefits: that is, it is conducive to resource conservation and environmental friendliness; First, promote the sustainable development of dryland agriculture.

Second, the advantages of "wheat/jade/bean" model

1. It helps farmers to increase their income and has remarkable economic benefits. The new model integrates no-tillage, straw mulching and direct seeding technology, which saves labor and costs and has high benefits. According to the investigation and statistics of Sichuan Agricultural Technology Extension Station in recent three years, the average yield per mu of soybean in the new model is 125.62kg, and the output value per mu is 416.99 yuan, while the raw grain per mu of sweet potato is 221.29kg, and the output value per mu is 29.6 yuan, and the output value per mu of soybean is 126.39 yuan higher than that of sweet potato. Compared with the "wheat/jade/potato" model, the new model saves 5.9 workers per mu after returning no-tillage straw to the field, and the income per mu can be increased by 118 yuan according to the 2 yuan of each worker; Planting soybeans can save seeds, fertilizers, pesticides and other expenses per mu compared with sweet potatoes, 15 yuan. Taken together, the economic benefit of the new wheat/jade/bean model is 259.35 yuan/mu higher than that of the traditional wheat/jade/potato model.

2. No-tillage and straw mulching cultivation are adopted in the new model with outstanding ecological benefits, which effectively reduces soil erosion. The research shows that the new model can reduce soil erosion by 1.6% and surface runoff by 85.1% compared with the "wheat/jade/potato" model; The soil total nitrogen content of corn and soybean increased by 4.11% and 7.29%, and the nitrogen utilization rate of corn increased by 39.21%. In addition, in the new model, the three crops of wheat, corn and soybean are rotated in micro-areas, which effectively avoids the obstacles of continuous cropping of soybean caused by continuous cropping, reduces the harm of pests and diseases, and realizes the increase of production and income.

3. Alleviate the contradiction between supply and demand, with obvious social benefits

China is the largest soybean importer in the world, with a perennial supply-demand gap of about 25 million tons, with an import volume of 37.436 million tons in 28; In recent years, the annual demand for soybeans in Sichuan Province is also gradually increasing, and the gap between production and demand is more than 1.5 million t. The new dry land model with soybean intercropping as the main body can save labor and reduce labor intensity, which can alleviate the shortage of rural labor force and promote the transfer of rural labor force; By expanding soybean planting area and increasing total soybean output, we can realize the adjustment of agricultural industrial structure, alleviate the contradiction between supply and demand of soybeans in China, improve people's dietary structure and promote the rapid development of soybean industry and animal husbandry.

4. Drought resistance and disaster avoidance, good loss reduction effect According to the statistics of Sichuan Agricultural Technology Extension Station for three consecutive years from 26 to 28, under the conditions of successive drought and earthquake disasters, the harvest area of soybean intercropping in the whole province reached 1.294 million mu, 2.613 million mu and 3.5 million mu respectively, with an average yield of 125.62kg per mu, showing the vigorous vitality and popularization and application prospect of the new model in the vast hilly and arid areas of Sichuan Province.

Third, the prospect of popularization and application of "wheat/jade/bean" model

Sichuan has a large proportion of dry land and a high multiple cropping index. The existing dry land area is 27.387 million mu, and the area of double cropping and triple cropping is 19.17 million mu, of which the sowing area of sweet potato is about 12 million mu, and the annual output of fresh potato is about 15 million t. With the development of pig breeding in Sichuan province from traditional free-range to intensive and large-scale, the original habit of feeding pigs with potato pieces and vines will be gradually replaced by industrial feed, and the demand for sweet potatoes will be further reduced. According to the calculation that Sichuan Province provides two-thirds of the raw materials for sweet potato products nationwide, the planting area of sweet potatoes can be reduced by nearly 8 million mu under the condition that the yield of sweet potatoes is gradually increased. In addition, wheat-corn, wheat-sweet potato and other double cropping patterns will be changed into "wheat (potato)/jade/bean" triple cropping, and the original four-cropping pattern dominated by summer, autumn and winter beans will be gradually optimized into triple cropping soybean, which will have a development potential of about 2 million mu. Therefore, through 8-1 years' development, by the end of the 12th Five-Year Plan, the sown area of interplanting soybean in Sichuan Province is expected to reach 1 million mu, which will produce about 1.6 million tons of soybean, directly increasing farmers' income by 1.264 billion yuan, saving 57 million laborers, saving 12 million kg of urea and saving about 2.593 billion yuan for farmers. Chongqing, Guizhou, Yunnan, Hubei, Guangxi and other provinces (regions) have also successfully interplanted soybeans with corn. If all the existing corn production modes are developed into the Yudou intercropping mode, the potential area of soybean intercropping in southern China will be 72,24, mu, with an annual yield of 11,523,8 tons of soybeans, which will increase income and reduce expenditure by 18,679 million yuan, which will surely make agricultural production in dry land in Sichuan and even in southern China step up to a new level and revitalize our country.

IV. Key points of cultivation techniques of "wheat/jade/bean" mode

1. Standardize the strip-shaped 2m-box-opening mode for crop rotation, with 1m (or 1.17m) for five rows (or six rows) of wheat, 1m (or .83m) for two rows of corn, and 2-2 rows of wheat after harvest.

2. No-tillage direct seeding, that is, no-tillage direct seeding soybean with straw mulching after wheat harvest; After corn is harvested, it is directly cut down and covered with empty rows. When wheat is sown, no-tillage direct seeding is implemented and corn stalks are covered with wheat rows.

3. Select improved varieties, and pay attention to the time and space collocation of three crops when selecting varieties. Soybean varieties with developed main stems, strong stems and large grains should be selected, such as Gongxuan No.1 and Nandou No.12; Wheat varieties with high yield, high quality and strong resistance should be selected; It is advisable to select middle-maturing maize varieties with high quality, high yield, high resistance (disease and insect resistance, drought resistance and lodging resistance) and compact plant type.

4. Sow soybeans in time and reasonably close planting. The sowing date is from May 25th to June 15th. Sow the soybeans before or after the rain according to the local weather forecast. Before sowing, seed selection is carried out to remove seeds with incomplete grains, mottled and diseased spots, and a small amount of water is stirred and dissolved with 5% carbendazim 5g/kg seeds, and then the seeds are evenly dressed, dried and sown. The sowing density is 6 ~ 7 5 plants per mu in furrow and grass land, with the row spacing within the belt of .33m and the nest spacing of .4 ~ .5 m; There are 7 ~ 9 plants per mu in two sets of soil (and above), with an inner row spacing of .33m and a nest spacing of about .3 ~ .4m.. When sowing, the seeds are sowed by digging a nest, and the seeds and fertilizers are separated. The fertilizers are applied to two sides of the nest near the corn, and the seeds are thrown to the other side of the nest, and 5-6 seeds are thrown into each nest. After sowing, fine soil is covered. When it grows to 3 leaves, the seedlings should be evenly distributed in time, and only 3 plants should be kept in each nest.

the sowing period of wheat is from the end of October to the beginning of November. Loam and sandy soil are sowed by seeder, while clay is sowed by sowing or digging holes and cutting ditches. When sowing, the corn stalks are fished out first, and then covered after the seeds are evenly sown, and the seed consumption per mu is 5-6 kg; Sow by machine, pry the nest or cut the ditch, the nest spacing is .13 ~ .17 m, the row spacing is .2m, 8 ~ 9 seeds are sowed in the nest (4 ~ 5 seedlings are reserved in the nest), and 7 ~ 8 thousand seedlings are reserved in the mu.

maize should be sown in time according to local conditions, in hilly areas in the first half of March and in mountainous areas in the last half of March. The sowing method is seeding or transplanting with fertilizer. When sowing or transplanting, the distance between the two sides of the wheat belt is .17～.2m, the row spacing is about .6m, and the nest spacing is .4～.47m Two plants are left in the nest, and 2,8 ~ 3, plants are planted per mu.

Weeds are removed by chemical herbicides or manually before sowing or during the growing period of crops every season. The herbicide can be selected from 8 ~ 1ml/mu of 25% Zuo Dan EC for wheat and corn, and 1 ~ 1ml/mu of 5% acetochlor EC for soybean, and 3kg of water can be sprayed evenly in the field.

5. Scientifically apply fertilizer, control flourishing and prevent soybean from lodging, and adopt the method of mainly applying phosphorus and potassium fertilizer, and applying 3-35 kg of calcium superphosphate and 8-1 kg of potassium sulfate per mu of base fertilizer; After corn harvest, topdressing should be applied with 5 ~ 8 kg urea per mu depending on the field growth, and individual plots with poor growth can be applied with 3 ~ 4 kg urea per mu after the rain at flowering stage. The fertilization level of wheat and corn is the same as that of "wheat/jade/potato" model.

when the main stem of soybean grows to 5 nodes (or branching stage), 3 ~ 6 mg/kg uniconazole (or Youkang) or 18 ~ 25 mg/kg paclobutrazol solution is used to evenly spray 4 ~ 5 kg water on the stems and leaves to control the growth. Spraying uniconazole with concentration of 3 ~ 6 mg/kg to 4 ~ 5 kg of water for individual fields that are still flourishing at the initial flowering stage of soybean.

6. Control pests and timely harvest. During the whole growth period, attention should be paid to monitoring and controlling root rot, virus diseases and aphids. As soon as symptoms appear, apply drugs in time to prevent and control them. Plants with serious root rot and virus diseases should also be pulled out in time and taken out of the field to be discarded. Use 5% thiophanate methyl WP or 65% zineb WPlg per mu to spray 5kg of water on stems and leaves to control root rot, and use 15 ~ 3g of 5% pirimicarb wettable powder or 15 ~ 2ml of 2.5% Laifuling EC to dilute water to control aphids, red spiders and other pests. The pest control of wheat and corn is the same as the "wheat/jade/potato" model.

The suitable harvest period of soybean is from yellow maturity to full maturity, and the suitable harvest period is that the pod skin is dry and hard, and threshing is carried out after harvesting. Wheat and corn are harvested in time when they are ripe, providing sufficient time and space resources for soybean growth.

(Communication: Ya 'an, College of Agriculture, Sichuan Agricultural University, 62514)