Because the row spacing is narrowed, the density of 45 cm double-row close-planted soybean increases, so when selecting varieties it is essential to choose varieties with strong, lodging-resistant stalks that are short or semi-short. In addition, according to the climate and geographical characteristics of Yi County, when selecting varieties one should choose those that mature slightly earlier than the standard variety maturity but not too early
Because the row spacing is narrowed, the density of 45 cm double-row close-planted soybean increases, so when selecting varieties it is essential to choose varieties with strong, lodging-resistant stalks that are short or semi-short. In addition, according to the climate and geographical characteristics of Yi County, when selecting varieties one should choose those that mature slightly earlier than the standard variety maturity but not too early, so as not to waste accumulated temperature and affect yield. At present, the varieties in our county that meet the varietal conditions and are suitable for narrow-row close-planting cultivation include Heinong 35, Heihe 19, Heihe 27, Hongfeng 12, Hongfeng 11, Hefeng 40, Suinong 11, Kennong 19, Kennong 18, Kenjiandou 25, Kenjiandou 27, Beifeng 11, etc. 1.2 Seed treatment Before sowing, seeds should be carefully selected by hand or with a soybean seed selector, removing impurity seeds, insect-damaged kernels and diseased-spot kernels, so that the seed moisture content is <13.5%, purity and cleanliness >98%, and germination rate >85%. To control root rot and the underground pest the two-striped leaf beetle, soybean seed coating agent should be used to treat the seeds; for untreated seeds, zinc fertilizer, or boron-molybdenum acid, or ammonium molybdate, etc., may be used for seed dressing. 2 Reasonable plowing and fine seedbed preparation 2.1 Plot selection and previous crop selection Choose plots that are flat, have deep tillage layers, relatively high soil fertility, and have undergone summer-autumn plowing or stubble-harrowing deep loosening; the previous crops should mainly be corn, potato and wheat. Do not plant on the same crop repeatedly, and do not plant on adjacent-stubble land. 2.2 Creating good soil tillage layer conditions Reasonable plowing and fine seedbed preparation are one of the fundamental measures for increasing soybean yield; they can reduce disease and pest damage and eliminate weeds, and can store water and preserve moisture and mature the soil, and are the basis for full and strong soybean seedlings. For flat-planting narrow-row close planting, timely hoeing and ridging during the growth period can effectively improve the soil's drought resistance, waterlogging resistance and warming capacity. If a plot without a foundation of deep loosening and deep plowing is encountered, plowing should be attempted as stubble-harrowing deep loosening or summer-autumn plowing to a depth of 18~20 cm, so as to create good soil tillage layer conditions, making the soil fine and crumbly, with adequate tillage depth and a level surface. 3 Scientific fertilization Combined with seedbed preparation, as base fertilizer, organic fertilizer with an organic matter content >8% should be applied all at once at more than 5 tons/hectare; when applying chemical fertilizer, trace elements and nitrogen, phosphorus and potassium should be applied in a balanced and reasonable manner according to soil testing formulas. Chemical fertilizer used as accumulated fertilizer should be applied 4~5 cm below the seed, or applied in layers 7~14 cm below the seed. On the basis of the conventional fertilization amount, it should be increased by 15%. At the early flowering stage of soybean and in the early stage when growth is relatively weak, monopotassium phosphate 1.5 kg/hectare plus 10 kg/hectare should be sprayed with 500 kg/hectare of water, or if this plot did not have trace fertilizer seed dressing or did not use trace fertilizer as seed fertilizer, trace fertilizer may also be added for spraying. 4 High-quality sowing When applying 45 cm double-row close planting, since the current varieties are mostly bred in conventional ridges under normal density, the density should not be too high, and ridge-top double-row equidistant precision sowing or mechanical flat sowing should be adopted. The small row spacing between the double rows is 10~12 cm, and the large row spacing is 45 cm. In northern regions, sowing may begin from May 5~15 when the sowing soil temperature is stably 7°C~8°C, with 360,000~460,000 seedlings retained per hectare; after sowing, cover with soil 3~5 cm and press, and during sowing ensure uniform insertion and consistent depth, with no missed seeds and no broken strips. 5 Chemical weeding Chemical weeding is the optimal choice in 45 cm double-row close planting, because limited by density or plant growth, manual weeding and mechanical weeding are not effective. In autumn when the temperature is stably below 10°C, combined with autumn seedbed preparation and when the soil temperature is suitable, autumn herbicide application may be carried out; the dosage should be 10%~20% more than spring application, and it can effectively control weeds in the following spring. A soybean-ethyl combination agent may also be used after sowing and before emergence, under relatively good soil moisture conditions, for soil sealing, with good weed-killing effect. If the pre-emergence weed control effect is poor, mechanical weed control such as with spike-tooth harrows may be used, or post-emergence chemical weed control may be carried out in a timely manner with agents such as bentazone and haloxyfop emulsifiable concentrate. 6 Disease and pest control For control of soybean root rot, during the soybean seedling stage the roots may be drenched or sprayed with 25% metalaxyl wettable powder at 800 times dilution; soybean aphids may be controlled by spraying with pirimicarb at 1500 times dilution or omethoate; red spider mites may be controlled by spraying with 1500 times dilution of insect-mite killer or pyridaben emulsifiable concentrate; for soybean pod borer, if the control threshold is reached, that is, when the previous year's insect-damaged rate is >5%, conventional spraying may be used with agents such as methomyl, deltamethrin and fast-killing spirit. For control of soybean sclerotinia stem rot, 50% vinclozolin wettable powder 1.2~1.5 kg per hectare or 50% procymidone should be used, mixed with 600 kg of water for spraying, and control should be carried out at the early flowering stage of soybean. 7 Combining promotion and control It is not good for soybean growth to be too weak or too vigorous. If early growth is too vigorous and growth continues too rapidly until the flowering stage, it will become a leggy field, leading to dangers such as flower and pod drop, lodging and yield reduction. Therefore, agents such as Fengshoubao, paclobutrazol and triiodobenzoic acid may be sprayed to suppress excessively growing plants, prevent lodging, increase flowers and preserve pods, and raise yield. If growth is too weak, and plants are short and ridge closure is late due to drought and various other reasons, urea may be used for topdressing outside the roots, or a mixed solution of monopotassium phosphate and urea may be sprayed for foliar topdressing at the early flowering stage of soybean. 8 Timely harvest Timely harvest at the soybean maturity stage is the key to a bumper harvest. A combine harvester may be used to harvest at the full maturity stage when all soybean leaves have fallen, without leaving bottom pods. Make the cleanliness rate >95%, broken kernels <5%, and total harvest loss <4%. To make the soybean commodity quality reach above the national third-grade standard, mechanical or manual careful selection should be carried out promptly after threshing. 9 Conclusion At present, adopting the 45 cm double-row close-planting technique in soybean cultivation can build a population structure of “uniform plants, equidistant spacing”, with innovative advantages in planting method, variety screening and application, and cultivation system, making the nutritional space of individual plants within the soybean population more scientific and reasonable, integrating a completely new cultivation technology system that is energy-saving, drought-resistant and low-tillage, and the cultivation route realizes the characteristics of “high density, high quality, high yield”, leading new soybean production and planting technology.
Because the row spacing is narrowed, the density of 45 cm double-row close-planted soybean increases, so when selecting varieties it is essential to choose varieties with strong, lodging-resistant stalks that are short or semi-short. In addition, according to the climate and geographical characteristics of Yi County, when selecting varieties one should choose those that mature slightly earlier than the standard variety maturity but not too early, so as not to waste accumulated temperature and affect yield. At present, the varieties in our county that meet the varietal conditions and are suitable for narrow-row close-planting cultivation include Heinong 35, Heihe 19, Heihe 27, Hongfeng 12, Hongfeng 11, Hefeng 40, Suinong 11, Kennong 19, Kennong 18, Kenjiandou 25, Kenjiandou 27, Beifeng 11, etc.
1.2 Seed treatment
Before sowing, seeds should be carefully selected by hand or with a soybean seed selector, removing impurity seeds, insect-damaged kernels and diseased-spot kernels, so that the seed moisture content is <13.5%, purity and cleanliness >98%, and germination rate >85%. To control root rot and the underground pest the two-striped leaf beetle, soybean seed coating agent should be used to treat the seeds; for untreated seeds, zinc fertilizer, or boron-molybdenum acid, or ammonium molybdate, etc., may be used for seed dressing.
2 Reasonable plowing and fine seedbed preparation
2.1 Plot selection and previous crop selection
Choose plots that are flat, have deep tillage layers, relatively high soil fertility, and have undergone summer-autumn plowing or stubble-harrowing deep loosening; the previous crops should mainly be corn, potato and wheat. Do not plant on the same crop repeatedly, and do not plant on adjacent-stubble land.
2.2 Creating good soil tillage layer conditions
Reasonable plowing and fine seedbed preparation are one of the fundamental measures for increasing soybean yield; they can reduce disease and pest damage and eliminate weeds, and can store water and preserve moisture and mature the soil, and are the basis for full and strong soybean seedlings. For flat-planting narrow-row close planting, timely hoeing and ridging during the growth period can effectively improve the soil's drought resistance, waterlogging resistance and warming capacity. If a plot without a foundation of deep loosening and deep plowing is encountered, plowing should be attempted as stubble-harrowing deep loosening or summer-autumn plowing to a depth of 18~20 cm, so as to create good soil tillage layer conditions, making the soil fine and crumbly, with adequate tillage depth and a level surface.
3 Scientific fertilization
Combined with seedbed preparation, as base fertilizer, organic fertilizer with an organic matter content >8% should be applied all at once at more than 5 tons/hectare; when applying chemical fertilizer, trace elements and nitrogen, phosphorus and potassium should be applied in a balanced and reasonable manner according to soil testing formulas. Chemical fertilizer used as accumulated fertilizer should be applied 4~5 cm below the seed, or applied in layers 7~14 cm below the seed. On the basis of the conventional fertilization amount, it should be increased by 15%. At the early flowering stage of soybean and in the early stage when growth is relatively weak, monopotassium phosphate 1.5 kg/hectare plus 10 kg/hectare should be sprayed with 500 kg/hectare of water, or if this plot did not have trace fertilizer seed dressing or did not use trace fertilizer as seed fertilizer, trace fertilizer may also be added for spraying.
4 High-quality sowing
When applying 45 cm double-row close planting, since the current varieties are mostly bred in conventional ridges under normal density, the density should not be too high, and ridge-top double-row equidistant precision sowing or mechanical flat sowing should be adopted. The small row spacing between the double rows is 10~12 cm, and the large row spacing is 45 cm. In northern regions, sowing may begin from May 5~15 when the sowing soil temperature is stably 7°C~8°C, with 360,000~460,000 seedlings retained per hectare; after sowing, cover with soil 3~5 cm and press, and during sowing ensure uniform insertion and consistent depth, with no missed seeds and no broken strips.
5 Chemical weeding
Chemical weeding is the optimal choice in 45 cm double-row close planting, because limited by density or plant growth, manual weeding and mechanical weeding are not effective. In autumn when the temperature is stably below 10°C, combined with autumn seedbed preparation and when the soil temperature is suitable, autumn herbicide application may be carried out; the dosage should be 10%~20% more than spring application, and it can effectively control weeds in the following spring. A soybean-ethyl combination agent may also be used after sowing and before emergence, under relatively good soil moisture conditions, for soil sealing, with good weed-killing effect. If the pre-emergence weed control effect is poor, mechanical weed control such as with spike-tooth harrows may be used, or post-emergence chemical weed control may be carried out in a timely manner with agents such as bentazone and haloxyfop emulsifiable concentrate.
6 Disease and pest control
For control of soybean root rot, during the soybean seedling stage the roots may be drenched or sprayed with 25% metalaxyl wettable powder at 800 times dilution; soybean aphids may be controlled by spraying with pirimicarb at 1500 times dilution or omethoate; red spider mites may be controlled by spraying with 1500 times dilution of insect-mite killer or pyridaben emulsifiable concentrate; for soybean pod borer, if the control threshold is reached, that is, when the previous year's insect-damaged rate is >5%, conventional spraying may be used with agents such as methomyl, deltamethrin and fast-killing spirit. For control of soybean sclerotinia stem rot, 50% vinclozolin wettable powder 1.2~1.5 kg per hectare or 50% procymidone should be used, mixed with 600 kg of water for spraying, and control should be carried out at the early flowering stage of soybean.
7 Combining promotion and control
It is not good for soybean growth to be too weak or too vigorous. If early growth is too vigorous and growth continues too rapidly until the flowering stage, it will become a leggy field, leading to dangers such as flower and pod drop, lodging and yield reduction. Therefore, agents such as Fengshoubao, paclobutrazol and triiodobenzoic acid may be sprayed to suppress excessively growing plants, prevent lodging, increase flowers and preserve pods, and raise yield. If growth is too weak, and plants are short and ridge closure is late due to drought and various other reasons, urea may be used for topdressing outside the roots, or a mixed solution of monopotassium phosphate and urea may be sprayed for foliar topdressing at the early flowering stage of soybean.
8 Timely harvest
Timely harvest at the soybean maturity stage is the key to a bumper harvest. A combine harvester may be used to harvest at the full maturity stage when all soybean leaves have fallen, without leaving bottom pods. Make the cleanliness rate >95%, broken kernels <5%, and total harvest loss <4%. To make the soybean commodity quality reach above the national third-grade standard, mechanical or manual careful selection should be carried out promptly after threshing.
9 Conclusion
At present, adopting the 45 cm double-row close-planting technique in soybean cultivation can build a population structure of “uniform plants, equidistant spacing”, with innovative advantages in planting method, variety screening and application, and cultivation system, making the nutritional space of individual plants within the soybean population more scientific and reasonable, integrating a completely new cultivation technology system that is energy-saving, drought-resistant and low-tillage, and the cultivation route realizes the characteristics of “high density, high quality, high yield”, leading new soybean production and planting technology.