Planting Performance and Application Prospects of Different Simplified Rice Cultivation Methods

1 Planting performance of several simplified rice cultivation methods

1.1.1 Actual harvested yield. The actual harvested yield was highest for machine-transplanted rice, with an average yield of 9000 kg/hm2; followed by hand-transplanted rice, with an average yield of 8850 kg/hm2; third was seedling-throwing rice, with an average yield of 8700 kg/hm2; fourth was wheat-intercropped rice, with a yield of 8400 kg/hm2; direct-seeded rice had the lowest yield, averaging 8250 kg/hm2.

1.1.2 Number of panicles per unit. Direct-seeded rice had the highest number of panicles per unit, with an average of 3.885 million panicles/hm2; machine-transplanted rice, seedling-throwing rice and wheat-intercropped rice all had around 3.600 million panicles/hm2; hand-transplanted rice had the lowest number of panicles, averaging 3.210 million panicles/hm2.

1.1.3 Total grains per panicle. The highest total grains per panicle was found in hand-transplanted rice, with 121 grains per panicle; machine-transplanted rice and seedling-throwing rice had 5-6 fewer grains than hand-transplanted rice; wheat-intercropped rice and direct-seeded rice had 10-12 fewer grains than hand-transplanted rice.

1.1.4 Seed-setting rate. Hand-transplanted rice had the highest seed-setting rate at 92%; followed by machine-transplanted rice and wheat-intercropped rice, which were 2%-3% lower than hand-transplanted rice; seedling-throwing rice and direct-seeded rice were the lowest, averaging 85%-86%, 6%-7% lower than hand-transplanted rice.

1.1.5 1000-grain weight. The highest was hand-transplanted rice, averaging 27.5 g; followed by machine-transplanted rice at 27.3 g; the lowest was direct-seeded rice at 25.5 g.

From the above analysis, it can be seen that hand-transplanted rice ranked first in total grains per panicle, seed-setting rate and 1000-grain weight, while its number of panicles was the lowest, because the transplanting quality was not guaranteed at transplanting and the transplanting density was relatively low.

1.2 Benefit analysis (Table 2) From the perspective of planting benefits, machine-transplanted rice had the best benefits, with a net benefit of 6465 yuan per hectare, 1155 yuan higher than hand-transplanted rice; followed by direct-seeded rice, with a net benefit of 6090 yuan per hectare, 780 yuan higher than hand-transplanted rice; third was wheat-intercropped rice, with a net benefit of 5880 yuan per hectare, 570 yuan higher than hand-transplanted rice; fourth was seedling-throwing rice, with a net benefit of 5865 yuan per hectare, 555 yuan higher than hand-transplanted rice; hand-transplanted rice was the lowest, with a net benefit of 5310 yuan per hectare.

1.3 Cost analysis (Table 3) Due to differences in rice cultivation methods, especially because direct-seeded rice and wheat-intercropped rice reduce the seedbed management cost in the seedling-raising procedure and the transplanting and seedling-throwing operations, the costs of various rice cultivation methods differ greatly. The highest total cost was hand-transplanted rice, averaging 8850 yuan per hectare, followed by seedling-throwing rice, machine-transplanted rice and wheat-intercropped rice; the lowest was direct-seeded rice, averaging 7110 yuan per hectare. Analyzing the cost of hand-transplanted rice, the high cost was mainly shown in two aspects. First, the cost of seedbed seedling management was high; hand-transplanted rice and seeds had the lowest cost, but seedbed management cost was relatively high, 420 yuan/hm2 higher than direct-seeded rice. Second, the cost of field transplanting was high; the field transplanting cost reached 1530 yuan/hm2, 855 yuan/hm2 higher than machine-transplanted rice.

1.4 Growth period A systematic follow-up survey was conducted on the growth period of the same variety, Xudao 3, under different rice cultivation methods. Different rice cultivation methods had a great impact on the growth period

The whole growth period of Xudao 3 under different rice cultivation methods decreased from 157 d for wheat-intercropped rice to 129 d for direct-seeded rice, a reduction of 28 d; the total number of leaves of Xudao 3 decreased from 17 leaves for hand-transplanted rice to 16 leaves for machine-transplanted rice, seedling-throwing rice and wheat-intercropped rice, while direct-seeded rice had the fewest total leaves, only 15 leaves.

The shortening of the whole growth period mainly occurred before jointing (Table 5). Compared with hand-transplanted rice, direct-seeded rice had a whole growth period shortened by 24 d. Among this, the number of days from sowing to jointing decreased by 13 d, accounting for 54% of the total reduction; the number of days from jointing to heading decreased by 5 d, accounting for 21%; the number of days from heading to maturity decreased by 6 d, accounting for 25%. Therefore, the difference in the whole growth period was mainly manifested in the shortening of the vegetative growth period.

2 Characteristics of different rice cultivation methods

2.1 Hand-transplanted rice When combined with dry seedling raising in fertile beds, compared with traditional wet seedling raising, hand-transplanted rice has the advantages of saving seedbed area, saving water, saving seeds, saving labor and reducing costs, and shows relatively good resistance to stripe disease. In particular, through the supporting application of biochemical agents, this technique is more convenient, the operation is simpler, seedling quality is better, and the seedling age elasticity is relatively large. After transplanting, the seedlings have strong vigor and tiller quickly. At present, with the large transfer of rural labor, there is a shortage of transplanting labor. Because the transplanting workload is large, the basic seedlings at transplanting cannot be guaranteed, which directly affects the number of panicles per hectare, thereby affecting yield and benefits.

2.2 Machine-transplanted rice Machine-transplanted rice has the advantages of saving labor and reducing costs, forming industrialization through the establishment of machine-transplanting rice associations, and promoting large-scale planting. However, in production, it has relatively high requirements for field preparation quality. Improper operation by machine operators can easily lead to phenomena such as broken rows and missing plants. At the same time, because the row spacing is relatively large, it affects sufficient panicle number, and the yield of some late-transplanted fields cannot be guaranteed. In particular, the yield of machine-transplanted rice after June 22 is generally around 7500 kg/hm2.

2.3 Wheat-intercropped rice Wheat-intercropped rice has the advantages of returning straw to the field, no-tillage and no seedling raising, environmental protection, labor saving and cost reduction. In production, four key points must be well managed: first, full and uniform seedlings; second, weeds; third, weedy rice; fourth, lodging.

2.4 Seedling-throwing rice Seedling-throwing rice has the advantages of saving labor and reducing costs, convenient operation, stable yield, and promoting large-scale planting. In production, when throwing seedlings, there are relatively high requirements for field surface preparation quality. In particular, if heavy rain occurs after throwing, floating seedlings are likely to occur. At the same time, field weeds must be controlled thoroughly.

2.5 Direct-seeded rice Direct-seeded rice has the advantages of simple operation, no need for seedbeds, labor saving, cost reduction, stable yield and high efficiency. At the same time, it avoids the peak period of the first generation of small brown planthopper and reduces the damage of stripe disease. Problems that must be noted in production include: 1) weeds are relatively serious; 2) excessive population in the later stage makes lodging easy; 3) if low temperature occurs in the later stage, safe full heading cannot be achieved.

3 Application prospects of several simplified rice cultivation methods

3.1 Developing machine-transplanted rice Machine-transplanted rice is the product of the organic combination of modern industry and traditional agriculture. It is an effective rice cultivation model for reducing agricultural labor, expanding planting scale and improving rice-growing benefits, and is the direction of future rice development. The main work needed at present is to develop machine-transplanting rice association organizations, improve supporting cultivation techniques for machine-transplanted rice, and especially conduct research on how to ensure the quality and timing of machine transplanting and achieve sufficient panicle number, so as to ensure the healthy and stable development of this technique.

3.2 Improving direct-seeded rice This rice cultivation method began to be applied on a small area in Guangyanghu Town, Baoying County in 2004, and is now gradually expanding throughout the county. In 2006, the area reported by towns in the county was 14,500 hm2, and actual application exceeded this figure, making it the simplified rice cultivation method with the largest utilized area. At present, the area of this rice cultivation method is also gradually expanding across the province. In the spring of 2006, the Institute of Agricultural Modernization of the Jiangsu Academy of Agricultural Sciences met the needs of the people and held multiple technical training sessions in various parts of the province. Therefore, Yangzhou City should increase technical strength, study the cultivation and management measures currently carried out spontaneously by the people, and combine them with existing advanced rice cultivation techniques for integrated assembly, so as to improve the cultivation and management technical level of direct-seeded rice.

3.3 Expanding wheat-intercropped rice Wheat-intercropped rice does not raise seedlings, does not plow and prepare fields, and does not transplant seedlings; it returns straw to the field, solves the problem of wheat straw burning, builds soil fertility, improves the soil, and is conducive to the sustainable development of agriculture. At the same time, because cultivation and management measures have been studied in depth, problems such as full seedlings, uniform seedlings, weedy rice and lodging have been relatively well solved. It is a key simplified rice cultivation method promoted in Yangzhou City. On the basis of demonstration and promotion in the previous two years, it is recommended to increase training, publicity and promotion efforts and expand its application area.

3.4 Stabilizing seedling-throwing rice Seedling-throwing rice has obvious advantages of saving effort and labor, high yield, high efficiency and simple operation, and is welcomed by farmers. In Baoying County, its application range is mainly concentrated in 3 townships: Fanshui, Anyi and Xiaoguanzhuang. The people in these areas have already mastered this technique skillfully, so the application area has remained relatively stable.