Accurate quantitative cultivation techniques of Rice

(1) determination of sowing date: the accumulation of population photosynthetic production in the heading-maturity stage determines the yield of rice, and the heading and maturity stage must be arranged under the best climatic conditions, which is called the best heading and fruiting stage. The highest seed setting rate and 1000-grain weight can be obtained at the end of flowering at the best heading and fruiting stage. The observation in Jiangsu showed that the seed setting rate of japonica rice was the highest when the daily average temperature at heading stage was about 25 ℃. The 1000-grain weight of indica rice was the highest when the average daily temperature was about 21 ℃ during grain filling-ripening stage (the temperature of indica rice was generally 2 ℃ higher than that of japonica rice). The perennial occurrence date of these two temperature indexes can be set as the best heading and fruiting period in the area. Then the suitable sowing date was determined according to the number of days from sowing to the best heading date. After the sowing date is determined, the seedling age determines the transplanting period. For example, for 5 varieties with elongated internodes, the suitable seedling age for manual planting should be controlled within 6 leaves (5 leaves and 1 heart). It is necessary to prolong the seedling age (7 leaves and 1 heart) and apply the dense fertilizer technique of sparse sowing to cultivate strong tiller seedlings and transplanting large seedlings. (2) determination of reasonable basic seedlings: reasonable basic seedlings are the starting point of reasonable groups. In order to increase the panicle rate of stems and tillers by 80-90%, and to achieve sufficient ears, we must start with the determination of reasonable basic seedlings. The calculation formula of reasonable basic seedling is: X (reasonable basic seedling (ten thousand)) = y (suitable panicle number per mu) × ES (reliable panicle number per plant) with the increase of fertilization level, too small row spacing makes rice row closed immediately after jointing stage, which seriously affects the photosynthetic productivity of population long panicle stage and flowering and fruiting stage, and restricts the increase of yield. Expanding row spacing, controlling the number of peak seedlings and closing period (booting stage) are the key measures to obtain high yield. The practice of high-yield cultivation has proved that on the basis of ensuring sufficient panicle, an important measure is to reduce the basal tiller fertilizer and increase the application rate of panicle fertilizer. Only by expanding the row spacing can we create the necessary conditions for increasing the amount of nitrogen fertilizer per ear. Enhance the assimilation ability of rice plants to nitrogen panicle fertilizer, balance sugar and nitrogen metabolism, bring a series of benefits: increase the panicle rate of tillers, enhance the development ability of spikelet differentiation, form large panicles, inhibit stem and leaf elongation, increase stem strength and lodging resistance; reduce diseases Promote the growth of roots in the middle and later stage (especially the upper roots), delay the senescence of leaves in the middle and lower parts of the fruiting stage, improve the ability of photosynthetic production and accumulation in the fruiting stage, play a significant role in increasing seed setting rate, grain weight, improving rice quality and taste, etc., and expand the row spacing, it can also increase the water temperature at the tillering stage and promote the tillering of rice in cold regions. (3) accurate quantification of fertilization: the accurate quantification of fertilization should first solve the two problems of the reasonable proportion of N, P, K and the accurate quantification of nitrogen fertilizer. The reasonable application ratio of N, P and K can be determined by soil testing formula test. The accurate quantification of nitrogen fertilizer needs to solve the reasonable total amount of nitrogen application and the ratio of tiller fertilizer to panicle fertilizer. The total amount of nitrogen fertilizer is calculated by Stanford difference method. The basic formula is as follows: total nitrogen application amount (kg / mu) = target yield requirement (kg)-soil nitrogen supply (kg) / nitrogen use efficiency (%) target yield N requirement = target yield × 100kg rice requirement / 100kg. The nitrogen requirement of 100kg rice with yield of 500kg to 750kg per mu of conventional middle and late maturing japonica rice in Jiangsu is generally 1.85kg per mu and 2.0kg per mu when 600kg is over 700kg. The nitrogen requirement of 100kg of indica hybrid rice in Jiangsu is lower than that of japonica rice of the same yield grade (0.2kg). The demand of soil nitrogen supply directly uses the rice yield (basic yield) and 100kg rice nitrogen requirement in the non-N blank area, and the rice nitrogen uptake calculated reflects the comprehensive nitrogen supply of soil. When the basic yield is 400kg / mu, the nitrogen requirement per 100kg rice is 1.7kg in clay and 1.5kg in sandy soil. According to the results of previous studies, the nitrogen utilization rate in the current season is 40%, which is not only the critical index value for high yield, but also the index value for the efficient use of nitrogen. Under the condition of reasonable total nitrogen, the yield was the highest when the ratio of basal tiller fertilizer to panicle fertilizer was 5 ∶ 5 ∶ 6, while in basal tillering fertilizer, the ratio of basal fertilizer to tiller fertilizer was 7:3, and the quantifier ratio of panicle fertilizer was 6 ∶ 4. Flower promoting fertilizer was applied at the tip of the fourth leaf, and flower protection fertilizer was applied at the tip of the second leaf. (4) quantitative control of water quantitative regulation of water quantitative regulation focuses on effectively controlling the occurrence of ineffective tillers and increasing the panicle rate of tillers in the early stage, and for the purpose of comprehensively improving population quality and enhancing photosynthetic productivity of fruiting populations in the middle and later stages. 1. Living plant tillering stage: living plant tillering stage is mainly irrigated in shallow water layer (2-3 cm). The main results are as follows: (1) the seedlings of medium and large seedlings are large and need water layer care after transplanting into the field, so as to meet the physiological and ecological demand for water, which is beneficial to adjust the suitable temperature and humidity in the field, maintain water balance, prevent wilting and reduce plant injury. promote rooting and living trees. Ammonium nitrogen was mainly absorbed by seedlings at tillering stage, and the water layer could promote the ammoniation of soil and the tillering growth of rice seedlings. Therefore, from transplanting to tillering stage, from physiological and ecological point of view, shallow water irrigation should be given priority to, combined with short-term dry ventilation between quantifier irrigation. (2) the seedling body of mechanically inserted seedlings is small, and the leaf evaporation is small. In addition, part of the soil in the root is transplanted, and keeping the soil moist after moving into the field can meet the requirements of physiological water demand. Its main purpose is to maintain soil ventilation and promote seedling rooting as soon as possible. There is no aquifer in cloudy days, thin water is irrigated on sunny days, and then thin water is added to dry water after 1-2 days. After a living seedling of one leaf age is grown, the water is cut off and exposed to the field, and the field is kept moist to further promote rooting. When the second leaf grew after transplanting, the seedling body was larger, and the shallow water layer was established with the application of tillering fertilizer and maintained until the whole effective tillering stage. 2. Shelve the field early. In the N-n-1 leaf age (N represents the total number of leaves of the main stem, n represents the number of elongated internodes), when the total number of tillers of the population reached about 80% of the number of seedlings per spike (70-90%) began to drain and shelve the field. The shelving effect occurred in the Nmurn leaf age, and the invalid tillering occurred from the N-n+1 leaf age was controlled. 3. Moist irrigation is carried out from jointing to mature stage, dry, dry and wet. Keeping the soil moist and solid, meeting the physiological water demand of rice, enhancing the root activity and improving the photosynthetic production and accumulation capacity of the population in the middle and later stage is one of the key technologies to improve the seed setting rate and grain weight.