Study On Agronomic Control For Direct Sowing Cotton Planted After Wheat Harvest Based On Mechanical Harvesting

The study conducted at Yangzhou University of Agriculture plots in 2013-2014 to special early maturing cotton varieties Guoxin early 12-1 and CCRI 50 for materials to live cotton after wheat planting pattern design density, chemical control of two factors, especially randomized block two factors early varieties and fertilizer, potash fertilizer as factors based on mechanized harvesting to achieve high yield and quality of cotton, plant type control, concentration boll, centralized boll opening and other key technologies. The main findings are as follows:High density (105,000 plants/hm2) with moderate chemical control (seedling 90 ml/hm, squaring stage 180 ml/hm2, flowering 360 ml/hm2, boll of 540 ml/hm2), the number of groups boll multi (958,500/hm2), high yield (3440.8 kg/hm2 lint), large boll. Density fiber lint, micronaire value, uniformity, maturity has little effect, but moderate chemical control is conducive to fiber length uniformity, improve maturity.Under the experimental conditions, moderate chemical control helps reduce plant height, keeping it suitable for mechanized harvesting requirements, lower density, and chemical control cooperation, fruiting branches are at the beginning of the section level height 20 cm or more, of the control system is shortened upper, middle and lower part of the fruit branch length, especially the upper part of fruiting length, moderate chemical control fruiting length mechanized harvesting within the required range. Meanwhile, the high density with moderate chemical control helps improve the fruit section volume groups and boll number, but also conducive to concentrated boll opening and defoliation, the formation of agronomic traits suitable for apheresis.After the high density planting wheat broadcast mode, with the nitrogen rate increased, the country welcomed two special early-maturing varieties of yield and composition of 12-1 and 50, height, nutrition and reproductive organs dry matter and nitrogen accumulation radiate added features, such as nitrogen application rate per hectare deal with 195 kg,120 kg of nitrogen rate than 45 kg yield 13.1% and 8.5%. However, the amount of nitrogen fertilizer per hectare,195kg,120kg between treatment differences were not significant. So Nitrogen 120 kg/ hm2 is more efficient. Potash applications to improve the boll volume and boll weight, and increases the amount of potassium increases; improving cotton plant chlorophyll content, increased stomatal conductance, net photosynthetic rate of increase, and with the amount of potash application improve and enhance boll rapid increase in the volume of 0-17 d after flowering,0-31 d after flowering and boll weight rapidly increasing. Its physiological mechanism showed Fv, Fm improve, increasing the electron transfer PS II improve PS II photochemical activity, while reducing Fo, improve resilience, fiber invertase improved, increased cellulose content.Defoliant ripening agents significantly increase the rate of wheat after defoliation and boll opening rate of live cotton, thidiazuron and ethephon respectively, the amount of defoliation rate at 900 g/hm and 4500 ml/hm about 90 percent, boll rate increased by more than 44.7%, in favor of centralized boll opening and apheresis. But also can significantly improve the boll weight. In addition, within thidiazuron and ethephon dose amount the scope of the test used next crop not affected wheat growth, germination rate, survival rate and dry with no significant difference between the control. But will lead to decline in canola transplanting survival, leaf shedding and dry matter accumulation decreased. So off next crop ripening agent rape leaves when applied technology needs to be further explored.