The Research On Planting Density And Fertilizer Effect Of Short-season Cultivating Of Cotton In The Yangtze River Region

In order to study the technology of the cotton’s high efficient direct seeding along Changjiang River area, especially in Hunan area, four kinds of different densities had been designed in the field to study under direct seeding condition The experiment studied the cotton yield and fiber quality canopy structure, canopy apparent photosynthesis influenced by the planting densities,allocations of row-spacing, date of seeding and nitrogen application rate.1.From June 14th to April 30th, the density of 30000/hm2-60000/hm2 range, the yield decreased with the sowing date postponed, and presented parabolic change with density increased.Sowed on April 30, the lint yield reached the highest of 2876.79kg/hm2 under 50000 plants/hm2 treatment, significantly higher than other treatments. The appropriate delay in the sowing period accelerated the growth process, and when the sowing time postponed to May 30th years, the fertility period can be controlled within 110 days.2. The fiber strength of 30000 plants per hectare was lower than that of the other three densities significantly. The fiber length, uniformity index, micronaire, tensile stretch have little effect and no significant difference by the growing density increased. The fiber length,micronaire,tensile stretch and fiber strength of the latest date of seeding was siginificantly different with those of the other 3 date of seeding3..The PAR of the high density group was higher than that of low density group.The PAR of wide-narrow row spacing group was higher than that of equal planting spacing. In the three stages,the transparency of full boll stage was the lowest at an average 56.09% of the full squaring stage.The transmissivity of direct light rate increased steadily with the process of growth rate.4. In late may increase density (60000 plants/hm2-90000 plants/hm2),The planting density, allocations of row-spacing,nitrogen application rate have significant effect on the net photosynthetic rate of full squaring stage and full boll stage.5. Different nitrogen has important significance in bolls of cotton population. The planting density play the important role of increase the yield of seed cotton and lint cotton. The yield of seed cotton and lint cotton are significantly influenced by three factors. The interactions of three factors had a significant effect on increase yield.6.Under C2 level of nitrogen(180kg/hm2),the fiber length, tensile stretch are much higher. The high density cotton population gets higher uniformity index than the low density. With same line spacing treatment, Uniformity index is higher than wide-and narrow-row treatmentCombined with the results of 2 years field experiment, the increase of density can improve the yield of the short season cotton. In 2013 the lint yield of 50000 plants/hm2 was the highest,2876.79kg/hm2. In 2014, the lint yield of 90000 plants/hm2 was the highest, 5240.81 kg/hm2. And when the date of seeding postponed to around May 30th, the fertility period can be controlled within 110 days, conductive to the whole mechanization.