Effects Of Soil Alkali Hydrolysable Nitrogen Concentration On Biomass And Nitrogen Accumulation Eigenvalues,Fiber Yield Ang Qualities Of Cotton Aftter Initial Flowering

As an important economic crop, cotton plays an important role in our countrys. Nitrogen is one of the limiting factors that affect cotton yield and quality. Nitrogen rate affects the concentration of soil alkali hydrolysable nitrogen, and the dynamic change of soil alkali hydrolysable nitrogen concentration (SAHNC) can affects biomass and nitrogen accumulation and fiber yield and qualities; analyzing the effects of SAHNC on them can provide a reasonable cultivation theory basis for cotton’s high yield. Two field experiments were conducted at Dongtai (120°19’E,32°52’N) and Dafeng (120°28’E,33°12’N) Jiangsu province, in2009and2010, severally, with a cultivar Xiangzamian8. The objectives in this study were (1) to study the effects of soil alkali hydrolysable nitrogen concentration on biomass and nitrogen accumulation eigenvalues of cotton after initial flowering,(2) to study the effects of soil alkali hydrolysable nitrogen concentration on nitrogen concentration and nitrogen accumulation in the subtending leaf of cotton boll after initial flowering,(3) to study the responses of soil alkali hydrolysable nitrogen concentration on fiber yield and qualities. The main results were as follows:1. Effects of soil alkali hydrolysable nitrogen concentration on biomass and nitrogen accumulation eigenvalues of cotton after initial floweringThat the change of SAHNC could be simulated with a cubic function, biomass and nitrogen accumulation of cotton could be simulated with logistic formula; average rate and duration of the SAHNC’s speedy reducing had significant correlation with the biggest rate and duration of speedy accumulation period of cotton’s biomass and nitrogen, and there were optimal average rate and duration of the SAHNC speedy reducing for cotton to had optimal biomass and nitrogen accumulation eigenvalue, and the optimal average rate and duration of the SAHNC speedy reducing were similar to the values that obtained under the nitrogen applied levels of375kg ha-1; cotton had highest fiber yield and optimal fiber qualities under the nitrogen applied levels of375kg ha-1. Therefore, optimal nitrogen applied level and nitrogen applied strategy can adjust the dynamic change of SAHNC, and it’s beneficial for biomass and nitrogen accumulation eigenvalue and the conformation of lint yield and qualities after initial flowering.2. Effects of soil alkali hydrolysable nitrogen on nitrogen concentration and nitrogen accumulation in the subtending leaf of cotton boll after initial flowering,The change of SAHNC, nitrogen concentration and nitrogen accumulation in the SAHNC SLCB could be simulated with a cubic function, power and logistic formula, severally. nitrogen concentration in the SLCB increases, the rate of nitrogen concentration in the SLCB reducing reduces with the increase of nitrogen rate, correspondingly; the biggest rate and duration of the SLCB’s nitrogen speedy accumulation period had significant correlation with average rate and duration of the SAHNC speedy reducing, and there were optimal average rate and duration of the SAHNC speedy reducing for cotton to had nitrogen accumulation eigenvalue in the SLCB, and the optimal average rate and duration of the SAHNC speedy reducing were similar to the values that obtained under the nitrogen rate of375kg ha-1; cotton had highest fiber yield under the nitrogen applied levels of375kg ha-1.Therefore, optimal nitrogen applied level and nitrogen applied strategy can adjust the dynamic change of SAHNC, and it’s beneficial for nitrogen concentration and nitrogen accumulation in the SLCB and the conformation of lint yield and qualities after initial flowering.3. Responses of soil alkali hydrolysable nitrogen concentration on fiber yield and qualitiesFiber yield and qualities indicated a first and then decreased trend with the increasing of nitrogen rate. The relationship between the dynamic change of SAHNC and final fiber yelid, micronaire and strength can be simulated with a quadratic function; it existed an optimal SAHNC that make sure cotton had high fiber yield and qualities during the flowering and boll stages, and the optimal SAHNC were similar to the concentration that obtained under the nitrogen rate of375kg ha-1. Therefore, we can get high fiber yield and qualities by regulating the SAHNC during the flowering and boll stages to fiber mature stage.