| The effects of five fertilizer models on cotton growth, physiological characters, also their fertilizer use efficiencies were studied under field condition with the material of Cang 198. Five treatments were conducted as CF1(common fertilizers, 100% of the total amount), CRF1(controlled release fertilizers, 100% of the total amount), CF2(common fertilizers, 80% of the total amount), CRF2(controlled release fertilizers, 80% of the total amount) and CK(no fertilizer), respectrively. Through the analysis of investigation and sampling in the important stages of cotton, this experiment was systematically studied the effects of controlled release fertilizers on the morphological, physiological and biochemical characters in cotton growth and development process, as well as the fertilizer use efficiency under different fertilizer models.The results were as follows:1. Compared with the common fertilizers (CF) in the same nutrient level, CRF had little effects on the height and stem diameter of cotton in the early stage, but the height and stem diameter of CRF were increased after full flowering. Though CRF reduced the number of fruit nodes of cotton, but the numbers of flower buds and bolls in the treatment of CRF were near to those in the treatment of CF under the same nutrient level.2. CRF could significantly increase the dry matter accumulation in each organ of cotton and the total dry matter accumulation of cotton, and increased the Nitrogen(N), Phosphorus(P) and Potassium(K) content of each organ. The dry matter accumulation in the treatment of CRF was higher than that of CF in the middle and late stages of cotton growth. Compared to the CF under the same nutrient level, the dry matter accumulation in the treatment of CRF1 and CRF2 were respectively improved by 36.53% and 35.03%. The dry matter distribution rate of reproductive organs in the treatment of CRF was lower than that of CF under the same nutrient level in the early period of reproductive organs appeared, but it was higher in the later period. In CRF treatment, the period of maximal dry matter distribution proportion appeared in advance. Compared with CF1, CRF1 decreased the N distribution in the main stem of cotton, and increased the N distribution in the bolls of cotton. Also CRF1 increased the P distribution in the flower buds and leaves of cotton, but decreased the P distribution in the bolls of cotton. As to K distribution, CRF1 increased in the bolls of cotton, but decreased in the main stem of cotton.3. Fertilization could increase the chlorophyll content of the function leaf. The chlorophyll content of the function leaf of CRF1 was significantly higher than that of CK on August 6th, and that was significantly higher than that of other fertilization treatments on August 21th, and that was very significantly higher than that of CF2 on September 12th. The chlorophyll contents of the function leaf of CRF were lower than those of CF under the same nutrient level in the early stage. But the result was opposite after full flowering. The effect of different models on the net photosynthetic rate of main stem function leaf was the same as the chlorophyll. The decreased value of Fv/Fm in CRF was lower than that of CF in that time, which showed that CRF reduced the impacts of stress situation on cotton plants.4. In early stage, the influences of CRF on MDA content and POD activity of the main stem function leaf were not obvious. But in the late stage, the MDA content decreased and POD activity were increased in the main stem function leaf of CRF, which showed that CRF reduced the lipid peroxidation degree and scavenged the reactive oxygen in the main stem function leaf in the late stage. The changes of MDA and POD showed that senescence could be delayed in CRF.5. In most of periods, the influences for cotton soluble protein and soluble sugar contents of CRF were small. But on August 6th, when the growth of cotton encountered adversity, the soluble protein and sugar contents of the main stem function leaf were changed. The soluble protein content of CRF2 was higher than those of CF2. While the soluble sugar content of CRF2 was significantly lower than that of CF2, CRF1 and CK. It was suggested that, in the low nutrient level under unsuitable condition, CRF promoted the protein synthesis and accelerated the transfer of nutrients of the main stem function leaves.6. Fertilization significantly increased the number of bolls of per plant, and the number of ineffective bolls. Compared to the CF under the same nutrient level, CRF increased the number of effective bolls of per plant and decreased the number of ineffective bolls. So it increased the ratio of effective bolls. The ratio of four kinds of bolls was optimized by CRF, and the total ratio of the bolls setting in hot days and a few early autumn days was increased by CRF. Compared to the CF under the same nutrient level, CRF1 and CRF2 respectively increased the seed cotton yield by 2.80% and 4.95%. The difference between the theoretical yield and actual yield of CK was the least, and it was 52.8 kg·hm-2 in seed cotton yield and 22.3 kg·hm-2 in lint cotton yield. Scince the effective bolls ratio was lower of CF than that of CRF, the difference between the oretical yield and actual yield of CF was higher than that of CRF. And it was 248.6 kg·hm-2 in seed cotton yield and 111.1 kg·hm-2 in lint cotton yield.7. Fertilization didn't have so much effect on fiber quality, but it could have some effect on micronaire. The micronaire of the bolls that opening in October of fertilization treatment were improved.8. In the same nutrient level, it was significantly improved in N dry matter production efficiency by CRF as compared with CF. The fertilizer input/output ratio, apparent recovery ratio, agronomic efficiency and absorption efficiency of N, P and K of CRF treatment were increased remarkably than CF. Soil nutrient contribution rate of CRF treatment was significantly decreased compared with CF. Compared with CF1, CRF1 increased the physiological efficiency of N by 27.77%, increased the agronomic efficiency of N by 121.32%, increased the absorption efficiency of N by 29.77%, and decreased the soil nutrient contribution rate of N by 22.34%.
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