Response Of Cotton Growth To Transplanting Date And Shading Of Soilless-Substrate Naked-Seedling And Transplanted

Soilless-substrate naked-seeding and trabsplanting,a Simplified Cultivation Techniques of high yield and quality with modern agriculture,and therefore has become the main simplified cotton cultivation technology.In recent years, the global warming trend has become serious, and the climate warming made the most northern bound of crop planting northward. For this reason, how to make use of the current resources of temperature and light was very necessary. In this article, two experiments were designed to investigate the effect of accumulated temperature and light on cotton.Experiment I:Effect of different transplanting date on the growth and development of transplanting cotton. The results are as follows:1. Different transplanting date influenced the growth period of transplanting cotton. The recovering stage and seeding stage became shorter with the postponement of the transplanting date, while bud stage kept the same and the flower and boll stage became longer.2.The root fresh weight, root dry weight, root area, root diameter and root length increased within the growth process. The later transplanting date is, the faster the root growed.3. Treatments of different transplanting dates showed the same variation tendency in soluble sugar (decline, increase and then decline), there were significant differences among different treatments. All treatments showed the same variation trends in the starch cotton (decline, increase decline and then increase),there were some differences between each treatment.4. Eight treatments showed the same variation tendency in dry weight and leaf area (increase, and then decline). With the postponement of the transplanting date, the time got shorter when the leaf area got the turning point. Different treatments influenced the growth of height. The growth rate of height became faster with the postponement of transplanting date. The time got shorter, when getting Cotton Top.5. Treatments of different transplanting dates showed the same variation in boll seed cotton weight and number of bolls per plant (increase, and then decline), and the control treatment (CK) was the turning point. The lint percentage rate kept the same before timely transplanting, while the lint percentage rate was lower after timely transplanting.6. The fiber length and specific strength of CK were the best in treatments of different transplanting dates. Treatments of the two latest transplanting dates, the fiber length was the shortest, while specific strength was smaller. The micronire of Zh60was smaller with the postponement of transplanting period. The micronire of Zh60performance firstly increased and then declined, and CK was the turning point. The elongation and uniformity of each species kept the same. There was no significant difference within the postponement of transplanting period.Experiment II:Effect of shading on the seedling growth of transplanting cotton. The results are as follows:1. During the recovering stage, different shading treatments significantly influenced the content of soluble sugar and starch accumulation capacity. The content of soluble sugar in control showed an upward trend, the three shading treatments showed a downward trend. The starch accumulation capacity in control treatment showed a downward trend, the three shading treatments showed an upward trend. After recovering-stage, the change of soluble sugar content and starch accumulation capacity had a similar tendency, but there were certain differences in different treatments.2. The SOD and POD activities increased before recovering-stage, and then decreased to a steady level finally. The SOD and POD activities of shading groups were lower than those of the control treatment.3. After recovering-stage, the leaf area, fresh weight, dry weight and plant height of shading groups were larger than those of the control treatment. The degree of shading during seedling period can alleviate the relative adversity of the substrate seeding-raising transplanted cotton and be beneficial to the growth and development of cotton seedlings.