Pay attention to seedling fertilizer and promote the early development of cotton seedlings

Recently, the author's investigation of the main cotton-producing areas in Hubei, Hunan, Anhui, Anhui and other provinces found that several new situations have emerged in cotton production this year. First, due to the reduced efficiency of cotton planting, many farmers have cotton fields. The selection of the area is very late, many of the unapplied base fertilizers, the cotton field fertility is insufficient; the second is the increase of wheat and rapeseed sputum, the corresponding delay in harvest, the early application of the base fertilizer can not be advanced; the third is the shortage of available nitrogen fertilizer on the agricultural resources market, it is difficult to meet cotton The demand for topdressing.  

Therefore, in the management of cotton seedling stage, we should highlight the use of topdressing as a remedy, attach importance to seedling stage topdressing, apply early seedling fertilizer, and promote early seedling early growth.  

Why should we put special emphasis on applying cotton seedlings? The reasons are as follows:  

First, the cotton seedling stage is the period with the highest nitrogen content in each growth period. The nitrogen metabolism in the seedling stage is the most active. The nitrogen content in this stage is more than 3.3%, which is higher than other growth stages.  

Second, the growth rate of the main roots of cotton seedlings is 4 to 5 times faster than that of the young stems. After the first true leaves of cotton are developed, the nutrients stored in the cotyledons are basically used up. If the fertilizer is insufficient, the extension of the main roots and the development of the lateral roots are inhibited. In production, we must make "strong seedlings grow roots first, and roots and deep seedlings are horizontal."  

Third, the temperature of cotton seedlings is relatively low, the light is less, the rain is more, the soil moisture is high, the permeability is poor, the microbial activity is blocked, the organic matter decomposition and nutrient release rate in cotton fields are slowed down. If the topdressing is late, the cotton roots are not easily absorb.  

Fourth, the strength of the cotton field is insufficient, the soil organic matter content is declining, and the storage fertilizer and fertilizer supply capacity are weakened.  

Fifth, some cotton fields are extensively cultivated, and the amount of base fertilizer applied is not much, and it is applied to the surface layer of the soil, and nutrient loss is more after the rain.  

Sixth, the application of good seedling fertilizer, one can increase the strong seedling coefficient of cotton; second, increase the number of true leaves; three can increase the true leaf area, improve photosynthetic efficiency; fourth can accelerate the growth process. According to the research of the agricultural scientific research department, after the emergence of three true leaves in cotton, the flower buds begin to differentiate. Applying the seedling fertilizer can promote the early growth and early development, so that the flower buds can be differentiated early, and then the buds, early flowering, early peaches and early maturity harvest.  

In the cotton seedling stage topdressing technology, the following improvements should be made: First, change the seedling fertilizer and not apply the seedling fertilizer to apply the seedling fertilizer early, use the nutrient seedling transplanting, and apply it on the seedling bed before transplanting. Sending the marrying fertilizer", after the transplanting, chasing the seedling fertilizer early; the second is to apply the late-acting fertilizer as the quick-acting fertilizer, and advocate the application of ammonium bicarbonate and urea. After the seedling, the fertilizer should be topdressed twice, and the 3~4 true leaves should be chased first. Times, 8-9 kg of ammonium bicarbonate per mu or 3~3.5 kg of urea. 6~7 pieces of true leaves, once again, 15 kg of ammonium bicarbonate per mu or 5 kg of urea. If the cotton field with sufficient base fertilizer is applied, it can be reduced as appropriate; the third is to change the application, the shallow application is to open the ditch or the deep application of the snoring to reduce the loss of fertilizer; the fourth is to change the dry application as water after application, to adjust the fertilizer with water, according to The amount of soil available nitrogen in the cotton seedling stage was 17.5 PPM (parts per million), and the soil available nitrogen content after watering was 25 PPM (million points), an increase of 7.5. PPM (million points), the effect is remarkable.