【摘要】 <正> 在研究棉花严重缺硼,发生“蕾而不花”现象,提出土壤速效硼0.2ppm为棉田严重缺硼临界指标,以及施用硼肥防治棉花“蕾而不花”的基础上,我们继续对棉花潜在性缺硼与有效施硼开展了研究应用工作。棉花潜在性缺硼,发生在中度和轻度缺硼的土壤上,范围广泛。为了确定这一范围,各国一些研究者研究棉花缺硼的土壤临界指标与施硼肥效,得到明显不同的结果,显然与土壤气候条件的不同有关。我更多还原

【Abstract】 1.According to the results of four-year pot experiments and 306 field experiments, soil available B 0.8 ppm was the threshold for the yield increase and decrease of cotton. Therefore, we suggested that soil available B 0.8 ppm may be used as the diagnostic criteria for the B deficiency latent cotton. It is an useful guide for applying B to cotton.2.According to the results of six-year experiments, the cotton petiolar band may be used as the morphological diagnostic criterion for latent B deficiency.3.In 1981—1982, the results of 317 field experiments indicated that the yield of ginned cotton was increased on the average of 12.7 jin/mu (or about 10.7%) .The gross output value was above 18 yuan/mu, whereas the cost of B application was 0.4—0.5 yuan/mu only, a highly significant effect on yield increase with a high economic efficiency.4.The main role of B application to cotton was the increase of bolls per plant, of single boll weight and lint percentage. The quality was improved also.5.The methods of B application to cotton are determined by the available B content in the soil. Where B is severely deficient, B fertilizer can be applied at sowing, with a rate of 1—1.5’ jin of borax per mu. However, when the soil is in a state of moderate or slight B deficiency, the most effective, economical and safe method of application is the foliar spray of 0.2% borax solution at the square, early bloom and early boll stages.更多还原