滴施酸化剂种类及用量对棉花生长的影响

Effects of Acidifier Types and Dosage on Cotton Growth

【目的】研究滴施酸化剂对根区土壤pH、有效锌、棉花根系及产量品质的影响,为棉花生产筛选出合适的酸化剂种类及用量。【方法】采用田间试验,设置3种酸化剂分别为硫酸铵(S)、草酸(C)、柠檬酸(N),3个酸化剂用量,对照(CK)不做酸处理,以硫酸铵替代每次追肥30%、50%、70%尿素的N确定硫酸铵及尿素用量,以酸化剂溶液提供等量H+为标准,确定其他酸化剂用量。【结果】在垂直方向上随酸化剂施用量的增加土壤pH降低0.05~0.24;在水平方向上随着酸化剂施用量的增加土壤pH降低2.3%~3.2%;无论在垂直方向还是水平方向上,距滴头越近或硫酸铵替代尿素比例越高的位置,土壤有效锌含量越高;在氮肥用量不变的情况下,30%~70%的氮肥用硫酸铵替代时,草酸、柠檬酸以等量H+滴施到棉花根区,0~30 cm根系干物质与CK相比均明显增加。根系干重为S_(3)>C_(3)≈N_(3)>CK;硫酸铵和草酸对棉花干物质积累最大,与对照相比,施用酸化剂提高了棉花的单铃重,显著增加了棉花单株结铃数,棉花产量随硫酸铵替代尿素比例的增加而增加;相比对照处理,酸化剂促进了纤维长度和比强度的增加,降低了整齐度及马克隆值。【结论】3种酸化剂中硫酸铵是最佳的酸化剂,替代尿素的比例为70%。

【Objective】Field experiments were conducted to study the effects of drip application of acidifier on soil pH,available zinc,cotton root system,yield and quality in root zone,so as to screen out suitable acidifier types and dosage for local cotton production.【Methods】Three kinds of Acidifiers,ammonium sulfate(S),oxalic acid(C)and citric acid(N),were set as the test control(CK)without acid treatment.The dosage of ammonium sulfate and urea was determined by substituting 30%,50%and 70%urea N for each top dressing.The same amount of H+was provided by acidifier solution as the standard,and then the dosage of other Acidifiers was determined.【Results】In the vertical direction,soil pH decreased by 0.05-0.24 with the increase of acidifier application rate;in the horizontal direction,soil pH decreased by 2.3%-3.2%with the increase of ammonium sulfate application rate;no matter in the vertical direction or in the horizontal direction,the closer the distance from the emitter or the higher the proportion of ammonium sulfate replacing urea,the higher the content of soil available zinc;when 30%-70%of nitrogen fertilizer was replaced by ammonium sulfate,oxalic acid and lime decreased When citric acid was applied to cotton root zone with the same amount of H+,the dry matter of 0-30 cm root increased significantly compared with CK.The results showed that the dry weight of root system was S_(3)>C_(3)≈N_(3)>CK;ammonium sulfate and oxalic acid had the largest accumulation of dry matter in cotton;compared with the control,the application of acidifier increased the single boll weight of cotton,significantly increased the number of bolls per plant,and the cotton yield increased with the increase of the proportion of ammonium sulfate replacing urea;compared with the control,acidifier promoted the increase of fiber length and specific strength,and reduced the uniformity and yield Micronaire value.【Conclusion】Among the three Acidifiers,ammonium sulfate is the best acidifier,and the proportion of replacing urea is 70%.