湖南烟区土壤含氯状况及烤烟施氯效应

对湖南省主要烟区3329个土壤样品中水溶性氯含量的测定结果表明,湖南省主要烟区土壤水溶性氯含量平均为16.6.mg/kg,在烤烟生长适宜的含氯范围内。不同烟区土壤中水溶性氯含量差异较大,湘西、湘中烟区,水溶性氯含量较低的土壤所占比例较大。田间试验表明,适量的氯素营养有利于提高烤烟旺长期叶片中的叶绿素含量和植株根系活力,提高烤烟生长前期Nrase的活性;在氯含量较低的土壤上,施入烟草的钾肥总量中,氯化钾所占比例为15%～30%时(以K2O计),烟叶可增产5.2%～16.9%,产值增加1911.0～7348.5元/hm2,中上等烟比例提高10.2～11.5个百分点,烟叶的品质也得到改善,不会造成土壤氯的积累。在湖南省乃至南方一些土壤氯含量较低的地区,在烟草上可考虑适当施用一定量的氯化钾部分代替硫酸钾,以降低肥料投入成本,提高烟叶的经济效益。

Status of chlorine content in tobacco-planting soils in Hunan province and tobacco responses on chlorine application

The analysis results of water-soluble Cl^- contents of 3329 soils samples from main tobacco-planting areas of Hunan province showed that the mean values of water-soluble Cl^- content was 16.6 mg/kg for these samples.There was a huge difference of Cl^- contents between the soils of different tobacco-planting areas.Soil with low water-soluble Cl^- content in western Hunan and central Hunan accounted for big portion.The results of field experiments showed that rational Cl^- application was favor of increasing chlorophyll content in leaves and root activity in tobacco plants at vigorous growth stage,and promoting NRase activity in leaves at early growth stage of tobacco plants.In lower Cl^- content soils,when dose of KCl(K₂O) accounting for 15%—30% of total potassium fertilizer,flue-cured tobacco yield increased 5.2%—16.9%,production value added 1911.0—7348.5 yuan/hm²,and the proportion of middle and superior tobacco leaves raised 10.2%—11.5%.The quality of flue-cured tobacco was also improved without causing Cl^- accumulation in soils.We could concluded that KCl should be partly be applied instead of K₂SO₄ from the soils with low Cl^- content in Hunan and south China from the point view of input cost and economic benefit of flue-cured tobacco.