烟田掺沙对土壤理化性质与烤烟养分积累的影响

Effects of Sand Mixing in Tobacco Fields on Soil Physicochemical Properties and Nutrient Accumulation of Flue-cured Tobacco

为解决植烟水稻土质地黏重、烤烟生长发育受阻的问题,以云南玉溪烤烟5年连作的水稻土为研究对象,通过掺沙改变土壤粒级组成,研究土壤水稳性团聚体组成、理化指标、酶活性以及烤烟养分吸收与干物质积累情况,并分析了其相关性。结果表明,与未掺沙处理比较,掺沙30%、60%后砂粒含量分别显著增加了44.55%、58.59%(p<0.05),黏粒、粉砂粒含量随掺沙量的增加而降低。掺沙后,<0.25 mm粒级团聚体含量显著降低(p<0.05),大团聚体含量增加,土壤团聚体稳定性大小为掺沙30%>掺沙60%>不掺沙;土壤pH、过氧化氢酶活性增加,有机质、速效钾等主要养分含量降低,掺沙30%后土壤蔗糖酶、酸性磷酸酶活性分别比不掺沙处理显著提高了20.42%、268.69%(p<0.05);烟株干物质、氮磷钾元素累积量均增加,其中掺沙30%时增幅最大,并且干物质和养分累积量也最高。Pearson相关分析与冗余分析表明,土壤机械组成对土壤性状和养分累积的影响显著,多数生长指标、土壤pH、过氧化氢酶活性与砂粒含量极显著正相关(p<0.01),与黏粒、粉砂粒含量极显著负相关(p<0.01),土壤团聚体稳定性与砂粒含量正相关。综上,本试验中水稻土掺沙比例为30%为宜,此比例掺沙可以明显改善土壤结构,改良土壤质量,阻滞土壤酸化,增加烟株对养分的吸收,促进烟株生长。

To find out the solutions to the problems of clayey soil texture and blocked growth and development of flue-cured tobacco,the paddy soil with continuous cropping of flue-cured tobacco for five years in Yuxi,Yunnan Province was taken as the research object.The composition of soil grain size was changed by exogenous sand mixing.The composition of soil water-stable aggregates,physicochemical indexes,enzyme activities,nutrient absorption,and dry matter accumulation of flue-cured tobacco were studied,and the correlation was analyzed.The results showed that compared with the treatment without sand mixing,the sand content increased by 44.55%and 58.59%after sand mixing of 30%and 60%(p<0.05),respectively.The content of clay and silt decreased with the increase of sand mixing.After sand incorporation,the content of<0.25 mm particle size agglomerates significantly decreased and the content of large agglomerates increased,and the stability of soil agglomerates was 30%sand incorporation>60%sand incorporation>no sand incorporation;Soil pH and catalase activity increased,organic matter,available potassium and other major nutrients decreased,and the activities of sucrase and acid phosphatase after 30%sand addition increased by 20.42%and 268.69%,compared with no sand addition.Pearson correlation analysis and redundancy analysis showed that the effect of soil mechanical composition on soil properties and nutrient accumulation was significant.Most of the growth indexes,soil pH,and catalase activity were positively correlated with sand content(p<0.01),and negatively correlated with clay and silt content(p<0.01).Soil aggregate stability was positively correlated with sand content.In summary,the proportion of 30%sand in paddy soil was appropriate in this experiment,which could significantly improve soil structure and quality,block soil acidification,enhance nutrient absorption,and promote tobacco plant growth.