滴喷灌施肥方式对土壤养分空间分异及茶苗根系生长的影响

Effects of Drip Irrigation and Spray Irrigation Fertilization on Spatial Differentiation of Soil Nutrients and Root Growth of Tea Seedlings

探究滴灌和喷灌对土壤理化和生物学性状及茶苗根系生长的影响,为科学灌溉施肥提供理论依据。土壤培养设置土施(SA)、喷施(FA)和滴施(DA)3种施肥方式,15,30,45,60天后,选取培养钵表土中心点为参照,根据距中心点水平和垂直方向距离差异,将培养土壤划分3个空间区域,观测pH、电导率、养分和生物学性质;茶树盆栽试验设置2个氮水平和土施、喷施、滴施3种施肥方式共6个处理,观测茶苗根系生长和形态。土培试验结果表明,FA与SA处理不同空间土壤区域无明显差异,而DA与FA之间差异明显,60天后离中心点水平5 cm、垂直0—10 cm的土壤区域内,其电导率、pH、碱解N、速效K和速效P含量DA较FA分别增加35.6%,30.7%,40.6%,34.3%和74.8%,区域内细菌、真菌和放线菌分别增加174.6%,167.0%和289.0%,脲酶和酸性磷酸酶活性呈相反变化,DA较FA分别降低42.5%和31.4%。盆栽试验结果表明,茶树根系生长整体表现为FA>SA>DA,FA较DA的茶苗根鲜重、根总长、根体积、根尖数、分支数和交叉数均明显提高,不同N水平之间的促根效应差异不明显。综上,施肥方式对土壤养分空间分布、土壤生物学特性及茶苗根系生长影响明显。DA滴头中心点微域土壤的电导率、养分含量和微生物数量较SA和FA增加显著,存在明显的微域集聚效应,而脲酶、酸性磷酸酶活性降低。DA施肥方式明显抑制茶苗根系生长,而FA则显著促进茶苗根系生长和形态建成。

This research investigated the effects of drip and spray irrigation on the physical, chemical and biological properties of the soil and root growth of tea seedlings, and could provide a theoretical basis for scientific irrigation and fertilization. Three types of fertilizer application were set up, soil application(SA), spray application(FA) and drip application(DA). After 15, 30, 45 and 60 days, the soil was divided into three spatial zones according to the difference in horizontal and vertical distance from the center of the topsoil of the culture bowl, and pH, conductivity, nutrients and biological properties were observed. In the pot experiment of tea seedlings, six treatments were set up, including two nitrogen levels and three fertilization methods of soil application, spraying and dropping. The root growth and morphology of tea seedlings were observed. The results of the soil culture showed that there was no significant difference between FA and SA treatments in different spatial soil regions, while there were significant differences between DA and FA. After 60 days, in the soil region 5 cm horizontally and 0—10 cm vertically from the center point, compared with FA, the conductivity, pH, content of alkali-hydrolyzed N, available K and available P of DA increased by 35.6%, 30.7%, 40.6%, 34.3% and 74.8%, respectively, and bacterial, fungal and actinomycetes in the region of DA increased by 174.6%, 167.0% and 289.0%, respectively. The activities of urease and acid phosphatase in the soil region of DA showed opposite trend, decreased by 42.5% and 31.4%, respectively, compared with FA. The results of pot experiment showed that the overall root growth of tea trees followed the order of FA>SA>DA, and the root fresh weight, total root length, root volume, root tip number, branch number and cross number of tea seedlings in the FA treatment were significantly higher than those of DA, while there was no significant difference in the root promoting effect among different N levels. In summary, fertilization methods had significant effects on the spatial distribution of soil nutrients, soil biological properties and root growth of tea seedlings. Compared with SA and FA, the conductivity, nutrient content and microbial population in the micro domain at the center of the DA drip head increased significantly, and there was a significant micro domain aggregation effect, while the urease and acid phosphatase activities decreased. DA significantly inhibited the root growth of tea seedlings, while FA significantly promoted the root growth and morphological establishment of tea seedlings.