Yan Xiao Li, Jia Li Ming, Dai Teng Fei
College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing 100083, China.
Ying Yong Sheng Tai Xue Bao. 2018 Jul;29(7):2195-2202. doi: 10.13287/j.1001-9332.201807.007.
By using surface drip irrigation, a field experiment including nine drip irrigation and fertigation treatments was carried out, with non-irrigation and non-fertilization as control (CK), to evaluate the integrative effects of water and nitrogen management on the increment of diameter, tree height, and stem volume, and the total nitrogen content in the 0-60 cm soil layer in the poplar (Populus ×euramericana cv. 'Guariento') plantations. There were three irrigation levels (irrigation was initiated when soil water potentials at 20 cm soil depth reached -75, -50 and -25 kPa) and three levels of nitrogen addition (150, 300 and 450 g·tree·a). Surface drip irrigation and fertigation treatments were applied in the gro-wing seasons of 2012 and 2013. The results showed that the combined treatments of water and nitrogen addition significantly increased growth and stem volume of the poplar plantation. In the first year of the experiment, the annual increment of stem volume was 11.54 m·hm·a in high water and high fertilizer treatment (soil water potentials of -25 kPa + nitrogen addition of 450 g·tree·a), which was 44.1% higher than that in the CK (8.01 m·hm·a). In the second year, the annual increment of stem volume was 27.85 m·hm·a in medium water and high fertilizer treatment (soil water potentials of -50 kPa + nitrogen addition of 450 g·tree·a), being 36.0% higher than that in CK (20.48 m·hm·a). The successive combined treatments signi-ficantly increased the total N content in the 0-20 cm soil layer, with total N content of each soil layer in the first and second year of the experiment being 12.3%-59.4% and 71.1%-81.1% higher than CK, respectively. The increments of diameter and tree height were significantly positively correlated with soil total N content. Nitrogen addition and the interactive effects of water and nitrogen addition significantly affected the diameter and height of trees and soil N content, while irrigation showed no significant effect. In conclusion, the combined drip irrigation and fertigation significantly increased growth and stem volume of the poplar plantation by promoting the soil fertility especially nitrogen availability in the topsoil.
通过采用地表滴灌，开展了一项包含9种滴灌施肥处理的田间试验，以不灌溉不施肥作为对照（CK），来评估水分和氮素管理对杨树（欧美杨品种‘Guariento’）人工林胸径、树高、材积生长量以及0至60厘米土层全氮含量的综合影响。试验设置了3个灌溉水平（当20厘米土层深度处的土壤水势达到-75、-50和-25千帕时开始灌溉）和3个施氮水平（150、300和450克·株·年）。在2012年和2013年的生长季进行地表滴灌施肥处理。结果表明，水分和氮素添加的组合处理显著增加了杨树人工林的生长量和材积。在试验的第一年，高水高肥处理（土壤水势为-25千帕+施氮量450克·株·年）的材积年生长量为11.54立方米·公顷·年，比对照（8.01立方米·公顷·年）高44.1%。在第二年，中水高肥处理（土壤水势为-50千帕+施氮量450克·株·年）的材积年生长量为27.85立方米·公顷·年，比对照（20.48立方米·公顷·年）高36.0%。连续的组合处理显著增加了0至20厘米土层的全氮含量，试验第一年和第二年各土层的全氮含量分别比对照高12.3%至59.4%和71.1%至81.1%。胸径和树高的生长量与土壤全氮含量显著正相关。施氮以及水分和氮素添加的交互作用显著影响树木的胸径和树高以及土壤氮含量，而灌溉未表现出显著影响。总之，滴灌施肥通过提高土壤肥力尤其是表土中的氮有效性，显著增加了杨树人工林的生长量和材积。
