雷州半岛旱季水肥管理对尾巨桉人工林生长的影响

Effect of Dry Season Water and Fertilizer Management on Growth of Eucalyptus urophylla × E. grandis Plantation on the Leizhou Peninsula

为揭示旱季水肥管理下的桉树生长特征,并为进一步提升桉树人工林生产力提供理论依据及数据支持,本研究以2 a生及5.5 a生尾巨桉人工林为研究对象,分析其在旱季加水肥、加水、加肥及CK 4种水肥管理措施下的生长响应。结果表明:林分尺度下旱季加水处理能显著(2 a生极显著)增加尾巨桉的胸径增长量,其中5.5a生较CK提高34.76%,2 a生较CK提高58.75%;单株尺度5.5 a生加水处理下的月径向生长量是CK处理的3.35倍;单独加肥处理对尾巨桉旱季生长促进较小;林分尺度下加水肥处理胸径增长量比CK胸径增长量分别提高了106%(5.5 a生)和76.7%(2 a生),同时也是单独加水处理的1.11倍(2 a生)和1.53倍(5.5 a生)。2 a生水肥处理也极显著(P<0.01)地促进其旱季的树高增长,比单独加水、单独加肥及CK分别提高了79.4%、124.5%及161%。单株尺度下月径向生长量加水肥处理分别是加水、加肥及CK的2.05、2.72及6.89倍。因此在旱季对尾巨桉人工林进行补水及补水肥(特别是补水肥),能够较大提高尾巨桉旱季的生长量,从而提高其林分生产力。

This study examined the growth characteristics of Eucalyptus under alternate water/irrigation and fertilizer regimes imposed during the dry season,and provides a theoretical basis and data support for improving the productivity of Eucalyptus plantations.For this,growth responses of 2-year and 5.5-year-old Eucalyptus urophylla×E.grandis plantations under four water and fertilizer regimes were analyzed.The regimes included:irrigation only,fertilizer only,irrigation plus fertilizer,and a control(CK)– all treatments/regimes were implemented during the dry season.The irrigation treatment significantly increased the DBH growth of the Eucalyptus urophylla×E.grandis plantations in the dry season,with 5.5-year-old plantation showing 34.8%higher growth than that of CK,and the 2-year-old showing 58.8%higher growth.Monthly radial growth under irrigation was 3.4 times higher than that of the CK treatment.Meanwhile,growth of E.urophylla×E.grandis was less affected by the addition of fertilizer alone,with DBH growth in irrigation and fertilizer treatment being 106%higher than that of the CK(5-year-old plantation)and 76.7%(2-year-old plantation)and also 1.11 times(2-year-old)and 1.53 times(5-year-old)that of the irrigated treatment.In the 2-year-old plantation,the irrigation plus fertilizer treatment also had significantly(P<0.01)higher height growth,with 79.4%,124.5%and 161%of the height growth of the irrigated,fertilizer and CK treatments respectively.The monthly DBH increase of average tree DBH in the irrigated plus fertilizer treatment was 2.1,2.7 and 6.9 times that of irrigated,fertilizer and CK control treatments respectively.It was concluded that in the dry season,the irrigated treatment and the irrigation plus fertilizer treatment greatly increased the growth of the E.urophylla×E.grandis and can therefore significantly improve forest plantation productivity.