桉树人工林中期施肥试验研究

对尾巨桉2.5 a生间伐后的林分进行施肥试验.结果表明,间伐后施用适量的N、P、K肥有明显的增产效果.以每株施用磷酸二铵(N、P)750 g、氯化钾(K肥)90~270 g、硼砂(B肥)0~30 g,即每株施N135 g、P2O5338 g、K2O50~100 g、B 0~5 g的增产效果最好,优化配比为N:P2O5:K2O:B=1∶2.5∶0.37~1.11∶0~0.04.在肥料元素合理配比下,磷酸二铵、氯化钾和硼砂的总施肥量控制在850~950 g/株,以单质肥料测算,则N、P2O5、K2O、B有效养分总量应控制在520~575 g/株范围.以该施肥组合方案进行实施,施肥后2.5 a林分平均胸径、树高和材积年均生长量分别达3 cm、3.2 m和0.10 m3以上,比未施肥的林分分别提高190%~200%、268%~273%和400%~465%,可净增加收入7~8万元/hm2.中期施肥对提高林分生长量和经营经济效益显著.

Medium-term Fertilization Experiment of Eucalyptus Plantation

The fertilization experiment was developed on the E.urophylla×E.grandis plantation of 2.5 years old after thinning and the result shows that： application proper amount of N,P,K fertilizer increase stands yield significantly after thinning,the fertilization of per tree DAP fertilizer（N,P） 750g,potassium chloride（K） 90~270g,borax（B） 0 ~ 30g that each N 135g,P2O5 338g,K2O 50~100g,B 0~5g of the best yield,optimum ratio for the N： P2O5： K2O： B = 1：2.5：0.37~1.11：0~0.04.Under rational ratio of the nutrients,the total amount of DAP,potassium chloride and borax fertilizer 850~950g per tree,calculating from single component fertilizer,the total available nutrients of N,P2O5,K2O,B should be controlled between 520 ~ 575 g per tree.The stands average growth of DBH,tree height and volume after 2.5 years fertilization are respectively 3cm,3.2m,0.10 m3 or more and increase 190%~200%,268%~273% and 400%~465% than those without fertilization,net income can be 70~80 thousand Yuan per hm2.The medium-term fertilization have increased forest growth and operating economic efficiency significantly.