地下滴灌条件下杨树速生丰产林生产力及效益分析

该文研究了北京沿河沙地Ⅰ-214杨树人工林地下滴灌和常规灌溉的林地生产力及效益.结果表明:与常规灌溉相比，地下滴灌能大大增加树木的生长量，提高林地生产力.2000年(栽植第4年)，地下滴灌区树木平均胸径、树高和单株材积分别达到21.18 cm、14.23 m 和0.181 5 m3，比常规灌溉增加了54.5%、36.9%和247.6%；林地生产力达到22.78～25.81 m3／(hm2·a)，比常规灌溉增加了3.9～4.6倍．地下滴灌应用于杨树速生丰产林培育经济效益优势显著.如不需租地且不需贷款情况下，地下滴灌条件下林地每年每公顷可盈利5 355元以上，资金生产率达到3.99，成本赢利率为2.67，是常规灌溉林地的3.43、1.70和2.32倍.在获取较大经济效益的同时，林地还能产生巨大的生态和社会效益，这部分效益如果货币化则更为可观．地下滴灌和常规灌溉林地的水、肥和能源利用效率存在极大的差异，1999年地下滴灌生产1 m3木材所消耗的资源分别为32.4 t/m3、13.5 kg/m3和2.8kW\5h/m3，常规灌溉区是其6.1、5.8和6.2倍．建议在干旱半干旱和季节性干旱地区营造速生丰产用材林时应结合当地经济条件推广地下滴灌技术，这不仅有利于水资源的可持续利用，而且将大幅度提高林地生产力，带动林业产业发展． 

Productivity and benefit analysis of fast-growing and high-yield plantations of poplar under subsurface drip irrigation

The productivity and benefit of the plantations of poplar Ⅰ-214 (Populus×euramericana ‘Ⅰ-214 ’) under subsurface drip irrigation(SDI) and normal irrigation(NI) at sandy soil of Beijing were studied in this paper. The results showed that the growth and yield of the plantations were increased more under SDI than NI. In 2000 (4 years after planted), the average D1.3, H and volume of trees were 21.18 cm, 14.23 m and 0.181 5 m3 under SDI, which were 54.5%、36.9% and 247.6% more than under NI; the productivity of the plantations under SDI reached 22.78～25.81 m3/(hm².a), which was 3.9～4.6 times more than under NI. The economic benefit of the plantation under SDI was also much greater. The profit, fund productivity rate and cost payoff rate of the plantation under SDI were 5 355 yuan(RMB)/(a·hm²), 3.99 and 2.67 respectively, which were 3.43, 1.70 and 2.32 times as much as under NI. Meanwhile, the ecological and social benefits of the plantation under SDI were much greater and the economic benefit increased significantly if these benefits could be converted into money. In addition, the efficiency of water using, fertilizer and energy of the plantations were more different between SDI and NI. In 1999, the used resources of water, fertilizer and electricity were 32.4 t/m3、13.5 kg/m³ and 2.8 kW\5h/m³ respectively when 1 m3 timber was produced by SDI, and the corresponding data under NI were 6.1, 5.8 and 6.2 times as much as under SDI. Therefore, extending the underground drip irrigation in developing the fast growing and high yield plantations in arid, sub arid and seasonal arid areas is suggested according to the local economic conditions. It could not only accelerate the sustainable usage of water resources, but also highly increase the plantation yield and improve the forestry development in China.