吉林省农安地区农田防护林生态经济效益分析

Analysis on Ecological-economic Benefits of Shelter Forest in Nong′an District of Jilin Province

对吉林省农安地区成熟防护林的农田林网的防风效应、水热效应和经济效益进行了调查研究。结果表明:由4条林带构成的林网,平均降低风速30.4%,最低风速出现在观测区背风面的3 H^10 H处,降低60%。林网内背风面1 H^10 H处和迎风面3~5 H处为增温区,日平均增温0.4~1.0℃。而林网内背风面15 H^35 H处和迎风面6 H处为低温区,日平均增温在0.3~0.5℃。2行林带在有效防风距离以内,相对湿度的提高最低,平均提高6.3个百分点。12行林带次之,平均提高10.1个百分点。6行林带最好,平均提高20.4个百分点。林网内玉米平均产量9 211.9 kg/hm2,比对照区增加14.1%。3~10 H增产幅度为17%~25%,属于增产率最高区。可见,农田防护林具有非常明显的防风效应、水热效应和经济效益,是农田基本建设的重要组成部分。

In this paper,the windproof effects,hydro-thermal effects and economic benefits of matured shelter-forest in Jilin Nong＇an District were investigated. The results showed that the forest-network formed by the four forest-belts,reducing 30.4% of the wind speed on average,and minimum wind speed appeared in the range of 3 H to 10 H （height of shelter belt）on the leeward side in observation area with reduction of 60%. The heating zones appeared in the range of 1 H to 10 H on the leeward side and 3 H to 5 H on the windward side. The daily average temperature increased by 0.4 ℃ to 1.0 ℃. However,the low temperature area appeared in the range of 15 H to 35 H on the leeward side and 6 H on the windward side. The daily average temperature was increased by 0.3 ℃ to 0.5 ℃. 2-line forest-belt within an effective distance of the windbreak ,the improvement of the relative humidity was the lowest,which had an average increase of 6.3 percentage points. 12-line forest-belt was next, which had an average increase of 10.1 percentage points. 6-line forest-beh was the best ,which had an average increase of 20.4 percentage points. Corn in forest-network yielded 9 211.9 kg/hm2 on average ,which had an increase of 14.1% compared with the contrast area.In the range of 3 H to 10 H site it＇s yielded 17% to 25%, which was the highest increasing area. It showed that farmland shelter-forest had very significant windproof effects, hydro-thermal effects and economic benefits, which was an important part of farmland capital construction.