速生杨在海河低平原农田土壤中的水分时空消耗规律  

Soil Water Consumption and Effects of Poplar in Farmland of the Low Hai River Plain

作　　者：尹春梅[1] 隋鹏[1] 陈源泉[1] 刘月华[1] 高旺盛[1] 

机构地区：[1]中国农业大学农学与生物技术学院区域农业发展研究中心,北京100094

出　　处：《中国农学通报》2008年第3期435-440,共6页Chinese Agricultural Science Bulletin

基　　金："十一五"国家科技支撑计划课题"粮食主产区农田生态健康管理关键技术研究与示范";"农田复合生物共生循环模式与技术研究"(2006BAD02A15;2007BAD89B01);"十一五"河北省科技攻关项目"黑龙港低平原区农林复合生产技术研究与示范"(06220115D)

摘　　要：为揭示农田杨树用材林无灌溉区表层及深层从幼龄开始的土壤水连续消耗规律,采用中子仪与土钻相结合的方法进行了4年土壤水分定位监测。数据表明：（1）4龄和5龄时杨树遭受极度水分胁迫,部分树木叶片盛夏开始干枯脱落,3龄、4龄和5龄单株杨树树高、胸径和材积年增长缓慢;（2）杨树2龄时,0~2m土壤水分大幅降低,此后长期处于较低状态。2m以下得不到降水补充,土壤含水量持续下降。3龄后杨树开始阶段性遭受不同程度水分胁迫;（3）至5龄末杨树的耗水层深度为5.6m;2m以下深层耗水特点为2龄、3龄和4龄杨树耗水层次逐年加深,5龄时未见加深,反而各层次耗水量均小于4龄杨树。可见其遭受严重干旱胁迫后生理活性降低。杨树从2龄末到5龄末的3年间2-5.6m土体土壤贮水量累计减少430mm,使得深层土壤有效水含量大幅下降,特别是2-4m土层,杨树5龄末时土壤水分接近萎蔫点,土壤储水调节能力下降。林龄增加后反而只能依靠降水,杨树生长面临威胁;（4）无灌溉杨树单作模式5年经济收益远远低于麦-玉模式。海河低平原区大面积推广的农田速生杨用材林将使这一地区深层土壤干燥化。杨树材积累积缓慢不利于土地集约利用,应采取一定的灌溉补水措施在合理用水的前提下促进杨树生长,或者以发展农田防护林为主。In order to reveal the impact of field timber forest on soil water consumption, neutron Instrument and soil auger methods was applied to monitor soil moisture for 5 years. The results showed that： （1） Poplars have decreased growth due to water stress. Some of leaves withered in August 2006 and 2007. The increment of Height, DBH and Volume of 3a to 5a poplar was slowed down; （2）when poplar was 2 years old, soil moisture in 0-2m soil layer reduced much rapidly and soil moisture content kept on a low level. No water was repaid in Soil layer below 2m so soil moisture continued reducing. When poplar was 3 years old, water stress happened occasionally; （3） Poplars consumes soil water as deep as 5.6m at Oct of 2007; the consumption layer in 2006 was deeper than in 2005, but every layer consumed less water in 2007. From age 2 to 4 of poplar, soil water consumption layer was deeper year by year, but it was converse at age 5. It was supposed that physiology activity slowed down after severity water stress. From age 2 to 5, it was added up to 430ram the water storage was reduced, so the available water reduced rapidly, especially in 2-4m layer drying at wilting. The capability of water-storage accommodation has descended. While poplars are more bigger year by year, water supply will turn to precipitation. Poplars will face more severity situation; （4） The benefit from poplar much lower than food production. Field timber forest may result in deeper soil drying in low plain of Hal river. Poplar＇s volume increment has slowed down which is bad to intensive utilization of farmland. So Irrigation should be taken to speed the growth and it is better to build farmland shelter-belt.

关 键 词：土壤水分消耗 深层耗水 杨树 海河低平原 水分胁迫 

分 类 号：S727.1[农业科学—林木遗传育种]