人为能量投入对农田生态系统净初级生产力的影响——以鲁西南地区为例

为了确定影响农田生态系统固碳能力的影响因子,在收集2000—2006年鲁西南地区农业生产统计数据的基础上,分析了该地区农田人为能量投入现状,并利用回归和逐步回归的方法研究了鲁西南地区人为能量投入对农田生态系统净初级生产力（NPP）的影响。结果表明：鲁西南地区农田人为能量投入中农膜的投入逐年增加,由2000年的14.6 kg/hm2增长到2006年的20.5 kg/hm2;化肥投入相对稳定（1200-1300 kg/hm2）,但总量仍增加;农药的投入呈先增加后降低的趋势,2004年达到最高（11.03 kg/hm2）;排灌机械、农用车辆的投入呈增长趋势,而单位面积劳动力的投入不断下降,2006年与2000年相比约减少0.65人/hm2。该地区农田生态系统NPP存在着东高西低的空间分布格局,历年均以东部（枣庄、济宁）高,平均NPP分别为616 g C/（m2·a）和588 g C/（m2·a）,西部（菏泽）低,仅有448 g C/（m2·a）;年际间呈现一定的波动性,但整体呈上升趋势。该地区农田NPP主要受人为能量投入的影响而与温度和降水的关系不大。单位面积化肥使用量、单位面积农膜使用量和农田灌溉比例在逐步回归模型中可以解释本区农田NPP方差的74.6%。因此,化肥、农膜、有效灌溉比等人为能量投入是影响该地区农田NPP提升的主要因素。

Effects of Anthropogenic Energy Input on Net Primary Productivity of Farmland Ecosystems——A Case Study of Southwest Shandong Province

In order to determine the impact factors on the carbon sequestration of farmland ecosystems, the status of anthropogenic energy input was analyzed and their effects on net primary productivity of farmland ecosystems were studied with the methods of regression and stepwise regression based on the statistical data of the year 2000 to 2006 of Shandong Province. The results indicated that： the amount of agricultural film inputinto farmland ecosystem increased from 14.6 kg/hm2 to 20.5 kg/hm relatively （1200-1300 kg/hm^2）, whereas the total descend at last, reaching the highest （11.03 kg/hm agricultural vehicles increased continuously; labor 2 in 2000 to 2006; fertilizers input kept stable fertilizers increased; pesticides input was ascend in first and 2） in 2004; the input of drainage and irrigation machinery and input per unit area declined about 0.65 person/hm2 in 2006, comparing with 2000. The higher average NPP were found in the east part of this area, Zaozhuang 616 g C/（m^2· a） and Jining 588 g C/（m^2·a） compared to the west part （Heze） averaged at 448 g C/（m^2·a）. The trend of NPP fluctuated but generally ascended. NPP of farmland ecosystems was mainly affected by anthropogenic energy input, other than climate factors （temperature and precipitation）. The stepwise regression selected the optimum model including total fertilizers, agricultural film per unit area and irrigation ratio. This model could account for 74.6% of the region farmland NPP variance, including fertilizers use per unit for 48.4%, agricultural film per unit and irrigation ratio for 14.6% and 11.6%, respectively. Therefore, the anthropogenic energy input such as fertilizers, agricultural film and effective irrigation ratio are the main factor for NPP improvement in this area.