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Chinese Agricultural Science Bulletin ›› 2013, Vol. 29 ›› Issue (26): 124-131.doi: 10.11924/j.issn.1000-6850.2012-1994

Special Issue: 农业生态

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

  

  • Received:2012-05-28 Revised:2012-07-30 Online:2013-09-15 Published:2013-09-15

Abstract: 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 input into farmland ecosystem increased from 14.6 kg/hm2 to 20.5 kg/hm2 in 2000-2006; fertilizers input kept stable relatively (1200-1300 kg/hm2), whereas the total fertilizers increased; pesticides input was ascend in first and descend at last, reaching the highest (11.03 kg/hm2) in 2004; the input of drainage and irrigation machinery and agricultural vehicles increased continuously; labor 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/(m2?a) and Jining 588 g C/(m2?a) compared to the west part (Heze) averaged at 448 g C/(m2?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.