科研之友
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摘要
Effective options for reducing P losses from P-enriched soils remain a major challenge, particularly in intensive agricultural areas. While different strategies have been shown to control P mobility (e. g., Ca- and Al-based soil amendments and riparian buffers), they provide no means to reduce in situ soil P concentrations. The objectives of this study were to: (i) investigate the potential P-removal capacity of four bioenergy crops (elephantgrass [Pennisetum purpureum Schumach.], sugarcane [Saccharum spp.], switchgrass [Panicum virgatum L.], and stargrass [Cynodon nlemfuensis Vanderyst]) grown on a manure-enriched soil, and (ii) examine the impacts of crop P uptake on soil P concentrations and surface groundwater quality. Treatments were distributed in a completely randomized design with four replicates. The greatest dry matter yields were observed for elephantgrass (average of 46 Mg ha(-1) yr(-1)) followed by sugarcane (average of 40 Mg ha(-1) yr(-1)). Tissue P concentrations were greater for stargrass (similar to 4 g kg(-1)) than elephantgrass (3.2 g kg(-1)) or sugarcane (1.9 g kg(-1)). Elephantgrass showed the greatest cumulative P removal (420 kg P ha(-1) during the 3-yr period). Soil P concentrations in the Ap horizon decreased with time, while an increase in soil P concentration was observed in the Bh horizon. Elephantgrass resulted in the lowest leachate P concentrations (similar to 0.5 mg P L-1) at the 60-cm depth. Crop species had no effect on leachate P at the 90-cm depth. Growth of elephantgrass as a biofuel feedstock appears to be an effective approach for remediation of excess soil P.
- 出版日期2013-2
