Phytoremediation of Soil Phosphorous with Crabgrass
Abstract
Nutrient buildup in pastures from repeated animal manure application may increase soil phosphorus (P) and contribute to eutrophication and water quality deterioration. Options to remove excess nutrients in pastures have been limited in the past. The objective of this 2-yr study was to evaluate the potential of crabgrass (Digitaria cilaris) to remove excess soil P from nutrient loaded soils. Red river crabgrass was planted in boxes containing Dennis, Richfield, and Kirkland soils in a greenhouse in 2010 and under ambient conditions in 2011. Ten years before this experiment, each soil received four different rates of commercial P fertilizer to raise soil test P to elevated levels. Average Mehlich-3 phosphorus (M3P) at the beginning of this experiment ranged from 57.0 to 836 mg kg-1. The experiment was a randomized block design with 12 treatments (three soils and four P levels) and three replications repeated for two growing seasons. The average biomass yield of crabgrass ranged from 9.90 to 14.2 Mg ha-1 with an overall average of 12.2 Mg ha-1 in 2010 and from 6.8 to 13.4 Mg ha-1 with an overall average of 10.7 Mg ha-1 in 2011. The harvested biomass contained an average of 0.45% P and 2.26% nitrogen (N) in 2010 and 0.37% P and 1.45% N in 2011. Therefore, the crabgrass removed an average of 49.1 kg P ha-1 and 237 kg N ha-1 per year. In addition, the concentration of P in the grass and P removed from the soil increased as STP increased although the biomass was not affected by STP. Crabgrass can serve as a good quality hay and as an effective plant for removing nutrients from soils.
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- OSU Theses [15752]