Jeq50242 898..902

Applications of manures to agricultural fields have increased soil test values for P to high levels in parts of the USA and thus increased the likelihood that P will be transported to surface water and degrade its quality. Waste paper applications to soils with high STP (soil test P) may decrease the risk of P transport to surface water by decreasing DRP (dissolved reactive P) by the formation of insoluble Al–P complexes and providing organic matter to improve infiltration. A field experiment was conducted near Booneville, AR (USA) to assess the effects of different rates of a waste paper product addition on STP, soil bulk density, and total soil C with a soil with approximately 45 mg Bray1-P kg soil (dry weight). A Leadvale silt loam soil (fine-silty, siliceous, thermic Typic Fragiudult) was amended with 0, 22, 44, or 88 Mg waste paper product ha to supply approximately 90, 170, or 350 kg Al ha, respectively. One year after additions, there was a strong negative correlation between waste paper product application rates and soil bulk density, and a strong positive correlation between rates and total soil C content. Soil bulk density and total C 2 yr after additions, and soil DRPand Bray1-P were not affected by waste paper additions. These results support the hypothesis that decreases in DRP in runoff from soils receiving waste paper additions were probably due to changes in soil organic matter and bulk density, rather than changes in the chemical forms of soil P. ENVIRONMENTAL concerns arising from land application of manures are leaching and runoff losses of P to ground and surface water (Sims et al., 1998). Concentrated animal feeding operations create enormous amounts of animal manure. In most instances, these manures are applied to agricultural fields located near the feeding operation. Long-term applications of animal manures to agricultural land have resulted in high STP levels. For example, Mehlich III extractant soil tests in 1999 showed that .60% of soil samples from counties in Arkansas with high-intensity poultry production had high STP and .30% were very high (DeLong et al., 2000). New technologies are needed to minimize the risk of P transport from soils with high STP to ground and surface water. One approach may involve the use of soil amendments. In certain instances, gypsum additions have been effective of reducing the loss of DRP in runoff from fields with high STP (Stout et al., 1998). The chief mechanism by which gypsum reduces DRP is by promoting the aggregation of soil particles, thus reducing the amount of P transported along with sediment in runoff (McCray and Sumner, 1990). It is possible that reduction in P losses also resulted from the formation of relatively insoluble Ca phosphate complexes when Ca from gypsum reacts with soluble phosphate. Gypsum can reduce DRP, even when STP is very high, if enough Ca is added. Three annual additions of 5.0 Mg gypsum ha decreased soil DRP in a thermic Udertic Paleustalf soil in Texas with Bray1-P values that approached 4000 mg P kg (Brauer et al., 2005); however, three annual applications of 1.5 Mg gypsum ha had no effect (Brauer et al., 2005). The higher rate of gypsum application added 3500 kg Ca ha, compared with 1000 kg Ca ha for the lower rate. Gypsum applications had no effect on Bray1-P values. Another soil amendment that can reduce soil DRP is alum (Moore et al., 1999). The chief mechanism by which alum reduces DRP losses is by immobilization of readily soluble P by the formation of relatively insoluble complexes between soil P and the added Al. Alum added to litter or as a soil amendment reduces DRP and thus reduces the likelihood that the P will be transported from agricultural land to surface water. It may be possible to add Al to soils to complex readily soluble P by adding a waste paper product. Waste paper contains significant quantities of Al, with levels routinely exceeding 3 g kg21 dry weight (Edwards et al., 1995). Aluminum was released into the soil solution when an amendment produced from waste paper and anhydrous NH4 (C/N ratio of 30:1) was added to soil (Edwards et al., 1995; Edwards, 1997; Lu et al., 1995, 1997). In these four studies, waste paper was added at 2 kg C m, which corresponds to |50 Mg waste paper ha. When this waste paper amendment was added to soils, N, Ca, Mg, and P foliar deficiency symptoms of corn seedlings were observed (Lu et al., 1995). These researchers hypothesized that plants growing in amended soils were P deficient as a result of the precipitation of P from the soil solution by Al. To overcome this problem, P was added to a weed control mulch product developed from recycled paper to reduce the toxic effects of Al (Smith et al., 1997; 1998). Therefore, it may be possible to use a soil amendment made from waste paper as a source of Al to reduce soil DRP. Results from a preliminary study indicated that the amount of P in runoff from a simulated rainfall on a thermic Udertic Paleustalf soil in Texas with Bray1-P values approaching 4000 mg P kg was reduced 1 mo after incorporation of a waste paper product (Livingston et al., 2002); however, Brauer et al. (2005) found no significant reductions in either soil Bray1-P or DRP 4 mo after waste paper addition. The amount of waste D. Brauer, USDA-ARS, Dale Bumpers Small Farms Research Center, 6883 Highway 23, Booneville, AR 72927. G. Aiken, USDA-ARS, Forage Animal Production Research Unit, University of Kentucky, Agricultural Science Building North, Lexington, KY 40506. Mentioning of a brand name does not imply endorsement of product over others by the USDA. Received 15 June 2005. *Corresponding author ([email protected]). Published in J. Environ. Qual. 35:898–902 (2006). Technical Reports: Waste Management doi:10.2134/jeq2005.0242 a ASA, CSSA, SSSA 677 S. Segoe Rd., Madison, WI 53711 USA Abbreviations: DRP, dissolved reactive P; LSSE, least square standard errors; MSS, mean sum of squares; STP, soil test P. R e p ro d u c e d fr o m J o u rn a l o f E n v ir o n m e n ta l Q u a lit y . P u b lis h e d b y A S A , C S S A , a n d S S S A . A ll c o p y ri g h ts re s e rv e d . 898 Published online April 26, 2006