Assessment of repeated application of poultry litter on phosphorus and nitrogen dynamics in loblolly pine: Implications for water quality

Poultry Litter Fertilization Impacts on Soil, Plant, and Water Characteristics in Loblolly Pine (Pinus taeda L.) Plantations and Silvopastures in the Mid-South USA

“…Soil in plots treated with broiler litter had greater N mineralization rates in the AR-FORvsPAST study, and a greater proportion of mineralized N was nitrified. There was also a significant positive correlation between NO 3 -N in soil and nitrification rates (Liechty et al, 2009). Similar results were observed in the STRAW study, in which both rates of poultry litter had greater N mineralization and nitrification than CONTROL and IF treatments (Blazier et al, 2008b).…”

“…This increase in the proportion of NO 3 -N in the SILVO study occurred in response to both rates of broiler litter tested; no such increase was observed in response to the inorganic fertilizer mixture (Blazier et al, 2008a). Results similar to the SILVO study were also found in the STRAW study; NO 3 -N increased in response to the treatment regime that included poultry litter, whereas no such increase was observed in response to non-fertilized treatments and the treatment regime that included a mixture of inorganic fertilizers (Liechty et al, 2009). Increases in soil NO 3 -N in response to poultry litter were attributable to greater nitrification rates (Table 7).…”

“…The relatively lower moisture content and available water holding capacity of the RAKE-IF treatment is consistent with its lower soil organic matter content because organic matter fosters soil moisture retention (Plaza et al, 2004;Powers et al, 2005). There were no differences in soil organic matter among treatments in the SILVO, SWITCH, LA-FORvsPAST, and AR-FORvsPAST studies (Blazier et al, 2008a;Liechty et al, 2009), in which litter was not removed. As such, increases in forage and/or tree yields from fertilization in these studies were not associated with concomitant increases in soil organic matter.…”

“…In the AR-FORvsPAST study, NO 3 -N significantly increased in the loblolly pine plantation and in pasture relative to the CONTROL treatment following two years of poultry litter application. The proportion of NO 3 -N to total exchangeable N was also greater in response to poultry litter than without litter application (Liechty et al, 2009). There was no difference in NO 3 -N concentrations among treatments in the SILVO study, but as in the AR-FORvsPAST study the ratio of NO 3 -N to total exchangeable N increased in response to poultry litter additions.…”

“…Soil exchangeable N, mineralization, nitrification, and pH in response to fertilization in loblolly pine plantations, silvopasture, and bahiagrass pasture in a series of trials conducted in the mid-South U.S.A. Means within rows followed by different letters differ at P < 0.05. Adapted in part from Liechty et al (2009) Although differences in soil NO 3 -N and nitrification between loblolly pine and bahiagrass pasture in the AR-FORvsPAST study in part reflected the differences in pH and C:N ratios of the soils in these two land uses (Richardson 2006), they also reflected the differences in uptake and use of available N forms by the loblolly pine and pastures. Although N mineralization and nitrification was greater in pasture when fertilized with poultry litter, the increase in NO 3 -N remaining in soil per unit increase in potential net nitrification was www.intechopen.com…”