|Sauer, Thomas - Tom|
|THOMAS, ANDRES - University Of Minnesota|
|BRYE, KRIS - University Of Arkansas|
|SKINNER, JERREL - University Of Arkansas|
|BRAHANA, JOHN - University Of Arkansas|
|DEFAUW, SHERRI - Pennsylvania State University|
|HAYS, PHILLIP - Us Geological Survey (USGS)|
|MOFFITT, DAVID - Texas A&M University|
|ROBINSON, JAMES - Natural Resources Conservation Service (NRCS, USDA)|
|JAMES, TRAVIS - Natural Resources Conservation Service (NRCS, USDA)|
|HICKIE, KEVIN - Arkansas Forestry Commission|
Submitted to: Nutrient Cycling in Agroecosystems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2014
Publication Date: 12/23/2015
Citation: Sauer, T.J., Coblentz, W.K., Thomas, A.L., Brye, K.R., Brauer, D.K., Skinner, J.V., Brahana, J.V., Defauw, S.L., Hays, P.D., Moffitt, D.C., Robinson, J.L., James, T.A., Hickie, K.A. 2015. Nutrient cycling in an agroforestry alley cropping system receiving poultry litter or nitrogen fertilizer. Nutrient Cycling in Agroecosystems. 101(2):167-179.
Interpretive Summary: Agroforestry involves growing trees with crops or grass in the same field. The advantages are that you can grow multiple crops in the same area. In this study, the trees were planted in wide rows with grass in the rows. The trees were to produce wood products and nuts and the grass were fed to livestock. The objective of this study was to measure how nutrients were cycled through the soil, grass, and trees and whether a significant amount of nitrate was transferred to groundwater. Oak, walnut, and pecan trees were planted in a field with orchardgrass growing between the tree rows. One half of the field received poultry litter (manure and bedding material) and the other half received nitrogen (N) fertilizer. Nutrient concentrations were measured in the soil, grass, and tree leaves and nitrate concentrations in soil water and groundwater. The results showed that poultry litter application increased soil phosphorus content indicating that the grass and trees could not use all of the applied phosphorus. Just applying N fertilizer resulted in lower concentrations of most nutrients in the soil indicating that depletion of soil nutrients would happen if additions of nutrients other than N were not made in the future. There were few differences in nitrate concentration in soil or groundwater with poultry litter or N fertilizer application. These results indicate the poultry litter is a good balanced source of nutrients, but enriches the soil with excess phophorus that may lead to water quality problems. This research is important to scientists, landowers, and policymakers interested in efficient use of animal manures and growing trees with crops for multiple incomes from the same land area.
Technical Abstract: Optimal utilization of animal manures as a plant nutrient source should also prevent adverse impacts on water quality. The objective of this study was to evaluate long-term poultry litter and N fertilizer application on nutrient cycling following establishment of an alley cropping system with eastern black walnut (Juglans nigra L.), pecan [Carya illinoensis (Wangenh.) K. Koch], and northern red oak (Quercus rubra L.) trees and orchardgrass (Dactylis glomerata L.). One half of a 4.25-ha site in northwestern Arkansas USA received broadcast applications of 3.9-6.7 Mg ha-1 fresh poultry litter and the other half 50-76 kg ha-1 N as NH4NO3 fertilizer each spring from 2001 to 2008. Macronutrient (N, P, K, Ca, Mg, and S) and micronutrient (Na, Fe, Mn, Zn, and Cu) concentrations in soil, forage, and tree leaf tissue were monitored along with NO3-N in soil water and groundwater. Poultry litter application resulted in significantly increased concentrations of each macronutrient except S with increases from 6.3 (N) to 121% (P). Nitrogen fertilizer application resulted in decreased concentrations from 2.1 (N) to 60.9% (S) for all macronutrients except Ca. Patterns of nutrient content in forage and tree leaf tissue did not generally follow patterns of soil nutrient concentrations suggesting nutrient sufficiency in most years and that climate and plant growth had a greater effect on nutrient uptake. Soil P with litter application increased 41.3 mg kg-1 over seven years (from 34.1 to 75.4), which may necessitate a lower litter application rate to avoid excessive P runoff.