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ARS Home » Southeast Area » Booneville, Arkansas » Dale Bumpers Small Farms Research Center » Research » Publications at this Location » Publication #381879

Research Project: Sustainable Small Farm and Organic Grass and Forage Production Systems for Livestock and Agroforestry

Location: Dale Bumpers Small Farms Research Center

Title: Evaluating tree growth factors into species-specific functional soil maps for improved agroforestry system efficiency

Author
item JIANG, ZHUODONG - Shenyang Agricultural University
item Owens, Phillip
item Ashworth, Amanda
item FUENTES, BRYAN - University Of Arkansas
item THOMAS, ANDREW - University Of Missouri
item Sauer, Thomas - Tom
item WANG, QUIBING - Shenyang Agricultural University

Submitted to: Agroforestry Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: Agroforestry systems play an important role in sustainable agroecosystems and diversification of agricultural practices. Planting and maintaining trees are a significant long-term investment, therefore, accurately and adequately quantifying the relationships between environmental factors and tree growth is needed to achieve maximum efficiency in these systems. Quantification of relationships among tree genetics, tree growth, soil variability, and soil-landscape features are needed in order to maximize efficiency in agroforestry systems. In this study, we found that tree species grew differently in different soils and landscape positions. This is an important finding because a field can be designed to maximize the growth potential of trees within an agroforestry system which will yield greater profit to producers.

Technical Abstract: Agroforestry systems play an important role in sustainable agroecosystems and diversification of agricultural practices. Planting and maintaining trees are a significant long-term investment, therefore, accurately and adequately quantifying the relationships between environmental factors and tree growth is needed to achieve maximum efficiency in these systems. Objectives of this study are to quantify environmental factors affecting growth of four tree species and to develop functional soil maps for each species in an agroforestry site located in northwest Arkansas, USA. The diameter at breast height (DBH), absolute growth rate (AGR), and neighborhood competition index (NCI) of 259 trees from four species (northern red oak [Quercus rubra], pecan [Carya illinoinensis], cottonwood [Populus deltoides], and sycamore [Platanus occidentalis]) were determined. A total of 51 topsoil samples were collected and analyzed in the laboratory, and 12 terrain attributes were derived from a 5-m digital elevation model. The relationships between AGR, soil, topography, and tree size were analyzed using Spearman correlation. Based on correlation analysis, functional soil maps (FSM) for each species were generated using the k-means cluster method by overlaying correlated soil and terrain attribute maps. Results showed tree size and terrain attributes were driving factors affecting tree growth rate relative to soil properties. The spatial variations in AGR among functional units were statistically compared within tree species and the areas with larger AGR were identified by the FSM. This study demonstrated that FSM could delineate areas with different AGR for the oak, cottonwood, and sycamore trees. The AGR of pecan trees did not vary among functional units. The generated functional soil maps may allow land managers to more precisely establish, fertilize, and manage agroforestry systems.