Water infiltration influenced by agroforestry and grass buffers for a grazed pasture system

Abstract

Agroforestry (AgB) and grass buffers (GB) are often adopted as alternative resource management tools in agroecosystems for environmental and economic benefits. The objective of this study was to compare the influence of AgB and GB systems under rotationally stocked (RP) and continuously stocked (CP) pasture systems on water infiltration measured using ponded infiltration and tension infiltration methods. Buffers were surrounded by a fence that prevented cattle from grazing within these areas. Soils at the site are Menfro silt loam (fine-silty, mixed, superactive, mesic Typic Hapludalf). Infiltration rates were measured using ponded ring infiltration units during 2 years for the four (AgB, GB, RP and CP) treatments with three replicates from two subareas within each treatment. Infiltration rate as a function of tension (at 50, 100, and 150 mm) was also measured using a tension infiltrometer. Water infiltration parameters were estimated using Green-Ampt and Parlange infiltration equations. Quasi-steady state infiltration rates (q s ) and field-saturated hydraulic conductivity (K fs ) for buffers were about 31 and 46 times higher as compared to pasture treatments, respectively. GreenAmpt and Parlange models appeared to fit measured data with r 2 values ranging from 0.91 to 0.98. The q s (measured with ponded method) in the first year for the GB treatment was the highest (221 mm h -1 ) and for the CP treatment was the lowest (3.7 mm h -1 ). For both years, estimated sorptivity (S) and saturated hydraulic conductivity (K s ) parameters were higher for buffer areas compared to the stocked pasture areas. Grazing reduced the infiltration rate for the pasture (RP and CP) treatments. Results show that the buffer areas have higher infiltration rates which imply lower runoff compared to pasture areas.

Improved APEX Model Simulation of Buffer Water Quality Benefits at Field Scale

“…Studies have documented increased infiltration rates in buffers (Schmitt et al, 1999) due to improved soil porosity and hydraulic conductivity (Udawatta and Anderson, 2008;Kumar et al, 2011;Larson and Safferman, 2012). Seobi et al (2005) and Kumar et al (2012) determined that soil hydraulic conductivity values were four to 16 times higher in an agroforestry buffer than in the associated cropland or pasture. Reported trapping effectiveness values of upland and edge-of-field buffers vary widely among studies: from 41% to 100% for sediment and from 27% to 96% for total phosphorus (TP) (Dillaha et al, 1989;Daniels and Gilliam, 1996;Schmitt et al, 1999;Mayer et al, 1999;Lee et al, 2000;Blanco-Canqui et al, 2004;Vianello et al, 2005;Bhattarai et al, 2009;Caron et al, 2010;Al-wadaey et al, 2012).…”

Agroforestry, grass, biofuel crop, and row‐crop management effects on soil water dynamics for claypan landscapes

“…This can be probably attributed to lower water consumption from this depth by this treatment and possibly higher clay content (claypan) which is concentrated in this depth, and also fewer changes in soil properties may have occurred in the 40‐cm depth under these systems. The argillic horizon claypan soil has higher micropores and fewer macropores and thus lower infiltration (Kumar et al., ; Zaibon et al., ).…”

“…Therefore, these conservation buffer and biomass systems are considered a good strategy to decrease surface runoff and increase water storage (Akdemir et al., ; Evans & Sadler, ; Zaibon et al., ). Also, enhanced water infiltration characteristics as affected by perennial vegetation management practices of trees and grasses can allow the soil system to be more resilient to severe variations in rainfall and climate (Jackson, Smith, Roberts, Wallace, & Ong, ; Kumar et al., ). Overall, buffer and biomass management systems preserve lower soil water contents throughout the growing season allowing the soil to store more water during runoff events (Udawatta et al., ).…”

“…This can be probably attributed to lower water consumption from this depth by this treatment and possibly higher clay content (claypan) which is concentrated in this depth, and also fewer changes in soil properties may have occurred in the 40-cm depth under these systems. The argillic horizon claypan soil has higher micropores and fewer macropores and thus lower infiltration (Kumar et al, 2012;Zaibon et al, 2017). Several studies were conducted by , Veum, Goyne, Kremer, and Motavalli (2012), Weerasekara et al (2016), and Alagele et al (2019b) on the same watersheds to evaluate soil organic carbon under these perennial management systems 9 to 11 and 21 yr after establishment for the GB and AB treatments and 6 yr after establishment of the BC treatment.…”

“…Therefore, integration of tree/grass and agricultural crops into an agroforestry/grass system can probably contribute to reduce soil erosion, improve soil and water quality, and enhance soil biodiversity (Lovell & Sullivan, 2006;Udawatta et al, 2002). Conservation buffers (buffer strips) are a species of trees or grass which are established as narrow strips of permanent vegetation widely prescribed to (i) improve water quality, infiltration, and landscape diversity and (ii) decrease sediment losses and soil erosion (Jose, 2012;Kumar, Anderson, Udawatta, & Kallenbach, 2012;Sahin, Anderson, & Udawatta, 2016;Schmitt, Dosskey, & Hoagland, 1999).…”