tem is more effective if tillage and planting are performed along the contour. Schwab et al. (1993) estimated soil Agroforestry production systems have been introduced in temperloss with the universal soil loss equation to be as low as ate regions to improve water quality and diversify farm income. Agro-5.1 Mg ha Ϫ1 yr Ϫ1 for strip cropping, which was comparaforestry and grass-legume buffer effects on soil hydraulic properties ble with soil loss with terraces. Grass buffer strips reduce for a Putnam soil (fine, smectitic, mesic Vertic Albaqualf) were evaluated in a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] water-runoff and increase infiltration upslope from the strips; shed in northeastern Missouri. The no-till management watershed Schmitt et al. (1999) observed that doubling the width was established in 1991 with agroforestry buffers implemented in 1997. of a 7.5-m-wide grass strip doubled water infiltration into Agroforestry buffers, 4.5 m wide and 36.5 m apart, consist of redtop the soil. A multispecies riparian buffer increased the infil-(Agrostis gigantea Roth), brome (Bromus spp.), and birdsfoot trefoil tration rate five times compared with cultivated and (Lotus corniculatus L.) with pin oak (Quercus palustris Muenchh.), grazed fields (Bharati et al., 2002). The infiltration rates swamp white oak (Q. bicolor Willd.), and bur oak (Q. macrocarpa for components of the riparian buffer were as follows: Michx.) trees. Soil cores (7.6 cm in diam. by 7.6 cm long) were collected silver maple (Acer saccharum Marsh.) Ͼ smooth brome from the treatments from four 10-cm depth increments to determine (Bromus inermis Leyss), timothy (Phleum pretense L.), saturated hydraulic conductivity (K sat), soil water retention, pore-size and Kentucky bluegrass (Poa pratensis L.) grass filter Ͼ distributions, and bulk density. Bulk density was 2.3% lower (P Ͻ 0.05) within the grass and agroforestry buffers compared with the row switchgrass (Panicum virgatum L.). They showed that crop areas. Total porosity and coarse mesoporosity (60-to 1000-m planting buffers can improve infiltration within 8 to diam.) were 3 and 33% higher (P Ͻ 0.05), respectively, for the grass 10 yr. Other studies also have demonstrated that perenand agroforestry buffer treatments than the row crop treatment. The nial vegetation can increase infiltration (Broersma et al., K sat was three and 14 times higher (P Ͻ 0.05) in the grass and agrofores-1995; Wood, 1977). try buffer treatments compared with the row crop treatment. Results Recently, a study was conducted to evaluate the efshow that the grass and agroforestry buffer treatments increased pofects of grass and agroforestry contour buffer strips on tential water storage by 0.90 cm and 1.1 cm per 30-cm depth compared runoff, sediment, and nutrient losses on a claypan soil with the row crop treatment. Although the claypan horizon will domi-(Udawatta et al., 2002). They found that these buffers nate the surface hydrology, buffers may provide some benefit by rereduced surface water runoff, sediment, total P...

Agroforestry practices are receiving increased attention in temperate zones due to their environmental and economic benefits. To test the hypothesis that agroforestry buffers reduce runoff by increased infiltration, water use, and water storage; profile water content and soil water infiltration were measured for a Putnam soil (fine, smectitic, mesic Vertic Albaqualf). The watershed was under no-till management with a corn (Zea mays L.)-soybean (Glycine max L.) rotation since 1991. Agroforestry buffer strips, 4.5 m wide and 36.5 m apart, were planted with redtop (Agrostis gigantea Roth), brome (Bromus spp.), and birdsfoot trefoil (Lotus corniculatus L.). Pin oak (Quercus palustris Muenchh.), swamp white oak (Q. bicolor Willd.) and bur oak (Q. macrocarpa Michx.) trees were planted at 3-m intervals in the center of the agroforestry buffers in 1997. Ponded water infiltration was measured in agroforestry and grass buffers and row crop areas. Water content in agroforestry and row crop areas at 5, 10, 20, and 40 cm depths were measured throughout the year. Quasi-steady infiltration rates were not different (P [ 0.05) among the treatments. Agroforestry had lower soil water content than row crop areas (P \ 0.05) during the growing season. Higher water content after the principal recharge event in the agroforestry treatment was attributed to better infiltration through the root system. Results show that agroforestry buffer strips reduce soil water content during critical times such as fallow periods, and increase water infiltration and water storage. Therefore, adoption of agroforestry buffer practices may reduce runoff and soil loss from watersheds in row crop management.