Importance of Soil and Cropping Systems in the Development of Regional Water Quality Policies

Abstract

Targeting certain soils and cropping systems may be necessary in consideration of regional water quality protection policies. However, little information is available relating soils and cropping practices to regional water quality problems. This study evaluates crop yield and NO3‐N movement to surface and groundwater on four soils and nine principal cropping systems in the High Plains region of Oklahoma. The cropping systems involve wheat (Triticum aestivum L.), grain sorghum [Sorghum bicolor (L.) Moench], and corn (Zea mays L.), and are part of a regional data base also containing soils and chemical management information. For each combination of crop, soil, cropping system, and chemical alternative, a 20‐yr simulation was made. The simulation was based on a modeling system that includes EPIC‐PST (crop growth/chemical movement model) interfaced with a Geographic Information System (GIS), Earthone. Results of each simulation included crop yield and NO3‐N movement in runoff and percolation. Results show wide variations in NO3‐N losses for different soils, irrigation systems, and cropping systems. When compared with continuous irrigated wheat and grain sorghum cropping systems, double‐cropped wheat‐grain sorghum resulted in greater NO3‐N loss in percolation. Compared with sprinkler and LEPA (low energy precision application) irrigation systems, furrow irrigation resulted in high NO3‐N loss on both fine‐textured and coarse‐textured soils, with significantly greater loss on the coarser‐textured soils. The modeling framework can be used to compare alternative water quality policies. Broad policies such as a restriction on the amount of N that can be applied per hectare can be compared with targeted policies, such as limiting N applications or irrigation water use on coarser soils or under furrow irrigation.

GIS Applications of Deterministic Solute Transport Models for Regional-Scale Assessment of Non-Point Source Pollutants in the Vadose Zone

“…Poiani and Bedford (1995) recently presented a cursory review of GE-based NPS pollution models emphasizing surface applications. Numerous hydrologic-water quality models of runoff and soil erosion have been used with a GIS to determine surface sources of NPS pollutants from watersheds (Pelletier, 1985;Potter et al, 1986;Oslin et al, 1988;Sivertun et al, 1988;DeRoo et al, 1989DeRoo et al, , 1992Rudra et al, 1991;Bhaskar et al, 1992;Drayton et al, 1992;Joao & Walsh, 1992;Tim et al, 1992;Walker et al, 1992;Wolfe, 1992;He et al, 1993;Heidtke & Auer, 1993;Levine et al, 1993;Mitchell et al, 1993;Warwick & Haness, 1994) agricultural areas (Hopkins & Clausen, 1985;Gilliland & Baxter-Potter, 1987;Hession & Shanholtz, 1988Panuska & Moore, 1991;Hamlett et al, 1992;Lee & White, 1992;Geleta et al, 1994;Tim & Jolly, 1994) and urban areas (Smith & Brilly, 1992;Smith, 1993;Ventura & Kim, 1993). In addition, several groundwater models have been coupled to a GIS to simulate water flow and/or NPS pol-lutants in aquifers (Kernodle & Philip, 1989;Baker & Panciera, 1990;Hinaman, 1993;Roaza et al, 1993;El-Kadi et al, 1994;Darling & Hubbard, 1994).…”

Water use efficiency, biomass production, nitrogen and potassium uptake and yield of tomato (Lycopersicon esculentum cv. Ratan) Planta grown under surface drip and flood irrigation

“…Higher nitrogen concentration in the leaves of tomato plants grown under drip irrigation was reported by Badr and Abou El-Yazid (2007). Geleta et al (1994) compared drip and flood irrigation and concluded that drip irrigation resulted in lower NO 3 -N loss. Nutrient transport from the soil solution to the root surface takes place by two simultaneous processes: convection in water flow and diffusion (Junk 1996).…”

Calibration of a crop model to irrigated water use using a genetic algorithm

“…Because its original focus was erosion-related, EPIC can simulate decade-scale or longer intervals. These features have suited EPIC to a broad range of applications, including plant nutrition studies (Cole et al, 1987;Dautrebande et al, 1999); national and international assessments of agroecological change impact (Brown and Rosenberg, 1999;Brown et al, 2000;Bernardos et al, 2001), including the High Plains Aquifer (Easterling III et al, 1993); irrigation planning and water use (Bryant et al, 1992;Ellis et al, 1993;Evers et al, 1998;Guerra et al, 2005); and regional studies (Geleta et al, 1994;Cabelguenne et al, 1995;Fortin and Moon, 2000).…”