Agricultural Practices Influence Dissolved Nutrients Leaching through Intact Soil Cores

Abstract

high water table was set in the Netherlands (Breeuwsma et al., 1995). Agricultural practices such as tillage, crop-Nitrogen and P leaching from agricultural land to ground water ping systems, and fertilizer applications influence soil poses a threat to water quality, but it may be possible to control nutrient concentrations and drainage rates, leading us dissolved nutrient leaching by choosing appropriate management practices. The objective of this study was to evaluate the effects of to believe that it may be possible to control NO 3-N and agricultural practices on dissolved N and dissolved P leaching from dissolved reactive P leaching from agricultural soils by topsoil to subsurface soil after crop harvest. Intact soil cores and small choosing appropriate management practices. disturbed soil columns were collected from a factorial (tillage ϫ crop ϫ Tillage has a twofold effect on nutrient leaching: first, fertilizer source) field experiment, 3 yr after the treatments were on soil nutrient concentrations and second, on water established. Soils were leached with synthetic rainwater in the laboraflow patterns. In general, tillage is expected to hasten tory and nutrient loads (kg ha Ϫ1) were calculated. Dissolved N and decomposition of residues, resulting in more N mineraldissolved P loads were not affected by tillage and were similar followization and nitrification. Thus, more NO 3-N loss is exing corn (Zea mays L.) (in a continuous corn rotation) and soybean pected in plowed than no-till soils (Power et al., 2001). [Glycine Max (L.) Merr.] (in a soybean/corn rotation) production. Soils Kanwar and Baker (1993) found greater NO 3-N concenreceiving inorganic fertilizer had a 70% greater nitrate (NO 3-N) load and 48% less dissolved reactive P than soils receiving organic fertilizer, trations in the 1.5-m depth of plowed than no-till soils. suggesting that fertilizing soils with a combination of inorganic and Yet, Eisenhauer et al. (1993) found that greater percolaorganic fertilizers might be a good way to reduce both NO 3-N and tion of water through no-till than plowed soils led to dissolved reactive P transport to water systems. The NO 3-N load inmore NO 3-N movement in the soil profile. Other recreased as the soil NO 3-N concentration increased (R 2 ϭ 0.36) while the searchers have found no consistent effects of tillage on dissolved reactive P load was positively related to the soil Mehlich-3

Crop Residue Effects on Organic Carbon, Nitrogen, and Phosphorus Concentrations and Loads in Runoff Water

“…It may be possible to control dissolved nutrient leaching by choosing appropriate management practices (Jiao, Hendershot, and Whalen 2004) since agricultural practices such as tillage, cropping systems, and fertilizer applications influence soil nutrient concentrations and drainage rates. In general, tillage is expected to hasten decomposition of residues, resulting in more N mineralization and nitrification.…”

No-tillage and manure applications increase aggregation and improve nutrient retention in a sandy-loam soil

“…Detailed information on the experiment layout, tillage methods, crop rotations and fertilizer sources have been reported by Jiao et al (2004). Briefly, it was a factorial split-plot experiment consisting of two tillage systems (conventional and no-tillage) and three crop rotations (continuous maize, soybean/maize or maize/ soybean; only one crop per year) as main plots (20 Â 24 m), and four fertilizer treatments as split plots (20 Â 6 m).…”

Monitoring corn and soybean agroecosystems after establishing no-tillage practices in Québec, Canada

“…Annual nutrient applications included about 30 m 3 ha -1 of liquid dairy manure as well as 100 to 140 kg N ha -1 from urea fertilizer. Further description of the site has been provided by Whalen et al (2003) and Jiao et al (2004).…”