Soil Nitrate Nitrogen Dynamics after Biosolids Application in a Tobosagrass Desert Grassland

Abstract

Dormant-season application of biosolids increases desert grass production more than growing season application in the first growing season after application. Differential patterns of NO3-N (plant available N) release following seasonal biosolids application may explain this response. Experiments were conducted to determine soil nitrate nitrogen dynamics following application of biosolids during two seasons in a tobosagrass [Hilaria mutica (Buckl.) Benth.] Chihuahuan Desert grassland. Biosolids were applied either in the dormant (early April) or growing (early July) season at 0, 18, or 34 dry Mg ha(-1). A polyester-nylon mulch was also applied to serve as a control that approximated the same physical effects on the soil surface as the biosolids but without any chemical effects. Supplemental irrigation was applied to half of the plots. Soil NO3-N was measured at two depths (0-5 and 5-15 cm) underneath biosolids (or mulch) and in interspace positions relative to surface location of biosolids (or mulch). Dormant-season biosolids application significantly increased soil NO3-N during the first growing season, and also increased soil NO3-N throughout the first growing season compared to growing-season biosolids application in a year of higher-than-average spring precipitation. In a year of lower-than-average spring precipitation, season of application did not affect soil NO3-N. Soil NO3-N was higher at both biosolids rates for both seasons of application than in the control treatment. Biosolids increased soil NO3-N compared to the inert mulch. Irrigation did not significantly affect soil NO3-N. Soil NO3-N was not significantly different underneath biosolids and in interspace positions. Surface soil NO3-N was higher during the first year of biosolids application, and subsurface soil NO3-N increased during the second year. Results showed that biosolids rate and season of application affected soil NO3-N measured during the growing season. Under dry spring-normal summer precipitation conditions, season of application did not affect soil NO3-N; in contrast, dormant season application increased soil NO3-N more than growing season application under wet spring-dry summer conditions.

Assessment of extractability of Cu, Cr, Ni, Pb and Zn in some chilean biosolid-amended soils by using BCR sequential extraction procedure

“…In order to determine the residual fraction, the recommended extraction protocol with aqua regia (ISO11466) was adapted for microwave oven use. Thus, the residue oxidizable fraction was digested with a concentrated mixture of HNO 3 and HCl (1:3 v/v), using a Milestone/mls 1200 Mega microwave oven.…”

“…3 However, a major obstacle for recycling is that this residue also contains various contaminants. Metals occurring as trace elements are of special concern because they may present toxic effects in the biota and accumulate in trophics webs.…”

Emergence and survival of blue grama with biosolids under greenhouse conditions

“…Our results suggest that the higher soil-nutrient availability (Fresquez et al, 1990;Martinez et al, 2003;Jurado-Guerra et al, 2006;Jurado et al, 2007) and the increase in soil moisture availability with biosolids application (Hahm and Wester, 2004;Moffet et al, 2005;Jurado et al, 2007) were partly responsible for the increase in biomass of surviving blue grama plants.…”

“…Wester et al (2003) reported several benefits of surface-applied biosolids to rehabilitate Chihuahuan desert grasslands. Among those benefits surfaceapplied biosolids have been shown to increase soil water infiltration and soil fertility (Rostagno and Sosebee, 2001;Moffet et al, 2005;Jurado-Guerra et al, 2006) as well as forage production of tobosagrass (Hilaria mutica Benth. ), alkali sacaton (Sporobolus airoides Torr.…”

Adsorption of Fungicides in Chilean Soils Incubated With Biosolids

“…[1][2][3] Sewage sludge can be recycled as a source of nutrients for plant growth and as a conditioner to improve physical and microbiological soil properties 4 . However, a major obstacle for recycling is that this residue also contains various contaminants 5 .…”