Influence of biosolids application on growth, nitrogen uptake, and photosynthesis of two desert grasses

Date

1999-12

Journal Title

Journal ISSN

Volume Title

Publisher

Texas Tech University

Abstract

This research is an evaluation of the effects of different rates and dates of biosolids application, as well as irrigation levels on biomass production, nitrogen absorption, and gas exchange characteristics of blue grama {Bouteloua gracilis) and tobosagrass {Hilaria mutica) in the Chihuahuan Desert, Individuals of blue grama and tobosagrass were transplanted into pots and grown under greenhouse conditions, Biosolids were applied in March (spring application) or Jime (summer application) at rates of 0, 7, 18, 34, and 90 dry Mg ha"'. Plants were irrigated at 40 or 80% soil field capacity. Treatments were combined in a factorial experiment and plants were arranged in a completely randomized block design. Application of biosolids produced an increase in available soil nitrogen, which favored an increase in shoot biomass of blue grama and tobosagrass. As biosolids rates and irrigation levels increased, biomass allocation increased in the shoots of the grasses. As biosolids rates and irrigation levels decreased, biomass allocation to the roots increased. Spring application of biosolids promoted greater soil nitrogen availability and higher plant growth than summer application of biosolids. Biosolids promoted higher nitrogen uptake and higher nitrogen concentrations in the shoots. Higher plant nitrogen concentrations were particularly favored by biosolids application when irrigation was not a limiting factor. Plant nitrogen concentrations were not strongly correlated with photosynthetic rates in both species. Leaf area, nitrogen concentrations, and photosynthesis rates in tobosagrass irrigated at 80% field capacity increased as biosolids rates increased. Increasing rates of biosolids in tobosagrass under the low irrigation level and in blue grama irrespective of irrigation level produced increases in leaf area, which corresponded with decreases in stomatal conductance and photosynthetic rates. Except for tobosagrass at high levels of irrigation, blue grama and tobosagrass seemed to have a mechanism of stomatal regulation to avoid excessive water loss in response to increments in leaf area.

Description

Keywords

Sewage sludge as fertilizer -- Case studies, Chihuahuan Desert (N.M.), Tobosa grass, Crops and nitrogen, Plants -- Photorespiration, Plants -- Effect of sewage on, Blue grama grass, Growth (Plants)

Citation