Effects of nickel, lead, and copper stress on the growth and biochemical responses of Aegilops tauschii seedlings.

Heavy metal pollution causes severe abiotic stress in cereal crops around the world. This study investigated the effects of different concentrations (0, 100, 200, and 300 mg·kg) of nickel, lead, and copper stress on the growth and biochemical responses of Aegilops tauschii seedlings, to provide a reference for research on the mechanism of invasion and screening potential sources of wheat tolerance genes. The results showed that nickel, lead, and copper stress caused a significant decrease in the contents of chlorophyll a, chlorophyll b, and chlorophyll (a + b) in A.

Effects of tree species and topography on soil and microbial biomass stoichiometry in Funiu Mountain, China.

Background: Soil and microbial biomass stoichiometry plays an important role in understanding nutrient cycling in terrestrial ecosystems. However, studies on soil and microbial biomass stoichiometry in forests are rare. This study investigated the effect of tree species and topographic factors on the ecological stoichiometry of soil and soil microbial biomass.

Effects of land use patterns on stream water quality: a case study of a small-scale watershed in the Three Gorges Reservoir Area, China.

In this study, we have considered the relationship between the spatial configuration of land use and water quality in the Three Gorges Reservoir Area. Using land use types, landscape metrics, and long-term water quality data, as well as statistical and spatial analysis, we determined that most water quality parameters were negatively correlated with non-wood forest and urban areas but were strongly positively correlated with the proportion of forest area. Landscape indices such as patch density, contagion, and the Shannon diversity index were able to predict some water quality indicators, but the mean shape index was not significantly related to the proportions of farmland and water in the study area.

[Effects of land use and landscape pattern on nitrogen and phosphorus exports in Lanlingxi Watershed of the Three Gorges Reservoir Area, China].

The temporal and spatial characteristics of N, P exports and effects of land use and landscape pattern on N, P exports were analyzed in the Lanlingxi Watershed of the Three Gorges Reservoir Area. The results showed that the TN, TP and NO3(-) -N were mainly generated by non-wood forest, the N, P exports in flood period (June to September) were significantly higher than the non-flood period (January to May). The NH4(+) -N export was derived from the residential area in the non-flood period, while from non-wood forest in the flood period.

[Nitrogen and phosphorus loss in different land use types and its response to environmental factors in the Three Gorges Reservoir area].

The control of agricultural non-point source pollution (AGNPS) is an urgent problem to be solved for the ecological environment construction in the Three Gorges Reservoir Area. We analyzed the nitrogen (N) and phosphorus (P) loss and its response to environmental factors through monitoring the nutrient loss in different land use types after returning farmland to forest. The results showed that: 1) The variability of nutrient concentration loss was strong in different land use types under different rainfall conditions, and the variability in the concentration of available nutrient was much higher than that of total nutrient; 2) Compared to farmland, the annual phosphorus loss of different land use types was reduced by 84.

[Dynamic change of non-point source pollution exported from Heigou watershed in Three Gorges Reservoir area].

Sediment and its associated pollutants entering a water body can be very destructive to the ecological health of that system. Based on GIS and AnnAGNPS model, A total of 60 combinations of various management treatments including five fertilizer levels (FL1-existing, FL2-70% of existing, FL3-recommended, FLA-70% of recommended, FL5-30% of recommended), four tillage practices (CT-conventional tillage, NT-no tillage, CS-contour strip cropping, RC-residue cover) and three kinds of annual rainfall (deficit, normal, abundant) have been evaluated. Results from model simulations indicate that runoff and sediment yield were not affected due to change in fertilizer doses, but there was a significant positive correlation between nutrient losses and fertilizer application rates; Conservation tillage practices such as NT, CS and RC would reduce sediment and sediment-bound nutrient losses significantly, they have very little benefit on soluble nitrogen and phosphorus losses.

[Reduction effects of agricultural management practices on non-point source pollution in a watershed in Three Gorges Reservoir Area].

Taking a typical watershed in the Three Gorges Reservoir Area (TGRA) as test object, the AnnAGNPS model was used to evaluate the reduction effects of different cropping, different fertilization level, conservation tillage practice (CTP), conservation reserve program (CRP), and conversion of cropland into forestland program (CCFP) on the output of agricultural non-point source pollution (NPS) in the watershed. The simulation results showed that different cropping had no significant difference in the effect of reducing sediment yield, but had significant difference in the effect of reducing phosphorus output. Fertilization level had significant effects on the outputs of total nitrogen and total phosphorus.

Reductions in non-point source pollution through different management practices for an agricultural watershed in the Three Gorges Reservoir Area.

Non-point source water pollution generated by agricultural production is considered a major environmental issue in the Three Gorges Reservoir Area (TGRA) of China. The Annualised Agricultural Non-Point Source Pollution (AnnAGNPS) model was selected to assess the impact of the application of various management treats, including seven crops, five fertilizer levels and three-group management practice scenarios, on water quality from Heigou River Watershed in TGRA. The scenario subsets include conservation tillage practice (CTP), conservation reserve program (CRP) and conversion of cropland into forestland program (CCFP).

[Nonpoint source pollution model, AnnAGNPS, assessment for a mixed forested watershed in Three Gorges Reservoir area].

Watershed models provide a cost-effective and efficient means of estimating the pollutant loadings entering surface waters, especially when combined with traditional water quality sampling and analyses. But there have often been questions about the accuracy or certainty of models and their predictions. The main goal of this study was to evaluate the performance of AnnAGNPS (Annualized AGricultural NonPoint Source)Pollution Model, in simulating runoff, sediment loading and nutrient loadings under Three Gorges Reservoir area.