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Zhang X.-Y.,Gansu Agricultural University | Zhang X.-Y.,Sino Us Centers For Grazingland Ecosystem Sustainability | Wang S.-S.,Gansu Agricultural University | Wang S.-S.,Sino Us Centers For Grazingland Ecosystem Sustainability | And 6 more authors.
Acta Prataculturae Sinica | Year: 2016

The aim of this research was to investigate the effects of potassium on alfalfa growth and its resistance to thrips. Two alfalfa varieties were chosen for the study; Gannong No.9 (thrip-resistant) and Gannong No.3 (thrip-susceptible). Potassium (K2O) was applied to field-grown plants at five different levels (0, 6, 9, 12, and 15 g/m2) during the peak thrip damage period, and then the damage index, the potassium and carbohydrate contents in leaves, and yield were evaluated. The results showed that the yields of both alfalfa varieties increased significantly with increasing K2O levels. The potassium, soluble sugars, starch, and lignin contents in old and heart leaves increased with increasing K2O levels, and the thrip damage index decreased significantly. The lowest damage index values were in the 9 g/m2 K2O treatment (decreased 47.60% and 46.11% for Gannong No.9 and Gannong No.3 with the control, respectively). The damage index, yield, and potassium, soluble sugars, starch, and lignin contents at the second cutting showed similar trends to those at the third cutting. The damage index at the third cutting was decreased 30.78% and 23.27% for Gannong No.9 and Gannong No.3 with the control, respectively. Correlation analyses indicated that the potassium content of plants at the second and third cuttings was significantly negatively correlated with the damage index when the K2O application rate was lower than 9 g/m2, but not significantly correlated with the damage index when the K2O application rate was higher than 12 g/m2. The damage index was lower in Gannong No.3 treated with potassium than in Gannong No.9 without potassium application. These results indicate that potassium can enhance the resistance of alfalfa to thrips by promoting the synthesis of carbohydrates (especially soluble sugars and starch) and plant growth. Therefore, potassium management is an effective method to increase the tolerance of alfalfa to thrips in the field. The most economical fertilizer application rate was 9 g K2O/m2 in this experiment. Copyright © ACTA PRATACULTURAE SINICA. All rights reserved.

Shi H.X.,Gansu Agricultural University | Shi H.X.,Key Laboratory of Grassland Ecosystem | Shi H.X.,Sino Us Centers For Grazingland Ecosystem Sustainability | Shi H.X.,Chinese Academy of Agricultural Sciences | And 10 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2016

Plant responses to grazing form part of an adaptation strategy that enables them to survive and reproduce. Plant phenotypic responses are important to characterize grazing-induced plant mechanisms in grassland ecosystems. In the present study, we investigated how grazing and enclosures affect individual traits of Poa alpigena, the primary plant species in alpine meadows of the Qinghai-Tibet Plateau. The objectives of our research were to (1) reveal the different P. alpigena stem and leaf response traits affected by grazing and enclosures, and (2) determine the sensitivity of the phenotypic plasticity of different traits during grazing.The present study was conducted using field experiments involving various grazing and enclosure conditions on the Qinghai-Tibet Plateau. We compared the effects of annual grazing (YG), summer grazing (SG), winter grazing (WG), 3-year enclosure (UG3), 5-year enclosure (UG5), and 12-year enclosure (UG12) on P. alpigena functional traits. The experimental data for YG, SG, WG, UG3, UG5, and UG12 were randomly collected from sample areas in early August 2014. Plants with intact organs were collected from six plots (1.0 m × 1.0 m), with nine collections from each plot for a total of 54 plant samples. Plant height, number of leaves, leaf length, leaf width, stem diameter, stem length, root length, root thickness, ear length, and other phenotypic traits were determined. Averages for leaf length and width were calculated using these data. Leaf area was measured using a digital scanner and image analysis software, and the average individual leaf area was calculated. After phenotypic traits were assessed and recorded, the stems, leaves, spikes, and roots were separated and dried. The dry weight of the stems, leaves, spikes, and roots of each plant was determined.The results showed that under long-term grazing conditions, there was a significant decrease (P < 0.05) in root weight, number of leaves, plant height, number of branches, leaf length, leaf width, leaf area, stem diameter, stem length, root length, root thickness, spike length, total leaf quality, stem weight, spike weight, and whole-plant weight. Under short-term enclosure conditions, the recovery of functional properties such as leaf width, leaf quality, simple leaf quality, stem weight, spike weight, and root weight was not significant (P > 0.05). The results suggest that the recovery of P. alpigena traits on degraded grassland due to short-term grazing were associated with conservation. We also determined the spectrum of P. alpigena trait plasticity and observed that phenotypic variations in spike weight, stem weight, total plant weight, number of tillers, stem length, and plant height were high, indicating that these characteristics are sensitive to grazing. Phenotypic variations in leaf width, number of leaves, stem diameter, and root diameter were low, suggesting that these are inert characteristics. Generally, phenotypic changes are significant in the adaptive strategy used by P. alpigena to manage the effects of long-term grazing. © 2016, Ecological Society of China. All rights reserved.

Zhang S.-W.,Gansu Agricultural University | Zhang S.-W.,Ministry of Education Key Laboratory of Grassland Ecosystem | Zhang S.-W.,Gansu Province Key Laboratory of Pratacultural Engineering | Zhang S.-W.,Sino Us Centers For Grazingland Ecosystem Sustainability | And 10 more authors.
Chinese Journal of Applied Ecology | Year: 2013

A laboratory experiment was conducted to study the parasitic and lethal effects of Trichoderma longibrachiatum conidia suspension on Heterodera avenae cysts. Different concentrations (1.5×105-1.5×107 cfu·mL-1) of T. longibrachiatum conidia suspension had strong parasitic and lethal effects on H. avenae cysts, and the effects differed significantly among the different concentrations. When treated with the T. longibrachiatum conidia suspension at a concentration of 1.5×107 cfu·mL-1, 96.7% of the H. avenae cysts were parasitized by the conidia at the 18th day, and the hatching rate of the cysts was inhibited by 91.2% at the 22nd day. The microscopic observation showed that at the initial parasitic stage, T. longibrachiatum conidia suspension adhered or parasitized on the cyst surface, germinated a large number of hyphae, and grew on the cyst surface, making the development of cyst embryo stopped and the contents in cysts flocculated, and even, some cysts started to deform, and small dark brown vacuoles formed on the cyst surface. At the later parasitic stage, the cysts were penetrated by dense mycelium, cysts were broken, their contents exosmosed, and the mycelium on the integument of some cysts produced conidiophores, on which, conidium were adhered or parasitized. It was considered that T. longibrachiatum could be used as a potential high-efficient bioagent to control the occurrence and damage of H. avenae.

Li J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Guo M.,Academy of Armored force Engineering | Yu J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Xia J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | And 3 more authors.
Advanced Materials Research | Year: 2012

Considering the various influencing factors of eco-environmental quality in Lake Dianchi Basin, the evaluation indexes of eco-environmental quality such as biological abundance index, vegetation coverage index, water network density index, land degradation index and environmental quality index are determined. The weight values of factor indexes are given by using the quantitative and qualitative model of analytic hierarchy process (AHP) and the eco-environmental quality of Lake Dianchi Basin was evaluated by using the quantitative and qualitative model of ecological index (EI). The evaluation results show that the grade of eco-environmental quality is weaker and the environment for human survival is harsh. The evaluation result is in good agreement with the results of previous studies. The evaluation system established in the paper can be regarded as a reference model for eco-environmental quality evaluation. © (2012) Trans Tech Publications.

Liu X.,Gansu Agricultural University | Liu X.,Sino Us Centers For Grazingland Ecosystem Sustainability | Guo J.,Gansu Agricultural University | Guo J.,Sino Us Centers For Grazingland Ecosystem Sustainability | And 7 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

According to Comprehensive and Sequential Classification System of Rangeland (CSCS) and ArcGIS platform, an improved interpolation method named analytic method based on multiple regression and residues (AMMRR), and 3 traditional interpolation methods, in conjunction with 1 km resolution DEM and meteorological data from 1961 to 2004 in China as main data sources, were applied in simulating the spatial distribution pattern of annual accumulative temperature (>0°C ∑θ) and annual precipitation (r), and carrying out classification for Chinese rangeland with AMMRR after the comparison among 4 interpolation methods. The results showed that: 1) The correlation coefficients between simulative and observational value of ∑θ and r were 0.976 and 0.974 with highly significant correlation (p<0.01) based on AMMRR, respectively. Its relative mean error (RME), mean absolute error (MAE) and root-mean-square error (RMSE) were entirely lower than traditional interpolation methods. 2) AMMRR method can remedy the shortcoming and heterogeneous distribution of meteorological stations, and fully reflect the vertical variation of meteorological factors in the regions of big net height via modifying residual errors between observational and simulative value and implementing multiple regression among meteorological factors and longitude, latitude, elevation. In the region with densely meteorological stations, the simulative effects of 4 simulative methods were highly agreement with each other, and the spatial distribution pattern of ∑θ and r were similar with their actual geographical conditions. Compared to the region of sparsely and heterogeneously meteorological stations, only AMMRR method with ideal interpolation effect can reflect the spatial heterogeneity of topography on the spatial distribution pattern of ∑θ and r in the small scale regions. 3) Associate with CSCS, Chinese rangeland could be classified into 41 classes exception of Tropical-extrarid tropical desert (VII A7). Subsequently Tropical-perhumid rain forest (VII F42), Sub-tropical perhumid evergreen broad leaved forest (VI F41), Warm-perhumid deciduous-evergreen broad leaved forest (V F40), Warm temperate perhumid deciduous broad leaved forest (IV F39) and Cool temperate perhumid mixed coniferous broad leaved forest (III F38), Cool temperate-humid forest steppe, deciduous broad leaved forest (III E31), Cool temperate-subhumid meadow steppe (III D24), Cool temperate semiarid temperate typical steppe (III C17) distributed with the decreasing ∑θ and r from south to north and from east to west, which indicated significantly zonality patterns.

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