@article {KNZ001963, title = {Following legume establishment, microbial and chemical associations facilitate improved productivity in degraded grasslands}, journal = {Plant and Soil}, volume = {443}, year = {2019}, pages = {273 - 292}, keywords = {LTER-KNZ}, doi = {10.1007/s11104-019-04169-9}, url = {http://link.springer.com/10.1007/s11104-019-04169-9}, author = {Zhou, Jiqiong and Zhang, Fengge and Huo, Yunqian and G.T. Wilson and Cobb, Adam B. and Xu, Xixi and Xiong, Xue and Liu, Lin and Zhang, Yingjun} } @article {KNZ001981, title = {Phosphorus and mowing improve native alfalfa establishment, facilitating restoration of grassland productivity and diversity}, journal = {Land Degradation \& Development}, volume = {30}, year = {2019}, pages = {647 - 657}, keywords = {LTER-KNZ}, doi = {10.1002/ldr.v30.610.1002/ldr.3251}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ldr.3251}, author = {Zhou, Jiqiong and G.T. Wilson and Cobb, Adam B. and Yang, Gaowen and Zhang, Yingjun} } @article {KNZ001905, title = {Defoliation and arbuscular mycorrhizal fungi shape plant communities in overgrazed semiarid grasslands}, journal = {Ecology}, volume = {99}, year = {2018}, pages = {1847 - 1856}, abstract = {

Overgrazing substantially contributes to global grassland degradation by decreasing plant community productivity and diversity through trampling, defoliation, and removal of nutrients. Arbuscular mycorrhizal (AM) fungi also play a critical role in plant community diversity, composition, and primary productivity, maintaining ecosystem functions. However, interactions between grazing disturbances, such as trampling and defoliation, and AM fungi in grassland communities are not well known. We examined influences of trampling, defoliation, and AM fungi on semiarid grassland plant community composition for 3\ yr, by comparing all combinations of these factors. Benomyl fungicide was applied to reduce AM fungal abundance. Overgrazing typically resulted in reduced dominance of Stipa Krylovii, contributing to degradation of typical steppe grasslands. Our results indicated trampling generally had little effect on plant community composition, unless combined with defoliation or AM fungal suppression. Defoliation was the main component of grazing that promoted dominance of Potentilla acaulis over Stipa krylovii and Artemisia frigida, presumably by alleviating light limitation. In non-defoliated plots, AM fungi promoted A.\ frigida, with a concomitant reduction in S.\ krylovii growth compared to corresponding AM suppressed plots. Our results indicate AM fungi and defoliation jointly suppress S.\ krylovii biomass; however, prolonged defoliation weakens mycorrhizal influence on plant community composition. These findings give new insight into dominant plant species shifts in degraded semiarid grasslands.

}, keywords = {LTER-KNZ}, doi = {10.1002/ecy.2401}, url = {https://doi.org/10.1002/ecy.2401}, author = {Yang, Xin and Shen, Yue and Liu, Nan and G.T. Wilson and Cobb, Adam B. and Zhang, Yingjun} } @article {KNZ001903, title = {Long-term effects of grazing and topography on extra-radical hyphae of arbuscular mycorrhizal fungi in semi-arid grasslands}, journal = {Mycorrhiza}, volume = {28}, year = {2018}, pages = {117 - 127}, abstract = {

Grazing and topography have drastic effects on plant communities and soil properties. These effects are thought to influence arbuscular mycorrhizal (AM) fungi. However, the simultaneous impacts of grazing pressure (sheep\ ha-1) and topography on plant and soil factors and their relationship to the production of extra-radical AM hyphae are not well understood. Our 10-year study assessed relationships between grazing, plant species richness, aboveground plant productivity, soil nutrients, edaphic properties, and AM hyphal length density (HLD) in different topographic areas (flat or sloped). We found HLD linearly declined with increasing grazing pressure (1.5-9.0 sheep\ ha-1) in sloped areas, but HLD was greatest at moderate grazing pressure (4.5 sheep\ ha-1) in flat areas. Structural equation modeling indicates grazing reduces HLD by altering soil nutrient dynamics in sloped areas, but non-linearly influences HLD through plant community and edaphic changes in flat areas. Our findings highlight how topography influences key plant and soil factors, thus regulating the effects of grazing pressure on extra-radical hyphal production of AM fungi in grasslands. Understanding how grazing and topography influence AM fungi in semi-arid grasslands is vital, as globally, severe human population pressure and increasing demand for food aggravate the grazing intensity in grasslands.

}, keywords = {LTER-KNZ}, doi = {10.1007/s00572-017-0812-x}, url = {http://link.springer.com/10.1007/s00572-017-0812-x}, author = {Ren, Haiyan and Gui, Weiyang and Yongfei Bai and Stein, Claudia and Rodrigues, Jorge L. M. and G.T. Wilson and Cobb, Adam B. and Zhang, Yingjun and Yang, Gaowen} } @article {KNZ001900, title = {Plant functional group influences arbuscular mycorrhizal fungal abundance and hyphal contribution to soil CO2 efflux in temperate grasslands}, journal = {Plant and Soil}, volume = {432}, year = {2018}, pages = {157-170}, abstract = {

Background and aims: Arbuscular mycorrhizal (AM) fungi are abundant in grassland ecosystem. We assessed AM hyphal contributions to soil CO2 efflux across plant functional groups to better quantify AM fungal influences on soil carbon dynamics.


Methods: We conducted a field experiment using in-growth mesocosms to partition soil CO2 efflux from roots, AM hyphae, and free-living soil microbes associated with C3 grasses, C4 grasses, forbs, and diverse plant communities from May to August in 2017.


Results: AM hyphae contributed \<10\% to total soil respiration in forb communities and diverse plant communities but accounted for as much as 32\% in C3 grasses. Plant functional groups differed in hyphal production efficiencies (the ratio of AM hyphal length to aboveground biomass), with the lowest in C3 grasses (0.47?\±?0.15 m g-1) and the greatest in forbs (3.27?\±?0.55 m g-1). Mowing reduced hyphal production efficiency of C4 grasses and forbs but did not affect total soil respiration. AM hyphal and microbial respiration peaked at the middle of the growing season, however there was no significant seasonal variation in root respiration.


Conclusion: AM hyphal respiration is an important pathway of carbon flux from plants to atmosphere. Shifts in plant community composition can influence soil carbon processes by regulating hyphal production and respiration.

}, keywords = {LTER-KNZ}, doi = {10.1007/s11104-018-3789-0}, url = {http://link.springer.com/10.1007/s11104-018-3789-0}, author = {Gui, Weiyang and Ren, Haiyan and Liu, Nan and Zhang, Yingjun and Cobb, Adam B. and G.T. Wilson and Sun, Xiao and Hu, Jian and Xiao, Yan and Zhang, Fengge and Yang, Gaowen} } @article {KNZ001904, title = {Trichoderma biofertilizer links to altered soil chemistry, altered microbial communities, and improved grassland biomass}, journal = {Frontiers in Microbiology}, volume = {9}, year = {2018}, pages = {848}, abstract = {

In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly (p = 0.019) increased following amendment with 9,000 kg ha\−1 of Trichoderma biofertilizer (composted cattle manure + inoculum) compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha\−1 biofertilizer). This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS) revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha\−1) increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella. Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella. According to our structural equation modeling (SEM), Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma biofertilizer could be an important tool for management of soils and ultimately grassland plant biomass.

}, keywords = {LTER-KNZ}, doi = {10.3389/fmicb.2018.00848}, url = {http://journal.frontiersin.org/article/10.3389/fmicb.2018.00848/full}, author = {Zhang, Fengge and Huo, Yunqian and Cobb, Adam B. and Luo, Gongwen and Zhou, Jiqiong and Yang, Gaowen and G.T. Wilson and Zhang, Yingjun} } @article {KNZ001907, title = {Small vegetation gaps increase reseeded yellow-flowered alfalfa performance and production in native grasslands}, journal = {Basic and Applied Ecology}, volume = {24}, year = {2017}, pages = {41 - 52}, abstract = {

Reseeding yellow-flowered alfalfa (YFA) in degraded grasslands may require a vegetation-free microsite for germination and subsequent establishment. This study aimed to examine the role of microclimates of different-sized vegetation gaps on seedling performance and adult plant production of YFA. Field microsites were established in the meadow steppe of Hulunber, Inner Mongolia, China. Seedling performance, plant production, the microclimate within vegetation gaps, and soil nutrients (plant-available N, P, and K, total N concentration) were assessed at the end of each growing season from 2013 to 2015. Our results indicate light availability, and topsoil temperature of each gap were significantly increased as gap size increased, while topsoil moisture and air relative moisture were decreased in larger gaps. Small gaps (diameter \≤10cm) improved seedling emergence, survival, biomass, and root nodulation, as compared with seedling performance associated with the larger gaps, presumably in response to increased shade and moisture. Additionally, large gaps (\>20 or \>40\ cm) were characterized by significantly lower plant-available P, total N concentrations, plant-available K, and soil pH. However, root exclusion treatments did not improve overall seedling performance, plant production, or soil properties, as compared to corresponding microsites with root presence, regardless of gap size. Our results suggest that reseeding YFA into grasslands where disturbance, such as light grazing, has resulted in small gaps will be more effective than in highly degraded grasslands.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.baae.2017.08.002}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1439179117300464}, author = {Zhou, Jiqiong and Zhang, Yingjun and G.T. Wilson and Cobb, Adam B. and Lu, Wenjie and Guo, Yanping} }