Grass Type Research Articles

Erianthus Plant: A Rich Silica Source for Extraction of Amorphous Silica

In this paper, Erianthus plant, a grass type of lignocellulosic biomass, is presented as an alternative source for the production of amorphous silica. Thermal treatment (combustion) of Erianthus plant under a controlled temperature of 600–900°C produces Erianthus Ash (EA). Then, silica powder was extracted from EA by the chemical extraction method. In this work, the effect of treatment temperature on the preparation of EA and extracted silica is studied. The EA samples and extracted silica are noted as EA600 – EA900 and Si600 – Si900 respectively with respect to the treatment temperature. To evaluate the effect of the concentration of NaOH solution on the purity of silica, NaOH solution (2–3 N) is verified in this work. The results revealed that the pure amorphous silica can be extracted using a 2.5 N NaOH solution from EA800. The percentage of amorphous silica with a purity of about 99% was confirmed by X-Ray Fluorescence (XRF).

Effects of Temperature and Salinity on Seed Germination of Three Common Grass Species.

Temperature and salinity significantly affect seed germination, but the joint effects of temperature and salinity on seed germination are still unclear. To explore such effects, a controlled experiment was conducted, where three temperature levels (i.e., 15, 20, and 25°C) and five salinity levels (i.e., 0, 25, 50, 100, and 200 mmol/L) were crossed, resulting in 15 treatments (i.e., 3 temperature levels × 5 salinity levels). Three typical grass species (Festuca arundinacea, Bromus inermis, and Elymus breviaristatus) were used, and 25 seeds of each species were sown in petri dishes under these treatments. Germination percentages and germination rates were calculated on the basis of the daily recorded germinated seed numbers of each species. Results showed that temperature and salinity significantly affected seed germination percentage and germination rate, which differed among species. Specifically, F. arundinacea had the highest germination percentage, followed by E. breviaristatus and B. inermis, with a similar pattern also found regarding the accumulated germination rate and daily germination rate. Generally, F. arundinacea was not sensitive to temperature within the range of 15–25°C, while the intermediate temperature level improved the germination percentage of B. inermis, and the highest temperature level benefited the germination percentage of E. breviaristatus. Moreover, F. arundinacea was also not sensitive to salinity within the range of 0–200 mmol/L, whereas high salinity levels significantly decreased the germination percentage of B. inermis and E. breviaristatus. Thus, temperature and salinity can jointly affect seed germination, but these differ among plant species. These results can improve our understanding of seed germination in saline soils in the face of climate change.

Effects of grass type on hydraulic response of the three-layer landfill cover system.

Soil column tests were conducted to investigate the effects of grass type on water infiltration in a three-layer landfill cover under drying and wetting conditions. Five soil columns were prepared, including one bare, two Bermuda grass-planted and the other two vetiver-planted. During the drying period, the suction of vetiver-planted soil column was the largest, while that of bare case was the lowest. During the wetting period, the infiltration rate shows a bimodal form due to the contrasting hydraulic properties of different soil layers. The infiltration rate of vetiver-planted soil column was the lowest, followed by Bermuda grass-planted and bare cases. Correspondingly, the vetiver-planted soil column retained the maximum suction and the deepest ponding depth during rainfall. This was likely due to the larger leaf area and deeper roots of vetiver than those of Bermuda grass, thus inducing the maximum initial suction by root water uptake before rainfall and reducing the water permeability by root occupations of soil pores. These results show that vetiver is more effective than Bermuda grass to reduce water percolation through the three-layer landfill cover.

Methane gas emissions from savanna fires: what analysis of local burning regimes in a working West African landscape tell us

Abstract. Savanna fires contribute significantly to greenhouse gas emissions. While it is recognized that these fires play a critical role in the global methane cycle, there are too few accurate estimates of emissions from West Africa, the continent's most active fire region. Most estimates of methane emissions contain high levels of uncertainty as they are based on generalizations of diverse landscapes that are burned by complex fire regimes. To improve estimates we used an approach grounded in the burning practices of people who set fires to working landscapes. We collected and analyzed smoke samples for 36 experimental fires using a canister method for the early dry season (EDS) and mid-dry season (MDS). We also collected data for savanna type, grass type, biomass composition and amount consumed, scorch height, speed of fire front, fire type, and ambient air conditions for two sites in Mali. We report values for fire intensity, combustion completeness, patchiness, modified combustion efficiency (MCE), emission factor (EF) and methane emission density. Our study found that mean methane EFs ranged from 3.83 g kg−1 in the EDS to 3.18 g kg−1 in the MDS, but the small sample did not provide enough power for this effect to be significant. We found head fires had nearly double the CH4 EF of backfires (5.12 g kg−1 to 2.74), a significant difference. Byram's fire intensity was a significant driver of CH4 EF but with weak effect. Methane emission density increased marginally from 0.839 g m−2 in the EDS to 0.875 g m−2 in the MDS, a difference that was not significant. Head fires, however, had much higher emission densities than backfires – 1.203 vs. 0.708 g m−2 – respectively, a significant difference. We suggest the reason for the higher methane emissions from head fires, which have higher intensity, is the longer flame lengths that burn green leaves on trees, releasing methane. We conclude that policies aimed at shifting the burning regime earlier to reduce methane emissions will not have the desired effects, especially if fire type is not considered. Future research should consider the state and amount of leafy biomass combusted in savanna fires.

Allergenicity to worldwide invasive grass Cortaderia selloana as environmental risk to public health

Allergies to grass pollen affects about 20% of the population worldwide. In the last few decades, the South American grass Cortaderia selloana (CS, Pampas grass) has expanded worldwide in a variety of countries including the USA, Australia and Western Europe. In many of these locations, CS has strikingly spread and has now been classified an invasive species. Many pernicious consequences of CS have been reported for local biodiversity, landscape and structures. However, the effect on human health has not been studied. To investigate this issue, we have chosen a European region on the northern cost of Spain where CS spread is overwhelming, Cantabria. We obtained CS pollen extract and analysed the allergenic reaction of 98 patients that were allergic to pollen of local grasses. We determined the skin reaction and the presence of specific IgE antibodies (sIgE) to CS or to a typical autochthonous grass, Phleum pratense. We also compared the seasonal symptoms with reported grass pollen counts in the area. The results strongly suggest that CS can cause respiratory allergies at a similar extent to the local grasses. Given that CS pollinises later than the local grasses, this would extend the period of grass allergies in the region for about three months every year, as stated by most of the patients. This is the first study reported on the effects of the striking expansion of CS on human health. Considering the strong impact that respiratory allergies have on the population, our results suggest that CS can currently constitute a relevant environmental health issue.

Ethnobotany of Weeds: Weed Flora of University of Maiduguri Teaching and Research Farm, Maiduguri Sudan Savanna, Borno State.

A survey was conducted at the University of Maiduguri Teaching and Research Farm (Sudan Savanna region of Nigeria) Maiduguri Borno State, between July and September, 2019. With aim of identifying weed species at the site, frequency of occurrence, morphological characteristics and their uses. The outcome of the survey shows that 51 (fifty-one) different weed species were identified belonging to 23 families (twenty-three). Most of the weeds identified have annual life cycle in nature except for some few weeds from tree seedlings which have perennial life cycle. Twenty (20) weeds species have high occurrence (above 70%). Morphologically, only the Poaceae families are among the grass type, Cyperaceae belonging to sedge type.All other 21 families are from the broad leaved type but further classified as shrubs, semi woody and woody plants. Almost all the weeds identified have medicinal, fodder, soup and mulch cover value to animals and man. Most important among them are Corchorus olitorius L., Panicum maximum Linn, Chloris pilosa Schumach., Faidherbia albida A. Cahev., Crotalaria medicaginea L., Calotropis procera (Aiton) W. T.

Combining targeted grass traits with red clover improves grassland performance and reduces need for nitrogen fertilisation

To increase ruminant production efficiency, the environmental impact of growing forage must be reduced, through lowering system inputs and increasing crop resilience to extreme weather. Here we examined the role of red clover (cv. AberClaret) in minimising nitrogen (N) requirements, alongside two novel grass varieties, (1) a festulolium (cv. AberNiche), developed for drought tolerance, with potential for deep-rooting, and (2) a ryegrass hybrid (cv. AberEcho), developed for high-sugar content, which may enhance ruminant N-uptake in-vivo. Field trials were conducted at two UK sites, growing festulolium and ryegrass ± red clover (at 29% of the seed mix weight) at a range of N fertilisation rates (0 – 600 kg N ha−1) for 2 years (six harvests). We assessed sward performance (N offtake, herbage quality, and grass N use efficiency), rooting depth and N transfer from clover to grasses using 15N natural abundance. Across both sites and years, dry matter yield and herbage-N content were overall greater from the swards that included clover. Dry matter yields from festulolium were not greater than from ryegrass under the drought conditions experienced in 2018, despite its greater root mass. Agronomic efficiency of fertiliser N was similar between grasses (19 – 22%), however the festulolium more effectively used endogenous soil N than the ryegrass. Inclusion of clover in the sward affected forage quality, with increased crude protein and metabolisable energy content and reduced sugar and fibre (NDF) content. Among the grass types, metabolisable energy was greater and NDF content less for ryegrass than for festulolium. A strong reliance on biological N fixation (80 – 94%) for clover was observed, however, N transfer from clover to the neighbouring grass was not evident from the ẟ15N signatures. We conclude that red clover is a viable fertiliser-N replacement strategy in short-term leys, and that grass varieties with improved herbage quality may provide a better option for optimising sward performance than drought tolerant grass varieties.

Plant bedding construction between 60,000 and 40,000 years ago at Border Cave, South Africa

Extraordinary preservation of plant remains provides an insight into the construction and materials of bedding at Border Cave, South Africa. Towards the back of the cave there are particularly thick layers of desiccated and charred grass and our botanical study is from bulk samples of these approximately 60,000 to 40,000 year-old layers (Members 3 BS, 2 WA, 2 BS and 1 BS Lower C). More than one type of panicoid grass was identified, sedge nutlets were present in the older layers and in Member 2 WA particularly, eudicotyledon leaves were preserved. Plant bedding construction may have altered slightly over time with the use of sedges decreasing in favour of grass. A small item that appears to be woven monocotyledon leaf blades was recovered from Member 1 BS Lower C (42,600 years old), potentially making it the oldest evidence of simple weaving. The bedding is generally desiccated rather than burned, and often lies on an ash base. It is possible that the site's occupants burned old bedding to provide an ash base for fresh bedding. The unique preservation of desiccated plant material from as early as 60,000 years ago may in part be due to these ashy surfaces.

Seasonal and interannual drought responses of vegetation in a California urbanized area measured using complementary remote sensing indices

The effects of drought can manifest in vegetation across an array of physiological responses and time scales. In metropolitan areas, vegetation provides shading and cooling during hot and dry conditions, but these benefits can be reduced with drought. While many studies have evaluated interannual vegetation drought responses, these responses to drought can be expressed diversely across seasons, especially in cities that regularly experience seasonal drought (e.g., in Mediterranean climates). Here, we evaluated seasonal and interannual drought responses across the dominant types of urban trees and grasses in the Santa Barbara, California, USA metropolitan area, primarily using Landsat imagery acquired from 2010 to 2019 as well as repeat Airborne Visible Infrared Imaging Spectrometer - Classic (AVIRIS-C) imagery acquired 2013–2015. To track vegetation types, we produced a random forest classification from 4 m AVIRIS-Next Generation (AVIRIS-NG) imagery acquired in June 2014 (overall accuracy = 86%; kappa = 0.85), thresholding to >90% pure pixels for most vegetation types in the coarser time series imagery. We monitored drought response from Landsat imagery using the Normalized Difference Vegetation Index (NDVI) and the difference in land surface temperature (ΔLST) between vegetation and developed/impervious surfaces. We used AVIRIS-C to measure equivalent water thickness (EWT), comparing it with NDVI. During drought years, NDVI was lower and ΔLST was closer to zero. Changes in EWT revealed seasonal adjustments by vegetation that were not readily apparent in the NDVI. To show how drought response expression in vegetation can vary by season, drought duration, and urban vegetation type, we examined the correlations of both NDVI and ΔLST to the Standardized Precipitation Evapotranspiration Index (SPEI) calculated over a range of time spans. For most vegetation types, the strongest correlations of NDVI to SPEI and ΔLST to SPEI were during the summer, except for annual grass and turfgrass NDVI, which had the strongest correlations in the winter. In general, NDVI and ΔLST for annual grass were most often correlated with SPEI at spans <12 months, particularly for NDVI. By contrast, NDVI and ΔLST for trees and turfgrass were commonly also correlated with SPEI at spans ≥12 months, in addition to seasonal time spans of <12 months. This study demonstrates the benefits of using functionally and seasonally distinctive remote sensing variables (NDVI, ΔLST, and EWT) together to quantify changes in vegetation canopy condition during droughts.

Influence of Temperature Conditions during Growth on Bioactive Compounds and Antioxidant Potential of Wheat and Barley Grasses.

Wheat and barley grasses are freshly sprouted leaves of wheat and barley seeds, and are rich sources of phytochemicals. This study was conducted to investigate the effects of day and night temperatures on the growth, bioactive compounds, and antioxidant potential of wheat and barley grasses. Briefly, each grass was cropped in an organic growing medium at 10/5 °C, 20/15 °C, and 30/25 °C (day/night temperature) in a growth chamber by maintaining specific light (12/12 h light/dark; light intensity 150 µmol photons m−2 s−1) and humidity (60%) conditions for 8 days. The highest growth parameters (height, weight, and yield) were observed at the 20/15 °C growth conditions in both types of grass. Conversely, the lowest growth parameters were observed at 10/5 °C. However, the low growth temperature of 10/5 °C resulted in increased levels of bioactive compounds (total phenol, total flavonoid, and total vitamin C), antioxidant activities (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid and 2,2-Diphenyl-1-picrylhydrazyl radical-scavenging activity)), and antioxidant enzymes (guaiacol peroxidase activity, catalase activity, and glutathione reductase) in both types of grass. Therefore, proper temperature growth conditions of wheat and barley grasses may be a convenient and efficient method to increase bioactive compounds and antioxidant potential in our diet to exploit the related health benefits.

The Bamboo Standing Stock Analysis in Karo Highland, North Sumatera - Indonesia

Bamboo is a type of grass with a high growth rate and can be a substitute for wood. The bamboo container is vast in range, so it is easy to cultivate. The number and distribution of Bamboo need to know how much Bamboo is available to meet market demand. This study aims to determine the standing stock of Bamboo in Karo districts. The method used is the multistage sampling method, which is to take samples on the map and continue with sampling in the field. Research shows that the dominant types are rope bamboo rope and green bamboo. The number of clumps found was between 600 and 1,600 per hectare. The average number of stems is 1,231 stems per ha. The most number clump bamboo ranges from 20 – 30 unit/ha; the most length bamboo section is between 25 – 30 cm.

Washing and Chopping Pre-treatment Effect of Vetiver Roots on Vetiver Oil Yield and Distillation Time

Vetiver is a type of grass mainly used for its roots to be extracted into vetiver oil. Despite the increasing market demand, the productivity of vetiver oil in Indonesia still consider low. One of the determinant factors of the extraction yield is the pre-treatment before distillation. This study aimed to determine the best pre-treatment method to improve the vetiver oil extraction using water and steam distillation by looking at the yield, distillation rate, and forecasted distillation duration. The distillation process was using water and steam distillation method for 9 hours. The data analysis method used Durbin-Watson autocorrelation analysis. The feasibility test of polynomial regression was modelled with the F test and ANOVA variance test. The result showed that the combination of washing 2-3 times and chopping pre-treatments of vetiver roots with a size of ± 5 cm could significantly increase the extracted vetiver oil by producing the highest yield (0.36% (wet-based) and 0.47% (dry based)), the highest extraction rate (0.057%/h) and the fastest forecasted duration of the distillation (10.5 hours). The combination of washing and chopping pre-treatments of vetiver roots was the best method and could be an economical solution for low productivity problems of vetiver oil in Indonesia.

Species composition, herbage mass and grass productivity influence pasture responses to kangaroo grazing in a temperate environment

SummaryUnderstanding the complexities of pasture responses (the overall seasonal gains or losses in herbage mass) under different environmental conditions is critical to the effective management of total grazing pressure, whether to achieve agricultural, cultural or biodiversity conservation outcomes. Whilst large‐scale management programmes for kangaroos (Macropus spp. and Osphranter spp.) occur across much of south‐eastern Australia, there is limited understanding of how such programmes influence the overall pasture response across different environmental contexts in the temperate environment. This study investigates the effects of potential grass productivity (measured as the growth of pasture protected from large herbivore grazing), initial herbage mass (measured as the attached, above‐ground component of grass tussocks), kangaroo density (measured at the site scale) and season on the overall pasture response in plots dominated by six common grass types from south‐eastern Australia. Using generalised additive mixed modelling, we demonstrate potential grass productivity (related to but not synonymous with grass palatability) to be the major predictor variable for pasture responses across all six grass types. Kangaroo density, either directly or via an interaction with initial herbage mass, was related to overall pasture responses for most grasses in spring and remained an important variable in favoured areas dominated by preferred Kangaroo Grass (Themeda triandra) and Redleg Grass (Bothriochloa macra) throughout the autumn survey period. Plots dominated by grazing‐tolerant species, including wallaby grasses (Rytidosperma spp.) and Phalaris (Phalaris aquatica; an introduced pasture grass), showed marginally positive pasture responses under higher kangaroo densities, whilst plots with Wild Oats (Avena fatua; an introduced annual grass) and less preferred native spear grasses (Austrostipa spp.) showed no significant effect of kangaroo density on pasture response. Results support a context‐specific mix of ‘bottom‐up’ (resource‐driven) and ‘top‐down’ (consumer‐driven) processes in temperate grassy ecosystems, highlighting the importance of considering landscape productivity, existing herbage mass and grass species composition when informing kangaroo management decisions.

Effect of different pasture legumes on growth profile and forage production of the selected native pasture grasses mix at different growth stages

The present experiment aimed to investigate the effect of introducing different pasture legumes on the growth profile and forage production of the selected native pasture grass species at different stages of growth. In a completely randomized design with 5 treatments and 5 replications, the mixture of Sorghum plumosum (SP) and Bothriochloa pertusa (BP) was introduced respectively with one of the forage legumes ie. Alysicarpus vaginalis (AV), Pueraria phasoloides (PP), Desmodium incanum (DI), and Clitoria ternatea (CT). Growth profile and forage production were measured at 40, 60, and 80 days after planting. Results showed that CT and PP significantly improved the growth and DM production of SP and suppressed (P<0.05) the growth of BP during the early vegetative stage but did not during the late vegetative stage. Introduction of legumes reduced (P<0.05) DM production of SP and the total forage production but improved (P<0.001) the DM production of B. pertusa as well as a leaf:stem ratio of both types of grass at the generative stage. PP had the highest (P<0.05) contribution of legumes to the total DM forage production during early and vegetative stages, meanwhile AV and DI during the generative stage. In conclusion, the introduction of forage legumes did not improve the DM production of both grass species but modify their growth profile toward a better quality as shown by increased leaf:stem ratio. P. phasoloides provide the highest foliage during the vegetative stage and A. vaginalis and D. incanum during the generative stage.

A termőhely, a gyeptípus és az időjárás szerepe néhány gyep hozamának alakulásában a hasznosítás intenzitásának függvényében

The lawn – following the forest – is the best manner of land use. 10.75 percent of Hungarian territory is grassland. 90-95 percent of the grass’s root system can be found in the upper 10 cm layer of the soil therefore and because of the large evaporating surface the grasses have a great water demand and weather sensitivity. Beside the nutritional ability and some extreme properties of soil (for ex. great salinity) there is an influence on formation of the grass-type and the yield. In our experiments the sites were utilised 2, 3 and 4 times yearly. At two sites for four years (2006-2009) and at one site for two years (2009-2010) the quantity and the distribution of the yield as well as other parameters were examined, which are not reported in this paper. This experiment is a part of a climate research project run at 27 sites in Austria. The laboratory analyses were carried out uniformly in the LFZ Raumberg- Gumpenstein Research Institute. The most important results of this study are the following: The productivity of the grass type formed on the Little Cumania lowland is very limited. In case of drought there was the highest yield decrease and at the same time in case of good precipitation there was the smallest increase of yield. The effect of grass utilization by late first cut at the poorestsoil site was very unfavourable. At the grass sites of better quality, the utilization manner of 3 or 4 growth, resulted in a better adaptation to the climatic extremities.

Tradeoffs between soil conservation and soil‐water retention: The role of vegetation pattern and density

AbstractBalancing erosion control and the water conservation service is the primary goal of intensive revegetation in water‐limited conditions. In this study, a field experiment was conducted in the dryland Chinese Loess Plateau (CLP), to investigate the role of vegetation pattern and density in their tradeoff between soil conservation (SC) and soil water retention (SWR). Five vegetation patterns (up‐slope covered, downslope covered, low and high uniformly covered, no coverage) with three levels of grass density (220 g m−2, 110 g m−2, and 0) were designed and implemented. A novel indicator EEW (the exchange between erosion reduction and water consumption), as the cost of any extra depletion of soil water to improve each unit of soil conservation, was used to represent the tradeoff during a complete dry‐wet‐dry soil water convert cycle. The higher EEW, the poorer tradeoff between SC and SWR. It was illustrated that higher vegetation density could promote SC but not inevitably suppress EEW. The present typical grass density in CLP, round 220 g m−2, was redundant in optimizing the SC‐SWR tradeoff. A concentrated and centralized vegetation distribution mainly in the downslope obtained an EEW at 11.6 mm m2 kg−1 and was confirmed as a favoured vegetation pattern. The simulated typical density and spatial pattern in CLP (about 220 g m−2 and uniformly distribution) had EEW at 20.5 mm m2 kg−1, by reducing the density to about 110 g m−2 and a downslope centralized vegetation redistribution, the EEW was reduced by 43.4%. Under long‐term drought conditions at dry‐wet‐dry cycles, soil water decreased more sharply in the Full‐covered plots, due to more evapotranspiration and vertical water loss caused by higher plant density, compared with half‐covered and bare soil plots. The present study confirmed that planted density and vegetation pattern can manipulate SC‐SWR tradeoff and it was thus possible to optimize it by adjusting revegetation's intensity and structures in practice.

EFFECT OF ROOT OF VETIVER GRASS AND THE SHEAR STRENGTH OF ROOT IN PERMEATED SOIL

Recently, bioengineering has been approached as one of the slope stabilizations techniques as it is inexpensive compared to the mechanical stabilization technique. However, numbers of slope failure still reoccur due to the limitation of the bioengineering technique knowledge. Proper bioengineering material and methods must be carefully selected to overcome the problem. The objectives of this research are to determine the physical and mechanical properties of soil with Vetiver Grass roots as well as the root properties of the Vetiver Grass since these grass types have been applied widely for slope stabilization. The physical properties of soil lab tests have been determined such as compaction test, Atterberg limits test and sieve analysis test. The mechanical properties of soil with and without root grasses have been carried out through the shear box test. For the identification of the root properties of Vetiver Grass, the root morphology and the diameter of the root has been identified. The results for the lab tests conducted showed that the soil with roots have a higher shear strength compared to soil without roots included with FOS (Factor of Safety) calculation proving that the soil with the aid of Vetiver Grass will be effective in retaining soil.

Factors shaping soil organic carbon stocks in grass covered orchards across China: A meta-analysis

Orchard grass coverage has been widely adopted to increase fruit yield by improving soil fertility. However, the impact of the environment on the changes in soil organic carbon (SOC) stocks consecutive to orchard grass coverage remain poorly quantified at a large scale. The present study aimed to examine the responses of SOC stocks to grass coverage at a soil depth of 0–30 cm in orchards compared to clean tillage. A total of 342 observations across China from 139 peer-reviewed publications were subjected to meta-analysis. Aggregated boosted tree analysis was performed, evaluating the determinants of SOC stocks, such as plant traits (e.g., fruit tree type, grass type, orchard age, and grass age), edaphic variables (e.g., initial SOC and nitrogen concentration, soil pH, and soil clay content), climatic factors (e.g., mean annual precipitation (MAP) and mean annual temperature (MAT)), and management practices (e.g., grass source, grass growing mode, fertilization, grass mowing, placement of mowed residues, and irrigation). On average, orchard grass coverage significantly enhanced SOC stocks by 21.47% (percentage change) compared to clean tillage. Biotic and abiotic factors influenced this increase in SOC stocks following grass coverage in orchards to different extents. Grass age and soil clay content were the main determinants driving the variation in the SOC stocks following grass coverage in orchards. Thus, we propose an efficient way to optimize C sequestration in grass covered orchards, regarding plant traits, climatic factors, edaphic variables, and management practices. Longer than 12 months of surface grass coverage with cultivated grass species in mature deciduous fruit orchards (≥5 years) efficiently increased SOC stocks. This is particularly the case for acidic (pH < 6.5) soils with low C content (SOM < 15 g kg−1) in areas with suitable rainfall and temperature conditions (MAP ≥ 400 mm, MAT ≥ 10 °C). Collectively, this meta-analysis identified orchard grass coverage as a promising practice for significantly increasing SOC stocks at 0–30 cm across large geospatial locations in China.

Maize Chlorotic Mottle Virus: Distribution, Alternative Hosts, Transmission Mechanisms and Management Options

Plant virus diseases are serious constraints to the productivity and profitability of a wide range of crops. Epidemics of existing plant virus diseases and the emergence of novel virus diseases have become a serious threat to subsistence and commercial agriculture. The knowledge of virus transmission and its survival helps to understand how the disease transmits from infected plant to healthy, where it reserved, and this will lead to identify the most important variables and focus efforts to develop sustainable management strategies. Maize chlorotic mottle virus (MCMV) is transmitted from location to location, and from plant to plant through various mechanisms (mechanically, seed, insect vectors, and soil) and many wild types of grass and cultivated crops, MCMV infected maize residue are used as its reservoirs. Different weed species and cultivated plants used as alternate hosts, and soil and seed transmissibility of MCMV are epidemiologically important and contribute to maintaining virus inoculum available in the absence of maize in the field and increase the chances of continuing its survival. Integrated disease management approach, regular field monitoring, assessment of virus symptoms, and rouging-out diseased plants are recommended to prevent further spread by insect vectors. Apart from this, because the disease is still widespread in various countries, intensive MCMV recruitment, combined with integrated disease management, requires ongoing practice in countries where MCMV is prevalent and in those countries that have not yet reported MCMV. Keywords : Integrated management; Insect vector; plant residue; Soil transmission; Zea mays DOI: 10.7176/JBAH/11-19-04 Publication date: October 31 st 2021

Long-term warming does not affect soil ecoenzyme activity and original microbial nutrient limitation on the Qinghai—Tibet Plateau

Microbes play an important role in the carbon cycle and nutrient flow of the soil ecosystem. However, the response of microbial activities to long-term warming over decades is poorly understood. To determine how warming changes ecoenzyme activity and microbial nutrient limitation, we conducted a long-term, 21 years, experiment, on the Qinghai—Tibet Plateau. We selected typical grass- and shrub-covered plots, used fiberglass open-top chambers (OTCs) to raise the temperature, conducted soil sampling at different depths, studied the response of nutrient-acquiring enzyme activity and stoichiometry, and conducted vector analysis of stoichiometry. Our results showed that long-term warming did not have a notable effect on the activity of nutrient-acquiring enzymes or enzymatic stoichiometry. However, Spearman correlation analysis indicated a significant and positive correlation between ecoenzyme activity and the available nutrients and microbial biomass in soil. Vector analysis of stoichiometry showed phosphorus limitation for all soil microbes at different depths, regardless of whether the soil experienced warming. These changes in enzymatic stoichiometry and vector analysis suggested that microbial nutrient limitation was not alleviated substantially by long-term warming, and warming did not considerably affect the stratification of microbial nutrient limitation. Our research has also shown that long-term warming does not significantly change soil ecoenzyme activity and original microbial nutrient limitation at different soil depths within the OTUs’ impact range. These results could help improve understanding of microbial thermal acclimation and response to future long-term global warming.