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The study aimed to investigate the impact of different levels of organic fertilizer on the yield, nutrient composition, and fermentation quality of ryegrass. Using the Bond variety of polyfloral ryegrass as the experimental material, four organic fertilizer application levels were set at 750 (Group 1), 1 000 (Group 2), 1 250 (Group 3), and 1 500 kg/hm2 (Group 4). The changes in yield, nutrient composition, and fermentation quality of polyfloral ryegrass under different levels of organic fertilizer application were explored. The results showed that the plant height and fresh grass yield of ryegrass in Group 3 and Group 4 were significantly higher than those in Group 1 ( P<0.05). The dry hay yield of ryegrass in the first cut was significantly higher in Group 3 compared to Group 1 and Group 2 ( P<0.05), and the dry hay yield in the third cut was significantly higher in Group 2, Group 3, and Group 4 compared to Group 1 ( P<0.05). The contentrations of crude protein of ryegrass in Group 3 and Group 4 were significantly higher than that in Group 1 and Group 2 ( P<0.05), and the contentration of neutral detergent fiber was significantly lower than that in Group 1 ( P<0.05). The contentration of crude protein of ensiled ryegrass in Group 3 and Group 4 was significantly higher than that in Group 1 ( P<0.05), while the contentrations of ammonia nitrogen, neutral detergent fiber, and acid detergent fiber were significantly lower than that in Group 1 ( P<0.05). The concentrations of lactic acid and acetic acid of ensiled ryegrass in Group 2, Group 3, and Group 4 were significantly higher than that in Group 1 ( P<0.05), and the concentration of lactic acid in Group 3 was significantly higher than that in Group 2 and Group 4 ( P<0.05). The contentration of crude protein of fermented ryegrass in Group 3 and Group 4 was significantly higher than that in Group 1 and Group 2 ( P<0.05), and the contentrations of neutral detergent fiber and acid detergent fiber were significantly lower than that in Group 1 ( P<0.05). The study indicates that applying 1 250 kg/hm2 of organic fertilizer during the cultivation of ryegrass resulted in better grass yield, nutrient composition, and fermentation quality. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the effect of replacing 10% silage alfalfa in the basic diet with silage ryegrass on the production performance, milk composition, and serum related indexes of dairy goats. A total of 40 healthy dairy goats with similar body weight, milk production, and parity were randomly divided into two groups with four replicates in each group and five goats in each replicate. The goats in the control group were fed a basic diet, while those in the experimental group were fed a diet containing 10% silage ryegrass instead of the basic diet with the same amount of silage alfalfa. The pretrial period was one week and the trial period was eight weeks (four weeks for both pregnancy and lactation). The results showed that compared to the control group, the weight of newborn lambs and the survival rate of weaned lambs in the experimental group significantly increased (P<0.05), the milk fat rate of dairy goats in the experimental group significantly increased (P<0.05), and the number of milk somatic cells significantly decreased (P<0.05). The levels of serum IgA, IgG, and GLB in the experimental group of dairy goats significantly increased (P<0.05), while the levels of triglycerides (TG) and total cholesterol (TC) significantly decreased (P<0.05). The study indicates that replacing 10% silage alfalfa in the basic diet with silage ryegrass can improve the survival rate of the dairy goat lambs and the growth performance of the young goats, and improve the feed intake, milk production, and immune function of the dairy goats, but have no significant impact on the serum antioxidant and liver function related indexes of the dairy goats. [ABSTRACT FROM AUTHOR]

In order to solve the problems of poor soil and shortage of guest soil for ecological restoration of gold mines in the arid steppe region of Northwest China, an experimental study on soil modifier vegetation restoration using biomass materials as soil modifier prepared from agricultural solid waste corn straw as raw materials was carried out. By analyzing the changes in pH, nutrient composition, and water retention capacity of modified soil, the modification mechanism of biomass materials on the restoration matrix was explored. Ryegrass, tall fescue, and dogtooth root are used as modifiers to verify the modification effect of biomass materials on poor soil. The results showed that biomass materials contain a large amount of humic acid and fulvic acid, which can significantly reduce the saline-alkali property of topsoil matrix, soil pH value decreasing from 8.80 to 7.39,and the pH improving significantly with the increase of the added proportion; the addition of biomass materials promoted the formation of soil aggregates with large particle size, soil bulk density decreased significantly, soil water retention capacity increased, and soil nutrients and organic matter contents increased significantly; the biomass of ryegrass, tall fescue and dogtooth root was the highest when the biomass content was 10 %-20 %,and the leaf width and plant height were better. [ABSTRACT FROM AUTHOR]

The study was to the effect of microbial silage sheep manure on producing rich selenium feed in goat production, to solve the problem of waste pollution in intensive and large-scale livestock and poultry production. The experiment used 10%, 15%, 20%, 25%, 30% sheep manure, mixed different proportions of ryegrass, crushed corn, Se-enriched Cardamine violifolia residue, and microbial fermentation inoculants for anaerobic silage fermentation. Through the detection of sensory evaluation, nutritional composition, safety evaluation indexes, selenium content of materials after fermentationand the effect on growth performance of goat. The results showed that after the silage of sheep manure and ryegrass, the odor of manure and ammonia completely disappeared, and the odor of manure changed from sticky and grainy before to soft, unclumpy fermented feed with bread flavor. The sensory rating of experimental groups was grade 2 or above. AFB1 in all experimental groups was less than 10 μg/kg, which was in line with the Feed Hygiene Standard (GB 13078--2017). The content of dry matter and crude protein were the highest in group Ⅳ, and the content of acid detergent fiber and neutral detergent fiber were the lowest. The final weight and average daily gain of goats were significantly increased, and feed to gain ratio was significantly decreased by 20% Se-enriched diet (P<0.05). The experiment indicates that the suitable ratio of sheep manure, ryegrass, corn and Se-enriched Cardamine violifolia residue for fermentation is 25∶65∶5∶5, which can improve the growth performance of goats. [ABSTRACT FROM AUTHOR]

The effects of nitrogen fertilizer and biochar on ryegrass Cd enrichment were examined in order to lessen the harm caused by cadmium（Cd） in soil. The effects of soil Cd pollution levels（0.3, 3, 5 mg/kg）, nitrogen fertilizer forms（nitrate nitrogen and ammonium nitrogen） and nitrogen fertilizer levels（0.1, 0.2, 0.5, 1 g/kg） on Cd forms and ryegrass enrichment were studied in pot experiment. According to the findings, biochar alone might repair free Cd in soil, compared to NH4+-N, combined application of NO3--N ryegrass has a stronger ability to absorb, migrate and enrich Cd. Under different Cd pollution concentrations, the maximum removal rates of Cd under different NO3--N levels could reach 30.23%,36.06%and 30.90%,respectively,while the maximum removal rates of Cd under different NH4+-N levels could reach 24.49%,28.05%and 24.79%.Combined correlation analysis revealed that pH played a significant role in the change of Cd morphology and Cd enrichment.When biochar and NO3--N were applied together,the content of Cd in the soil could be reduced more quickly and effectively,which was better suited for the safe application of Cd-polluted soil. [ABSTRACT FROM AUTHOR]

The experiment was to study the allelopathic effect of alfalfa extract on seed germination of perennial ryegrass. The effect of five extracts (0, 2.5, 5.0, 10.0 and 20.0 g/L) from roots, stems and leaves of alfalfa wl-963-HQ on seed germination and seedling growth of perennial ryegrass were determined by Petri dish filter paper method. The results showed that the germination rate, germination potential, germination index and vigor index of the seeds decreased obviously with the increase of the concentration of the extracts from the roots, stems and leaves of alfalfa. The root and leaf extracts of alfalfa had a stronger inhibitory effect on the germination of perennial ryegrass seeds. When the concentration was 20.0 g/L, perennial ryegrass seeds could not germinate normally. Alfalfa extract had no inhibitory effect on root length and seedling height of perennial ryegrass seedlings, but had significant effect on seedling weight. The extracts from the roots, stems and leaves of alfalfa significantly decreased the chlorophyll content of perennial ryegrass seedlings (P<0.05), and the POD activity was significantly increased (P<0.05). Compared with the control group, CAT activity of perennial ryegrass seedlings was significantly increased when the stem extract of alfalfa was 10.0 and 20.0 g/L (P<0.05). The study indicates that alfalfa extract has obvious allelopathy on perennial ryegrass, and reasonable row spacing was needed to reduce allelopathy when the two herbage are mixed. [ABSTRACT FROM AUTHOR]

A total of seven kinds of 16 common roughages of Yunnan mutton sheep were collected from southern (Honghe), northern (Qujing), western (Chuxiong, Dali) and central (Kunming) of Yunnan Province, respectively. Cornell net carbohydrate protein system (CNCPS) was used to evaluate the nutritional value of common roughages of Yunnan meat sheep. The results showed that among 16 roughage samples, the non-protein nitrogen (PA) content of corn silage in central region was the highest, and the barley stalk in northern region was the lowest. The content of rapidly degradable true protein (PB1) in broad bean bran in western region was the highest, and the highland barley stem in northern region was the lowest. The carbohydrate (CHO) content of wheat straw in central region was the highest, the CHO content of corn silage was significantly higher than that of other roughages except the central wheat straw (P<0.05), and CHO content of ryegrass in central region was the lowest. The experiment indicates that corn silage in western China has lower content of unavailable fiber and protein, higher nutritional value, and can be used as a kind of high-quality fiber feed resource. [ABSTRACT FROM AUTHOR]

A vegetation concrete protection has been one of the most widely used technologies for the bare steep slopes in the ecology fields. Among them, the vegetation evapotranspiration can determine the regional distribution of available water resources in the soil-vegetation-atmosphere system. It is also a high demand to evaluate the utilization of water resources for the high-steep slope. In this study, a systematic evaluation was made of the ecological benefit of herbs planted in vegetation concrete under the buried drip irrigation in soil. An improved Penman-Monteith formula was also adopted to calculate the actual crop evapotranspiration (ETc) and the crop coefficient for the herbs, including Lolium perenne L., Festuca arundinacea, Poa annua L. and the mixed-grass seeds of “Lolium perenne L.+Festuca arundinacea+Poa annua L.” Hence, the experimental materials were prepared, and the slope planting soil was selected as the composite artificial soil. Subsequently, the improved Penman-Monteith formula was established for the slope ecological restoration using the slope coefficient factor, according to the project requirement of ecological slope protection. Specifically, the test grass was sown in the surface layer of the proportioned vegetation concrete that was attached to the slope model, when installing the irrigation equipment. The irrigation system was also designed to ensure the same amount of irrigation per day using the average evapotranspiration of plants and irrigation water utilization coefficient. Moreover, the evapotranspiration test was conducted to balance the water resource for the daily vegetation evapotranspiration to measure. In addition, the equipment for buried drip irrigation in soil and slope sprinkler irrigation were installed on two slope models in fields. The results revealed that the actual evapotranspiration and crop coefficient of Festuca arundinacea were the largest, followed by Lolium perenne L. and the lowest of Poa annua L. All the determination coefficients R² were not less than 0.847 for the linear fitting of the actual crop evapotranspiration and crop coefficient. There was a small difference in evapotranspiration of each plant at the initial stage of the maintenance, particularly at around 4.2 mm/d. After finishing maintenance, the largest and lowest evapotranspiration were obtained for the mixed grass, and Lolium perenne L., which were about 6.2 and 5.7 mm/d, respectively. In the first 20 days of the maintenance stage, there was no significant difference in the actual evapotranspiration of Lolium perenne L., Festuca arundinacea and mixed grass, except Poa annua L. More importantly, the Lolium perenne L., Poa annua L. and mixed grass greatly varied after 20 days, but there was no significant difference in the evapotranspiration of each grass after 30 days. The differences in the evapotranspiration of four herbs increased with time. Particularly, the evapotranspiration of mixed grass was lower than those of Lolium perenne L. and Festuca arundinacea at the early stage, but rose significantly at the later stage. The crop coefficient of mixed grass was also greater than those of the rest of single grass over 50 days. Taking the 30th day (one month) as a threshold, there was only a little divergence of crop coefficient within 30 days. Moreover, there was the largest variation of crop coefficient at the initial stage of growth, indicating a downward trend for the monthly increase. However, the values of crop coefficient were similar for the Lolium perenne L. and Festuca arundinacea at any period. As such, the obtained crop coefficients were utilized to calculate the vegetation ecological value for the evaluation of the ecological benefits of the technology of buried drip irrigation in soil and slope sprinkler irrigation. The results showed that the vegetation ecological value increased with the maintenance time, indicating a positive impact of two technologies on the value. Additionally, the slope sprinkler irrigation presented a higher vegetation ecological value than the buried drip irrigation in soil for the vegetation growth in the early stage of the slope model test. Nevertheless, the buried drip irrigation in soil was superior to the ecological benefit during the middle stage. In a word, the vegetation ecological benefit of buried drip irrigation in soil was better than that of slope sprinkler irrigation, where the ecological value was 40.7%-1 444.0% higher than that of slope sprinkler irrigation. [ABSTRACT FROM AUTHOR]

[ObjectivesJ The aim of the present study was to explore the potential of two pigment synthesis inhibitors, pyraclonil and isoxaflutole, in the control of herbicide-resistant grass weeds in wheat fields. [Methods ] The activity of pyraclonil and isoxaflutole against resistant grass weeds in wheat field, the saf.ety to different wheat varieties, and the toxicity of the screened herhicide-safener combinations to the weeds in wheat fields were detennined by whole plant determination. [ Results J It was found that pyraclonil ( 210 g · hm -2 ) could cause fresh weight inhibition more than 90% for the fonoxaprop-P-ethyl-resistant Alopecurus japonicus population JCJT -2, the mesosulfuron-methyl-resistant A. aequalis populations JTJT-1 and the fonoxaprop-P-ethyl-resistant Beckmannia syzigachne population JYGC, hut it was not safe to wheat. However, when pyraclonil ( 210 g · hm -2 ) was applied with mefonpyr-diethyl, pyrimidine and isoxadifon-11hyl at 6.57 g · hm -2 respectively, the fresh weight inhibition of 'Zhoumai 27' would he less than 1 %. Meanwhile, the combination of pyraclonil with safeners could still inhibit the fresh weight of JYGC by 100%. lsoxaflutole ( 300 g · hm -2 ) could reach more than 80% fresh weight inhibition to JCJT -2, JYGC and JTJT-1, hut it was not saf"e to wheat. When isoxaflutole ( 300 g · hm -2 ) applied with isoxadifon-ethyl acid at the range of 9.38-37.50 g· hm -2, the fresh weight inhibition rates to' Anke 1401' population were less than 5%. And the combination of isoxaflutole with safeners could still inhibit the fresh weight of JTJT-1 by 90%. It was also found that the combination of pyraclonil+mefonpyr-diethyl(210 g·hm -2 +6.57 g·hm -2 )exhihit high toxicity to all the tested weeds except for Lolium multifiorum and Bromus japonicas. And the combination of isoxaflutole+isoxadifon-ethyl ( 300 g · hm -2 +9.38 g · hm -2 ) exhibited high toxicity to all the tested weeds except for L. multiflorum, B. japonicas and Geranium carolinianum. [ Conclusions] The inhibitory d:foct of the two combinations on the fresh weight of seedlings of some wheat v;u-ieties could be greatdy 1uluced compared \Vith the herbicides themselves. And these two combinations exhibited high toxicity to three resistant grass weeds populations (JYGC, .IT.TY - l and .TC.TT -2) as wdl as to several common weeds in wheat fidds, which suggested the potential to he IL~ed to control weeds in wheat fidds. [ABSTRACT FROM AUTHOR]

In order to further understand the potential mechanisms of grassland structure and function in response to soil phosphorus deficiency under future elevated CO2 concentration, we examined the effects of elevated CO2 concentration and phosphorus deficiency on the stomatal traits and leaf gas exchange parameters of annual ryegrass with environmental growth chambers, where the CO2 concentration was accurately controlled at 400 µmol/mol or 800 µmol/mol and meanwhile these grasses were fertilized with six phosphorus levels including 0.004 mmol/L (P0.004), 0.012 mmol/L (P0.012), 0.02 mmol/L (P0.02), 0.06 mmol/L (P0.06), 0.1 mmol/L (P0.1) and 0.5 mmol/L (P0.5). Our results showed that: (1) The elevated CO2 concentration significantly decreased the stomatal density of plants under lower phosphorus levels, but increased the stomatal density of annual ryegrass grown at higher phosphorus levels (0.1 mmol/L and 0.5 mmol/L); Meanwhile, elevated CO2 concentration obviously decreased the stomatal openness of annual ryegrass, and made the spatial distribution pattern of stomata more regular when plants were grown at the phosphorus level of 0.06 mmol/L. (2) The elevated CO2 concentration substantially enhanced the net photosynthetic rates (Pn) of annual ryegrass treated with higher phosphorus levels (0.1 mmol/L and 0.5 mmol/L), but reduced the Pn of plants subjected to lower phosphorus levels, and thus increased the water use efficiency (WUE) of annual ryegrass at high phosphorus levels. (3) The responses of chlorophyll contents to elevated CO2 concentration were different among the six phosphorus levels, and elevated CO2 concentration substantially changed the ratio of chlorophyll a/b at higher phosphorus levels. (4) The total plant biomass and allocation between aboveground and belowground were obviously changed by phosphorus deficiency, and elevated CO2 concentration featured CO2 fertilization effect on the aboveground biomass of annual ryegrass at higher phosphorus levels. These results suggested that the responses of stomatal traits and leaf gas exchange efficiency to elevated CO2 concentration were obviously asymmetry between low and high phosphorus levels. These grasses under higher phosphorus levels optimized the leaf gas exchange efficiency by increasing the stomatal density and stomatal openness as well as regulating the spatial distribution pattern of stomata, and thus plants might benefit from CO2 fertilization effect under elevated CO2 concentration. By contrast, annual ryegrass plants subjected to low phosphorus levels down-regulated the morphological traits of stoma and the regular pattern of distribution, and decreased leaf gas exchange efficiency of annual ryegrass to adapt the low phosphorus conditions under high CO2 concentration. Our results may have significant importance on further understanding the potential mechanisms of grassland ecosystem structure and function in response to elevated CO2 concentration and phosphorus deficiency under future climate change. [ABSTRACT FROM AUTHOR]

Plants generally behave in different response mechanisms under stress. This study aims to reveal the effects of biochar on photosynthesis and antioxidant system of ryegrass and alfalfa at the early stage of salt-alkali stress. Four treatments were conducted in the pot experiment: saline-alkali stress treatment (C0, 150 mmol/L equal mol NaCl, Na2CO3, NaHCO3 mixed saline solution), saline-alkali stress +1% biochar (C1), saline-alkali stress +3% biochar (C2), saline-alkali stress +5% biochar (C3), and set blank control (CK) without additives. Conventional cultivation was also carried out before the experiment, and then a stress test was conducted 40 d later. The stress treatment lasted for a total of 14 d, where 100 mL mixed saline solution was added to C0, C1, C2, and C3 treatments at one time, and 100 mL deionized water was added to CK treatment. Subsequently, the response of ryegrass and alfalfa was determined on the 14th day of the experiment, including growth indices, photosynthetic characteristics, malondialdehyde content, and antioxidant enzyme activities under various levels of biochar addition. The results showed as follows: 1) 14 d salt-alkali treatment dominated the growth of ryegrass and alfalfa. Specifically, there was a significant decrease in biomass accumulation, net photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO2 concentration. But there was no significant effect on the chlorophyll content and root length. Furthermore, the content of malondialdehyde increased significantly, indicating the antioxidant system responded positively. Similarly, the activities of superoxide dismutase, peroxidase, and catalase increased to alleviate the saline-alkali stress on plants. 2) The addition of biochar effectively improved the stress resistance of perennial ryegrass and alfalfa, thereby inducing a positive response in the antioxidant system. As such, the salinity-alkalinity stress was effectively relieved, particularly from the osmotic stress. The malondialdehyde content decreased obviously, whereas the alfalfa superoxide dismutase increased significantly, indicating that the perennial ryegrass antioxidant system was given a priority with the decomposition of hydrogen peroxide enzyme. The biomass, plant height, and root length of ryegrass and alfalfa increased by 48.50%-82.34%, 31.19%--44.16%, and 17.15%-48.09%, respectively, under 3% biochar treatment, compared with that under the salt-alkali stress. Additionally, the stomatal conductance and transpiration rate increased by 118.69%-358.99%, and 98.66%-526.53%, and the chlorophyll content and net photosynthetic rate increased by 7.97% and 519.09%, respectively. 3) The antioxidant enzyme activities and malondialdehyde content of ryegrass and alfalfa remained stable or decreased with the increase of biochar amount under the short-term salt-alkali stress. A trend was also found that the promoting at a low supplemental level and inhibiting at a high supplemental level for the growth indexes and photosynthetic characteristics. Consequently, there was a significant effect of salinity-alkalinity stress on the growth of perennial ryegrass and alfalfa, where a positive response was found at the beginning of stress. Correspondingly, an optimal addition of biochar can be expected to improve the stress resistance of perennial ryegrass and alfalfa, while the positive reaction of the oxidation system can effectively relieve the short-term salinity-alkalinity stress. The best effect was also achieved in the 3% biochar application. The findings can provide a sound reference for the scientific application of biochar to promote crop growth and yield. [ABSTRACT FROM AUTHOR]

Hunan is the main double cropping rice production area in the middle reaches of the Yangtze River. A long-term experiment of a winter crop-double cropping rice rotation system began in 2004 on a red paddy soil in Hunan Province. The experiment consisted of five treatments, including fallow-double cropping rice, potato-double cropping rice, ryegrass-double cropping rice, milk vetch-double cropping rice, and rape-double cropping rice, with three replicates of all the treatments. In order to optimize winter crop-double cropping rice rotation pattern, promote efficient use of resources, and increase farmers′ income, the efficiencies of solar radiation and heat resource, and the economic benefit of the five rotation systems were analyzed and compared in 2017. The annual solar radiation use efficiency of potato-double cropping rice rotation system was significantly higher than other models. Compared with ryegrass-double cropping rice, milk vetch-double cropping rice, and rape-double cropping rice, solar radiation productive efficiency of potato-double cropping rice rotation system was significantly increased by 0.16, 0.18 g·MJ-1, and 0.21 g·MJ-1, respectively. The accumulated heat productive efficiency of the potato-double cropping rice rotation system was significantly increased by 1.24, 1.36 kg·hm-2 ·℃-1 ·d-1, and 1.52 kg·hm-2 ·℃-1 ·d-1, respectively. There were no significant differences in phosphorus nutrient biomass production efficiency of the five rotation systems. The order of nitrogen nutrient biomass production efficiency was potato-double cropping rice（73.23）>fallow-double cropping rice（69.84）> rape-double cropping rice（68.30）>ryegrass-double cropping rice（65.47）>milk vetch-double cropping rice（60.99）. The order of potassium nutrient biomass production efficiency was milk vetch-double cropping rice（70.63）>fallow-double cropping rice（66.10）>rapedouble cropping rice（57.58）>ryegrass-double cropping rice（56.37）>potato-double cropping rice（47.91）. There was no significant differences in the NPK partial factor productivity of early rice and late rice in the five rotation systems（P>0.05）, and there was a significant difference in the NPK harvest index of late rice（P<0.05）. The order of the economic benefits was potato-double cropping rice>rapedouble cropping rice>ryegrass-double cropping rice>milk vetch-double cropping rice>fallow-double cropping rice. The potato-double cropping rice was high input and high output type, ryegrass-double cropping rice and rape-double cropping rice were low input and middle output type, and milk vetch-double cropping rice was low input and low output type. The results indicate that the potato-double cropping rice rotation system is suitable for popularization and application in Hunan double cropping rice area. [ABSTRACT FROM AUTHOR]

In order to examine the ecological effects of planting grass in kiwifruit orchards in Shiyan, Hubei Province, we selected two kiwifruit orchards located in Changpingtang and Gaoling villages as study sites. We assessed the effects of two grass planting methods, namely, artificial and natural grass planting, and selected white clover and ryegrass as artificial grass types. The effects of artificial and natural grass planting on soil nutrients, weed species and quantity, and fruit yield and quality were compared and analyzed. The results showed that compared with natural grass planting, artificial grass planting could effectively reduce the number and quantity of weed species, particularly in response to planting white clover. It also increased the contents of soil organic matter, alkali-hydrolyzed nitrogen, available phosphorus, and available potassium in the two kiwifruit orchards, and reduced the pH value of alkaline soil. Furthermore, of the two artificial grass types assessed, ryegrass was found to have a better effect on reducing soil pH than white clover. However, neither of the grass planting methods had a significant effect with respect to improving soil temperature, or fruit yield and quality, although artificial grass planting was found to significantly increase soil humidity in the Gaoling kiwifruit orchard（P<0.05）. With an extension of planting time, planting ryegrass clearly increased the contents of soil alkali-hydrolyzed nitrogen, available phosphorus, and available potassium. The findings of this study revealed that compared with planting natural grass and white clover, planting ryegrass was more suitable for kiwifruit orchards in Shiyan, Hubei Province. [ABSTRACT FROM AUTHOR]

This study was performed in a tea garden in Xupingsi Village, Tanjiawan Town, Yunyang District, Shiyan City, Hubei Province, to evaluate the effects of different mulching crop patterns on soil microbial community functions in 0~15 and 15~30 cm soil layers of the tea garden. Four treatments were selected：Natural grasses（CK）, ryegrass+white clover（EZ）, ryegrass+white clover+bluegrass+red clover（SZ）, and ryegrass+white clover+bluegrass+red clover+purple fescue+hairy raccoon+cosmos+zinnia（BZ）. The results showed that the activities of urease, invertase, catalase, and phosphatase in the 0~15 cm soil layer treated with SZ were higher than those in the other treatments; The activities of urease, catalase, and phosphatase in the 15~30 cm soil layer treated with SZ were higher than those in the other treatments, whereas the activity of invertase was lower than that in the other mulching treatments. The mulching crops increased the average well color development（AWCD）of microbial communities in the 0~15 cm soil layer; AWCD was the highest in the SZ treatment, indicating the highest utilization efficiency of the carbon source. The mulching crops improved the soil microbial richness index, evenness index, and dominance index in the 0~15 cm soil layer, but had few effects on these parameters in the 15~30 cm soil layer. The results indicate that the mulching crops can improve soil enzyme activity and microbial community functional diversity, and SZ treatment had the best effect on the 0~15 cm soil layer. The findings of this study would be able to provide a theoretical basis for analyzing the effects of different mulching crop patterns on soil functional diversity of microbial communities in tea plantations in the future. [ABSTRACT FROM AUTHOR]

[Objective] to provide the suitable turfgrass varieties for soil bioremediation in Hg2+ contaminated region. [Method] The leaf chlorophyll content, Fv/Fm, soluble sugar content, SOD activity, MDA content, leaf relative conductance and N, P and K accumulation characteristics of four tested turgrass varieties were determined by a pot simulation experiment of Hg2+ stress. [Result] With increase of Hg2+concentration, the leaf chlorophyll content, Fv/Fm and N, P and K accumulation declined continuously, soluble sugar content and SOD activity showed a first rising and then declining trend, and MDA content and leaf relative conductance increased continuously. The leaf chlorophyll content, Fv/Fm, soluble sugar content, SOD activity and N, P and K accumulation of four turgrass varieties under 75-100 mg/kg Hg2+ stress reduced significantly compared with CK but MDA content and relative conductance increased significantly. High Hg2+ concentration had the significant effects on leaf cell membrane permeability and N, P and K accumulation of seedlings of four tested turfgrass varieties, which severely inhibited plant growth and causes death of plants. [Conclusion] The annual ryegrass variety (Shengyan) with the strongest tolerance to Hg2+ stress among four tested turfgrass varieties can be selected as the optimized tufgrass variety for bioremediation of Hg2+-contaminated soil. [ABSTRACT FROM AUTHOR]

Global atmospheric CO2 concentration has been increased from 280 μmol/mol to over 400 μmol/mol following the 19th century industrial revolution, and may even be over 800 μmol/mol at the end of this century, which may lead to drastic impacts on the structure and function of natural and managed ecosystems. We studied the effects of doubling CO2 concentration on physiological traits and water use efficiency of 5 crop species soybean (Glycine max (L.) Merr.), winter wheat (Triticum aestivum L.), kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.), and tall fescue (Festuca arundinacea Schreb.) using 8 environmental growth chambers that could accurately control the CO2 concentration at 400 μmol/mol or 800 μmol/mol. Leaf gas exchange measurement was performed with a portable photosynthesis system (Li-6400XT). Photosynthesis vs intercellular CO2 curves were obtained to fit the maximum carboxylation rate of Rubisco, and the maximum electron transfer rate mediated ribulose bisphosphate regeneration. Meanwhile, we also obtained the stomatal conductance, intercellular CO2 concentration, transpiration rate, and leaf water use efficiency of crops. Results showed that doubling CO2 concentration significantly increased the net photosynthetic rate of perennial ryegrass (P<0.05), but barely affected that of the other 4 crops (all P>0.05). Our results from two-way ANOVA showed that crop species and CO2 concentration has significantly interactive effects on net photosynthetic rate, stomatal conductance, and transpiration rate of the 5 crops. Meanwhile, elevating CO2 concentration decreased the stomatal conductance and transpiration rate of crops except for soybean and winter wheat. As a result, elevating CO2 concentration increased the water use efficiency of perennial ryegrass, kentucky bluegrass, and tall fescue by 175%, 161%, and 74%, suggesting that grass species may be more sensitive to elevated CO2 concentration than soybean and winter wheat. Both the increased net photosynthetic rates and the decreased transpiration rate may contribute to the enhanced water use efficiency, whereas the contributions from the net photosynthetic rate and the transpiration rate depend on crop species. The increased leaf photosynthesis contributed the enhancement of water use efficiency for perennial ryegrass and tall fescue by 67% and 37%, respectively. Moreover, elevated CO2 concentration barely affected the relative growth rate, root/shoot ratio, and total biomass of soybean plants, but dramatically increased the root/shoot ratio, and total biomass of winter wheat. Meanwhile, we also found that elevated CO2 concentration had little effect on the relative growth rate, root/shoot ratio of the 3 grass species, while significantly enhanced the total biomass of tall fescue. These results suggested that crops in response to elevated CO2 concentration was obviously species dependent. Additionally, our results also showed positively linear relationships between leaf nitrogen content and transpiration rate of crops except for soybean. Overall, our results suggest that the responses of physiological traits and water use efficiency to doubling CO2 concentration depend on crop species under future climate change. [ABSTRACT FROM AUTHOR]