Effects of Amino Acid Foliar Fertilizer on the Yield and Quality of Different Vegetables

In order to explore the effects of amino acid foliar fertilizer on the yield and quality of different vegetables, we tested the spraying of an amino acid foliar fertilizer(Wanfeng 2) onto the leaves of cucumbers, eggplants and water spinach through contrast experiment in a greenhouse. The results showed that the yield increments of amino acid foliar fertilizer treatments in cucumbers, eggplants and water spinach were 11.57%, 4.43% and 12.41% respectively, and the output-input ratios were 64.52 ∶ 1, 53.31 ∶ 1 and 55.14 ∶ 1 respectively. Amino acid foliar fertilizer can influence the quality of greenhouse vegetables. The total sugar content of the cucumbers, eggplants, and water spinach significantly increased by 12.00%, 22.30%and 12.10% respectively. The vitamin C content increased by 4.76%, 24.80%, and10.90% respectively compared with the control. In conclusion, the spraying of amino acid foliar fertilizer could improve the yield and the nutritive quality of vegetables such as cucumbers, eggplants and water spinach.

The impact of nitrogen amendment and crop growth on dissolved organic carbon in soil solution

Dissolved organic carbon(DOC) is an important component of the terrestrial carbon cycle.However,the sources and controlling factors of DOC in soils remain uncertain.In this study,the effects of nitrogen(N) amendment and crop growth on DOC in soil solution were examined at a maize-wheat rotated field located in the central Sichuan Basin in southwestern China.Nitrogen treatments in this study included 150 kg N ha-1 season-1,200 kg N ha-1 season-1 and the control without any fertilizer application.During the whole experimental period,we observed significant decreases(p<0.05) in DOC concentrations in the sampled soil solutions associated with increase in N inputs at the bare soil plots,but no change in DOC at the plots with crop growth.The estimated average contributions of plantderived DOC were 16%,24% and 32% of total DOC in the summer maize season and 21%,32% and 38% in the winter wheat season along with the gradient of N fertilizer application rates.The results implied thatthe crop growth could play a key role in the soil DOC production,and the N input enhanced DOC production by increasing crop growth.The relationship between the DOC concentrations and the crop root biomass was statistically significant for both the maize and winter wheat seasons.Our observations indicated that crop growth exerted greater influence on the seasonal variability of DOC concentration in soil solutions at the experimental site,which overwhelmed the effect of soil native organic matter decomposition on DOC concentrations in soil solutions.

Effects of Winter Planting Milk Vetch on Yield and PartialProductivity of Nitrogen Fertilizer of Machine-transplantedDouble-cropping Rice under Straw Returning to the Field

From 2017 to 2018,the effects of winter planting of milk vetch on yield and partial productivity of nitrogen fertilizer of machine-transplanted double-cropping rice under straw returning were studied in Ningxiang city,Hunan Province.The results showed that the dry matter accumulation,effective panicle,yield and partial productivity of nitrogen fertilizer in the stem,leaf,panicle and aboveground parts of early and late rice treated with winter planting milk vetch and straw returning were signi ficantly higher than those treated with straw returning only.Among them,the effective panicles of early and late rice increased by 2.58%,3.18%(2017)and 5.22%,6.32%(2018),respectively.Yield increased by 11.85%,10.07%(2017)and 12.42%,10.92%(2018),annual partial productivity of nitrogen fertilizer increased by 10.90%(2017)and 11.66%(2018),respectively.In conclusion,winter planting milk vetch under straw returning is beneficial to increase dry matter accumulation,rice yield and partial productivity of nitrogen fertilizer in mechanized double cropping rice.

Effect of different fertilization on spring cabbage (<i>Brassica oleracea L. var. capitata</i>) production and fertilizer use efficiencies

Just after transplanting, the vegetable has difficulty in nutrients uptake. To explore the effect of different fertilization on spring cabbage (Brassica oleracea L. var. capitata) production and fertilizer use efficiencies, this experiment consisting of six treatments was implemented and divided into three groups: 1) no fertilizer (NF) and vegetable planting fertilizer (VPF);2) conventional fertilizer (CF) and conventional fertilizer + vegetable planting fertilizer (CVPF);3) reduced fertilizer application (RFA) and reduced fertilizer application + vegetable planting fertilizer (RVPF). The results of this experiment indicated that the yields of spring cabbage treated by VPF increased by 38.20% in VPF, 16.00% in CVPF and 20.40% in RVPF than their controls respectively. Additionally, the VPF helped improve the total and economic yields of the spring cabbage in all groups, and the economic benefits increased by 38.21% in VPF, 15.97% in CVPF and 20.42% in RVPF than their controls respectively. Finally, the VPF was of benefit to spring cabbage to exploit the soil nutrients and helped improve the chemical fertilizer use efficiencies. Therefore, it is an efficient, economical and ecological fertilization for vegetable production to apply chemical fertilizers in combination with VPF.

Isolation and Selection of Beneficial Microorganism Used for Peanut Growing in Sandy Soil of Binhdinh Province, Vietnam

With the aim to apply the beneficial microorganisms to peanut （groundnut （Arachis hypogaea）） growing in sandy soil of Binhdinh province in Vietnam, the paper was conducted to study the isolation, selection of N-fixing, phosphate, potassium solubilizing and slime producing microorganism from sandy soil and peanut root samples, and evaluate the capability of selected isolates to adapt to the sandy soil condition. The isolation and selection of beneficial microbes were based on the biological activity of isolates, which was determined by acetylene reduction assay and nodulation on the peanut for Rhizobium spp., by testing the capability to solubilize Ca3（PO4）2 or fenspat in the growth medium for phosphate, potassium solubilizing microbes, and by measurement of the viscosity of Hansen medium for slime producing microorganism. All isolates were evaluated for the effectiveness on the nutrition uptake and growth of peanut by carrying out at the greenhouse and field experiments. To evaluate the adaptation of selected isolates to the sandy soil condition, the experiments were carried out in the laboratory to determine the microbial density in suitable medium, containing different NaCI concentrations or with different pH or at different temperatures. The results showed that rhizobial strain RA18 had an N-fixing activity value of 3,458 ＋ 10.95 nmol C2H2/plant and can supply 30% of N required for peanut. The bacterial strain P 1107 is able to solubilize phosphate and can increase phosphorus uptake by 30% in peanut. Further, inoculation of peanut with the bacterial strain S3.1 can save 30% required mineral potassium, and the Lipomyces strain PT5.1 can produce the slime, which can provide the sandy soil to keep moisture for 15 d longer than the control without the inoculation. All selected isolates are able to grow at temperatures from 20 ℃ to 35 ℃, pH from 4.5 to 6.0 and the salinity of 0.2%o-0.6%o NaCI, and can well adapt to the sandy soil conditions.

Studies on the Mechanism of Single Basal Application of Controlled-Release Fertilizers for Increasing Yield of Rice (Oryza sativa L.)

This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice （Oryza sativa L.）. Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance （CRF1） and polymer materials （CRF3） increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer （RSF1）. Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.

Genetic Analysis and Mapping of TWH Gene in Rice Twisted Hull Mutant

A mutant with twisted hulls was found in a breeding population of rice （Oryza sativa L.）. The mutant shows less grain weight and inferior grain quality in addition to twisted hulls. Genetic analysis indicated that the phenotype of mutant was controlled by a single recessive gene （temporarily designated as TW（H）. To map the TWH gene, an F2 population was generated by crossing the twh mutant to R725, an indica rice variety with normal hulls. For bulked segregant analysis, the bulk of mutant plants was prepared by mixing equal amount of plant tissue from 10 twisted-hull plants and the bulk of normal plants was obtained by pooling equal amount tissue of 10 normal-hull plants. Two hundred and seven pairs of simple sequence repeat （SSR） primers, which are distributed on 12 rice chromosomes, were used for polymorphism analysis of the parents and the two bulks. The TWH locus was initially mapped close to the SSR marker RM526 on chromosome 2. Therefore, further mapping was performed using 50 pairs of SSR primers around the marker RM526. The TWH was delimited between the SSR markers RM14128 and RM208 on the long arm of chromosome 2 at the genetic distances of 1.4 cM and 2.7 cM, respectively. These results provide the foundation for further fine mapping, cloning and functional analysis of the TWH gene.

Antioxidative and hepatoprotective activities of a novel polysaccharide (LSAP) from Lepista sordida mycelia

A novel alkali-soluble polysaccharide from Lepista sordida(LSAP)mycelia with antioxidative and hepatoprotective activities was characterized.The weight-average molecular weight and number-average molecular weight of LSAP were 1.442×10^(3) and 6.05×10^(2) kDa,respectively.LSAP was consisted of glucose(57.9%),xylose(31.8%),and small amounts of rhamnose,arabinose,galactose,glucuronic acid,and galacturonic acid(1.2%–3.1%).The FT-IR and 2D NMR confi rmed that LSAP was composed of Xylp,Araf,4-O-Me-α-D-GlcpA,(1→4)-linkedβ-D-Glcp,and(1→4)-α-D-GalA,andβ-glycosidic linkages between these sugar units.LSAP displayed notable effects on 1,1-dephenyl-2-picryhydrazyl(DPPH)radical scavenging,hydrogen peroxide scavenging,lipid peroxidation inhibitory ability,reducing power and Fe^(2+)chelating property.These biological effects were further verifi ed by suppressing CCl_(4)-induced oxidative liver damage in mice at doses of 100 and 200 mg/kg.Administration of LSAP in mice prior to CCl_(4) signifi cantly prevented the CCl_(4)-induced elevation in serum alanine aminotransferase,aspartate aminotransferase,and hepatic malondialdehyde.Mice treated with LSAP demonstrated to increase activities in superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)in the liver.We also found out that LSAP prevented CCl_(4)-induced oxidative liver histological alteration.LSAP may exert hepatoprotective effects against CCl_(4)-induced damage through antioxidant mechanisms in model mice.

Fixation of Multiple Metals in Contaminated Soil by Different Passivators

The effects of 4 passivators, zeolite, lime, red mud and peanut shell biochar, on the fixation of Cd, Pb, Cu and Zn in acidic multi-metal contaminated soils were studied by passivator culture experiment in order to screen out the passivator with better fixation effects. The results showed that the soil pH values of zeolite, lime, red mud and peanut shell biochar increased significantly by 0.511.02, 0.821.29, 0.720.89 and 0.300.35 respectively. The effects of 4 passivators on the fixation of Cd and Zn in soil are lime>red mud>zeolite>peanut shell biochar. The order of effects on the fixation of Pb is red mud>lime>zeolite>peanut shell biochar. The order of the fixation effects of Cu is red mud>lime>peanut shell carbon>zeolite. The contents of Cd, Pb, Cu and Zn in the extractable state of CaCl2 decreased with the increase in the dosage of 4 passivators. Lime and red mud showed good fixation effects on Cd, Pb, Cu and Zn. The contents of Cd, Pb, Cu and Zn in the extractable state of CaCl2 at the low dosage(2.5 g/kg) of lime and red mud decreased by 41%, 84%, 76% and 83% respectively. Soil pH value was negatively correlated with CaCl2-Cd, Pb, Cu and Zn(P<0.01). Lime and red mud had significant fixation effects on Cd, Pb, Cu and Zn in acidic multi-metal contaminated soils at low application dosages.

Effects of Winter Cover Crop and Straw Returning on the Functional Diversity of Rhizosphere Microflora in Double-crop Rice Paddies

The functional diversity of rhizosphere microflora which is also known as the “microbial community” is a sensitive indicator of soil quality subject to the type of winter cover crop and straw returning.In order to evaluate the effects of different winter cover crops and returning patterns on the functional diversity of rhizosphere microflora in double-crop rice paddies,we designed five winter cover crops and straw returning combinations to analyze their effects on the functional diversity of rhizosphere microflora in rice paddies: ryegrass (Lolium multiflorumL.)–double-crop rice (Ry),milk vetch (Astragalus sinicus L.)–double-crop rice (Mv),Rape (Brassica napus L.)–Double-crop rice (Ra), Potato (Solanum tuberosum L.)–double-crop rice (Po),and winter fallow–doublecrop rice (CK,the control).In this paper,the average well color development (AWCD) in Biolog-GN plates indicated the capacity for carbon utilization by the rhizosphere microbial community.We analyzed the rhizosphere microbial community functional diversity of the paddy soils with the above five treatments by using the Biolog-GN system.The results showed that applications of winter cover crop and straw returning caused high increases in AWCD compared with CK,and the AWCD values for samples with Po treatment was greater than those with Ry and CK treatments at the early and late rice maturity stages. It was concluded that applications of winter cover crop and straw returning can cause changes in the carbon utilization efficiency of rhizosphere microflora.There were differences in the genetic diversity of the rhizosphere microflora among different treatments at the maturity stage of early and late rice.The richness,Shannon,and McIntosh Index under different winter cover crop and straw returning treatments were significantly different.The highest indexes were observed in the Po treatment and the lowest in the CK at the maturity stage of early and late rice.The richness, Shannon,and McIntosh Index under different treatments ranked in descending order is as follows: Po>Ra>Mv>Ry>CK.Principal Component Analysis (PCA) of substrate reactions were conducted in this research.The results indicated that the pattern of carbon source utilization varied with winter cover crop treatments,and that carbohydrates and amino acids were the main carbon sources of rhizosphere microorganisms.To conclude,the application of winter cover crop and straw returning to paddy fields could significantly increase the carbon source utilization, species richness,and species evenness of rhizosphere microflora in double-crop rice paddies.

Application of Soil Amendments Reduced Cadmium Bioavailability but Restrained Soybean Growth

The soybean is a crop which easily accumulates cadmium(Cd),which threatens human health.To assess the impact of the application of classic soil amendments on the Cd concentration in the soybean and the Cd bioavailability in the soil,a field study was conducted in Xiangtan Country(XT)and Liling City(LL),with inorganic-organic-microbial matter(T1)and silicon-calcium-magnesium oxide from natural minerals(T2)as two soil amendments in this study.The results indicated that the soil pH in the two sites increased significantly,up to 0.7~1.1 units and the Cd concentration in the stem,leaf,husk and seed in the two sites decreased differently.Of which,the soil available Cd in Xiangtan County(XT)decreased by 11.9%~16.0%,the enrichment factor(EF)and translocation factor(TF)reduced by 37.9%and 23.5%,respectively.Both soil amendments were effective in increasing the soil pH,reducing the seed and soil available Cd,but the soil organic matter,total N,stem length and grain yields decreased slightly.In conclusion,the Cd bioavailability was reduced but the soybean growth was restrained with the application of the soil amendments.

Combined application of organic manure and chemical fertilizers stabilizes soil N-cycling microflora

Straw and manure are widely applied to agricultural systems,and greatly shape soil N-cycling microflora.However,we still lack a comprehensive understanding of how these organic materials structure soil N-cycling microbial communities.In this study,metagenomic analysis was performed to investigate the compositional variation in N-cycling microbial communities in a 30-year long-term experiment under five fertilization regimes:no fertilization(Control),chemical fertilization only(NPK),and NPK with wheat straw(NPK+HS),pig manure(NPK+PM),and cow manure(NPK+CM).Long-term NPK application differentially changed N-cycling gene abundance and greatly altered N-cycling microbial community structure.NPK+HS resulted in a similar pattern to NPK in terms of gene abundance and community structure.However,NPK+PM and NPK+CM significantly increased most genes and resulted in a community similar to that of the Control.Further analysis revealed that serious soil acidification caused by long-term NPK fertilization was a major factor for the variation in N-cycling microbial communities.The addition of alkaline manure,rather than wheat straw,stabilized the N-cycling microbial community structure presumably by alleviating soil acidification.These results revealed the strong impact of soil acidification on microbial N-cycling communities and illustrated the possibility of resolving nitrogen-related environmental problems by manipulating pH in acidified agricultural soils.

AOA and AOB communities respond differently to changes of soil pH under long-term fertilization

Archaeal and bacterial ammonia-oxidizers drive the first step of nitrification,ammonia oxidation.Despite their importance,the relative contribution of soil factors influencing the abundance,diversity and community composition of ammonia oxidizing archaea(AOA)and bacteria(AOB)are seldom compared.In this study,the AOA and AOB communities in soils from a long-term fertilization experiment(which formed gradients of pH and nutrients)were measured using 454 pyrosequencing of the amoA gene.Results showed that both AOA and AOB communities were influenced by fertilization practice.Changes of AOA abundance,diversity and community structure were closely correlated with a single factor,soil pH,and the abundance and diversity of AOA were lower under the acidified treatments.By contrast,AOB abundance was higher in the acidified soil than in the control soil while AOB diversity was little impacted by soil acidification,and both the abundance and diversity of AOB were most highly correlated with soil carbon and available phosphorus.These results indicated that AOB diversity seemed more resistant to soil acidification than that of AOA,and also suggested that AOB have greater ecophysiological diversity and broader range of habitats than AOA in this lime concretion black soil,and the potential contribution of AOB to ammonia oxidation in acid environments should not be overlooked.

Optimization of nitrogen fertilizer rate under integrated rice management in a hilly area of Southwest China

China has the world’s highest nitrogen(N)application rate,and the lowest N use efficiency(NUE).With the crop yield increasing,serious N pollution is also caused.An in-situ field experiment(2011–2015)was conducted to examine the effects of three N levels,0(i.e.,no fertilizer N addition to soil),120,and 180 kg N ha-1,using integrated rice management(IRM).We investigated rice yield,aboveground N uptake,and soil surface N budget in a hilly region of Southwest China.Compared to traditional rice management(TRM),IRM integrated raised beds,plastic mulch,furrow irrigation,and triangular transplanting,which significantly improved rice grain yield,straw biomass,aboveground N uptake,and NUE.Integrated rice management significantly improved 15N recovery efficiency(by 10%)and significantly reduced the ratio of potential15N loss(by 8%–12%).Among all treatments,the 120 kg N ha-1 level under IRM achieved the highest 15N recovery efficiency(32%)and 15N residual efficiency(29%),with the lowest 15N loss ratio(39%).After rice harvest,the residual N fertilizer did not achieve a full replenishment of soil N consumption,as the replenishing effect was insufficient(ranging from-31 to-49 kg N ha-1).Furthermore,soil surface N budget showed a surplus(69–146 kg N ha-1)under all treatments,and the N surplus was lower under IRM than TRM.These results indicate IRM as a reliable and stable method for high rice yield and high NUE,while exerting a minor risk of N loss.In the hilly area of Southwest China,the optimized N fertilizer application rate under IRM was found to be 100–150 kg N ha-1.

Effects of disinfection efficiency on microbial communities and corrosion processes in drinking water distribution systems simulated with actual running conditions

The effects of disinfection efficiency on microbial communities and the corrosion of cast iron pipes in drinking water distribution systems(DWDSs) were studied.Two annular reactors(ARs) that simulated actual running conditions with UV/Cl2 disinfection and chlorination alone were used.High chlorine consumption and corrosion rate were found in the AR with UV/Cl2.According to functional genes and pyrosequencing tests, a high percentage of iron recycling bacteria was detected within the biofilm of the AR with Cl2 at early running stage, whereas siderophore-producing bacteria were dominant in the biofilm of the AR with UV/Cl2.At the early running stage, the sequential use of UV light and an initial high chlorine dosage suppressed the biomass and iron-recycling bacteria in both bulk water and biofilms, thereby forming less protective scales against further corrosion, which enhanced chlorine consumption.Non-metric multidimensional scaling analysis showed that the bacterial communities in the ARs shaped from within rather than being imported by influents.These results indicate that the initial high disinfection efficiency within the distribution system had not contributed to the accumulation of iron-recycling bacteria at the early running stages.This study offer certain implications for controlling corrosion and water quality in DWDSs.

Effect of long-term fertilization on bacterial communities in wheat endosphere

Fertilization has been shown to exert a significant influence on soil microorganisms and directly and indirectly influences plant growth and survival in agroecosystems. However, it is unknown whether fertilization affects endophytic microbial communities, which are ubiquitous and intimately associated with plant growth and health. Herein, we investigated endophytic bacterial communities in wheat leaves and roots under different long-term fertilization regimes,including NPK chemical fertilizer and NPK chemical fertilizer combined with wheat straw, pig manure, or cow manure. Endophytic bacterial community composition considerably differed in leaves and roots. Although different fertilization treatments did not affect the endophytic bacterial species richness or phylogenetic diversity in either leaves or roots, the community composition was significantly altered, particularly in roots. The endophytic bacterial co-occurrence network in leaves was more complex and stable than that in roots. Furthermore, many of the keystone species that were identified by their topological positions in the co-occurrence networks of leaves and roots were involved in plant growth and fitness. The total relative abundance of keystone species was the highest in the NPK plus cow manure treatment in both leaves and roots. Overall, our results suggest that different fertilization regimes can strongly affect endophytic bacterial communities, and the combination of NPK fertilizer and cow manure promoted the relative abundance of the key endophytic bacterial microbiota in both leaves and roots, which might be beneficial for plants in agroecosystems.