Dietary bamboo leaf flavonoids improve quality and microstructure of broiler meat by changing untargeted metabolome

Background Dietary bamboo leaf flavonoids(BLFs)are rarely used in poultry production,and it is unknown whether they influence meat texture profile,perceived color,or microstructure.Results A total of 720 one-day-old Arbor Acres broilers were supplemented with a basal diet with 20 mg bacitracin/kg,50 mg BLFs/kg,or 250 mg BLFs/kg or without additions.Data showed that the dietary BLFs significantly(P<0.05)changed growth performance and the texture profile.In particular,BLFs increased birds’average daily gain and average daily feed intake,decreased the feed:gain ratio and mortality rate,improved elasticity of breast meat,enhanced the gumminess of breast and leg meat,and decreased the hardness of breast meat.Moreover,a significant(P<0.05)increase in redness(a*)and chroma(c*)of breast meat and c*and water-holding capacity of leg meat was found in BLF-supplemented broilers compared with control broilers.In addition,BLFs supplementation significantly decreased(P<0.05)theβ-sheet ratio and serum malondialdehyde and increased theβ-turn ratio of protein secondary structure,superoxide dismutase,and glutathione peroxidase of breast meat and total antioxidant capacity and catalase of serum.Based on the analysis of untargeted metabolome,BLFs treatment considerably altered 14 metabolites of the breast meat,including flavonoids,amino acids,and organic acids,as well as phenolic and aromatic compounds.Conclusions Dietary BLFs supplementation could play a beneficial role in improving meat quality and sensory color in the poultry industry by changing protein secondary structures and modulating metabolites.

Temporal changes in mixing effects on litter decay and nitrogen release in a boreal riparian forest in northeastern China

In riparian forests,litter decay provides essential energy and nutrients for both terrestrial and fluvial ecosystems.Litter mixing effects(LMEs)are crucial in regulating litter decay and nutrient dynamics,yet how LMEs change over time is unclear in riparian forests.In this study,leaf litter of three common species(Alnus sibirica Fisch.ex Turcz,Betula platyphylla Sukaczev,and Betula fruticosa Pall.)were mixed in an equal mass ratio and LMEs were measured for mass and nitrogen(N)remaining in whole litter mixtures over a 3-year period in a boreal riparian forest,northeastern China.LMEs were also assessed for component litter mass and N remaining by separating litter mixtures by species.During the decay of litter mixtures,antagonistic effects on mass and N remaining were dominant after one and two years of decay,whereas only additive effects were observed after three years.LMEs correlated negatively with functional diversity after the first and two years of decay but disappeared after three years.When sorting litter mixtures by species,non-additive LMEs on mass and N remaining decreased over incubation time.Moreover,non-additive LMEs were more frequent for litter of both B.platyphylla and B.fruticosa with lower N concentration than for A.sibirica litter with higher N concentration.These results indicate that incubation time is a key determinant of litter mixing effects during decay and highlight that late-stage litter mixture decay may be predicted from single litter decay dynamics in boreal riparian forests.

Exogenous application of bio-stimulants and growth retardants improve nutrient absorption and fiber quality in upland cotton

Background Natural and synthetic plant growth regulators are essential for plant health,likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stability.In the present study,we have evaluated the effects of foliar applied plant growth regulators,i.e.,moringa leaf extract(MLE)and mepiquat chloride(MC)alone and in combination MC and MLE on the conventional cotton cultivar(CIM 573)and transgenic one(CIM 598).The growth regulators were applied at the start of bloom,45 and 90 days after blooming.Results The application of MC and MLE at 90 days after blooming significantly improved the relative growth rate,net assimilation rate,the number of bolls per plant,and seed cotton yield.Likewise,the combined application of MLE and MC at 90 days after blooming significantly boosted the nitrogen uptake in locules,as well as the phosphorus and potassium uptake in the leaves of both cotton cultivars.The application of MLE alone has considerably improved the nitrogen uptake in leaves,and phosphorus and potassium contents in locules of Bt and conventional cotton cultivars.Similarly,Bt cotton treated with MLE at 90 days after blooming produced significantly higher ginning out turn and oil contents.Treatment in combination(MLE+MC)at 90 days after blooming produced considerably higher micronaire value,fiber strength,and staple length in conventional cultivar.Conclusion The natural growth enhancer,MLE is a rich source of minerals and zeatin,improving the nutrient absorption and quality of cotton fiber in both conventional and Bt cotton cultivars.

Nutrient dynamics associated with leaf litter decomposition of three agroforestry tree species (Azadirachta indica, Dalbergia sissoo, and Melia azedarach) of Bangladesh

Azadirachta indica A. Juss, Dalbergia, sissoo Roxb., and Melia azedarach L. are little studied species in nutrient return capabilities from leaf litter decomposition to maintenance of the soil fertility despite their importance in agroforestry practices of Bangladesh. A leaf litter decomposition experiment was conducted using a litterbag teeh7 nique to assess the nutrient reaun efficiency of these species. The de- composition rate of leaf litter was highest for M. azedarach and lowest for D. sissoo. Rainfall and temperature of study sites showed a significant （p〈0.05） positive relationship with the rate of leaf litter decomposition. The highest decay constant was observed for M. azedarach （6.67）. Nitrogen and Phosphorus concentration in leaf litter showed a decreased trend sharply at the end of the first month, whereas rapid decrease of Potassium concentration was reported within 10 days. Conversely, higher concentration of nutrient was observed at the later stages of decomposition. All three species showed a similar pattern of nutrient release （K 〉 N 〉 P） during the decomposition process of leaf litter. Among the studied species, D. sissoo was best in terms of N and P return and A. indica was best in terms of K return.

Leaching of dissolved organic matter from seagrass leaf litter and its biogeochemical implications

Dissolved organic matter（DOM） represents a significant source of nutrients that supports the microbial-based food web in seagrass ecosystems. However, there is little information on how the various fractions of DOM from seagrass leaves contributed to the coastal biogeochemical cycles. To address this gap, we carried out a 30-day laboratory chamber experiment on tropical seagrasses Thalassia hemprichii and Enhalus acoroides. After 30 days of incubation, on average 22% carbon（C）, 70% nitrogen（N） and 38% phosphorus（P） of these two species of seagrass leaf litter was released. The average leached dissolved organic carbon（DOC）, dissolved organic nitrogen（DON） and dissolved organic phosphorus（DOP） of these two species of seagrass leaf litter accounted for 55%, 95% and 65% of the total C, N and P lost, respectively. In the absence of microbes, about 75% of the total amount of DOC, monosaccharides（MCHO）, DON and DOP were quickly released via leaching from both seagrass species in the first 9 days. Subsequently, little DOM was released during the remainder of the experiment. The leaching rates of DOC, DON and DOP were approximately 110, 40 and 0.70 μmol/（g·d）. Leaching rates of DOM were attributed to the nonstructural carbohydrates and other labile organic matter within the seagrass leaf. Thalassia hemprichii leached more DOC, DOP and MCHO than E. acoroides. In contrast, E. acoroides leached higher concentrations of DON than T. hemprichii, with the overall leachate also having a higher DON： DOP ratio. These results indicate that there is an overall higher amount of DOM leachate from T. hemprichii than that of E. acoroides that is available to the seagrass ecosystem. According to the logarithmic model for DOM release and the in situ leaf litter production（the Xincun Bay, South China Sea）, the seagrass leaf litter of these two seagrass species could release approximately 4×10~3 mol/d DOC, 1.4×10~3 mol/d DON and 25 mol/d DOP into the seawater. In addition to providing readily available nutrients for the microbial food web, the remaining particulate organic matter（POM）from the litter would also enter microbial remineralization processes. What is not remineralized from either DOM or POM fractions has potential to contribute to the permanent carbon stocks.

Effects of leaf removal and cluster thinning on berry quality of Vitis vinifera cultivars in the region of Weibei Dryland in China

Leaf removal and cluster thinning were carried out prior to veraison to evaluate the effects on berry quality of two Vitis vinifera cultivars（Cabernet Sauvignon and Ugni Blanc） in the Weibei Dryland of China in 2013 and 2014, and comprehensive analysis of the chemical and volatile composition in berries was performed. The results showed that content of reducing sugar in both varieties was not affected while total acid was generally decreased by leaf removal and cluster thinning. The pH of berry juice was correspondingly higher in most treatment groups. Meanwhile, promoting effects on accumulation of total phenols, tannin in both varieties and total anthocyanins in Cabernet Sauvignon were found. As for monomeric anthocyanins, percentage of malvidin and its derivatives was decreased by leaf removal and cluster thinning. Besides, cinnamylated anthocyanins decreased with the intensity of cluster thinning. The accumulation of non-anthocyanin phenolics was similarly affected in the two varieties. Notably, cluster thinning was more effective on enhancing the phenolics content than leaf removal. The combination of middle level of leaf removal and cluster thinning was the most favor to the accumulation of phenolic acids. Furthermore, cluster thinning could also significantly enhance the synthesis of flavanols and stilbenes. Lastly, content and variety of aroma compounds in both grape varieties were also significantly affected by the treatments. The results provided a theoretical basis for a combination of leaf removal and cluster thinning to improve quality of grapes and wines.

Postharvest Quality and Physiological Behavior of Sweet Potato (Ipomoea batatas Lam.) Leaf Stalks Under Three Temperatures

Sweet potato （Ipomoea batatas Lam.） leaf stalks were cut into 20 cm length, and stored at 20, 6, and 2℃. The respiration rate, ethylene production, ascorbic acid, free amino acid, total chlorophyll content, freshness, and shelf life were determined during storage to investigate the effect of storage temperatures on the quality and physiological responses in sweet potato leaf stalks. Wound responses were observed as high respiration rate and ethylene production immediately after cutting. Sweet potato leaf stalks were found to be sensitive to chilling injury manifested as browning and water-soaking on the surface at 2℃. In contrast, sweet potato leaf stalks were susceptible to senescence, exhibited by etiolating and yellowing, at 20℃. Loss in weight and chlorophyll was minimized under low temperatures. High temperatures also caused the accumulation of amino acids with a significant loss of ascorbic acid and chlorophyll. Sweet potato leaf stalks had a storage life of 16 days at 6℃, 8 days at 2℃, and 6 days at 20℃, respectively.

A comparison of decomposition dynamics among green tree leaves,partially decomposed tree leaf litter and their mixture in a warm temperate forest ecosystem

Decomposition dynamics were compared among green tree leaves, partially decomposed tree leaf litter （i.e., decayed tree leaf litter on forest floor） and a mixture of the two in a warm temperate forest ecosystem in central China to test the influence of litter chemical quality on the degree of decomposition. The study was conducted in situ at two contrasting forest sites, an oak forest dominated by Quercus aliena var. acuteserrata Maxim., and a mixed pine and oak forest dominated by Pinus armandii Franch. and Q. aliena var. acuteserrata. We found marked differences in the rate of decomposition among litter types at both forest sites; the litter decom- position constant, k, was about 39 % greater at the oak forest site and more than 70 % greater at the pine-oak forest site, for green leaves than for partially decomposed leaf litter. The decomposition dynamics and temporal changes in litter chemistry of the three litter types also greatly differed between the two forest sites. At both forest sites, the higher rate of decomposition for the green leaves was associated with a and lower carbon to N ratio higher nitrogen （N） content （C/N） and acid-unhydrolyz- able residue to N ratio （AUR/N）. We did not find any non- additive effects when mixing green leaves and partially decomposed leaf litter. Our findings support the con- tention that litter chemical quality is one of the most important determinants of litter decomposition in forest ecosystems at the local or regional scale, but the effect of litter chemical quality on decomposition differs between the contrasting forest types and may vary with the stage of decomposition.

Effects of leaf litter extraction fluid from dominant forest tree species on functional characteristics of soil microbial communities

The effects of extraction fluids from the leaf litter from different dominant tree species on the functional characteristics of the soil microbial community were studied to understand how changes in soil quality and synergism between plants and soil contribute to the process of forest succession. Leaf litter from dominant tree species at different stages of succession were collected and extracted with sterile deionized water. After treating the soil of abandoned land with the different extraction fluids, we analyzed changes in carbon utilization of the soil microbial community in Biolog EcoPlates, then considered these results with those of our previous study on forest vegetation succession in the Malan forest. The leaf litter enhanced the metabolic capacity and functional diversity of the soil microbes, especially in the following combinations： the leaf litter of Quercus liaotungensis-Pinus tabulae- formis, P. tabulaeformis-Betula platyphylla, Q. liaotun- gensis and P. tabulaeformiss. Second, when litter from onespecies evaluated, the species enhanced metabolism and diversity in the order of their successional relationship： B. Platyphylla 〈 P. tabulaeformis 〈 Q. liaotungensis. After soils were treated with different leaf litters at 25 ℃ for 7 days, the sorting pattern of the PCA values, based on the similarity of carbon source utilization by the soil microbes, corresponded to the successional pattern on the basis of the similarity of community composition of forest plants. Thus, changes in soil properties caused by leaf litter from different dominant trees probably play a unique role in the successional pattern of a forest community. We thus pro- pose a successional mechanism that underlies the natural succession process within the Malan forest region. When the dominant forest species of the climax successional stage develops during the early successional stages, its forest litter probably alters soil properties such that the soil becomes unsuitable for the gradual growth and regenera- tion of the original dominant tree species but promotes the growth and establishment of later-invasive plants. In this way, the originally dominant species is replaced by the newly dominant tree species during forest succession.

Leaf litter ecological fate in the Schelde Estuary in Belgium

Two dominant species of Willow( Salix triandra )and Reed (Phragmites australis) along the Schelde Estuary(in Belgium)were selected in this research. The pigments of higher plant was used as biomarkers, the decomposition process of the two species were studied after they fall into the Schelde Estuary. After statistical analysis(Spearman rank order correlation, P <0 05), the results has shown the decomposition dynamics pattern of the pigments, and the willow showed different pattern in comparing with the reed, e.g. Chlorophyll a decomposition dynamics for willow is: y 1=12196 x 2 - 175895 x +1E+06+ k , R 2=0 5706 while for reed is: y 2=-37878 x 2+229782 x +734282+ k , R 2=0 9065 The precise time of the leaf litter spent in the water was also calculated as were less than 24 days, 24-37 days, longer than 37 days(willow)and less than 24 days, longer than 24 days(reed), the leaf litter fate of the two dominant species in the Schelde Estuary was also compared.

Effects of Different Fertilization Treatments on Soil, Leaf Nutrient and Fruit Quality of Citrus grandis var. longanyou

The five-year-old “Longanyou” trees were used as the experimental material to study the effects of different fertilization treatments. The nutrient contents in soil and leaves, fruit yield and quality were determined, and then the correlations were analyzed. The results showed that: 1) The soil nutrient contents of 0 - 20 cm depth were more than the 20 - 40 cm, and the trends of nutrient contents of the 0 - 20 cm soil layers were as follows: treatment 2 (T2) > treatment 3 (T3) > treatment 4 (T4) > treatment 1(T1) > control (CK). However, the 20 - 40 cm depth had not significant difference between different treatments, but T2, T4 and T3 were higher than T1 and CK. It indicated that the soil effective nutrient content increased in T2 and T3. 2) Compared with the control, the content of K and B elements was improved obviously in leaves with the increase of organic manure application. The contents of P (1.60 g·kg-1), B (26.00 mg·kg-1) and Mg (1.18 g·kg-1) were the highest, and other nutrients contents were also higher, indicating that T2 could effectively improve the leaves’ nutrient contents. 3) The fruit yield per plant was the highest in T2 (95.40 kg plant-1), and the single fruit weight, total sugar, sugar and acid ratio, vitamin C were also the highest, but titratable acid was lower. It indicated that T2 effectively improved fruit yield and quality. 4) There were positive correlations between multiple factors of soil nutrients and the quality index, such as fruit peel thickness, total sugar, solid acid ratio, sugar and acid ratio, Vc content and single yield etc. There was significant correlation between K, B, Zn, Fe contents and fruit yield and quality index, and the contents of B, Zn and Fe in leaves were significantly correlated with soil nutrient, indicating that the contents of K, B, Zn, Fe in soil and leaf were closely related to fruit yield and quality. In sum, the T2 was the best fertilization scheme for orchard management practice of “Longanyou”.

Impact of tree litter identity, litter diversity and habitat quality on litter decomposition rates in tropical moist evergreen forest

Background:Attempts to restore degraded highlands by tree planting are common in East Africa.However,up till now,little attention has been given to effects of tree species choice on litter decomposition and nutrient recycling.Method:In this study,three indigenous and two exotic tree species were selected for a litter decomposition study.The objective was to identify optimal tree species combinations and tree diversity levels for the restoration of degraded land via enhanced litter turnover.Litterbags were installed in June 2019 into potential restoration sites(disturbed natural forest and forest plantation)and compared to intact natural forest.The tested tree leaf litters included five monospecific litters,ten mixtures of three species and one mixture of five species.Standard green and rooibos tea were used for comparison.A total of 1,033 litters were retrieved for weight loss analysis after one,three,six,and twelve months of incubation.Results:The finding indicates a significant effect of both litter quality and litter diversity on litter decomposition.The nitrogen-fixing native tree Millettia ferruginea showed a comparable decomposition rate as the fast decom-posing green tea.The exotic conifer Cupressus lusitanica and the native recalcitrant Syzygium guineense have even a lower decomposition rate than the slowly decomposing rooibos tea.A significant correlation was observed be-tween litter mass loss and initial leaf litter chemical composition.Moreover,we found positive non-additive ef-fects for litter mixtures including nutrient-rich and negative non-additive effects for litter mixtures including poor leaf litters respectively.Conclusion:These findings suggest that both litter quality and litter diversity play an important role in decom-position processes and therefore in the restoration of degraded tropical moist evergreen forest.

Effect of Rolled Leaf Gene Rl_(t) on Grain Quality in Hybrid Rice

Effects of rolled leaf gene Rl（t） on grain quality characters of hybrid rice were analyzed by using three pairs of rolled leaf near-isogenic lines under two fertilizer treatments. Under normal fertilizer level （e.g. 450 kg urea per ha）, head rice rates and milled rice recovery of rolled leaf hybrids were significantly higher than those of corresponding non-rolled crosses, while the chalky rice rate and chalkiness were all lower. Of the RVA profiles, the peak viscosity, the hot paste viscosity and the breakdown viscosity of the rolled were all higher than those of the corresponding non-rolled ones to various degrees. Increasing fertilizer application for promoting panicle development increased the brown, milled and head rice rates except for Shanyou 63, furthermore, significant difference of head rice rates existed between the rolled leaf Shanyou 559 and Shanyou 559; while the peak viscosity, the hot paste viscosity and the breakdown viscosity all decreased to different levels; changes of values of other characters had no apparent regularity. It suggested that Rl（t） could improve rice quality under certain conditions.

Effect of Leaf Litter Treatment on Soil Microbial Biomass

Soil microbial biomass is an active fraction of soil organic matter. It shows quicker response than soil organic matter to any change in the soil environment. Being an index of soil fertility, it plays a key role in the decomposition of litters and fast release of available nutrients. Leaf litters of leguminous and non-leguminous species in alone and mixed form were applied as treatments in the soil to observe the changes in the magnitude of soil microbial biomass. Soil microbial biomass C and N were determined by chloroform fumigation extraction method. Increment in the concentration of microbial biomass C and N was higher in the treatments with leguminous leaf litter (497 - 571 μgCg?1, 48 - 55 μgNg?1) than the non-leguminous one (256 - 414 μgCg?1;22 - 36 μgNg?1). However, when non-leguminous litters were mixed with leguminous litters then the values increased distinctly (350 - 465 μgCg?1, 28 - 48 μgNg?1). On the basis of increment in soil microbial biomass, leaf litters of the species considered potential to improve soil nutrients are—Cassia siamea and Dalbergia sissoo from leguminous trees, Anthocephalus + Cassia and Shorea + Dalbergia from mixed form of non-leguminous and leguminous one and Eichhornia crassipes, an alien aquatic macrophyte. The leaf litters of these species can be used as source of organic matter to improve the crop yield.

Responses of Soil Fauna Structure and Leaf Litter Decomposition to Effective Microorganism Treatments in Da Hinggan Mountains,China

Microorganisms are nutritious resources for various soil fauna.Although soil fauna grazing affects microorganism composition and decomposition rate,the responses of soil fauna and leaf litter decomposition to added microorganism is little understood.In this study,in the coniferous and broad-leaved mixed forest of Tahe County in the northern Da Hinggan Mountains,China,three sampling sites(each has an area of 10 m2) were selected.The first two sites were sprinkled with 250 times(EM1) and 1000 times(EM2) diluted effective microorganism(EM) preparations evenly,and the third site was sprinkled with the same volume of water as a control site.The responses of soil fauna structure and leaf litter decomposition to EM treatment were conducted during three years.The results revealed that EM treatment resulted in significant increase of soil organic matter.The number of soil fauna in the EM1 and EM2 sites increased by 12.88% and 2.23% compared to the control site,and among them springtails and mites showed the highest increase.However,the groups of soil fauna in the EM1 and EM2 sites decreased by 6 and 9,respectively.And the changes in the diversity and evenness index were relatively complicated.EM treatment slowed the decomposition of broad-leaved litter,but accelerated the decomposition of coniferous litter.However,the decomposition rate of broad-leaved litter was still higher than that of coniferous litter.The results of this study suggested that the added microorganisms could help individual growth of soil fauna,and this method led to a change in the process of leaf litter decomposition.This paper did not analyze the activity of soil microorganisms,thus it is difficult to clearly explain the complex relationships among litter type,soil fauna and soil microorganisms.Further research on this subject is needed.

Genotypic variation in root morphology, cotton subtending leaf physiology and fiber quality against nitrogen

Background:Nitrogen(N)is important for improving various morphological and physiological processes of cotton but their contribution to fiber quality is still lacking.Aims:The current study aimed to explore the relationship between root morphology,subtending leaf physiology,and fiber quality of contrasting N-efficient cotton genotypes in response to N.Methods:We analyzed the above parameters of CCRI 69(N-efficient)and Xinluzao-30(XLZ-30,N-inefficient)under control(2.5 mmol·L^(-1))and high N(5 mmol·L^(-1))conditions.Results:The results showed that root morphological traits were increased in CCRI-69 under control conditions than high N.Subtending leaf morphology,chlorophyll and carotenoid contents,free amino acids,and soluble proteins were higher under high N as compared with the control.However,soluble sugars,fructose,sucrose contents,and sucrose phosphate synthase were higher under control conditions than high N across the growth stages.Irrespective of the N conditions,all morphological and physiological traits of cotton subtending leaf were higher in CCRI-69 than XLZ-30.Except for fiber uniformity,fiber quality traits like fiber length,strength,micronaire,and elongation were improved under control conditions than high N.Between the genotypes,CCRI-69 had significantly higher fiber length,strength,micronaire,and elongation as compared with XLZ-30.Strong positive correlations were found between root morphology,soluble sugars,sucrose content,and sucrose phosphate synthase activity with fiber quality traits,respectively.Conclusions:These findings suggest that CCRI-69 performed better in terms of growth and fiber quality under relatively low N condition,which will help to reduce fertilizer use,the cost of production,and environmental pollution.

Effects of soil fauna on leaf litter decomposition under different land uses in eastern coast of China

Soil fauna decompose litter, whereas land use changes may significantly alter the composition and structure of soil fauna assemblages. However, little is known of the effects of land-use on the contribution of soil fauna to litter decomposition. We studied the impacts of soil fauna on the decomposition of litter from poplar trees under three different land uses （i.e. poplar-crop integrated system, poplar plantation, and cropland）, from December 2013 to December 2014, in a coastal area of Northern Jiangsu Province. We collected litter samples in litterbags with three mesh sizes （5, 1 and 0. 01 mm, respectively） to quantify the contribution of various soil fauna to the decomposition of poplar leaf litter. Litter decomposition rates differed significantly by land use and were highest in the cropland, intermediate in the poplar-crop integrated system, and lowest in the poplar plantation. Soil fauna in the poplar-crop integrated system was characterized by the highest numbers of taxa and individuals, and highest Margalef＇s diversity, which suggested that agro-forestry ecosystems may support a greater quantity, distribution, and biodiversity of soil fauna than can single-species agriculture or plantation forestry. The individuals and groups of soil fauna in the macro-mesh litterbags were higher than in the meso-mesh litterbags underthe same land use types. The average contribution rate of meso- and micro-fauna to litter decomposition was 18.46%, which was higher than the contribution rate of macro-fauna （3.31%）. The percentage of remaining litter mass was inversely related to the density of the soil fauna （P 〈 0.05） in poplar plantations; however, was unrelated in the poplar-crop integrated system and cropland. This may have been the result of anthropogenic interference in poplar-crop integrated systems and croplands. Our study suggested that when land-use change alters vegetation types, it can affect species composition and the structure of soil fauna assemblages, which, in turn, affects litter decomposition.

Relationship Between the N Concentration of the Leaf Subtending Boll and the Cotton Fiber Quality

This experiments were conducted in Nanjing （118~50＂E, 32~02＂N） and Xuzhou （117~11 ＂E, 34~15＂N）, Jiangsu Province, China, to study the response of fiber quality to the N concentration of the leaf subtending boll in cotton （Gossypium hirsutum L.）. Results suggested that the N dilution curve of the leaf subtending boll can accurately indicate the stage- specific plant N status for fiber development. Fiber strength is likely to be the most variable fiber quality index responding to the leaf N variation which is different in cultivars. Fiber length was the most stable index among strength, length, micronaire, and elongation. There existed an optimum leaf N concentration for fiber strength development in each stage. The optimum leaf N regression curve was very close to the N dilution curve in the middle positional fruiting branches under the 240 kg N ha-1 soil N application rate.

Dependency of litter decomposition on litter quality,climate change,and grassland type in the alpine grassland of Tianshan Mountains,Northwest China

Litter decomposition is an important component of the nutrient recycling process and is highly sensitive to climate change.However,the impacts of warming and increased precipitation on litter decomposition have not been well studied,especially in the alpine grassland of Tianshan Mountains.We conducted a manipulative warming and increased precipitation experiment combined with different grassland types to examine the impact of litter quality and climate change on the litter decomposition rate based on three dominant species(Astragalus mongholicus,Potentilla anserina,and Festuca ovina)in Tianshan Mountains from 2019 to 2021.The results of this study indicated there were significant differences in litter quality,specific leaf area,and leaf dry matter content.In addition,litter quality exerted significant effects on litter decomposition,and the litter decomposition rate varied in different grassland types.Increased precipitation significantly accelerated the litter decomposition of P.anserina;however,it had no significant effect on the litter decomposition of A.mongholicus and F.ovina.However,warming consistently decreased the litter decomposition rate,with the strongest impact on the litter decomposition of F.ovina.There was a significant interaction between increased precipitation and litter type,but there was no significant interaction between warming and litter type.These results indicated that warming and increased precipitation significantly influenced litter decomposition;however,the strength was dependent on litter quality.In addition,soil water content played a crucial role in regulating litter decomposition in different grassland types.Moreover,we found that the litter decomposition rate exhibited a hump-shaped or linear response to the increase of soil water content.Our study emphasizes that ongoing climate change significantly altered litter decomposition in the alpine grassland,which is of great significance for understanding the nutrient supply and turnover of litter.

Assessment of the Effects of Poultry Litter on Surface Runoff Water Quality from Agricultural Lands

The use of pelletized poultry litter (PPL) as a substitute for inorganic fertilizers is increasingly being en-couraged in states like Delaware which have a considerable surplus of poultry litter. However, we know very little about the impacts of PPL on runoff water quality and whether it is an environmentally-sound and sus-tainable alternative to inorganic fertilizer. To address these questions we compared the exports of nutrients (NH4-N, NO3-N and PO4-P) and trace elements (As, Cu, and Zn) in surface runoff from agricultural plots receiving PPL, raw poultry litter (RPL), urea and no-fertilizer (control) treatments. The study was conducted on agricultural land located in Middletown, Delaware with corn as the cover crop. The experimental plots were 5 m wide and 12 m long with reduced tillage and no-tillage management practices. Sampling was con-ducted for six natural rainfall events from April through August 2008. Nutrient (NH4-N, NO3-N and PO4-P) exports from plots receiving PPL were less than those with urea or raw litter applications. While exports of trace elements from the PPL treatment exceeded those from urea, they were much lower than the corre-sponding exports from the RPL treatments. Mass exports of nutrients and trace elements were correlated with event size (rainfall amount) but were not correlated with timing of event (days since litter application). Results from this study suggest that the use of PPL in combination with no-tillage may provide an environ-mentally safe alternative to synthetic fertilizers.