Drought has become one of the major constraints to agricultural development, particularly in areas that lack water. Studying the effects of different water stresses on the photosynthesis, growth, yield, water use efficiency (WUE) and irrigation water productivity (IWP) of winter wheat will provide data for the development of scientific irrigation strategies for water-saving agricultural methods. According to the size of the field water capacity, four different water stress levels were set, i.e., 30–40% (severe stress), 40–50% (moderate stress), 50–60% (mild stress) and 60–80% (well-watered) of field water capacity, controlling the amount of irrigation through an automatic irrigation system. The results showed that the seasonal changes in photosynthetic parameters, such as net photosynthetic rate (Pn), intercellular carbon concentration (Ci), stomatal conductance (Gs) and transpiration (E), significantly decreased under moderate and severe stress. As a result, the height, biomass and grain size of winter wheat decreased significantly, which led to low WUE and IWP. The Pn of the mild stress group only slightly decreased compared to that of the well-watered group, and was actually higher during the flowering and grain-filling stages, resulting in increases in dry biomass and 1000 grain weight of 2.07% and 1.95%, respectively. Higher WUE and IWP were attributed to higher yields and less water use. Thus, mild stress (60–80% field water capacity) resulted in the optimal use of water resources without a significant reduction in yield in the North China Plain (NCP). Therefore, mild stress can be considered a suitable environment for winter wheat growth in arid areas.

Our previous study demonstrated increased expression of Heat shock protein (Hsp) 90 in the skin of patients with systemic sclerosis (SSc). We aimed to evaluate plasma Hsp90 in SSc and characterize its association with SSc-related features. Ninety-two SSc patients and 92 age-/sex-matched healthy controls were recruited for the cross-sectional analysis. The longitudinal analysis comprised 30 patients with SSc associated interstitial lung disease (ILD) routinely treated with cyclophosphamide. Hsp90 was increased in SSc compared to healthy controls. Hsp90 correlated positively with C-reactive protein and negatively with pulmonary function tests: forced vital capacity and diffusing capacity for carbon monoxide (DLCO). In patients with diffuse cutaneous (dc) SSc, Hsp90 positively correlated with the modified Rodnan skin score. In SSc-ILD patients treated with cyclophosphamide, no differences in Hsp90 were found between baseline and after 1, 6, or 12 months of therapy. However, baseline Hsp90 predicts the 12-month change in DLCO. This study shows that Hsp90 plasma levels are increased in SSc patients compared to age-/sex-matched healthy controls. Elevated Hsp90 in SSc is associated with increased inflammatory activity, worse lung functions, and in dcSSc, with the extent of skin involvement. Baseline plasma Hsp90 predicts the 12-month change in DLCO in SSc-ILD patients treated with cyclophosphamide.

Signaling through the Ror2 receptor tyrosine kinase promotes invadopodia formation for tumor invasion. Here, we identify intraflagellar transport 20 (IFT20) as a new target of this signaling in tumors that lack primary cilia, and find that IFT20 mediates the ability of Ror2 signaling to induce the invasiveness of these tumors. We also find that IFT20 regulates the nucleation of Golgi-derived microtubules by affecting the GM130-AKAP450 complex, which promotes Golgi ribbon formation in achieving polarized secretion for cell migration and invasion. Furthermore, IFT20 promotes the efficiency of transport through the Golgi complex. These findings shed new insights into how Ror2 signaling promotes tumor invasiveness, and also advance the understanding of how Golgi structure and transport can be regulated.

Groundwater plays a major role in agro-hydrological processes in the North China Plain (NCP). The NCP is facing a water deficit, due to a rapid decline in the water table because of the double cropping system. A two crop (maize and wheat) rotation is required to balance the food supply and demand, which leads to an imbalance between evapotranspiration (ET) and precipitation. Thus, there has been a decline of about 1.35 m yr−1 of groundwater (Luancheng Agroecosystem Experimental Station (LAES), NCP) during the last 10 years. Lysimeter experiments were conducted under different irrigation treatments (flood, surface drip, and subsurface drip) to account for ET in the selection of a suitable irrigation method. Subsurface drip irrigation reduced ET by 26% compared to flood irrigation, and 15% compared to surface drip irrigation, with significant grain yield and biomass formation due to decreased evaporation losses. Grain yield, yield components, and above ground biomass were similar in subsurface drip and flood irrigation. However, these biomass parameters were lower with surface drip irrigation. Furthermore, subsurface drip irrigation increased the crop water productivity (24.95%) and irrigation water productivity (19.59%) compared to flood irrigation. The subsurface irrigated plants showed an increase in net photosynthesis (~10%), higher intrinsic water use efficiency (~36%), lower transpiration rate (~22%), and saved 80 mm of water compared to flood irrigation. Our findings indicate that subsurface drip irrigation can be adopted in the NCP to increase water use efficiency, optimize grain yield, and minimize water loss in order to address scarcity.

Wheat is one of the major staple food of the world, which is badly affected by water deficit stress. To fulfill the dietary needs of increasing population with depleting water resources there is need to adopt technologies which result in sufficient crop yield with less water consumption. One of them is partial root zone drying (PRD). Keeping in view these conditions, a wire house experiment was conducted at University College of Agriculture and Environmental Sciences, The Islamia University Bahawalpur during 2015, to screen out the different wheat genotypes for PRD. Five approved local wheat cultivars (V= Galaxy-2013, V= Punjab-2011, V = Faisalabad-2008, V = Lasani-2008 and V = V.8200) and two irrigation levels (I = control irrigation and I = PRD irrigation) with completely randomized design having four replications were used in the experiment. Among the varieties Galaxy-2013 performed the best and attained maximum plant height, leaf area, stomatal conductance, photosynthesis, total sugars, proline contents and antioxidant enzymes activities and minimum values of all growth and physiological parameters were recorded in variety V.8200. For irrigation levels, higher values of growth, physiological and water related parameters were recorded in control treatment (I) except leaf water potential, osmotic potential, total sugars and proline contents. However enzymes activities were higher under PRD treatment for all varieties. It was concluded that Galaxy-2013 was the most compatible and V.8200 was the most susceptible variety under PRD condition, respectively and more quality traits and enzymatic activities were recorded under PRD condition as compared to control treatment.Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The physiological responses of potato (Solanum tuberosum L. cv. Folva) to partial root-zone drying (PRD) were investigated in potted plants in a greenhouse (GH) and in plants grown in the field under an automatic rain-out-shelter. In the GH, irrigation was applied daily to the whole root system (FI), or to one-half of the root system while the other half was dried, for 9 d. In the field, the plants were drip irrigated either to the whole root system near field capacity (FI) or using 70% water of FI to one side of the roots, and shifted to the other side every 5-10 d (PRD). PRD plants had a similar midday leaf water potential to that of FI, whereas in the GH their root water potential (Psi(r)) was significantly lowered after 5 d. Stomatal conductance (g(s)) was more sensitive to PRD than photosynthesis (A) particularly in the field, leading to greater intrinsic water use efficiency (WUE) (i.e. A/g(s)) in PRD than in FI plants on several days. In PRD, the xylem sap abscisic acid concentration ([ABA](xylem)) increased exponentially with decreasing Psi(r); and the relative [ABA](xylem) (PRD/FI) increased exponentially as the fraction of transpirable soil water (FTSW) in the drying side decreased. In the field, the leaf area index was slightly less in PRD than in FI treatment, while tuber biomass was similar for the two treatments. Compared with FI, PRD treatment saved 30% water and increased crop water use efficiency (WUE) by 59%. Restrictions on leaf area expansion and g(s) by PRD-induced ABA signals might have contributed to reduced water use and increased WUE.

The purpose of this study was to investigate whether combining plastic-covered ridge and furrow planting (RF) and supplemental irrigation based on measuring soil moisture (SIMSM) can increase the grain yield and water use efficiency (WUE) of wheat (Triticum aestivum L.) in irrigated fields of Loess Plateau, China. In 2016–2018, the experiment was conducted at Doukou experimental farm (34°36′ N, 108°52′ E) with two plant systems (RF and traditional planting (TF)) and three irrigation treatments (S1 and S2: SIMSM with a target relative soil water content of 85% and 100%, respectively). The results suggest that under the TF system, SIMSM decreased the grain yield and nitrogen utilization. The reason for this may be the local low precipitation. However, the combination of RF and S2 significantly increased the WUE, protein and wet gluten concentration in the grain. In addition, the grain yield of the RF plus S2 treatment was not significantly different than that of the traditional irrigation method. These results suggest that combining RF and SIMSM with a target relative soil water content of 100% is beneficial to the synergistic improvement of the wheat yield, the wheat quality, and the water and fertilizer use efficiency in irrigated fields on the Loess Plateau.

Exploring suitable split nitrogen management is essential for winter wheat production in the Huang-Huai-Hai Plain of China (HPC) under water-saving irrigation conditions, which can increase grain and protein yields by improving nitrogen translocation, metabolic enzyme activity and grain nitrogen accumulation.

缓/控释肥料是21世纪肥料发展的重要方向,对维护中国粮食安全、提高肥料利用率,实现农业生产与生态协调发展、节本增效和节能减排等方面均具有十分重要的意义。本文在总结缓/控释肥定义、作用机制、研究现状的基础上,阐述了缓/控释肥在农业生产中的应用效果和在应用及推广中存在的问题,提出了相应的对策和建议,展望了缓/控释肥的发展前景,以期为缓/控释肥的研究提供理论依据。

In this study, a novel multi-coated slow release compound fertilizer based on natural rubber (NR) was prepared and characterized. Firstly, NR was grafted with poly-acrylic acid by in-situ radical solution polymerization to synthesize poly-acrylic acid grafted natural rubber (NR-g-PAA), the reaction conditions were optimized to increase the water absorption properties of NR-g-PAA. Through a series of characterization and test, the structure, morphology, thermal properties and biodegradability of NR-g-PAA were determined. Subsequently, a multi-nutrient fertilizer core was fabricated with urea, KHPO, and attapulgite by pan granulation. Then the fertilizer core was coated by NR as the inner layer and NR-g-PAA as the outer layer. Meanwhile, the slow release behavior of the compound fertilizer in soil was also studied. Results showed that the maximum water absorbency of NR-g-PAA is 744.00 ± 14.38%. The release rate of N, P and K in 30 days for NR/NR-g-PAA coated fertilizer was about 54.35 ± 1.49%, 51.18 ± 2.15% and 44.37 ± 1.38%, respectively, showing that the nutrient element release can last for >30 days. Overall, the novel method introduced in this study can inform the development of NR based controlled release fertilizers.Copyright © 2020 Elsevier B.V. All rights reserved.

Conventional urea is lost due to its high water solubility and microbial transformations which results low agriculture productivity and environmental pollution. To solve these problems, rosin adduct-coated controlled release urea fertilizer (RA-CRUF) was prepared. Properties of rosin adduct with maleic anhydride were optimized during synthesis by varying the reaction temperature (120, 140 and 160 degrees C), reaction time (2, 4, 6 h) and coating repeats (3, 6, 9 cycles). Twenty different rosin adduct compositions were coated by spraying of rosin adduct on urea to prepare RA-CRUF. The best optimized response of urea release for RA-CRUF was 510.00 mg L-1 in water at optimized values of coating repeats (6.79 cycles), reaction time (4.71 h) and reaction temperature (137.39 degrees C). The Fourier Transformed Infrared Spectroscopy confirmed the reaction of rosin with maleic anhydride at wavenumber 1780 cm(-1) and 1856 cm(-1) correspond to carbonyl of cyclic anhydride group. The optical microscopy analysis of surface and cross view of RA-CRUF showed a high homogeneity of coating surface. The cumulative urea release was 41.76% and 47.23% for RA-CRUF compared 100% and 82.6% for conventional urea in clay loam texture and loam texture soils respectively. RA-CRUF effect on growth performance of maize plant showed healthy growth and increase in chlorophyll contents up to 51.11 mg g(-1) (clay loam texture soil) and 87.55 mg g(-1) (loam texture soil).

Rising world population is expected to increase the demand for nitrogen fertilizers to improve crop yield and ensure food security. With existing challenges on low nutrient use efficiency (NUE) of urea and its environmental concerns, controlled release fertilizers (CRFs) have become a potential solution by formulating them to synchronize nutrient release according to the requirement of plants. However, the most significant challenge that persists is the “tailing” effect, which reduces the economic benefits in terms of maximum fertilizer utilization. High materials cost is also a significant obstacle restraining the widespread application of CRF in agriculture. The first part of this review covers issues related to the application of conventional fertilizer and CRFs in general. In the subsequent sections, different raw materials utilized to form CRFs, focusing on inorganic and organic materials and synthetic and natural polymers alongside their physical and chemical preparation methods, are compared. Important factors affecting rate of release, mechanism of release and mathematical modelling approaches to predict nutrient release are also discussed. This review aims to provide a better overview of the developments regarding CRFs in the past ten years, and trends are identified and analyzed to provide an insight for future works in the field of agriculture.

【目的】通过对华北地区一年两熟种植模式下冬小麦生长季不同施肥和灌溉处理下土壤细菌群落的研究，揭示长期不同施肥和灌溉制度下土壤细菌数量、多样性和群落结构的变化规律。为科学施肥和灌溉，提高农田地力和维持土壤微生物多样性等提供依据。【方法】依托中国农业大学吴桥实验站，选取长期施肥和灌溉定位试验的6个处理冬小麦收获后耕层土壤为研究对象，分别为化肥+不灌溉（CI0）、化肥+拔节期灌溉（CI1）、化肥+拔节期灌溉+灌浆期灌溉（CI2）、有机肥+不灌溉（MI0）、有机肥+拔节期灌溉（MI1）和有机肥+拔节期灌溉+灌浆期灌溉（MI2）。借助荧光定量PCR技术和Illumina Miseq高通量测序平台，以16S rRNA基因为标靶，研究长期不同施肥和灌溉制度对土壤细菌数量、多样性和群落结构的影响，并分析细菌数量、多样性和群落结构变化与土壤理化性质的相关性。【结果】灌溉显著提高了土壤含水量和土壤pH，施有机肥比施化肥显著提高了土壤有机碳含量。不同处理细菌16S rRNA基因拷贝数为每克干土4.34×109—1.39×1010。灌溉显著提高了细菌数量，化肥和有机肥处理分别提高了1.17—1.60和0.76—1.93倍。多样性指数结果表明灌溉显著影响细菌群落α多样性指数，施肥对细菌群落α多样性指数的影响均不显著。门水平上，18个样品共获得39个类群，其中变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、绿弯菌门（Chloroflexi）、酸杆菌门（Acidobacteria）和拟杆菌门（Bacteroidetes）为优势类群，相对丰度共占77.22%—86.28%。不同处理间放线菌门（11.09%—27.01%）、拟杆菌门（5.45%—12.13%）和Saccharibacteria（2.41%—3.77%）的相对丰度差异显著。灌溉显著降低了放线菌门和Saccharibacteria的相对丰度，化肥和有机肥处理分别降低了36.48%—48.03%、22.17%—33.67%和15.21%—45.54%、13.40%—23.97%。层次聚类和主成分分析结果显示施肥和灌溉对细菌群落结构都产生影响，相同灌溉次数处理的细菌群落结构相似，而相同施肥处理间细菌群落结构差异较大，表明灌溉对细菌群落结构的影响强于施肥。此外，土壤含水量、土壤pH、全氮含量和有机碳含量与细菌数量、α多样性指数和群落结构存在一定的显著相关关系。【结论】灌溉显著改变了细菌数量、多样性和群落结构，施肥对细菌数量和群落结构的影响较小。土壤含水量和土壤pH是造成土壤细菌数量、多样性和群落结构差异的主要原因。

Bacterial community composition and diversity was studied in alpine tundra soils across a plant species and moisture gradient in 20 y-old experimental plots with four nutrient addition regimes (control, nitrogen (N), phosphorus (P) or both nutrients). Different bacterial communities inhabited different alpine meadows, reflecting differences in moisture, nutrients and plant species. Bacterial community alpha-diversity metrics were strongly correlated with plant richness and the production of forbs. After meadow type, N addition proved the strongest determinant of bacterial community structure. Structural Equation Modeling demonstrated that tundra bacterial community responses to N addition occur via changes in plant community composition and soil pH resulting from N inputs, thus disentangling the influence of direct (resource availability) vs. indirect (changes in plant community structure and soil pH) N effects that have remained unexplored in past work examining bacterial responses to long-term N inputs in these vulnerable environments. Across meadow types, the relative influence of these indirect N effects on bacterial community structure varied. In explicitly evaluating the relative importance of direct and indirect effects of long-term N addition on bacterial communities, this study provides new mechanistic understandings of the interaction between plant and microbial community responses to N inputs amidst environmental change.

Despite recognition of the importance of soil bacteria to terrestrial ecosystem functioning there is little consensus on the factors regulating belowground biodiversity. Here we present a multi-scale spatial assessment of soil bacterial community profiles across Great Britain (> 1000 soil cores), and show the first landscape scale map of bacterial distributions across a nation. Bacterial diversity and community dissimilarities, assessed using terminal restriction fragment length polymorphism, were most strongly related to soil pH providing a large-scale confirmation of the role of pH in structuring bacterial taxa. However, while α diversity was positively related to pH, the converse was true for β diversity (between sample variance in α diversity). β diversity was found to be greatest in acidic soils, corresponding with greater environmental heterogeneity. Analyses of clone libraries revealed the pH effects were predominantly manifest at the level of broad bacterial taxonomic groups, with acidic soils being dominated by few taxa (notably the group 1 Acidobacteria and Alphaproteobacteria). We also noted significant correlations between bacterial communities and most other measured environmental variables (soil chemistry, aboveground features and climatic variables), together with significant spatial correlations at close distances. In particular, bacterial and plant communities were closely related signifying no strong evidence that soil bacteria are driven by different ecological processes to those governing higher organisms. We conclude that broad scale surveys are useful in identifying distinct soil biomes comprising reproducible communities of dominant taxa. Together these results provide a baseline ecological framework with which to pursue future research on both soil microbial function, and more explicit biome based assessments of the local ecological drivers of bacterial biodiversity.© 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Biochar (BC) is a material that finds many applications in agriculture and environmental activities. The aim of the study was to define the influence of biochar produced from various organic materials: mellow compost (MC), stabilized municipal sewage sludge (MSS), pine sawdust (PS), sycamore sawdust (SS) and oak leaves (OL) on soil enzyme activity, as well as its relations with carbon and nitrogen content. After a 60-day incubation of soil and BC, the activity of dehydrogenases (DEH), catalase (CAT), alkaline (AlP) and acid (AcP) phosphatases was investigated. The basic parameters of soil were also determined: TOC, TN, DOM, pH in H2O, available phosphorus (AP). The highest AP content was obtained in the S + MSS, S + OL and S + MC variants. Enzyme activity was highest in soil with MSS BC, regardless of incubation time. After 60 days, the activity of soil enzymes was inhibited. The obtained results indicate that the response of enzymatic activity to biochar depends on the feedstock material and the incubation time. When using BC as an exogenous matter, it is necessary to determine the TOC/TN ratio. For the very wide range of this parameter, supplemental nitrogen fertilization or mixtures of different biochars should be applied.

\n\nThis paper reviews the interactions between water and nitrogen from physiological, agronomic, economic, breeding and modelling perspectives. Our primary focus is wheat; we consider forage crops, sorghum and legumes where relevant aspects of water–nitrogen interactions have been advanced.\nFrom a physiological perspective, we ask: How does nitrogen deficit influence the water economy of the crop? How does water deficit influence the nitrogen economy of the crop? How do combined water and nitrogen deficit affect crop growth and yield? We emphasise synergies, and the nitrogen-driven trade-off between the efficiency in the use of water and nitrogen. The concept of nitrogen–water co-limitation is discussed briefly.\nFrom agronomic and economic perspectives, the need to match supply of nitrogen and water is recognised, but this remains a challenge in dryland systems with uncertain rainfall. Under-fertilisation commonly causes gaps between actual and water-limited potential yield. We discuss risk aversion and the role of seasonal rainfall forecasts to manage risk.\nFrom a breeding perspective, we ask how selection for yield has changed crop traits relating to water and nitrogen. Changes in nitrogen traits are more common and profound than changes in water-related traits. Comparison of shifts in the wheat phenotype in Australia, UK, Argentina and Italy suggests that improving yield per unit nitrogen uptake is straightforward; it requires selection for yield and allowing grain protein concentration to drift unchecked. A more interesting proposition is to increase nitrogen uptake to match yield gains and conserve protein in grain. Increased stomatal conductance is a conspicuous response to selection for yield which partially conflicts with the perception that reduced conductance at high vapour pressure deficit is required to increase water- use efficiency; but high stomatal conductance at high vapour pressure deficit may be adaptive for thermal stress.\nFrom a modelling perspective, water and nitrogen are linked in multiple ways. In crops where water limits growth, reduced biomass reduces nitrogen demand. Reciprocally, nitrogen limitation during crop expansion reduces leaf area index and increases the soil evaporation : transpiration ratio. Water–nitrogen interactions are also captured in the water-driven uptake of nitrogen by mass flow and diffusion and in the water-driven processes of nitrogen in soil (e.g. mineralisation).\nThe paper concludes with suggestions for future research on water-nitrogen interactions.\n

于2012—2014年两个小麦生长季，以全生育期不灌水（W₀）为对照，设置3个测墒补灌处理，即拔节和开花期使0～140 cm土层土壤平均相对含水量分别为65%(W₁)、70%(W₂)和75%(W_3)，研究其对土壤水利用、小麦氮素积累转运和土壤硝态氮分布及籽粒产量的影响.结果表明： W₂处理土壤贮水消耗量及占总耗水量的比例和灌溉水占总耗水量的比例较高，且吸收利用100～140 cm土层土壤贮水量较高.开花期营养器官氮素积累量及开花后氮素积累量均为W₂、W₃＞W₁＞W₀，成熟期营养器官氮素积累量为W₃＞W₂＞W₁＞W₀，营养器官氮素向籽粒中的转移量和成熟期籽粒氮素积累量均为W₂＞W₃＞W₁＞W₀.成熟期0～60 cm土层硝态氮含量表现为W₀＞W₁＞W₂＞W_3，80～140 cm土层为W₃显著高于其他处理，140～200 cm土层各处理间无显著差异.W₂处理的籽粒产量、水分利用效率、氮素吸收效率及氮肥偏生产力均最高.在本试验条件下，综合考虑籽粒产量、水分利用效率、氮素吸收效率及土壤硝态氮的淋溶，W₂处理是高产节水生态安全的最佳灌溉处理.

We conducted a two-year field experiment on winter wheat (Triticum aestivum L.) from 2016–2018 to compare the effects of reducing nitrogen application rate in spring under three irrigation methods on grain yield (GY), water and nitrogen use efficiency in the North China Plain (NCP). Across the two years, GY of conventional irrigation (CI), micro-sprinkling irrigation (SI) and drip irrigation (DI) decreased by 6.35%, 9.84% and 6.83%, respectively, in the reduced nitrogen application rate (N45) than the recommended nitrogen application rate (N90). However, micro-irrigation (SI and DI) significantly increased GY relative to CI under the same nitrogen application rate, and no significant difference was observed in GY between SI and DI under N45, while SI obtained the highest GY under N90. The difference among different treatments in GY was mainly due to the variation in grain weight. The seasonal evapotranspiration (ET) in N45 was decreased more significantly than N90, and there was no significantly difference in ET among different irrigation methods under N45, but micro-irrigation significantly decreased the ET relative to CI under N90. Micro-irrigation significantly improved water use efficiency (WUE) compared to CI at the same nitrogen application rate. Under N45, compared with CI, WUE in SI and DI increased by 9.09% and 4.70%, respectively; however, the WUE increased by 15.9% and 7.23%, respectively, under N90. Reducing nitrogen application rate did not have a significant impact on WUE under CI, but it did have a substantial negative impact on SI and DI. Nitrogen accumulation in wheat plants at maturity (NAM) in N45 deceased significantly compared with N90 under the same irrigation method. Compared with CI under the same nitrogen application rate, micro-irrigation treatments significantly increased NAM, while SI was the largest. In comparison to N90, under three irrigation methods, N45 significantly increased nitrogen fertilizer use efficiency (NfUE). The highest NfUE was attained in SI, followed by DI, while CI was the lowest. Moreover, N45 significantly decreased soil NO3−-N accumulation (SNC) in three irrigation methods, and micro-irrigation significantly decreased the SNC in deep soil layers compared with CI when nitrogen is applied at the same level. Overall, micro-irrigation with a reduced nitrogen application rate in spring can achieve a relatively higher production of winter wheat while increasing the use efficiency of water and nitrogen and reducing soil NO3−-N leaching into deep soil layers in the NCP.

经过2年滴灌小麦大田试验，研究不同灌水定额和不同施氮水平，这2个试验因素下小麦土壤硝态氮运移、氮平衡及水氮利用效率的变化情况。结果表明：2年内小麦各生育阶段耗水量和耗水模数均表现为抽穗扬花期=灌浆期>拔节孕穗期>分蘖期=成熟期>出苗期。在0～100 cm各处理在各生育期的硝态氮含量随土壤深度呈现减小趋势，表现出“上高下低”的趋势；其中土壤硝态氮含量均在0～20 cm出现最大值。在0～60 cm硝态氮含量与施氮量成正比，各处理下各生育期在80～100 cm土层的硝态氮变幅不大。当施氮量超过248 kg/hm²再增加施氮量，籽粒产量增加不明显，甚至有降低趋势，且影响籽粒吸收氮素。当灌水量大于390 mm，有很大部分水量因深层渗漏而损失，大量硝态氮也随着水分的渗漏而淋溶。此试验氮素损失中，淋溶的损失是主要途径，大部分硝态氮随水分渗漏被淋洗至60 cm以下的深层土壤中，且随施氮量的增加硝态氮淋溶更为严重。经过2年试验表明，施肥量在179～248 kg/hm²，灌水定额为45 mm，灌溉定额为390～405 mm的水氮组合，其表观损失较低，水氮利用效率较高，是适宜干旱地区多砾石砂土条件下的最佳水肥组合。

A large body of literature is available on wound healing in humans. Nonetheless, a standardized ex vivo wound model without disruption of the dermal compartment has not been put forward with compelling justification. Here, we present a novel wound model based on application of negative pressure and its effects for epidermal regeneration and immune cell behaviour. Importantly, the basement membrane remained intact after blister roof removal and keratinocytes were absent in the wounded area. Upon six days of culture, the wound was covered with one to three-cell thick K14+Ki67+ keratinocyte layers, indicating that proliferation and migration were involved in wound closure. After eight to twelve days, a multi-layered epidermis was formed expressing epidermal differentiation markers (K10, filaggrin, DSG-1, CDSN). Investigations about immune cell-specific manners revealed more T cells in the blister roof epidermis compared to normal epidermis. We identified several cell populations in blister roof epidermis and suction blister fluid that are absent in normal epidermis which correlated with their decrease in the dermis, indicating a dermal efflux upon negative pressure. Together, our model recapitulates the main features of epithelial wound regeneration, and can be applied for testing wound healing therapies and investigating underlying mechanisms.