Residual plastic film decreases crop yield and water use efficiency through direct negative effects on soil physicochemical properties and root growth.

Film mulching has been extensively used to improve agricultural production in arid regions of China. However, without sufficient mulch film recovery, large amounts of residual film accumulated in the farmland, which would affect crop yield and water use efficiency (WUE). In order to comprehensively analyze the effects of residual film on crop yield and WUE, and clarify its influencing mechanism, present study adopted a meta-analysis to systematically evaluate the impacts of residual film on soil physicochemical properties, crop root growth, yield, and WUE.

A comparative study of various drought indices at different timescales and over different record lengths in the arid area of northwest China.

Although many drought indices have been developed to monitor drought conditions, their applicability differs across climatic regions, which results in different characteristics of drought index assessments at different timescales and over different record lengths. Therefore, the applicability of precipitation-based and precipitation-evapotranspiration/temperature-based drought indices was examined in this study using the Generalized Extreme Value Index (GEVI), Homogeneity Index (HI) of precipitation and temperature, K index (K), precipitation anomaly percentage (Pa), Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Precipitation Index (SPI), and China-Z Index (CZI) over different record lengths and at a timescale range of 1-24 months. In addition, the results that were obtained using these indices were compared with the Self-Calibrating Palmer Drought Severity Index (scPDSI).

Evolution of drought characteristics and propagation from meteorological to agricultural drought under the influences of climate change and human activities.

Understanding the propagation of agricultural droughts (AD) is important to comprehensively assess drought events and develop early warning systems. The present study aims to assess the impacts of climate change and human activities on drought characteristics and propagation from meteorological drought (MD) to AD in the Yellow River Basin (YRB) over the 1950-2021 period using the Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized Soil Moisture Index (SSMI). In total, the YRB was classified into three groups of catchments for spring wheat and four groups of catchments for winter wheat based on different human influence degrees (HId).

The role of root size and root efficiency in grain production, and water-and nitrogen-use efficiency in wheat.

Background: The root system is the major plant organ involved in water and nutrient acquisition, influencing plant growth and productivity. However, the relative importance of root size and uptake efficiency remains undetermined. A pot experiment was conducted using two wheat varieties with different root sizes to evaluate their capacity for water and nitrogen (N) uptake and their effects on grain production, water-use efficiency (WUE), and N-use efficiency (NUE) under two water treatments combined with three N levels.

Root pruning improves maize water-use efficiency by root water absorption.

Root systems are an important component of plants that impact crop water-use efficiency (WUE) and yield. This study examined the effects of root pruning on maize yield, WUE, and water uptake under pot and hydroponic conditions. The pot experiment showed that root pruning significantly decreased root/shoot ratio.

Carbon balance and controlling factors in a summer maize agroecosystem in the Guanzhong Plain, China.

Background: Quantifying the carbon balance of agroecosystems and clarifying the factors controlling it are essential for estimating the regional carbon cycle and global carbon balance.

Results: Based on the eddy covariance (EC) technique and soil respiration observations during the 2017 and 2019 summer maize growing seasons, this study analyzed the carbon balance and revealed the factors controlling carbon fluxes in the summer maize agroecosystem. Green leaf area index was the most important factor affecting net ecosystem exchange (NEE), total primary productivity, and total ecosystem respiration (TER) in the rapid development stage during the growing season, followed by soil water content.

[Effects of Straw Returning on Soil Ammonia Volatilization Under Different Production Conditions Based on Meta-analysis].

In order to explore the response of Chinese farmland soil ammonia volatilization to straw returning to the field under different production conditions, this study used no straw returning as a control. Through the collection of published literature test data, the Meta-analysis method was used to quantitatively study the effects of different natural factors and, under the conditions of farmland management measures, the effect of returning straw to the field on the emission reduction of soil ammonia volatilization. At the same time, through partial correlation analysis, the main influencing factors of ammonia volatilization under the condition of returning straw to the field were found, and the ammonia volatilization was quantified.

Photosynthesis of winter wheat effectively reflected multiple physiological responses under short-term drought-rewatering conditions.

Background: Based on the interrelationship among photosynthesis (Pn), water consumption and drought resistance physiology under water changes, this study aimed to explore whether easily measured Pn could be used to reflect the physiological state of winter wheat and soil moisture. The study was a greenhouse pot experiment, with three growth periods and four gradients of moisture.

Results: The instantaneous water use efficiency of wheat improved significantly under short-term regulated deficit irrigation conditions.

Effects of growth-stage-based limited irrigation management on the growth, yields, and radiation utilization efficiency of winter wheat in northwest China.

Background: As a common abiotic stress, water deficit stress has a negative impact on the growth and yield of many field crops worldwide. In this study, a mobile rain shelter experiment was conducted in the 2017-2019 growing seasons to investigate the effects of water stress at different growth stages on various traits in winter wheat, including plant height, leaf area index (LAI), biomass, radiation use efficiency (RUE), leaf photosynthetic traits, and yield.

Results: Three different limited irrigation treatments were applied: no irrigation at all stages (T0), no irrigation at the reviving and jointing stages (T1), and no irrigation at the heading and grain-filling stages (T2).

Propagation of meteorological to hydrological drought for different climate regions in China.

Drought can lead to considerable agricultural, ecological, and societal damage. Improving our understanding of the propagation relationship between meteorological and hydrological drought is necessary to lessen drought impacts. The different drought responses and underlying mechanisms among different climate types are not yet sufficiently understood.

[Effect of Water-Fertilizer-Gas Coupling on Soil NO Emission and Yield in Greenhouse Tomato].

To reveal the effect of water, fertilizer, and gas coupling on soil NO emissions in greenhouse tomato soil and suggest appropriate measures for increasing yield and reducing NO emissions, static chamber-gas chromatography was used to study the effects of soil NO emissions. The variation laws of soil temperature, water-filled pore space (WFPS), NO-N content, and O content and the influence mechanism of NO emission under the condition of water-fertilizer-gas coupling were analyzed. Aerated conditions comprised two water levels, 0.

Spatial and temporal effects of drought on Chinese vegetation under different coverage levels.

Land surface vegetation dynamics are strongly affected by drought. Thus, understanding the responses of vegetation to drought can inform measures to increase biome stability. In this study, the normalized difference vegetation index (NDVI) and the Palmer drought severity index (PDSI) were utilized to investigate the relationship between vegetation activity and drought across different drought regions and ecological community types from 1982 to 2015.

Soil CO emissions from summer maize fields under deficit irrigation.

Irrigation practice is one of the main factors affecting soil carbon dioxide (CO) emission from croplands and therefore on global warming. As a water-saving irrigation practice, the deficit irrigation has been widely used in summer maize fields and is expected to adapt to the shortage of water resources in Northwest China. In this study, we examined the impacts of deficit irrigation practices on soil CO emissions through a plot experiment with different irrigation regimes in a summer maize field in Northwest China.

[Effects of Water Deficit on Greenhouse Gas Emission in Wheat Field in Different Periods].

Field experiments and static chamber-gas chromatography analysis were conducted in 2016-2017 to study the effects of deficit irrigation on CO, NO, and CH emissions from soils of winter wheat fields and to optimize irrigation management measures in the Guanzhong Plain of China. Three irrigation levels (full irrigation, 100%; medium water deficit, 80%; and severe water deficit, 60%) were set during the three important growth periods of winter wheat (overwintering, jointing to heading, and heading to filling periods), with 6 distinct treatments (CK, T1, T2, T3, T4, T5, in which CK treatment is full irrigation, and others are water deficit treatments). The dynamic characteristics of the emission fluxes of the three greenhouse gases were described.

Deficit irrigation effectively reduces soil carbon dioxide emissions from wheat fields in Northwest China.

Background: An irrigation regime is an important factor in regulating soil CO emissions from wheat fields. Deficit irrigation can be applied easily in the fields and has been implemented in northwest China. Previous studies have mainly focused on the effects of deficit irrigation on crop yield and quality.

Experiment and simulation of supersaturated total dissolved gas dissipation: Focus on the effect of confluence types.

Total dissolved gas supersaturation (TDGS) downstream caused by spill discharge from high dams can easily cause fish to suffer from gas bubble disease (GBD). One potential approach to mitigate the impact of TDGS is at the confluence of a downstream tributary, where the introduction of low-TDG water might provide refuge space for fish. In this study, we carried out a series of flume experimental cases and established a three-dimensional TDGS model at confluences.

Capability of crop water content for revealing variability of winter wheat grain yield and soil moisture under limited irrigation.

Winter wheat (Triticum aestivum L.) is a major crop in the Guanzhong Plain, China. Understanding its water status is important for irrigation planning.

Pattern of Protein Expression in Developing Wheat Grains Identified through Proteomic Analysis.

Grain development is one of the biological processes, which contributes to the final grain yield. To understand the molecular changes taking place during the early grain development, we profiled proteomes of two common wheat cultivars P271 and Chinese Spring (CS) with large and small grains, respectively at three grain developmental stages (4, 8, and 12 days post anthesis). An iTRAQ (isobaric tags for relative and absolute quantitation) based proteomics approach was used for this purpose.

[Application of stationary wavelet transformation to winter wheat SPAD hyperspectral monitoring].

By field trials, the canopy hyperspectral reflectance and chlorophyll content (SPAD) for winter wheat during 2010 and 2011 growth periods were measured by the ASD portable spectrometer and portable chlorophyll meter SPAD-502, respectively. The canopy spectral characteristics of different SPAD values were analyzed in different growth periods. The winter wheat SPAD estimation models based on normalized difference vegetation index (NDVI), ratio vegetation index (RVI) and wavelet energy coefficients were established in different growth periods.

[Estimation of Fraction of Absorbed Photosynthetically Active Radiation for Winter Wheat Based on Hyperspectral Characteristic Parameters].

Estimating fraction of absorbed photosynthetically active radiation (FPAR) precisely has great importance for detecting vegetation water content, energy and carbon cycle balance. Based on this, ASD FieldSpec 3 and SunScan canopy analyzer were applied to measure the canopy spectral reflectance and photosynthetically active radiation over whole growth stage of winter wheat. Canopy reflectance spectral data was used to build up 24 hyperspectral characteristic parameters and the correlation between FPAR and different spectral characteristic parameters were analyzed to establish the estimation model of FPAR for winter wheat.

[Effects of water deficit at seedling stage on maize root development and anatomical structure].

A pot experiment was conducted to study the effects of water deficit at seedling stage on the root development and anatomical structure of maize. Four treatments were installed, i.e.

Experimental study of colonic anastomosis with a degradable stent in a porcine model.

Background: Intestinal anastomosis is a major technical component of gastrointestinal procedures. We have developed a new procedure of colonic anastomosis with a degradable stent. This article evaluates this procedure.

[Calculation of crop evapotranspiration in greenhouse].

Based on Penman-Monteith equation, a simplified formula for calculating the crop evapotranspiration in greenhouse was deduced by introducing the parameter of crop canopy height and modifying the item of aerodynamics related to wind velocity. The deductive procedure was analyzed theoretically, and the formula was validated with meteorological data. The results showed that the modified Penman-Monteith equation had a higher precision of prediction, with a relative deviation of 4.

[A comprehensive quantitative assessment model for arid area's basin water-soil environment quality].

The existing assessment models for water-soil environment quality are usually established on the relationships between assessment indicators and their assessment criteria. Such kinds of models are varied with regional scale, and always need a mass of calculation work. This paper tried to find a general assessment model based on a given water-soil quality assessment criteria.