Increased Soil Water Research Articles

Counseling on the Utilization of Fruit Waste as an Alternative to Liquid Organic Fertilizer in the Tangga Takat Village, District of Seberang Ulu II, Palembang City

Fruit waste is considered a waste material that cannot be used anymore, so that its existence has not been properly utilized by the community. Even though fruit waste can still be reused as material for making liquid organic fertilizer (POC). Liquid organic fertilizer made from fruit waste is a type of fertilizer that has many benefits, both for plants and the environment. Liquid organic fertilizer is environmentally friendly and safe for humans and animals. Liquid organic fertilizer also improves soil structure, increases soil fertility, and increases soil water holding capacity, besides being environmentally friendly, reduces soil pollution, and protects soil health. This community service activity aims to provide knowledge and skills to the community about reusing fruit waste by processing it into liquid organic fertilizer (POC). The location of the community service was carried out at the Tangga Takat village head office, Seberang Ulu II District, Palembang City, on February 24 2022. The method used was counseling and training for the community about processing fruit waste into liquid organic fertilizer. This activity brought together 25 enthusiastic participants in a discussion and question and answer session during the training. The results of this community service show that the method of community service in the form of consultation, training and question and answer is very suitable for motivating the community in processing fruit waste into liquid organic fertilizer.

Interannual fires as a source for subarctic summer decadal climate variability mediated by permafrost thawing

Climate model simulations run under the Coupled Model Intercomparison Project Phase 6 (CMIP6) use an inhomogeneous biomass burning aerosol (BBA) emission dataset, which exhibits pronounced interannual variability from 1997–2014 due to the infusion of satellite data. Using the Community Earth System Model version 2 Large Ensemble (CESM2-LE) with original and smoothed CMIP6 BBA forcings, we show that the CMIP6 data inhomogeneity causes spurious decadal subarctic land warming. During years with reduced aerosol concentrations, increased solar radiation can trigger abrupt subarctic permafrost thawing, increased soil water drainage, upper soil drying, and subsequent surface warming. This slow process, which is further amplified by nonlinear cloud-aerosol interactions, cannot be completely offset during years of increased aerosol fluxes, thereby reddening surface temperature spectra in response to large-amplitude interannual aerosol forcing. More generally, our CESM2 experiments identify a pathway for generating decadal variability in high latitudes, involving interannual shortwave forcing and slow nonlinear soil responses.

Thinning effectively mitigates the decline of aging Mongolian pine plantations by alleviating drought stress and enhancing plant carbon balance

Intensifying drought around the globe poses strong challenges to the growth and survival of trees, emphasizing the urgency of understanding the physiological mechanisms of drought-induced tree decline and mortality and the necessity of using silvicultural approaches to mitigate drought effects on tree growth. We experimentally explored whether thinning enhances tree growth vigor and drought resilience in early aging Mongolian pine (Pinus sylvestris var. mongolica Litv.) plantations in a water-limited area of Northeast China using dendrochronological methods. Meanwhile, we compared plant hydraulic traits, water relations, and non-structural carbohydrate concentrations between trees growing in the thinned and un-thinned stands with the aim of unraveling the physiological mechanisms underlying the density effects on tree growth performance. The results showed that basal area increments of Mongolian pine trees in the high-density plantations started to decline continuously at tree cambium age of around 15 years over about a decade, while thinning effectively reversed their growth decline. Trees in thinned stands exhibited significantly higher predawn leaf water potentials, higher stem hydraulic conductivities, and larger carbon reserves than trees in un-thinned stands. Although trees growing in high-density stands maintained as low risks of xylem hydraulic dysfunction as trees growing in low-density stands, that was at the cost of substantially reducing tree crown size through branch mortality that unavoidably undermined their carbon balance at the whole-plant level. Consistently, trees growing in the thinned low-density stands showed significantly higher levels of non-structural carbohydrate reserve in stems and enhanced growth resilience to extreme drought than trees growing in the high-density reference stands. Our results suggest that thinning can effectively enhance xylem hydraulic transport efficiency and reduce the risk of carbon imbalance by increasing soil water availability and hence mitigates the early aging of Mongolian pine plantations in water-limited environments.

Assessing hydrological sensitivity to future climate change over the Canadian southern boreal forest

This study develops a physically based hydrological process model using the Cold Region Hydrological Modelling (CRHM) platform to simulate the water budget storages and fluxes over the Canadian southern boreal forest (SBF). Evaluation of the CRHM-based model in a well-gauged SBF basin, White Gull Creek (WGC), Saskatchewan, Canada, indicated quite good performance in reproducing historical observations of streamflow, snow water equivalent (SWE), evapotranspiration (ET) and soil moisture without parameter calibration from streamflow. The entire SBF was then evenly divided into 2243 virtual basins, each of which was structured and parameterized with the same land cover, soil and hydrological parameters as the WGC basin, but with local latitude and topography in order to examine the sensitivity of governing hydrological processes to future climate variability and perturbation. Hydrological sensitivity in the virtual basins was assessed by examining the differences between hydrological simulations driven by 4-km gridded convection-permitting Weather Research and Forecasting (WRF) outputs in the current period (ctrl, 2001–2013) and a Pseudo Global Warming period (pgw, 2087–2099). The WRF simulation in the pgw period was forced by a perturbation of the same boundary conditions from ERA reanalysis data as for the ctrl period, and the perturbation was based on the ensemble-mean of projected changes from the CMIP5 RCP 8.5 emission scenario. Results showed that temperature would increase by 4.5℃ to 7℃ over the SBF but increases in annual precipitation of 15–24% would more than compensate for the effects of warming on runoff generation and result in greater streamflow volumes. Annual streamflow volumes would increase by 64 mm (35%) and 95 mm (16%) in the west and east, and by 48 mm (17%) in the central SBF. Annual snowfall and maximum SWE would decrease by 89–109 mm (∼29%) in the east, 3–8 mm (∼6%) in the west, and 31–50 mm (∼20%) in the central SBF. Annual mean soil moisture storage would decrease by 54–56 mm (27%) in the west and central, and by only 37 mm (14%) in the east SBF. Decreases in soil moisture would be caused by reduced soil freezing and enhanced thawing under future warming which would increase soil water loss from ET, subsurface runoff and percolation into groundwater storage. The larger sensitivity of streamflow and snow processes in the east SBF is partly due to the wetter climate and the larger increase in annual precipitation, the later also buffered the sensitivity of soil moisture to warming. These results show that the SBF would switch to a higher water yield region, dominated by rainfall-runoff fed streamflow over a longer snow-free season, and provide first-order guidance for sustainable water management of the SBF in the future.

Impact of Nanoparticles from Ball-Milled Date Palm Biochar on the Hydro-Physical Characteristics of Sandy Soils

Water management in sandy soils (Typic Torripsamments) is crucial in sustaining agricultural production. The main goal of this research was to assess the impact of date palm biochar on the physical properties of sandy soil with different particle sizes of biochar (macro and nano). For nano-biochar preparation, stick chips were established into a tubular furnace with nitrogen air and heated to 400–450 °C, which was accompanied by a holding period of 4 h. The ball-milled biochar was inclined via ball grinding in a model number PQN2.110 planetary mill and within jars (500 mL), and the biochar-to-sphere mass ratio was 1:100. The sphere-milling apparatus was processed at a speed of 300 rpm for 13 h. Laboratory experiments were carried out at one rate—biochar 5%—and three depths (0.0–5, 5–10, and 10–15 cm). Applying macro-biochar reduced cumulative evaporation compared to the control by 4%, 24%, and 14% for the macro-biochar particles at soil depths. In contrast, biochar reduced cumulative evaporation compared to the control by 8%, 12%, and 4% for the nano-biochar particles at the soil depths tested. Adding biochar significantly raised the amount of retained water, with the highest level recorded at the 5–10 cm depth, while the variations were significantly lower between the macro and nano-biochar when in the direction of the soil surface (0–5 cm), indicating the significance of mixing biochar with the top 10 cm of the soil to increase its ability to reduce evaporation and increase the amount of water retained in the soils. It could be concluded that applying at the top of the coarse soil can positively impact soil hydro-physical properties and increase soil water availability to plants.

Salicylic Acid and Pyraclostrobin Can Mitigate Salinity Stress and Improve Anti-Oxidative Enzyme Activities, Photosynthesis, and Soybean Production under Saline–Alkali Regions

Soybean is a widespread crop in semi-arid regions of China, where soil salinity often increases and has a significant harmful impact on production, which will be a huge challenge in the coming years. Salicylic acid (SA) and pyraclostrobin are strobilurin-based bactericides (PBF). Under rainfall-harvesting conditions in covered ridges, the exogenous application of SA and PBF can improve the growth performance of soybeans, thereby reducing the adverse effects of soil salinity. The objectives of this research are to evaluate the potential effects of SA and PBF on soybean growth in two different regions, Harbin and Daqing. A two-year study was performed with the following four treatments: HCK: Harbin location with control; SA1+PBF1: salicylic acid (5 mL L−1) with pyraclostrobin (3 mL L−1); SA2+PBF2: salicylic acid (10 mL L−1) with pyraclostrobin (6 mL L−1); DCK: Daqing location with control. The results showed that in the Harbin region, SA2+PBF2 treatment reduced the evapotranspiration (ET) rate, increased soil water storage (SWS) during branching and flowering stages, and achieved a maximum photosynthesis rate. Moreover, this improvement is due to the reduction of MDA and oxidative damage in soybean at various growth stages. At different growth stages, the treatment of Harbin soybean with SA2+PBF2 significantly increased the activity of CAT, POD, SOD, and SP, while the content of MDA, H2O2, and O2− also decreased significantly. In the treatment of SA2+PBF2 in Harbin, the scavenging ability of free H2O2 and O2− was higher, and the activity of antioxidant enzymes was better. This was due to a worse level of lipid-peroxidation which successfully protected the photosynthesis mechanism and considerably increased water use efficiency (WUE) (46.3%) and grain yield (57.5%). Therefore, using plastic mulch with SA2+PBF2 treatment can be an effective water-saving management strategy, improving anti-oxidant enzyme activities, photosynthesis, and soybean production.

Border row effects on the distribution of root and soil resources in maize–soybean strip intercropping systems

The cause of yield increase in crop strip intercropping is often inseparable from the boundary effect, and the distribution of roots and nutrients in the below-ground has an important influence on plant growth. However, previous studies on the boundary effect of intercropping have mainly focused on the above-ground part, and the state of the below-ground part is unknown. So we investigated the distribution of roots, water and NO3—N in the belowground part of the border row(adjacent rows of two crops in intercropping) in a maize and soybean strip intercropping system at different plant growth stage. There were three treatments in this experiment: maize monocrop, soybean monocrop and maize–soybean intercrop (four rows of maize and four rows of soybean). The distribution of maize roots extended beyond and below the border with the soybean rows and was concentrated in the 0–20 cm soil layer, while the growth of intercropped soybean roots was inhibited by maize. Intercropping increased the soil water content (SWC) in soybean rows at the podding stage and in maize rows at the drumming stage, and intercropping had a greatly effect on SWC of the system as a whole. Intercropping also increased the soil NO3—N content (SNC) in the intercropping system at the podding stage and had a negative effect at the drumming stage, and the effect of SNC in the intercropped maize rows was wider, while for intercropped soybean it was limited to the adjacent rows of soybean. The effect of intercropping on SWC and SNC occurred mainly in the 20–60 cm soil layer. Intercropping increased the grain weight of maize and decreased the grain weight and pods per soybean plant. Overall, the root system of maize in the border rows in the intercropping pattern extended into the soybean rows, intercropping increased soil water and soil nitrate-N levels in maize during the critical yield formation period, resulting in increased maize yields, while soybean was negatively affected in the intercropping pattern resulting in reduced yields, and we have calculated that intercropping maize and soybean has advantages in terms of land productivity and water use.

Cultivation and Nitrogen Management Practices Effect on Soil Carbon Fractions, Greenhouse Gas Emissions, and Maize Production under Dry-Land Farming System

Effective nitrogen management practices by using two cultivation techniques can improve corn productivity and soil carbon components such as soil carbon storage, microbial biomass carbon (MBC), carbon management index (CMI), and water-soluble carbon (WSC). It is essential to ensure the long-term protection of dry-land agricultural systems. However, excessive application of nitrogen fertilizer reduces the efficiency of nitrogen use and also leads to increased greenhouse gas emissions from farming soil and several other ecological problems. Therefore, we conducted field trials under two planting methods during 2019–2020: P: plastic mulching ridges; F: traditional flat planting with nitrogen management practices, i.e., 0: no nitrogen fertilizer; FN: a common nitrogen fertilizer rate for farmers of 290 kg ha−1; ON: optimal nitrogen application rate of 230 kg ha−1; ON75%+DCD: 25% reduction in optimal nitrogen fertilizer rate + dicyandiamide; ON75%+NC: 25% reduction in optimal nitrogen rate + nano-carbon. The results showed that compared to other treatments, the PON75%+DCD treatment significantly increased soil water storage, water use efficiency (WUE), and nitrogen use efficiency (NUE) because total evapotranspiration (ET) and GHG were reduced. Under the PON75%+DCD or PON75%+NC, the soil carbon storage significantly (50% or 47%) increased. The PON75%+DCD treatment is more effective in improving MBC, CMI, and WSC, although it increases gaseous carbon emissions more than all other treatments. Compared with FFN, under the PON75%+DCD treatment, the overall CH4, N2O, and CO2 emissions are all reduced. Under the PON75%+DCD treatment, the area scale GWP (52.7%), yield scale GWP (90.3%), biomass yield (22.7%), WUE (42.6%), NUE (80.0%), and grain yield (32.1%) significantly increased compared with FFN, which might offset the negative ecological impacts connected with climate change. The PON75%+DCD treatment can have obvious benefits in terms of increasing yield and reducing emissions. It can be recommended to ensure future food security and optimal planting and nitrogen management practices in response to climate change.

Application of Organic Fertilizers Optimizes Water Consumption Characteristics and Improves Seed Yield of Oilseed Flax in Semi-Arid Areas of the Loess Plateau

Organic fertilizers are an important source of nutrients for improving farmland fertility. To explore high-yield, efficient and green production technology for oilseed flax in dryland agricultural areas, a field split plot experiment was conducted in the semi-arid area of the Loess Plateau in northwest China from April to August in 2020 and 2021. The study compared and analyzed the effects of different nutrient sources and their application rates on water consumption characteristics, grain yield and water use efficiency of oilseed flax. The main plots were fertilizer types (sheep manure, chicken manure and chemical fertilizer), while the subplots were fertilizer application rates (sheep manure: S1-12,500 kg·hm−2 and S2-25,000 kg·hm−2; chicken manure: C1-5800 kg·hm−2 and C2-11,600 kg·hm−2; chemical fertilizer: F1-N 112.5 kg·hm−2, P 75 kg·hm−2, K 67.5 kg·hm−2 and F2-N 225 kg·hm−2, P2O5 150 kg·hm−2, K2O 135 kg·hm−2). The results showed that compared with chemical fertilizers, organic fertilizers significantly increased the soil water storage capacity of the 0–160 cm soil layer during the whole growth period of oilseed flax and significantly reduced water consumption. During two growing seasons, the application of 25,000 kg·hm−2 sheep manure significantly reduced water consumption during the seedling-bud period and green fruit period-maturity period of oilseed flax by 16.13% and 23.19% compared with CK, respectively. Thousand-grain weight, yield and water use efficiency were significantly increased by 14.70%, 48.32% and 61.29%, respectively. These results indicate that the application of 25,000 kg·hm−2 sheep manure can significantly increase soil water storage capacity of the 0–160 cm soil layer, reduce water consumption during the whole growth period of oilseed flax and thus improve grain yield and water use efficiency of oilseed flax. It is a suitable fertilization technology for the high-yield, efficient and green production of oilseed flax in the semi-arid areas of northwest Loess Plateau.

Permafrost characteristics and potential influencing factors in the lake regions of Hoh Xil, Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau (QTP) is one of the regions in the world where permafrost and lakes are widely developed. Yet, the current understanding of permafrost characteristics surrounding large alpine lakes is still not clear. Based on the observation of permafrost surrounding Zonag Lake and Yanhu Lake (>100 km2) in the Hoh Xil region since 2012, we first investigated the permafrost characteristics and potential influencing factors around large alpine lakes on the QTP. The results indicate that the large alpine lakes have only a marginal thermal effect on the surrounding permafrost. Except for the sites located at the lake bottom and adjacent to the lakeshore, cold permafrost is extensively developed around the lakes, where the mean annual ground temperature is below −1.0℃, and the permafrost thickness is generally more than 40 m. Moreover, significant differences exist in ground temperature between boreholes located in the Yanhu Lake basin and those outside the basin, which the permafrost temperature in the lake basin is remarkably lower. These phenomena are closely related to the high soil water content around lakes. Statistical results show that ground temperature decreases and permafrost thickness increases gradually with increasing soil water content. The latent heat effects play an important role in the thermal dynamics of permafrost, which can buffer the increase of permafrost temperature under climate warming. Meanwhile, the salinity of water can weaken the thermal erosion effect of the lake on the surrounding permafrost to a certain extent. Overall, the permafrost thermal regime in the lake regions is not only controlled by altitude but also affected by soil water content. This study will provide us with a basis for understanding the state and characteristics of the frozen ground around lakes in the permafrost regions of the QTP, as well as for conducting research on the interaction of frozen ground with lakes and even the atmosphere.

Direct evidence and mechanism for biocrusts-induced improvements in pore structure of dryland soil and the hydrological implications

As a crucial living skin inhabiting the soil-atmosphere interface, biocrusts play a vital role in various soil properties and processes, especially surface soil pore structure and soil pore-related hydrological processes, such as infiltration and evaporation. However, it remains unclear how biocrusts affect pore structure in the micrometric point of view. In this study, X-ray computed tomography and image analysis were employed to quantify the differences in soil pore structure between bare soil and three types of biocrusts (cyanobacterial, cyanobacterial-moss mixed, and moss crusts) at 0–50 mm depth. Three-dimensional images were segmented and analyzed to assess morphological and geometrical properties, such as porosity, pore volume, degree of anisotropy, Euler number, pore shape, pore connectivity, and pore tortuosity. Our results showed that the porosity of three types of biocrusts was, on average, 100% higher than bare soil, and the porosity ranked in order of moss crusts > mixed crusts > cyanobacterial crusts > bare soil. In comparison to bare soil, pore surface area density, mean pore volume, and node density of biocrusts were increased by 45%, 422%, and 52% on average, respectively. Biocrusts had larger fractal dimensions but lower degrees of anisotropy, mean tortuosity, and Euler number, which indicates the pore structure of biocrust became more complex and stable with higher connectivity compared to bare soil. Additionally, elongated pores had the largest contribution to porosity, and these pore proportions were significantly higher in biocrusts than bare soil. More importantly, the pore network model and network analysis revealed that biocrusts have a higher connected porosity (17% vs. 4%), connected porosity/isolated porosity (11.7 vs. 0.6), average coordination number (8 vs. 5), and number of channels (14,480 vs. 807), but a lower average channel length (2.7 vs. 3.8 mm), which indicates that the physical and topological structures of pore network in biocrusts were reconfigured and exhibited a better pore network connectivity. Moreover, the biocrusts increased soil water holding capacity by 87% on average, but decreased saturated hydraulic conductivity by 55% as compared to bare soil. From the reshaped pore structure, improved soil water holding capacity, and decreased infiltrability of the biocrusts in comparison to bare soil, we conclude that biocrusts play a vital role in surface soil water balance, which subsequently affect surface hydrological processes (e.g., runoff generation and evaporation) in drylands.

Potential Use of Olive Mill Wastewater Spreading in Olive Orchards for Improving Soil Fertility and Olive Oil Quality Under Semi-Arid Environment

ABSTRACT In Tunisia, olive growing and olive oil production represent a key element of the agricultural and economic sectors. Furthermore, olive producing areas are mostly located in semi-arid and arid regions with low water availability. On the other hand, olive oil industry generates high liquid effluent volumes (olive mill wastewater (OMW)) that represent a major environmental concern, and therefore must be appropriately managed. Accordingly, spreading OMW on agricultural lands in water scare areas may help to sustain dry lands productivity. In this study, we investigated the long-term effects of OMW spreading to an olive orchard in a semi-arid region. Physicochemical and biological properties of soil as well as olive oil quality were monitored. OMW was applied, after the end of the olive milling season, at annual dose of 50 m3 ha−1 y−1 every 2 years. The findings revealed that the OMW application increased soil water content. Moreover, OMW positively affected soil fertility, and increased, soil organic matter and biological activity. The overall results of this study indicate that OMW spreading at doses of 50 m3 ha−1 y−1 in a semi-arid region improves soil physicochemical properties and does not have a negative impact on olive oil quality. Additionally, direct spreading of OMW, if applied every 2 years, could be a sustainable practice in olive orchards under semi-arid environments.

Reducing Deep Percolation Losses Using a Geotextile Layer at Different Soil Depths and Irrigation Levels for Lettuce Crop (Lactuca sativa L. var. capitata) (Limor)

Due to rising food demand and the limitation of water resources, achieving water security is essential. The lettuce crop is affected when grown under limited water supplies as it produces small heads, especially during the late growing stage. For this reason, it is important to maximize water use efficiency and crop productivity. Two successive experiments were conducted during 2021 and 2022 to reduce losses via deep percolation using a geotextile layer at different soil depths under different irrigation levels of the lettuce crop (Lactuca sativa L. var. capitata). This study aims to reduce water losses due to deep percolation and improve crop growth and yield parameters for iceberg lettuce under subsurface drip irrigation in sandy loam soil conditions. In order to achieve these aims, different amounts of irrigation (100, 80, and 60% of crop evapotranspiration “ETc”) and a geotextile layer at different soil depths (20, 30, and 40 cm from the soil surface) were used. The results revealed that the use of a geotextile layer with 20 and 30 cm depths significantly improved irrigation application efficiency and noticeably increased soil water content in the root zone. The observed results during both seasons showed that geotextile layers at 20, 30, and 40 cm depths under irrigation of 100% ETc significantly increased vegetative growth characteristics (plant height, head diameter, head circumference, head volume, plant fresh weight, and leaf area) and crop productivity compared to the control (without geotextile). In particular, the geotextile layer at a 30 cm depth under irrigation of 100% of ETc was the most statistically effective treatment in this study, with yield values of 69.3 and 67.5 t ha−1 in the two seasons, respectively. However, the treatments of geotextile layers at 20 and 30 cm depths under irrigation of 80% of ETc also recorded statistically effective results for crop growth parameters and yield in this study. In general, geotextiles can be used at different depths as an irrigation management practice to reduce deep percolation in the field.

Growth and Yield Response and Water Use Efficiency of Cotton under Film-Mulched Drip Irrigation to Magnetized Ionized Water and Bacillus subtilis in Saline Soil in Xinjiang

In irrigated agriculture, the combination of multiple regulation measures is an effective method to improve saline soil and promote crop growth. Magnetized ionized water irrigation is considered a promising irrigation water activation technique, while the use of Bacillus subtilis for soil amelioration is environmentally friendly. In this study, magnetized ionized water irrigation and B. subtilis were used to promote cotton growth under film-mulched drip irrigation (FMDI) in saline soil. A two-year field experiment was conducted to investigate the effects of differing B. subtilis amounts under two irrigation water types (non-magnetized-ionized water (NMIW) and magnetized ionized water (MIW)) on the growth (plant height, leaf area index, shoot dry matter and chlorophyll content) and the yield of cotton, as well as the soil water content, salts accumulation, water use efficiency (WUE) and irrigation water use efficiency (IWUE) under FMDI in a saline soil in southern Xinjiang. Five amounts of B. subtilis (0, 15, 30, 45 and 60 kg ha−1) under NMIW (designated as B0, B1, B2, B3 and B4) and MIW (designated as M, MB1, MB2, MB3 and MB4) were applied to the field experiments. The results showed that MIW and B. subtilis increased soil water content and reduced salts accumulation in the 0–40 cm soil layers compared with B0. Moreover, the two measures significantly (p < 0.01) increased cotton plant height, leaf area index, shoot dry matter and chlorophyll content compared with B0. Seed cotton yield, WUE and IWUE were also observed to significantly increase (p < 0.05). Compared with the NMIW treatments, the MIW treatments increased seed cotton yield by 2.1–12.2%, increased WUE by 0.2–9.0%, and increased IWUE by 2.1–12.2%. Under MIW, with the B. subtilis amount as an independent variable, quadratic function relationships with seed cotton yield, WUE and IWUE were established. By taking the first derivative of the quadratic function, the highest seed cotton yield, WUE and IWUE were obtained with the B. subtilis amounts of 51.8, 55.0 and 51.4 kg ha−1, respectively. Based on comprehensive consideration of seed cotton yield, WUE, IWUE and salts accumulation in soil, 51.4 kg ha−1 of B. subtilis under MIW treatment is recommended for cotton cultivated under FMDI in a saline soil of southern Xinjiang, China.

Biometric and morphological adjustments of Eugenia. dysenterica DC. seedlings in response to increased soil water deficit

Water stress can affect all aspects of plant growth and development, compromising its productive potential. The cultivation of fruit species native to the Cerrado and the study of their behavior under conditions of low water availability are necessary activities, in view of their socioeconomic and environmental potential. This study was conducted to evaluate the effect of water deficit on growth and biomass production of the cagaita tree (Eugenia dysenterica DC.), a species endemic to the Cerrado (Brazilian Savannah). The experiment was performed in a greenhouse for 120 days in a randomized block design (RBD), with a double factorial arrangement (2x5), corresponding to two cagaita mother plants and five water conditions. We evaluated the growth and leaf, stem and root functional characteristics. The most severe water deficit conditions reduced shoot growth, number of leaves, production of biomass and dry matter and increased the specific and per plant mass root length of cagaita plants. Deficit extension had negative effects on its growth and development. There was a statistical difference between mother plants, with mother plant 2 being more resistant to drought. The application of a severe or longer water deficit affected shoot growth and reduced the appearance of new leaves. The stress caused by water deficiency allowed an increase in root functional characteristics, supporting the hypothesis that plants under adverse conditions focus on higher biomass production and convert a higher amount of dry matter into the roots. Leaf area did not show to be a functional characteristic, explaining the stress effects in E. dysenterica DC plants.

Assessment of the Effects of Fencing Enclosure on Soil Quality Based on Minimum Data Set in Biru County of the Qinghai–Tibet Plateau, China

Fencing enclosures play an important role in improving ecological quality. There is a direct impact of implementing fencing enclosures on the change in soil quality. The soil quality index was used to examine the effects of fencing enclosures for different years (7 and 11 years) on soil quality in Biru County of Qinghai–Tibet Plateau, China. The fencing enclosure significantly increased soil water content, non-capillary porosity, soil organic matter, total nitrogen, total phosphorus, and alkali-hydrolyzable nitrogen, and significantly decreased the soil bulk density. The soil quality gradually improved as the fencing enclosure time length increased, probably due to the increase of vegetation coverage and biomass under the fencing enclosure. The minimum data set was composed of soil organic matter, capillary porosity, total potassium, and non-capillary porosity. The minimum data set was significantly correlated with the total data set and could replace the total data set for soil quality evaluation in the fencing enclosure project area. In summary, our study reflects that fencing enclosures significantly improve soil quality, and the implementation of the fencing enclosure project will effectively curb land degradation in Biru County of the Qinghai–Tibet Plateau, China.

Factors governing soil hydrological function under long‐term tillage practices: Insight into soil water repellency

AbstractDrought is increasingly common due to frequent occurrences of extreme weather events, which further increases soil water repellency (SWR). It could reinforce the effect of SWR on soil functions under conservation tillage systems. However, the relationship between SWR and soil hydrological function is still unclear. We studied the impacts of SWR and soil structure on soil hydrological function. Three treatments were conducted in a long‐term tillage experiment: conventional tillage (CT), reduced tillage (RT), and no‐tillage (NT). Tillage, soil depth, and growth period had significant influences on SWR, soil structure (i.e., penetration resistance [PR], total porosity [TP], and mean weight diameter [MWD]), and soil hydrological functions (i.e., water storage, least limiting water range [LLWR], and plant available water). Compared to CT, NT and RT increased the water repellency index (RI) in 0–20 cm by 13.8%–40.1% and 6.5%–18.2% during the growth period. RI played a prominent role in increasing soil water storage compared to soil TP, PR, MWD, and SOC. PR was the most critical influence on LLWR compared to other variables. A structural equation model revealed that SWR directly affected soil hydrological function, whereas the effect of SWR (0.24) was smaller than that of soil structure (0.67). In addition, soil structure had a direct influence on SWR, indicating that the effect of SWR could be regulated by soil structure. Overall, this study showed a link between SWR and soil hydrological function and provides deeper fundamental insights into the role of SWR on the sustainability of conservation tillage.

Cover cropping impacts on soil water and carbon in dryland cropping system.

Incorporating cover crops into the rotation is a practice applied across many parts of the globe to enhance soil biological activities. In dryland farming, where crop production is highly dependent on rainfall and soil water storage, cover cropping can affect soil water, yet its effects on soil hydrological and biological health require further investigation. The objective of this study was to evaluate the effect of different timing of summer sorghum cover crop termination on soil water, total and labile organic carbon, arbuscular mycorrhizal fungi and their mediating effects on wheat yield. Through on-farm trial, soil characteristics along with wheat biomass, yield and grain quality were monitored. In comparison with the control (fallow), the early terminated cover crop was the most effective at retaining greater soil water at wheat sowing by 1~4% in 0-45cm soil profile. An increase in water use efficiency, yield and grain protein by 10%, 12% and 5% was observed under early termination. Under late terminated summer cover crop, there was 7% soil water depletion at wheat planting which resulted in 61% decline in yield. However, late-terminated cover crop achieved the greatest gain in soil total and particulate organic carbon by 17% and 72% and arbuscular mycorrhizal fungal Group A and B concentration by 356% and 251%. Summer cover crop incorporation resulted in a rapid gain in labile organic carbon, which constituted hotspots for arbuscular mycorrhizal fungi growth, conversely, fungal activities increased labile organic carbon availability. The combined effect of increased soil water at sowing and over the growing season, organic carbon, and microbial activities contributed to greater yield. The findings suggest that summer cover cropping with timely termination can have implications in managing soil water at sowing time and enhancing soil water storage during the season, soil carbon, and facilitating microbial activities while enhancing productivity in the dryland cropping system.

Soil moisture and temperature dynamics in juvenile and mature forest as a result of tree growth, hydrometeorological forcings, and drought

AbstractAfforestation, as one of the major drivers of land cover change, has the potential to provide a wide range of ecosystem services. Aside from carbon sequestration, afforestation can improve hydrological regulation by increasing soil water storage capacity and reducing surface water runoff. However, afforested areas are rarely studied over time scales appropriate to determine when changes in soil hydrological processes occur as the planted (mixed) forests establish and grow. This study investigates the seasonal soil moisture and temperature dynamics, as well as the event‐based responses to precipitation and dry periods, for a mature and a juvenile forest ecosystem over a 5‐year time period. Generally, soil moisture was higher in the juvenile forest than in the mature forest, suggesting a lower physiological water demand. Following the 2018 drought, soil moisture dynamics in the growing juvenile plantation began to match those of the mature forest, owing to canopy development and possibly also to internal resilience mechanisms of the young forest to these external hot weather perturbations. Soil temperature dynamics in the juvenile plantation followed air temperature patterns closely, indicating lower thermal regulation capacity compared to the mature forest. While our findings show that an aggrading juvenile plantation achieves mature forest shallow soil moisture storage dynamics at an early stage, well before physiological maturity, this was not the case for soil temperature. Our results shed light on long‐term trends of seasonal and event‐based responses of soil moisture and temperatures in different‐aged forest systems, which can be used to inform future assessments of hydrological and ecosystem responses to disturbances and forest management.

Optimized management strategy increased grain yield, promoted nitrogen balance, and improved water productivity in winter wheat.

The increasing costs of agricultural production and environmental concerns reinforce the need to reduce resource inputs. Improvements in nitrogen (N) use efficiency (NUE) and water productivity (WP) are critical for sustainable agriculture. We aimed to optimize management strategy to increase wheat grain yield, promote N balance, and improve NUE and WP. A 3-year experiment was conducted with four integrated treatments: conventional practice treatment (CP); improvement of conventional practice treatment (ICP); high-yield management treatment (HY), which aimed for maximizing grain yield regardless of resource inputs cost; and integrated soil and crop system management treatment (ISM), which aimed for testing an optimal combination of sowing date, seeding rate, and fertilization and irrigation management. The average grain yield for ISM was 95.86% of that for HY and was 5.99% and 21.72% higher than that for ICP and CP, respectively. ISM promoted N balance as relatively higher aboveground N uptake, lower inorganic N residue, and lowest inorganic N loss. The average NUE for ISM was 4.15% lower than that for ICP and was remarkably higher than that for HY and CP by 26.36% and 52.37%, respectively. The increased soil water consumption under ISM was mainly due to its increased root length density. Along with a high level of grain yield, ISM obtained a relatively adequate water supply due to the effective use of soil water storage, thereby increasing the average WP by 3.63%-38.10% in comparison with other integrated management treatments. These results demonstrated that optimized management strategy (appropriately delaying sowing date, increasing seeding rate, and optimizing fertilization and irrigation management) used under ISM could promote N balance and improve WP while increasing grain yield and NUE in winter wheat. Therefore, ISM can be considered a recommendable management strategy in the target region.