Mean Soil Research Articles

Comparative Analysis of Land and Air Temperature in Romania since A.D. 1961

Daily time series with continuous records of mean air and soil temperature from 127 meteorological stations—fairly distributed over the country—were used to compute monthly temperature trends, as well as changes in the timing of the first and the last frost days over Romania since 1961. Results show that the frequency of the number of days with daily temperature averages below 0 °C in case of air and soil surface temperature is stable for most months, except for January, when (for both soil and air temperature), the number of days with a temperature below 0 °C is decreasing in the majority of the stations. The occurrence of the first day with (mean air and soil surface) temperatures below 0 °C, presents a delay in the south, south-east, and west, and an earlier occurrence in eastern and central regions. The occurrence of the last day with a mean air and soil surface temperature below 0 °C shows a stable trend for most stations (except for some small areas in the north, south-east and south-west of Romania). The regime of the land temperature is more stable, due to the physical characteristics of the soil, compared to the more versatile atmosphere. Linkages between thermal parameters and large-scale atmospheric circulation are also discussed.

Enhancing Soil Aggregate Stability and Organic Carbon in Northwestern China through Straw, Biochar, and Nitrogen Supplementation

Enhancing soil stability through the incorporation of straw and biochar is well documented. Nevertheless, the combined impact of straw, biochar, and nitrogen supplementation on soil aggregates and organic carbon still needs to be explored, with limited attention given to various sieving methods in the existing literature. Therefore, the current experiment used four sieving methods—routine wet sieving (RoutW), fast-wetting sieving (FastW), slow-wetting sieving (SlowW), and wetting–stirring sieving (WetS)—to investigate the effects of adding straw (0 or 4.5 t ha−1), biochar (from maize straw, 0 or 15 t ha−1), and N (0 or 100 kg ha−1) on soil aggregate stability and soil organic C in silt–loam soil of rainfed farmland in northwest China. The field experiment was started in 2014; soil samples were collected in 2021. The results revealed that straw returned, biochar, and N addition significantly increased soil mean weight diameter (MWD) and soil organic C (SOC). Compared to CN0 (zero-amendment) plots, straw returned with nitrogen addition (SN100) significantly increased the MWD of aggregates by 130.3% (RoutW), 121.66% (FastW), 73.94% (SlowW), and 91.78% (WetS) in the 0–30 cm soil layer. The addition of biochar and nitrogen (BN100) treatment showed the most significant effects on the relative slaking index (RSI), relative mechanical breakdown index (RMI), and SOC; compared with CN0 treatment, BN100 plots can reduce RSI and RMI by 42.90% and 54.66% and increase SOC by 53.27% for all soil layers. Therefore, adding organic materials with N can enhance the stability of soil aggregates and SOC of silt–loam soils in northwest China. Integrating biochar as an organic soil amendment in the agricultural practices of northwest China presents a multifaceted solution that addresses soil health, crop productivity, and environmental sustainability. The current study provides valuable insights that support adopting this innovative approach, paving the way for future sustainable agricultural practices that can benefit both the region and the global community.

Long-term species-level observations indicate the critical role of soil moisture in regulating China's grassland productivity relative to phenological and climatic factors

As a sensitive indicator of climate change and a key variable in ecosystem surface-atmosphere interaction, vegetation phenology, and the growing season length, as well as climatic factors (i.e., temperature, precipitation, and sunshine duration) are widely recognized as key factors influencing vegetation productivity. Recent studies have highlighted the importance of soil moisture in regulating grassland productivity. However, the relative importance of phenology, climatic factors, and soil moisture to plant species-level productivity across China's grasslands remains poorly understood. Here, we use nearly four decades (1981 to 2018) of in situ species-level observations from 17 stations distributed across grasslands in China to examine the key mechanisms that control grassland productivity. The results reveal that soil moisture is the strongest determinant of the interannual variability in grassland productivity. In contrast, the spring/autumn phenology, the length of vegetation growing season, and climate factors have relatively minor impacts. Generally, annual aboveground biomass increases by 3.9 to 25.3 g∙m2 (dry weight) with a 1 % increase in growing season mean soil moisture across the stations. Specifically, the sensitivity of productivity to moisture in wetter and colder environments (e.g., alpine meadows) is significantly higher than that in drier and warmer environments (e.g., temperate desert steppes). In contrast, the sensitivity to the precipitation of the latter is greater than the former. The effect of soil moisture is the most pronounced during summer. Dominant herb productivity is more sensitive to soil moisture than the others. Moreover, multivariate regression analyses show that the primary climatic factors and their attributions to variations in soil moisture differ among the stations, indicating the interaction between climate and soil moisture is very complex. Our study highlights the interspecific difference in the soil moisture dependence of grassland productivity and provides guidance to climate change impact assessments in grassland ecosystems.

Zeolite application coupled with film mulched drip irrigation enhances crop yield with less N2O emissions in peanut field

Zeolite has been previously reported to increase nitrogen (N) use efficiency in lowland paddy fields. However, few results are available regarding its effect on N2O emissions from upland field, especially with mulched drip irrigation. In present study, two-year peanut field experiments were conducted utilizing a split-plot design to assess the impact of zeolite application and irrigation regimes on plant dry weight and N accumulation, soil inorganic N content, peanut yield, N2O emissions, and soil physicochemical properties. Different irrigation regimes (MD, mulched drip irrigation; RF, rain-fed) as well as zeolite application rates (0 t ha−1 (Z0, control), 5 t ha−1 (Z5), and 10 t ha−1 (Z10)) were applied. Results showed that the MD treatment increased plant dry weight, N accumulation, soil NH4+-N, NO3−-N content and mean soil temperature compared to the RF control. Furthermore, cumulative N2O emissions and peanut yield were raised by 24.3% and 15.8%, respectively, with the MD treatment. The increased peanut yield by mulched drip irrigation might be resulted from the promoted soil inorganic N, soil temperature, and plant N accumulation. Regardless of irrigation, zeolite addition increased dry weight and N accumulation during all measured stages except seedling, mean soil NH4+-N, NO3−-N content, mean soil pH, and peanut yield. In contrast, cumulative N2O emissions were decreased compared to the non-zeolite control. Moreover, findings showed that Z10 performed better in increasing peanut yield by 12.7% and decreasing N2O emissions by 35.7% than Z5. Increasing soil inorganic N content with zeolite addition contributed to improve plant N accumulation and promote dry weight and peanut yield. Furthermore, the reduction of N2O emissions by zeolite was related to improved soil inorganic N and pH. Though MD increased N2O emissions, the MDZ10 treatment had 20.6% of cumulative N2O emissions lower than the conventional practice (RFZ0), indicating that zeolite application alleviated the adverse effect of mulched drip irrigation on N2O emissions. It was concluded that zeolite dose at 10 t ha−1 coupled with mulched drip irrigation gave a high peanut yield with less N2O emissions. Our findings could be adopted in arid areas to enhance peanut production and mitigate environmental risk induced by N2O emissions.

Fruit Quality and Plant Productivity of A Cherry Tomato (Solanum lycopersicum var. cerasiforme) Grown under Different Irrigation Regimes during the Reproductive Phase

The impact of water deficit severity and the specific growth stages at which water stress is applied have been found to have significant implications for both tomato yield and fruit quality. Recent findings have highlighted the influence of water deficits during the reproductive phase on tomato fruit quality. This study aimed to assess the effects of deficit irrigation on tomato fruit quality and overall plant productivity. Cherry tomatoes (Solanum lycopersicum var. cerasiforme) were grown in a greenhouse from August to November 2022. Three distinct watering regimes were implemented: Daily watering (T1), watering every 3 days (T2) and watering every 7 days (T3), starting from the flowering stage and continuing through subsequent plant development stages. The mean soil metric potentials (SMP) were −4.9, −29.7 and −52.8 kPa for T1, T2 and T3, respectively. Various traits of fruit size, fruit biomass, total soluble solids (TSS), water content, glucose content and lycopene content were measured. Additionally, the overall plant biomass and root-to-shoot ratio were evaluated. The results revealed that traits of the fruit size, such as diameter, length, volume and fresh weight, were most favorable when plants were subjected to the T2 watering regime, while higher and lower watering frequencies led to smaller fruit sizes. Interestingly, the TSS concentration had the most pronounced response to drought stress, indicating increased fruit sweetness. However, the fruit water content, glucose content and lycopene content remained unaffected by the different watering regimes. Furthermore, plants subjected to the T3 with the minimum SMP at −196.4 kPa exhibited enhanced development of the root system, prioritizing resource acquisition such as water and mineral nutrients over shoot components. In conclusion, this study provided valuable insights for agricultural practitioners, offering a range of alternatives that can inform optimal irrigation strategies that effectively enhance the quality of cherry tomato yields. HIGHLIGHTS Water deficits during the reproductive phase have a notable impact on tomato fruit quality Three distinct watering regimes, including daily watering (T1), watering every 3 days (T2) and watering every 7 days (T3), were implemented, with mean soil metric potentials for T1, T2 and T3 recorded at −4.9, −29.7 and −52.8 kPa, respectively T2 watering regime resulted in the most favorable fruit size (diameter, length, volume and fresh weight), while higher and lower watering frequencies led to smaller fruit sizes Total soluble solid concentration showed a pronounced response to drought stress, indicating increased fruit sweetness, while glucose content and lycopene content were unaffected by different watering regimes The study provides valuable insights for agricultural practitioners, suggesting alternative irrigation strategies to enhance the quality of cherry tomato yields GRAPHICAL ABSTRACT

Latitudinal patterns and drivers of plant lignin and microbial necromass accumulation in forest soils: Disentangling microbial and abiotic controls

Plant- and microbial-derived compounds are the two primary sources of the soil organic carbon (SOC) pool. However, whether and how biotic and abiotic factors regulate the means through which microbes and plants contribute to SOC accumulation at a regional scale remains unclear. This study investigated the distribution patterns of plant lignin components and microbial necromass in soils, as indicated by lignin phenols and amino sugars across five latitudinal forests in eastern China. The contents of plant lignin and microbial necromass in the soil increased with increasing latitude. However, their contributions to SOC followed quadratic patterns with increasing latitude. Given its positive relationship with SOC content in all examined forests, microbial necromass seemed to play a more critical role in SOC accumulation than lignin phenols. Moreover, plant lignin and microbial necromass accumulation and their contributions to SOC were mainly influenced by the joint effects of climatic variables, microbial traits, and soil properties, but their importance was divergent. Specifically, the mean annual temperature (MAT) and soil phosphorus content were central to plant lignin accumulation, whereas MAT and the microbial richness: biomass ratio mainly controlled microbial necromass accumulation. These findings demonstrate that microbial necromass plays a more critical role than plant lignin in forest SOC accumulation and further highlight the importance of microbial traits in microbial necromass accumulation.

Assessment of Selected Physical and Chemical Soil Properties and Organic Carbon Stock, Under Different Land-Uses in Melka Gura Subwatershed of North Shewa Zone, Oromia, Ethiopia

A study conducted in Melka Gura Subwatershed to assess soil properties across three types of land uses plantation forest, grazing land, and cultivated land from 2022 to 2023 found that all land uses had loam soil, except for the plantation forest, which had sandy loam. The mean soil BD in the study area ranged from 1.06 to 1.39 g/cm3. Conversely, plantation forest soil and grazing land had the highest mean AWC (194.8 mm/m) at 0–20 cm depth. The highest mean values of sand, silt, TP, pH, AP, exchangeable basic cations, CEC, SOC, TN, and SOC stock (68.62-ton ha-1) were registered in the soil of plantation forest land. The highest mean values of BD (1.39 g/cm3), clay content (19%), Ex. A, and Ex. Al were recorded in the soil of cultivated land. The average values of clay, BD, FC, PWP, pH, PBS, and exchangeable bases all indicated an increasing trend from the surface toward the subsurface. The highest mean value of SOCS (68.62 tons’ ha-1) was discovered in plantation forest land and the lowest in cultivated land. The differences in soil management practices could be the major reasons for variations in soil properties across land-use types. Further studies are needed on the effects of land-use change on fertility-related soil properties in relation to integrated soil and water conservation practices to reduce further land degradation.

Soil respiration and its response to climate change and anthropogenic factors in a karst plateau wetland, southwest China.

It is important to investigate the responses of greenhouse gases to climate change (temperature, precipitation) and anthropogenic factors in plateau wetland. Based on the DNDC model, we used meteorological, soil, and land cover data to simulate the soil CO2 emission pattern and its responses to climate change and anthropogenic factors in Guizhou, China. The results showed that the mean soil CO2 emission flux in the Caohai Karst Plateau Wetland was 5.89 ± 0.17 t·C·ha-1·yr-1 from 2000 to 2019, and the annual variation showed an increasing trend with the rate of 23.02 kg·C·ha-1·yr-1. The soil total annual mean CO2 emissions were 70.62 ± 2.04 Gg·C·yr-1 (annual growth rate was 0.28 Gg·C·yr-1). Caohai wetland has great spatial heterogeneity. The emissions around Caohai Lake were high (the areas with high, middle, and low values accounted for 3.07%, 70.96%, and 25.97%, respectively), and the emission pattern was characterized by a decrease in radiation from Caohai Lake to the periphery. In addition, the cropland and forest areas exhibited high intensities (7.21 ± 0.15 t·C·ha-1·yr-1 and 6.73 ± 0.58 t·C·ha-1·yr-1, respectively) and high total emissions (54.97 ± 1.16 Gg·C·yr-1 and 10.24 ± 0.88 Gg·C·yr-1, respectively). Croplands and forests were the major land cover types controlling soil CO2 emissions in the Caohai wetland, while anthropogenic factors (cultivation) significantly increased soil CO2 emissions. Results showed that the soil CO2 emissions were positively correlated with temperature and precipitation; and the temperature change had a greater impact on soil respiration than the change in precipitation. Our results indicated that future climate change (increased temperature and precipitation) may promote an increase in soil CO2 emissions in karst plateau wetlands, and reasonable control measures (e.g. returning cropland to lakes and reducing anthropogenic factors) are the keys to controlling CO2 emissions.

Reliability analysis and risk assessment of pile-reinforced slopes considering spatial soil variability and site investigation

ABSTRACT Site investigation data is of great significance for practical slope stability analyses and designs. Previous studies on the probabilistic analysis of pile-reinforced slopes, however, rarely considered the influence of site-specific information, which may lead to a biased judgment of the stability of the soil-pile system, thus resulting in unreasonable designs. This paper proposes a new integrated probabilistic framework to analyse the probabilistic characteristics and quantitative risk of the pile-reinforced slopes considering site investigation data. Particularly, with the aid of the framework, the responses of the stabilising piles under different schemes of investigation boreholes are systematically studied. The Random Finite Difference Method within the framework of Monte Carlo Simulation (MCS) and Subset simulation is employed to explore the uncertainty within the pile-reinforced slope and the associated pile responses. A soil slope is taken as an illustrative example to validate the effectiveness of the proposed framework through various parametric studies on the investigation scheme of boreholes (e.g., numbers, locations, and sampling intervals). It is found that the stability results obtained from the deterministic analysis with mean soil properties and the conventional unconditional random field MCS may be biased compared to the results by the proposed framework considering real-site situations.

Integrating RUSLE Model with Cloud-Based Geospatial Analysis: A Google Earth Engine Approach for Soil Erosion Assessment in the Satluj Watershed

This study employed an advanced geospatial methodology using the Google Earth Engine (GEE) platform to assess soil erosion in the Satluj Watershed thoroughly. To achieve this, the Revised Universal Soil Loss Equation (RUSLE) model was integrated into the study, which was revealed through several analytical tiers, each with a unique function. The study commenced with estimating the R factor, which was carried out using annual precipitation data from the Climate Hazards Group Infra-Red Precipitation with Station (CHIRPS). The erodibility of the soil, which the K factor describes, was then calculated using the USDA soil texture classifications taken from the Open Land Map. The third layer emphasizes the LS factor, which analyzes slope data and how they affect soil erosion rates, using digital elevation models. To understand the impact of vegetation on soil conservation, the fourth layer presents the C factor, which evaluates changes in land cover, and the Normalized Difference Vegetation Index (NDVI) derived from Sentinel-2 data. The P factor incorporates MODIS data to assess the types of land cover and slope conditions. Combining these layers with the RUSLE model produces a thorough soil loss map, revealing different levels of soil erosion throughout the Satluj Watershed. The preliminary findings indicate that 3.3% of the watershed had slight soil loss, 0.2% had moderate loss, and 1.2% had high soil erosion rates. And 92% had severe rates of soil erosion. After a thorough investigation, the detected regions were divided into risk classifications, providing vital information for the watershed’s land management and conservation plans. The mean soil loss throughout the watershed was determined to be 10,740 tons/ha/year. This novel method creates a strong foundation for evaluating soil erosion, while also highlighting the value of the cloud-based geospatial analysis and the RUSLE model in comprehending intricate environmental processes.

Effects of conventional soil and water conservation measures on soil moisture of sloping land in the loess region

ABSTRACT Traditional soil conservation measures were widely recognized for their excellent ability to promote rainwater infiltration in the loess region. However, little is known about how these measures affect the soil moisture variations under natural rainfall conditions. To compare their effects on soil water content, four different treatments were conducted at runoff plots, i.e., super absorbent polymer amendment (SCR), ridge–furrow rainwater harvesting with plastic mulching (CRP), the same measure with CRP but without mulching (CRN), and flat planting (FSN, control), soil moisture at multiple slope positions and depths were periodically measured. The results showed that in the top 0- to 30-cm soil, SCR and CRN relatively greatly varied with time, yet CRP and FSN changed less. The mean soil water content of these treatments generally followed the pattern of CRN > SCR > CRP > FSN. Responding to a heavy rainfall event, the recharge and depletion rates of soil water storage generally showed similar patterns of SCR > CRN > CRP > FSN in the topsoil, yet in the deeper soil they followed the patterns of CRP > CRN > FSN > SCR. It suggested that SCR and CRN could improve the water accumulation and infiltration performances in the topsoil, and thus may be more suitable for rain-fed crop planting on sloping farmlands of the loess region.

Elucidating waterhemp (Amaranthus tuberculatus) suppression from cereal rye cover crop biomass

AbstractCereal rye (Secale cereale L.) as a cover crop can be an effective nonchemical tool for waterhemp [Amaranthus tuberculatus (Moq.) Sauer] suppression in crop production. Previous studies have evaluated A. tuberculatus suppression by cereal rye as part of weed management programs but have not investigated the underlying mechanism of suppression by the cover crop. This study aimed to investigate the effect of cereal rye biomass on A. tuberculatus emergence and development, and on soil environmental parameters (temperature, moisture, and light transmittance) that are key triggers of A. tuberculatus germination to elucidate the mechanism of suppression by the cover crop. A dose–response study was conducted under field conditions in Brooklyn and Janesville, WI, from 2021 to 2023. Cereal rye biomass from a fall-planted field was harvested at anthesis in the spring and dried to constant weight at 60 C to provide 0.0, 0.6, 1.2, 2.4, 4.8, 7.2, 9.6, and 12.0 Mg ha−1 of dry biomass that was evenly distributed over 1.9 m−2 plots. Increasing cereal rye biomass reduced A. tuberculatus height, biomass, and density. An average ED50 of 5.2 Mg ha−1 of biomass was needed to reduce A. tuberculatus density by 50%. Low levels of biomass (≤2.38 Mg ha−1) augmented A. tuberculatus density due to an increase in soil moisture underneath the mulch compared with bare soil. Cereal rye biomass decreased the amount of sunlight reaching the soil, which resulted in lower mean soil temperature and temperature amplitude throughout the day (9.3 and 2.7 C temperature amplitude at 0 and 12.0 Mg ha−1, respectively). Prevention of A. tuberculatus germination by this thermal effect is likely the main mechanism of A. tuberculatus suppression from the cereal rye cover crop. Our results support biomass from cereal rye cover crop effectively suppressing A. tuberculatus and contributing to the integrated management of A. tuberculatus.

Soil erosion and sediment export analysis for watershed management options in Fakisi watershed of the Abbay basin of Ethiopia

Soil erosion by water is one of the major environmental threats and it not only decreases agricultural productivity but also reduces water availability. This study aimed to estimate soil erosion and sediment yield and prioritize sub-watersheds for management options with RUSLE methodology in the Fakisi watershed, Northwestern Ethiopian highlands. Digital topography, rainfall, land cover, land management, and soil datasets were used to develop RUSLE model parameters. The study revealed that 339,031 tons of soil was lost annually and the mean soil loss was 35 t ha− 1 yr−1. Severe to extremely severe erosion was observed at 14.9 % of the watershed which accounted for 58 % of the total soil loss. The sediment delivery ratio (SDR) of the watershed was between 0.17–0.43 and the mean annual sediment yield was estimated at 27.2 t ha−1 yr−1. The sensitivity analysis revealed that soil erodibility and land management were the factors most contributing to the soil erosion processes. Sub-watersheds (SW9, SW6, SW10, SW7, and SW8) accounted for 72.4 % of the total erosion and covered 56 % of the overall watershed. These sub-watersheds were designated as significant erosion zones and recommended to implement integrated soil conservation interventions to deter the high soil loss and sediment yield.

Insights on seasonal solifluction processes in warm permafrost Arctic landscape using a dense monitoring approach across adjacent hillslopes

Solifluction processes in the Arctic are highly complex, introducing uncertainties in estimating current and future soil carbon storage and fluxes, and assessment of hillslope and infrastructure stability. This study aims to enhance our understanding of triggers and drivers of soil movement of permafrost-affected hillslopes in the Arctic. To achieve this, we established an extensive soil deformation and temperature sensor network, covering 48 locations across multiple hillslopes within a 1 km2 watershed on the Seward Peninsula, AK. We report depth-resolved measurements down to 1.8 m depth for May to September 2022, a period conducive to soil movement due to deepening thaw layers and frequent rain events. Over this period, surface movements of up to 334 mm were recorded. In general, these movements occur close to the thawing front, and are initiated as thawing reaches depths of 0.4–0.75 m. The largest movements were observed at the top of the south-east facing slope, where soil temperatures are cold (mean annual soil temperatures averaging −1.13 °C) and slopes are steeper than 15°. Our analysis highlights three primary factors influencing movements: slope angle, soil thermal conditions, and thaw depth. The latter two significantly impact the generation of pore water pressures at the thaw–freeze interface. Specifically, soil thermal conditions govern the liquid water content, while thaw depth influences both the height of the water column and, consequently, the pressure at the thawing front. These factors affect soil properties, such as cohesion and internal friction angle, which are crucial determinants of slope stability. This underscores the significance of a precise understanding of subsurface thermal conditions, including spatial and temporal variability in soil temperature and thaw depth, when assessing and predicting slope instabilities. Based on our observations, we developed a factor of safety proxy that consistently falls below the triggering threshold for all probes exhibiting displacements exceeding 50 mm. This study offers novel insights into patterns and triggers of hillslope movements in the Arctic and provides a venue to evaluate their impact on soil redistribution.

Dynamics of soil penetration resistance, moisture depletion pattern and crop productivity determined by mechanized cultivation and lifesaving irrigation in zero till blackgram

Rice fallow black gram is grown under the residual moisture situation as a relay crop in heavy texture montmorillonite clay soil under zero till condition. Since the crop is raised during post monsoon season, the crop often experiences terminal stress due to limited water availability and no rainfall. Surface irrigation in montmorillonite clay soil is determent to pulse crop as inundation causes wilting. Therefore, zero tilled rice fallow black gram has to be supplemented with micro irrigation at flowering stage (35 days after sowing) to alleviate moisture stress and to increase the productivity as well. Hence micro farm pond in a corner of one ha field was created to harvest the rain water during monsoon season and the same was utilized to supplement the crop with lifesaving irrigation through mobile sprinkler at flowering stage for the crop grown under conservation agriculture. Soil cracking is also the common phenomena of montmorillonite clay soil where evaporations losses would be more through crack surfaces. The present study was therefore conducted to study the changes in the soil physical properties, crop establishment and productivity in conjunction with mechanized sowing and harvest and supplemental mobile sprinkler irrigation. Sowing of black gram by broadcasting 10 days prior to the manual harvest of rice, manual drawn single row seed drill after the machine harvest of rice and sowing by broadcasting at 4 days prior to machine harvest of rice was experimented separately and in combination with lifesaving irrigation. Results indicated that the number of wheel passes and lifesaving irrigation had a very strong impact on soil penetration resistance and soil moisture. Combined harvester followed by no till seed drill increased the soil penetration resistance in all the layers (0–5 cm, 5–10 cm and 10–15 cm). Two passes of wheel increased the mean soil penetration resistance from 407 KPa to 502 KPa. The soil penetration resistance (0–5 cm) at harvest shown that black gram sown by manual broadcasting 10 days prior to manual harvest of paddy supplemented with life irrigation on 30 DAS reduced the soil penetration resistance from 690 Kpa to 500 Kpa, 740 Kpa to 600 Kpa and 760 Kpa to 620 Kpa respectively at 0–5 cm, 5–10 cm and 10–15 cm layer. In general, moisture depletion rate was rapid in the surface layer of 0–5 cm as compared to other layers of 5–10 cm and 10–15 cm up to 30 DAS (Flowering stage). The moisture content and the soil penetration resistance had an inverse relationship. The soil penetration resistance also had an inverse relationship with the root length in which the root length lowers as the soil penetration resistance increases. The soil crack measured at 60 DAS was deeper with no till seed drill (width of 3.94 cm and depth of 13.67 cm) which was mainly due to surface layer compaction. The relative water content, specific leaf weight and chlorophyll content were significantly improved through the supplemental irrigation given on 30 DAS irrespective of crop establishment methods. The results further indicated that compaction of ploughed layer in the moist soil due to combined harvester and no till seed drill had a negative impact on yield (457 kg ha−1), which was improved by 19.03 per cent due to increased soil moisture with supplemental irrigation. The mean yield increase across different treatments due to supplemental lifesaving irrigation through mobile sprinkler was 20.4 per cent.

Pear Production (Pyrus communis L.) in Jerusalem, Palestine

Pear is a tree belonging to the Rosaceae family, sensitive to different environmental conditions. It is spread in East and West Asia, America and the European Union, and its production has an economic role for many countries of the world, including Palestine. Average annual temperatures and precipitation were analyzed using data from the Palestinian Meteorological Station affiliated with the city of Jerusalem, which was recorded between the years (1993-2014), and equal to the number of years of pear production, noting that the data for pear production was taken from the Palestinian Central Bureau of Statistics. On the other hand, we used Professor Salvador Ravers Martins' methodology to classify the Earth in the process of analyzing environmental factors, there are two aspects of the factors: The first is climatic, which is the amount of rain or precipitation, mean monthly temperature and soil water reserve, and the second factor is the bioclimatic, which is annual ombrothermic index, simple continentality index, compensated thermicity index, and water deficit. Moreover, we used Professor Salvador Rivers Martinez's methodology for classifying the land in the process of analyzing dependent and independents factors (environmental factors). There are two aspects to the factors: First is climatic, precipitation, mean monthly temperature and soil water reserve, and the second factor (bioclimatic factor), as simple continentality thermicity index, annual ombrothermic index, water deficit and compensated thermicity index.

Spatial Quantification of Cropland Soil Erosion Dynamics in the Yunnan Plateau Based on Sampling Survey and Multi-Source LUCC Data

The mapping and dynamic monitoring of large-scale cropland erosion rates are critical for agricultural planning but extremely challenging. In this study, using field investigation data collected from 20,155 land parcels in 2817 sample units in the National Soil Erosion Survey, as well as land use change data for two decades from the National Land Use/Cover Database of China (NLUD-C), we proposed a new point-to-surface approach to quantitatively assess long-term cropland erosion based on the CSLE model and non-homologous data voting. The results show that cropland in Yunnan suffers from serious problems, with an unsustainable mean soil erosion rate of 40.47 t/(ha·a) and an erosion ratio of 70.11%, which are significantly higher than those of other land types. Engineering control measures (ECMS) have a profound impact on reducing soil erosion; the soil erosion rates of cropland with and without ECMs differ more than five-fold. Over the past two decades, the cropland area in Yunnan has continued to decrease, with a net reduction of 7461.83 km2 and a ratio of −10.55%, causing a corresponding 0.32 × 108 t (12.12%) reduction in cropland soil loss. We also quantified the impact of different LUCC scenarios on cropland erosion, and extraordinarily high variability was found in soil loss in different basins and periods. Conversion from cropland to forest contributes the most to cropland erosion reduction, while conversion from grassland to cropland contributes 56.18% of the increase in soil erosion. Considering the current speed of cropland regulation, it is the sharp reduction in land area that leads to cropland erosion reduction rather than treatments. The choice between the Grain for Green Policy and Cropland Protecting Strategy in mountainous areas should be made carefully, with understanding and collaboration between different roles.

Soil erosion-based sub-watershed prioritization through coupling various crop management and erosivity scenarios using game theory

The soil erosion of the watershed is different in temporal and spatial scales due to complex climatic and environmental conditions and their dynamic state over time. Accordingly, it is necessary to prioritize sub-watersheds based on their dynamic conditions to reduce the destructive effects of soil erosion. However, this issue has to be sufficiently reported on the scale of the watershed. Towards that, a game theory-based prioritization approach was planned concerning changes in vegetation cover and rainfall in the Shazand Watershed of the Markazi Province, Iran. To achieve the purpose of the study, the amount of soil erosion was first estimated in different scenarios resulting from the changes in rainfall erosivity and vegetation cover using the RUSLE model. Next, pairwise comparisons between 24 sub-watersheds in all scenarios were made based on the sub-watersheds' ranks in soil erosion in each scenario. Considering all scenarios, the priority of the sub-watersheds was assessed using the Condorcet approach. The results showed that the mean soil erosion in the watershed ranged from 5.4 and 36 t ha−1 y−1 while applying various scenarios. It is worth mentioning that the prioritization results obtained from the Condorcet algorithm and the current soil erosion rate are highly similar. On the other hand, sub-watersheds 2 and 9 were selected as the first and last priority, providing an appropriate roadmap for managers and relevant departments to adopt appropriate soil erosion inhibition measures.

Soil erosion resistance of gully system under different plant communities on the Loess Plateau of China

AbstractGully erosion, considered as a type of intensive erosion, is the dominant source of sediment at small watershed scales in certain environments. Variation of vegetation may result in the changes in near soil surface characteristics, which likely further affect the resistance of gully systems to erosion. However, the potential effects of near soil surface characteristics of plant communities on resistance to erosion are still unclear in gully systems. This study was performed to investigate the variations in resistance of gully systems to erosion under different plant communities and to identify the dominant influencing factors leading to these variations on the Loess Plateau. Five typical plant communities (two grasses, two shrubs and one forest) that distributed on different gully systems were selected. Six hundred undisturbed soil samples collected from different sites of gully systems were subjected to detach by overland flow under six different shear stresses (6.66 to 15.02 Pa). The results showed that the mean soil detachment capacity of gully systems covered by grass and shrub communities was 0.15 and 0.37 times to that of gully system covered by forest. Compared to forest gully systems, rill erodibility reduced by 29.8% to 85.6% for the other four plant communities. The relative rill erodibility of different vegetation communities generally increased from grass to shrub and forest communities. The critical shear stress of forest gully system was 58.7% and 63.8% of gully systems covered by grass (6.22 Pa) and shrub (5.73 Pa) communities. Bulk density, soil cohesion, water stable aggregate, root mass density, and the thickness of biological soil crust were the dominant factors affecting the resistance of gully systems to soil erosion. Rill erodibility decreased logarithmically with increasing soil cohesion, water stable aggregate and root mass density. Critical shear stress increased with the increase of soil cohesion and root mass density as a power function, and linearly with the increase of water stable aggregate. These results show how vegetation can mitigate against the erosion induced by concentrated flow in relatively stable gully systems.

Spatiotemporal characteristics and variability in the thermal state of permafrost on the Qinghai–Tibet Plateau

AbstractPermafrost degradation on the Qinghai–Tibet Plateau (QTP) has significant impacts on climate, hydrology, and engineering and environmental systems. To understand the temporal and spatial characteristics of permafrost on the QTP, we quantified the variation in active layer thickness (ALT), permafrost thermal state, and future permafrost change under different scenarios using observational data, reanalysis data, and the numerical permafrost model. Generally, ALT ranged from 0.5 to 6.0 m with an average of 2.39 m, and mean annual ground temperature (at a depth of zero annual amplitude for ground temperature) mainly ranged between 0 and −3°C with an average of −0.85°C. The soil temperatures in different layers based on the ERA5‐Land data revealed even stronger increasing trends, for example, 0.245, 0.245, 0.244, and 0.238°C/decade at depths of 0–7, 7–28, 28–100, and 100–289 cm from 1980 to 2021, compared to those during the period from 1960 to 2021, which were 0.153, 0.156, 0.155, and 0.149°C/decade, respectively. The average warming trends in annual mean soil temperature were 0.153 and 0.243°C/decade from 1960 to 2021 and 1980 to 2021, respectively. The average rate of thickening of the ALT among the 10 active layer observation sites was 2.84 cm/year. There was a significant warming trend in ground temperature above ~15 m with warming of 0.063 to 0.120, 0.026 to 0.182, 0.101 to 0.314, and 0.189 to 0.303°C/decade at the QTB01, QTB06, QTB08, and XDTGT sites, respectively, and yearly minimum ground temperatures exhibited stronger warming trends than maximum ground temperatures. In addition, the simulation revealed significant increases in ground temperature at the Xidatan (XDT) and Tanggula (TGL) sites under both historical and future Representative Concentration Pathway (RCP) scenarios, but the increases in ground temperature were significantly greater at TGL than XDT. These findings provide important information for understanding the variability in permafrost degradation processes and improving simulations of permafrost change under climate change on the QTP.