Soil Water Conservation Research Articles

Role of Land Use Dynamic Nature and Their Influence on Soil Physico-Chemical Properties in Various Watersheds in Ethiopia

Land-use changes have remarkable effects on the dynamics of soil properties. The lowest mean of bulk density, the highest fraction of clay, soil pH, soil organic matter, total nitrogen, available phosphorus, cation exchange capacity, and exchangeable base were recorded in forest land. Also, soil depth data might fluctuate with increasing soil depth. This variation might be due to inappropriate land use management led to disturbance of soil nutrient status, indicating that the soil condition in the cultivated land and plantation forest is getting below the condition of soils under natural forest and grazing lands. Therefore, needs immediate intervention to protect the remnant natural forest and to replenish the degraded soil properties proper land use plans and soil water conservations are important to enhance and sustain soil fertility and agricultural productivity.

Compounding morphometric parameters for prioritization of vulnerable watersheds for land restoration planning in Beas sub basin, India using geospatial techniques

Abstract The Beas sub basin falling under the Indus basin in Northern India is experiencing notable changes due to human interventions since the rise of civilization in the Indus valley. The incessant anthropogenic pressure, infrastructural development, deforestation and encroachment have made the sub basin more vulnerable to land degradation, erosion and landslides. Thus this study attempts to classify the watersheds based on morphometric characteristics and prioritize the watersheds for sub basin management as a whole so that restoration process can concentrate on the high risk prone watersheds. In this study ALOS PALSAR DEM of 12.5 meters was used to extract the drainage network, watershed, catchment sub basin and basin boundary complemented by topographic and hydrological maps. The study analyses 49 morphometric parameters under categories like linear, areal and relief characteristics. The result classifies the erosion capacity of total 4126 streams with the cumulative length of 12,287.51 km over a sub basin area of 19,338.8 Km2. The morphometric parameters were integrated for each watershed and compound factor was given to rank vulnerability in the GIS environment. The results depicted that sub watershed numbers 2, 6, 12, 16 were high risk prone and underlined as an area which requires immediate attention for soil water conservation measures.

Enhancing Soybean and Maize Yields through Improved Nitrogen and Soil Water Use Efficiencies: A 40-Year Study on the Impact of Farmyard Manure Amendment in Northeast China.

The combined application of manure and chemical fertilizers has been recognized as a critical factor driving significant changes in crop yield and nutrient use efficiency, holding the potential to optimize agricultural management to achieve high yields. In this 40-year study, we investigated the effect of manure amendment on soybean and maize yields, water and nitrogen use efficiencies (WUE and NUE), and water and mineral N storage at 0-100 cm soil depths from 2017 to 2018 to explore the optimization of fertilization management strategies for soybean and maize production in Northeast China. To elucidate the impact of chemical fertilizers and manure, twelve treatments-control (CK); single N fertilizer at a low rate (N1) and that at a high rate (N2); N1, phosphorus (P), and potassium (K) fertilizer (N1PK); manure alone at 13.5 and 27 t ha-1 (M1 and M2); and those combined with N, P, or K fertilizer (M1N1, M1N2, and M1N1PK and M2N1, M2N2, and M2N1PK)-were selected and studied. The results showed that long-term amendment with manure significantly increased crop biomass and yield in the soybean-maize-maize rotation system. Combining with manure increased the WUE, the partial factor productivity of N fertilizer (PFPN), and N physiological efficiency (PEN) in both the soybean and maize seasons; conserved soil water (mainly at 40-60 cm); and increased soil N retention (in the upper 60 cm layer), which reduced the risk of N leaching, with a better effect being observed after the application of 13.5 t ha-1 manure. These results provide insight into the potential of using fertilization management strategies that include amendment with 13.5 t ha-1 manure in combination with N, P, and K fertilizer in the maize season and only chemical fertilizer in the soybean season, as these results indicate that such strategies can achieve high yields and be used to implement agricultural sustainable development in brown soil regions in Northeast China.

Soil Water in Different Management Systems of Coffee-Pine Agroforestry and Its Relation to Coffee Bean Yields

Coffee-pine agroforestry is a common land use system in Indonesia, that provides several benefits, including increased soil fertility, biodiversity, and economic returns. However, the management of coffee-pine agroforestry systems can significantly impact on soil water dynamics, affecting coffee bean yields. This study investigated the effects of different management systems on soil water dynamics and coffee bean yields in a coffee-pine agroforestry system in UB Forest, Malang East Java, Indonesia. Five different management systems were evaluated: (i) no management, (ii) pruned coffee with no fertilizer, (iii) pruned coffee with added organic fertilizer, (iv) pruned coffee with added organic-inorganic mix fertilizer, with a planting distance of pine trees of 3 x 2 m, and (v) pruned coffee with added organic-inorganic mix fertilizer under pine trees with a planting distance of 6 x 2 m. The soil water dynamics were measured at depths of 0-0.2 m with a soil moisture sensor and connected with a data logger measured within a year, started in April 2022. Coffee bean yield was measured with 100 coffee plants, then converted to production on ton ha−1. The results showed that the different management systems significantly impacted soil water dynamics and coffee bean yields. The combination of pruning and fertilization is a promising management strategy for increasing coffee bean yields in coffee-pine agroforestry systems. The consequent better growth of coffee plants impacts increasing soil water extraction. This study provides valuable insights for farmers and forest managers who are interested in improving the productivity of coffee-pine agroforestry systems and conserving soil water or sometimes needing water addition through irrigation.

Local Context Capacity Building Needs for Climate Change Adaptation among Smallholder Farmers in Uganda: Policy and Practice Implications

Climate change impacts threaten sustainable development efforts. The magnitude of the impacts, however, varies with the socio-ecological characteristics of locations. This is the reason there is consensus on the necessity for climate change adaptive capacity building that is country driven, and based on, and responsive to, local needs. However, information on context specific capacity building needs in developing countries is not readily available. The objective of this study was to establish location specific awareness, training, educational research and technology capacity building needs for climate change adaptation among smallholder farmers in Uganda. Semi-structured questionnaires were used with 465 households from five agro-ecological zones, selected based on the level of vulnerability of agricultural systems to the main climate variation and change hazards. Results reveal substantial capacity building needs in all the zones. The majority of the farmers needed capacity building for interventions on soil-water conservation practices for adapting to drought and unpredictable rainfall. For all zones, education, research, and technology were perceived as key needs. However, the needs varied among zones. These results demonstrate the importance of context specificity in adaptation efforts. The study provides agro-ecological and social system specific information for climate change adaptation planning and policy interventions for effective capacity building.

Assessment of Sesame Farmers’ Perception and Adaptation Strategy to Climate Change in Machina Local Government Area, of Yobe State, Nigeria

The study was conducted to assess sesame farmers’ perception and adaptive measures to climate change in Machina Local Government area of Yobe State, Nigeria. The data was collected from randomly sampled 63 sesame farmers in the study area. Descriptive statistics and Likert scale tools were used to analyze the collected data. The results’ findings show that sesame production is dominated by married male farmers (92.1%) that have an average age of 42 years, farm size average of 1.14 hectares, and an average farming experience of 15 years in the study area. The farmers were also found to have a household size average of 11 members; as well majority of them were found to have formal education ranging from Primary (31%), secondary (28%) and tertiary education (20%). The study findings further revealed farmers in the study area strongly agreed to perceive climate change majorly through an observed change in pattern of temperature (61.9%), and change in the pattern of temperature (46%). Meanwhile, climate change adaptive strategies used by farmers were majorly increased soil water conservation (3.17), use of chemicals, fertilizers, manure and pesticides (2.65) and using different tillage systems (2.52). The sesame farmers faced challenges of inadequate capital (69.8%), pest and disease attack (55.6%) as well as high cost of production inputs (54%). It can therefore be recommended that inputs subsidies and training on early warning systems of climate change shall be given to the farmers so as to improve their control measures to climate change.

Evaluation of environmental impact on cocoa production and processing under life cycle assessment method: From beans to liquor

This study aimed to identify the environmental impact on cocoa production and processing based on the life cycle assessment method (LCA). The major contribution of this study is to evaluate the environmental performance of a chocolate liquor in order to reveal the significant environmental hotspots along the entire supply chain. This is achieved through two main steps. First, the LCA method is applied to identify the environmental implications of managing the production and processing cocoa to become chocolate liquor. The LCA is performed based on the international ISO 14040–14043 series. Secondly, a sensitivity analysis was carried out to evaluate the impact of five proposed improvement options to discover whether any occurring potential environmental impacts will be reduced. The kind of scenarios are: reducing pesticides by 50 % (option 1); using compost instead of fertilizer (option 2); avoid burning stubble (option 3), conserving soil water (option 4) and applying alternative energy sources (option 5). As a result, the most significant environmental impact for the upstream and core processing was human toxicity potential (HTP) and cumulative energy demand (CED), 89 % and 59 %, respectively. In addition, the impact of the proposed improvement has significantly reduced environmental impacts (HTP, 68 %) and achieved savings (IDR 18800, 17.7 %). Survey data includes the entire supply chain, with a detailed focus on production and processing stages for an Indonesian chocolate company. This study only dealt with cocoa beans that generated 1 kg of chocolate liquor.

No-tillage enhances soil water storage, grain yield and water use efficiency in dryland wheat (Triticum aestivum) and maize (Zea mays) cropping systems: a global meta-analysis.

Climate change significantly affects crop production and is a threat to global food security. Conventional tillage (CT) is the primary tillage practice in rain-fed areas to conserve soil moisture. Despite previous research on the effect of tillage methods on different cropping systems, a comparison of tillage methods on soil water storage, crop yield and crop water use in wheat (Triticum aestivum ) and maize (Zea mays ) under different soil textures, precipitation and temperature patterns is needed. We reviewed 119 published articles and used meta-analysis to assess the effects of three conservation tillage practices (NT, no-tillage; RT, reduced tillage; ST, subsoil tillage), on precipitation storage efficiency (PSE), soil water storage at crop planting (SWSp), grain yield, evapotranspiration (ET) and water use efficiency (WUE) under varying precipitation and temperature patterns and soil textures in dryland wheat and maize, with CT as the control treatment. Conservation tillage methods increased PSE, SWSp, grain yield, ET and WUE in both winter wheat-fallow and spring maize cropping systems. More precipitation water was conserved in fine-textured soils than in medium-textured and coarse-textured soils, which improved ET. Conservation tillage increased soil water conservation and yield under high mean annual precipitation (MAP) and moderate mean annual temperature (MAT) conditions in winter wheat. However, soil water conservation and yield were greater under MAP <400mm and moderate MAT. We conclude that conservation tillage could be promising for increasing precipitation storage, soil water conservation and crop yield in regions with medium to low MAPs and medium to high MATs.

Examination of Farmers’ Perception on Adaptation Measures Toward Modifying Climatic Challenges for Agricultural Sustainability in Northern Nigeria

This study examines farmers’ perceptions on adaptation measures toward modifying climatic challenges for agricultural sustainability in northern Nigeria. The data were mainly derived from several sources, including maps of Nigeria and the selected States, population figures from records of the National Population Commission and from internet and library sources, as well as from questionnaire survey of farmers’ opinions. Stepwise sampling technique was employed in the selection of respondents for the questionnaire survey. Frequency tabulations and ANOVA were used to collate and analyze the variations within and between states in the farmers’ measures of modifying environmental challenges in northern Nigeria. It was concluded that 86% of the farmers were positive about climatic adaptation measures in Northern Nigeria, to the extent that there is no variation within and between states (F-value = 0.016), across the region. It was recommended that efforts at improving local or indigenous practices of water harvesting and soil water conservation should be promoted.

Effect of Sprayable Biobased Polymers on Soybean Growth and Yield, Weed Suppression, Soil Temperature, Soil-Water, Evapotranspiration and Soil Quality Variables

HIGHLIGHTSNovel sprayable biobased polymer (BBP) has been developed.BBP impact on soil temperature, soil water content, evapotranspiration, weed suppression, and soybean productivity were investigated.BBP moderated extreme high soil temperatures and resulted in an average of 3.4°C temperature moderation.BBP resulted in soil water conservation as compared with the control without BBP application.Weed number and weed dry matter were significantly lower with the BBP applications than the control.BBP increased nitrogen, organic matter content, and hydrogen content with no impact on sulfur content.Abstract. A novel sprayable biobased polymer (BBP) (bioplastic) has been developed from poultry feathers and woody biomass using chemical and thermochemical methods. Its potential impacts on soil temperature; soil water content (SWC); crop evapotranspiration (ETc); weed [common Waterhemp (WH) (Amaranthus tuberculatus) and Palmer Amaranth (PA) (Amaranthus palmeri)] suppression under soybean (SB) production; soybean growth, yield, number of pods, soybean dry matter production, 100-kernel number; and soil health variables [carbon (OMC), nitrogen (N), hydrogen (H), and sulfur (S) content, C/N ratio, and C/H ratio] were investigated. Treatments were WH+SB and PA+SB with and without BBP (control) applications. BBP moderated extreme high temperatures and resulted in 2.8°C moderation in the WH plots and 3.9°C in the PA plots with an average of 3.4°C. SWC values for the WH+SB and PA+SB with BBP were significantly (P &amp;lt; 0.05) higher than those in the WH+SB and PA+SB without BBP applications, indicating soil-water conservation effect of BBP due to reduced surface soil evaporation. There were only slight differences in daily ETc between the treatments. ETc values ranged from 0.35 to 4.9, from 0.31 to 4.9, from 0.25 to 4.9, and from 0.25 to 4.8 mm/d for the control WH+SB without BBP, WH+SB with BBP, control PA+SB without BBP, and PA+SB with BBP applications, respectively. The cumulative ETc values slightly differed between the treatments and were 329, 314, 313, and 294 mm for the same treatments, respectively. BBP suppressed WH by 42% and controlled PA by 57% without any herbicide applications. Weed dry matter production in the control WH+SB without BBP, WH+SB with BBP, control PA+SB without BBP, and PA+SB with BBP applications were 30, 15, 46.3, and 19.9 gr, respectively. Both weed number and weed dry matter for WH+SB and PA+SB were significantly lower with the BBP applications than the control. Significantly greater plant height with BBP applications did not translate into significantly higher soybean productivity under WH+SB. The higher plant height and lower number of weeds in the WH+SB with BBP treatment did not result in higher soybean dry matter production, number of pods, pod weight, or 100-kernel weight. The increases in N, OMC, and H content with BBP application were significant for both WH+SB and PA+SB with BBP as compared with their controls. The increase in S content was not significant for WH+SB or PA+SB. The increase in C:N ratio due to BBP application was significant, but the change in C:H ratio was not. Experimental results showed important positive impacts of developed BBP formulations in agricultural applications with the potential to increase productivity. Further research is needed to quantify and validate these potential positive impacts of BBP for other cropping systems in different soil and climatic conditions. Keywords: Biopolymer, Soil health, Soil productivity, Soybean, Weeds.

Impacts of Conventional Plowing on The Bearing Capacity of Ferralitic Soil in Benin Republic

The present work involved a study of the impact of tillage on soil resistance using a three-body disc plow hitched to a 60 hp tractor, on soil structure. All plowing was carried out on the same day with this plow on 21 plots, divided into 3 blocks of 7 elementary plots serving as treatments. Treatments are designated P0. P1, P2, P4, P8, P12, and P15 corresponding to plowing frequencies: 0, 2, 4, 8, 12, and 15. The P0 treatment is used as a control. The tests were carried out in accordance with the standards: NF P 94-050.1995, for water content by weight, NF EN 1097-3.1998, for apparent density, and NF EN 1097-6.2001 for porosity. Soil conductivity was determined using the Muntz method. The results show that plowing at a minimum frequency of one or two per cycle provides better soil resistance. Two plowings per cycle gave better soil resistance (20.8 (0.27) bc; 19.6 (0.27) d), water content (0.016 (0.002) b ; 0.015 (0.002) b). Soil hardness and density decrease with increasing water content, while porosity increases with plowing frequency (0.437 (0.017) a to 0.478 (0.017) a). For this type of soil, one or two plowings are more than enough to maintain better soil resistance and water conservation. This work has enabled rural actors, and farm machinery operators in particular, to better carry out tillage operations. Keywords: Agricultural soil, soil tillage, mechanical properties, penetration resistance, Benin Republic.

Assessing the Impacts of Soil Water Conservation Activities and Slope Position on the Soil Properties of the Gelda Watershed, Northwest Ethiopia

Assessing the Impacts of Soil Water Conservation Activities and Slope Position on the Soil Properties of the Gelda Watershed, Northwest Ethiopia

Supporting Water-Food-Land Nexus policy coherence through integrated agrifood advisory and extension system in Egypt

Building policy coherence is significant in governing natural resources, especially in a changing climate and growing population. Designing and implementing coherent climate-adaptive water productivity policies through holistic and integrated knowledge could manage the growing demand for food and water, and sustain small-scale farmers’ livelihoods and economies, which is the aim of this research. This study focuses on the analysis of power dynamics and the social network that evolves around the control of information and technical assistance that shape policy narratives. Results showed that donors and financial institutions are the primary powers to control and organize knowledge and technical assistance linked to soil-water conservation especially when it’s combined with mobilizing relevant funds. Many smallholder farmers still adopt traditional patterns of cultivation due to the siloed knowledge gaps in the extension services of governmental entities, the unreachability of extension services, the lack of trust in their guidance, and the absence of innovations’ scalability. Building integrated extension services between ministries, by providing equal and suitable financial packages. This would be feasible by managing the coordination with financial institutions, monetary and non-monetary incentives, and building on existing farmers’ collective organizations and farmers’ pioneers to enable a sociological transition to water productivity.

Evaluation of Farmers Knowledge, Vulnerability and Adapting Capacity to Climate Change: A Scenario in Bundelkhand Region

Agriculture production in the Bundelkhand region is highly vulnerable to the climate change. To examine the perception, awareness, extent of knowledge on climate change and its impact on agriculture production with coping strategies, a research study was conducted with randomly selected, 70 sample farmers household from two villages of Datia district. More than 80 per cent farmer feels that climate change is serious issue, and it affects water availability and crop production. 77 percent respondents from watershed area expressed their view, that climate change reduced crop yield followed by the reduction in milk yield, disease and pest incidence, rainfall reduction and environment effect. Results shows that respondents of Jigna village (under watershed area) are reported to be more aware about impact of climate change (temp., rainfall, wind velocity) as compared to Dalipura village. Farmers from both villages were reported deforestation, intensified industrialize and air pollution as reason for consequence of climate change. Intensify research efforts and Enlightenment campaign as efforts to overcome climate change are reported by majority of respondents. Changes in existing cropping pattern and soil-water conservation measures suggested as coping-strategies for climate change.

TILLAGE PRACTICES AFFECT THE WATER CONSERVATION BENEFITS OF RAINWATER HARVESTING IN SEMI-ARID CONDITIONS

Livelihood in the Pothwar region of Pakistan is largely dependent on rainwater. Therefore, storing and conserving rainwater for its subsequent use when required is crucial. Amongst various means of in-field moisture conservation, tillage practices play a dynamic role, especially in loose soils of Pothwar area. Under this study, the efficiency of commonly used tillage implements i.e., mould board (MB) plough, disc plough and cultivator, was evaluated for moisture conservation and improvement in wheat (Triticum aestivum L) yield. The three years’ study showed that maximum soil moisture and grain yield were obtained in the field tilled with MB plough followed by disc plough. It has been observed that soil water was improved by 11.3, 10.6, 9.9 and 11.5 % in the treatment of MB plough, while this increase was recorded as 5.7, 9.0, 5.2 and 6.8 % in disc plough as compared to cultivator at sowing, 02 months &amp; 04 months after sowing and harvesting stage, respectively. In the treatment of MB plough, improvements were observed as a wheat grain yield 16%, wheat straw yield 19%, productive tillers 6% and plant height by 2%. Furthermore, MB plough enhanced its productivity and profitability with the highest benefit-cost ratio of 1.83. The role of disc plough in soil water conservation and crop productivity enhancement was observed less than MB plough. The current study observed that use of MB plough is beneficial in soil water conservation and improvement of crop yield.

Water management and irrigation for bulb onion (Allium cepa L.) growth and development in the Papua New Guinea Highlands

Water is crucial for nutrient intake, transportation, temperature regulation, and photosynthesis in bulb onion (Allium cepa L.) growth and development. Water scarcity, caused by climate variability and particularly during prolonged dry periods, has proved to be an obstacle to cultivating bulb onions in the Papua New Guinea (PNG) Highlands. Farmers have a limited grasp of the interdependence of soil, water, and plants. They have traditionally depended on precipitation, and water from streams and rivers, to irrigate their bulb onion crops. The main method for providing irrigation support is manual irrigation, with agricultural organisations assisting with basic irrigation technologies. Despite farmers and organisations efforts to improve irrigation practices, the prolonged dry season still raises labour demands for bulb onion farms. Farmers’ lack of knowledge about irrigation technology and soil water conservation contributes to this issue. Moreover, the lack of irrigation suppliers worsens the issue of limited soil water in onion farms. This paper gives an overview of onion production in PNG, focusing on irrigation practices and constraints in the Highlands region. It aims to stress irrigation’s importance in crop growth and explore PNG’s irrigation methods and soil moisture conservation practices. There is a need for a sustainable irrigation and soil water conservation system that is easy to use and incorporates crop water requirements. This system is vital for watering onions and conserving soil moisture, promoting their growth and yield. In this context, the use of mulch and irrigation systems can preserve and enhance soil moisture during prolonged dry phases.

Optimizing ecosystem function multifunctionality with cover crops for improved agronomic and environmental outcomes in dryland cropping systems

CONTEXTIntegrating cover crop mixtures into dryland crop-fallow rotations may foster ecological intensification by enhancing ecosystem function multifunctionality compared with conventional fallows and monoculture cover crops. However, the expression of functional traits in cover crop mixtures is influenced by arrays of agronomic and environmental filters that differently influence cover crop performance. OBJECTIVETo (1) determine the identity and diversity effects of different cover crop functional types on ecosystem functions and trade-offs, and (2) determine the optimal cover crop mixture that maximizes ecosystem function multifunctionality in a subtropical dryland environment. METHODSUsing three-site-year field experiments, we assessed if cover crop mixtures enhanced ecosystem function multifunctionality (MF) above that of monoculture cover crops and conventional fallow. We measured a range of ecosystem functions as indicators of three major ecosystem service categories: 1) provisioning services (biomass production, cash crop yield, and profitability); 2) supporting services (weed suppression, soil active carbon accrual, soil aggregate distribution, nitrogen (N) mineralization, N supply, and N retention); and 3) regulating services (parasitic nematode suppression, promotion of free-living nematodes, soil respiration, and soil water conservation). RESULTS AND CONCLUSIONSWe found greater suite of ecosystem functions following mixture cover crops compared to monocultures, likely due to synergistic trait combinations that increased ecosystem function multifunctionality. The legume and forage brassica monocultures had consistently low multifunctionality (MF < 0.5). The oat:legume mixture resulted in the highest multifunctionality (MF > 0.5), driven by moderate water use and aboveground biomass production, and high groundcover residency, thus favouring higher cash crop yields and system profitability. They also generated overall improvements in soil health by providing additional carbon inputs, increasing the proportion of larger soil aggregates, and improving soil food web structure. We predicted the optimum cover crop mixture to maximize ecosystem function multifunctionality was 64% oat, 36% legume and 0% forage brassica. SIGNIFICANCEThis study offers novel insight into the agronomic and environmental impacts of replacing fallow with cover crops in a subtropical dryland. It shows that integrating mixture of oat:legume cover crops can increase multifunctionality. Further research is required on the extent of ecosystem trade-offs between competing ecosystem functions. The predicted optimum cover crop mixture composition will likely vary when different ecosystem functions are considered or if long-term experiment data are used. Hence, the recommended optimum cover crop mixture must be interpreted with caution and cover crop selection should be based on practical recommendations according to target management goals.

Plants Performance in the coal mining restoration area in Tabang, East Kalimantan

Coal mining production in East Kalimantan use open mining methods that changes ecosystem performance. After mining activity, the company is obligate to restore and rehabilitate the area to improve the land conditions. The study aims to evaluate plant performance in four different plants age to give brief information in restoration and rehabilitation in post coal mining land. Four different ages of two species, Falcataria falcata and Enterolobium cyclocarpum, were measured for diameter, height, and survival rate in the 0.25 ha of the plot sample. The measurement indicated that Falcataria falcata could reach diameter and height rate per year in 2.89 centimetres and 2.08 meters, respectively. As comparison, The Enterolobium cyclocarpum diameter performance could reach 3.54 centimetres per year; however, height performances only reach 1.75 meter per year. The first species indicated better indication for the standing performance; however, the other species indicated better performance in the canopy cover that could be advantage for soil micro climate and water conservation.

Sub-Shrub Components Change the Soil Water Storage Response to Daily Precipitation and Air Temperature in the Loess Plateau

Soil water shortage has become a severe issue in ecological restoration and sustainable development in the Loess Plateau, facing the challenges of climate change and vegetation restoration. This study monitored the soil water content in surface soil (0–40 cm) with different sub-shrub component treatments, including the natural condition (NC), the canopy plus the roots (CR) and only the roots (OR), to analyze the change in soil water storage (∆W) and its response to precipitation (P) and air temperature (Ta) on a daily scale. P was the main factor controlling the daily ∆W, contributing 49–52% to the variation in the daily ∆W, and Ta only explained 6–21% of the variation. Minimum P amounts of 0.74–1.12 mm and maximum Ta of 29.09–32.00 °C were the thresholds required to increase soil water storage (W). Sub-shrub components showed significant influences on soil water conservation. We found that the ∆W hierarchy for each sub-shrub treatment was NC (1.73 mm) &gt; CR (0.71 mm) &gt; OR (0.56 mm) on rainy days and NC (−0.53 mm) &lt; CR (−0.36 mm) &lt; OR (−0.06 mm) on no-rain days. Additionally, the hierarchy of the rainwater retention rate was NC (26.43%) &gt; OR (13.71%) &gt; CR (4.58%). Thus, a canopy could increase infiltration and hugely consume soil water at the same time, while litter could weaken or offset the canopy’s effects and the roots promote infiltration with little evaporation loss.

Impact of biochar on the antibiotic resistome and associated microbial functions in rhizosphere and bulk soil in water-saving and flooding irrigated paddy fields

The addition of biochar in paddies under the condition of water-saving irrigation can simultaneously achieve soil improvement and water conservation, but little is known about the role of these two regulations in mediating the fate of antibiotic resistome in paddy soils. Here, metagenomic analysis was conducted to investigate the effects and intrinsic mechanisms of biochar application and irrigation patterns on propagation of antibiotic resistance genes (ARGs) in paddy soils. The addition of biochar in paddy soil resulted in a reduction of approximately 1.32%–8.01% in the total absolute abundance of ARGs and 0.60%–22.09% in the numbers of ARG subtype. Compared with flooding irrigation, the numbers of detected ARG subtype were reduced by 1.60%–22.90%, but the total absolute abundance of ARGs increased by 0.06%–5.79% in water-saving irrigation paddy soils. Moreover, the combined treatments of flooding irrigation and biochar could significantly reduce the abundance of ARGs in paddy soils. The incremental antibiotic resistance in soil induced by water-saving irrigation was likewise mitigated by the addition of biochar. Correlation analyses indicated that, the differences in soil physicochemical properties under biochar addition or irrigation treatments contributed to the corresponding changes in the abundance of ARGs. Moreover, the variations of microbial community diversity, multidrug efflux abundance and transport system-related genes in paddy soil were also important for mediating the corresponding differences in the abundance of ARGs under the conditions of biochar addition or irrigation treatments. The findings of this study demonstrated the effectiveness of biochar application in mitigating antibiotic resistance in paddy soils. However, it also highlighted a potential concern relating to the elevated antibiotic resistance associated with water-saving irrigation in paddy fields. Consequently, these results contribute to a deeper comprehension of the environmental risks posed by ARGs in paddy soils.