Water Infiltration Rate Research Articles

Review of Adoption and Impact Assessment on Conservation Agriculture in Ethiopia

Conservation agriculture plays a great role in improving farming land productivity and mitigating climate change impact. It is a concept for resource-saving agricultural crop production that strives to achieve acceptable profits together with high and sustained production levels while concurrently conserving the environment. The paper initially investigates theoretical concepts of conservation agriculture in Ethiopia. It then reviews the adaptation level of conservation agriculture by farm households and its impact on their productivity. The various challenges for the adoption of Conservation agriculture are lack of knowledge in CA at the expertise and farmers' level; the belief of farmers on tillage, technical, social, financial, and policy issues; the market does not supply them with the necessary seeds to carry out intercropping; high input costs, low input availability, and associated high opportunity costs for crop residue; and also lack biomass and residues. Its major impacts are increased labor productivity at the time of soil preparation; it helps with water harvesting strategy; the benefit of crop residue retention is a higher content of organic matter in the soil and higher water infiltration rates, which reduces surface runoff and soil erosion significantly.

Effects of Straw Mulching on Near-Surface Hydrological Process and Soil Loss in Slope Farmland of Red Soil

Slope farmland is prone to soil erosion, especially in sub/tropical regions. However, our understanding of near-surface hydrology characteristics and their controlled factors in red soil sloping farmland remains limited. Here, we conducted simulated rainfall experiments to assess the impact of rainfall pattern, straw mulching, and soil structure on near-surface hydrological processes of red soil sloping farmland of southern China. Results showed that: (1) short duration-high intensity rain caused greater surface runoff and sediment production than did long duration-low intensity rain, whereas the variation pattern of subsurface flow exhibited the opposite trend; (2) tillage behavior could weaken the surface runoff intensity and promote the development of subsurface flow; (3) straw mulching increased the water infiltration rate and associated subsurface flow production (increased by 1.33~12.71 times), and thus reduced the surface runoff production (reduced by 99.68~100%). These findings highlight the crucial roles of rainfall pattern and straw mulching in regulating the spatial distribution pattern of rainwater and suggest that straw mulching can effectively reduce soil erosion via accelerating water infiltration and subsurface flow form in slope farmland of soil erosion in southern China.

Plant water stress, not termite herbivory, causes Namibia’s fairy circles

The fairy circles of Namibia form a remarkable gap pattern in arid grassland along the Namib Desert. The origin of the fairy circles is subject to an ongoing debate. Solving the mystery of the fairy circles (FCs) requires the right timing in fieldwork after rainfall, as the newly appearing grasses complete their life cycle within only a few weeks. Here we followed the rains along the Namib between 2020 and 2022 and assessed the cause of the grass death within FCs at different time intervals after grass-triggering rainfall. To assess whether termite herbivory was the cause, we used grass excavations and observations on the roots and shoots. To test if edaphic differences may explain the grass death in FCs, we undertook infiltration measurements in 10 FC-hotspot regions. Finally, we used continuous soil-moisture measurements from the dry into the rainy seasons to examine how the newly emerging grasses affect the soil-water content in space and time. Generally, in study plots that received grass-triggering rainfall most recently, the roots of the dead grasses in FCs were in 100 % of the cases undamaged, root-shoot ratios were significantly greater, and the roots were as long or even longer as those of the surrounding matrix grasses outside of the FCs. This indicates that drought stress caused grasses in the FCs to invest resources into roots to reach the percolating water. The results also show that the cause of the grass death in fairy circles was not induced by termite herbivory. Also, we found no systematic differences in the rate of water infiltration between FCs and the matrix, hence the plant wilting cannot result from quicker percolation within FCs. However, the soil-moisture measurements indicate that the matrix grasses strongly depleted the upper soil water of the FCs after rainfall, which explains why most grasses cannot establish and quickly die in the FCs. The research shows that grass death in fairy circles occurs immediately after rainfall due to plant water stress but not due to termite activity. Our results conform with previous fieldwork, pattern analysis and theoretical modeling, suggesting that Namibia’s fairy circles are a self-organized vegetation phenomenon induced by ecohydrological feedbacks.

Wetting front of soil infiltration test by real-time sensing in prototype system real-time wetting front in soil infiltration tests

Agriculture is the most water-demanding economic activity. Nevertheless, the monitoring of agricultural production systems can improve the soil water condition and contribute to soil conservation, as well as increase irrigation efficiency through quick and assertive decision-making. Thus, the objective of this work was to carry out a real-time evaluation of the wetting front (WF), the water infiltration rate in the soil, and to verify whether the system performance can affect infiltration test data in a Red Latosol with clayey and very clayey textures. The public domain prototype system consisted of a permeameter, and 10 soil moisture sensors that were calibrated by the oven drying method and inserted into a PVC pipe from 10 cm to 100 cm depth. The equipment allowed the evaluation of the wetting front and calculation of the infiltration rate and water retention and variations along the soil profile. Data were analyzed using descriptive statistics using RStudio and Excel. The results showed that the prototype system is effective to simulate the water infiltration rate in the two soil textures analyzed at low cost.

Hydrochemical evolution characteristics and genesis of groundwater under long-term infiltration (2007—2018) of reclaimed water in Chaobai River, Beijing

The reuse of reclaimed water (RW) for river ecological restoration in global water-shortage regions has inevitably brought some potential risks for groundwater. However, little is known about the effects of reclaimed water on the hydrochemical evolution of groundwater especially under long-term infiltration conditions. Herein, 11-years monitoring data (2007–2018) of reclaimed water and groundwater were adopted to analyze the characteristics and genesis of groundwater hydrochemical evolution under long-term infiltration of reclaimed water from Jian River to Chaobai River in Beijing. The results showed that the hydrochemical components in groundwater totally performed a significant increase in Na+, Cl–, and K+and decrease in Ca2+, Mg2+, and HCO3– concentration after long-term infiltration of reclaimed water. Meanwhile, a significant hydrochemical evolution difference between the groundwater of Jian River and Chaobai River was observed. In Jian River, the hydrochemical type in groundwater shifted gradually from HCO3–Ca·Mg to the type of HCO3·Cl–Na·Ca approaching reclaimed water. In contrast, the hydrochemical evolution in the Chaobai River shows an obvious opposite trend from HCO3–Ca·Mg to HCO3·Cl–Na·Mg and finally deviating reclaimed water type of Cl·HCO3·SO4–Na. PHREEQC simulation indicated that the differences in hydrochemical evolution were mediated synergically by sediment thickness and geochemical processes (e.g. mixing and sulfate reduction). In such mediators, thinner sediment and strong mixing in the Jian River were confirmed to be the genesis of groundwater hydrochemical evolution progressively approaching reclaimed water. Different from the Jian River, multiple regression analyses revealed that the genesis of groundwater hydrochemical evolution in the Chaobai River was divided into two stages according to the increase of sediment thickness. Reclaimed water quality and infiltration amount are the leading proposed cause in the initial stage (2007–2008) due to thinner sediment formation, contributing 53.5% and 29.8% within the 95% confidence interval, respectively. Subsequently, the rise in sediment thickness is proved to play a crucial role in groundwater hydrochemical evolution trend away from reclaimed water (2009–2018), with a contribution of 41.6% within the 95% confidence interval. It is mainly attributed to the reduced reclaimed water infiltration rate and favorable sulfate reduction conditions. These findings advance our understanding on groundwater hydrochemical evolution under long-term infiltration of reclaimed water and also guide future prediction of evolution trends.

Rancang Bangun Double Ring Infiltrometer Untuk Pengukuran Penambahan Ketinggian Sabut Kelapa

Infiltrometer technology is a water infiltration system that can measure water levels in a certain area to determine the maximum water infiltration rate so that natural disasters can not occur arising from the lack of infiltration land. The purpose of this study is to determine the design of the double ring infiltrometer to determine the effect of increasing the height of coconut husk, the stages in the fabrication process of the double ring infiltrometer, the effect of adding the height of coconut husk, and the validation results in the infiltrometer rate measurement process. The fabrication method carried out is by rolling process and welding process. The material used in this study is stainless steel grade 304 (SS 304). The measurement results show that the addition of coconut husk will inhibit the rate of water absorption into the soil when compared to open soil with an average change in infiltration rate for 0.006 mm/s for the initial infiltration rate and 0.004mm/s for the constant infiltration rate. Thus, it can be concluded that the addition of coconut husk as a ground cover does not have much impact on the rate of water infiltration into the soil, especially in the direction of water infiltration perpendicular to the ground. So that coconut coir can be said to be a safe material to use as a ground surface cover compared to concrete, castings, or asphalt.

Rancang Bangun Double Ring Infiltrometer Untuk Pengukuran Pengaruh Penambahan Ketinggian Pasir

Double ring infiltrometer is a tool to measure the rate of infiltration into the soil. The design of the double ring infiltrometer has 3 stages, the first using 304 stainless steel material, the next stage is the rolling process using a rolling machine 6 × 1300 mm BB613RL, and the last stage is the welding process using TIG welding. The effect of adding sand on changes in the infiltration rate that occurs in the two rings, in this change the slowing of the infiltration rate does occur because the sand blocks the infiltration of water directly into the soil. However, the slowdown in the infiltration rate that occurs tends to be very small so that it can be said that it has no significant effect on the infiltration rate without sand. The results of the measurements showed that the initial and constant infiltration rates slowed down with a change in the average infiltration rate that occurred, namely 0.005 mm/s at the initial infiltration rate and 0.002 mm/s at a constant infiltration rate. Thus it can be concluded that the addition of sand as a ground cover does not have much impact on the rate of water infiltration into the soil, especially in the direction of water infiltration perpendicular to the soil. So that this sand can be said to be a safe material to use as a ground cover compared to concrete, castings, or asphalt.

China sewage treatment engineering issues assessment

Urban clean water is an important component of water resources management and is essential for achieving the United Nations Sustainable Development Goal. The Chinese government has attached great importance to urban sewage treatment and clean water resources. Unfortunately, the urban water quality has not shown a corresponding improvement with the increasing investment in the construction of urban sewage treatment infrastructures. In this study, we established a quantitative assessment index framework for engineering issues of urban sewage treatment system, including the lacking rate of a sewage pipe network, external water infiltration rate of a sewage pipe network, surplus rate of a sewage treatment plant, and discharge rate of untreated sewage. Then the assessment for engineering issues of urban sewage treatment system in China was conducted from the national level, provincial level and city level for the first time, with the Chinese government's open data and statistics. The results showed that the lacking rate of sewage pipe networks in China was 53%, the external water infiltration rate of sewage pipe networks was 34%, the surplus rate of sewage treatment plants was 54%, and the discharge rate of untreated sewage was 38%. The engineering efficiency of urban sewage treatment system in China was not high and varied among provinces and cities. In many urban areas, sewage pipe networks were incomplete or defective, lack and external water infiltration of sewage pipe networks are common, as well as misconnection of stormwater pipelines; and the problem of sewage direct discharge is serious. Improving the engineering efficiency of urban sewage treatment system, completing, repairment and reconstruction of sewage pipelines were the top priority of urban clean water in China. The assessment index framework established in this study can provide scientific basis for further advancing urban clean water, and the assessment for engineering issues of urban sewage treatment system is significant for the sustainable development of urban water resources.

Rotational horse grazing and dry weather maximize infiltration into soil macropores

Growing livestock populations have intensified the potential for detrimental effects of grazing on grassland soils globally. Grazing management techniques can mitigate these effects but they are livestock-specific and studies on horse grazing are rare. The objective of this work was to compare the effects of rotational grazing (i.e., livestock graze sub-sections of a pasture in sequence) with the continuous approach to grazing on (1) rates of water infiltration (i) at slightly negative pressure potentials (h, −15, −10, −5, −3.5, −1 hPa), (2) saturated hydraulic conductivity (Ksat), and (3) bulk density (BD). At a site in New Jersey, USA, one pair of pastures was managed with rotational grazing while another pair experienced continuous grazing. Twelve Standardbred mares were grazed for two years at a stocking rate of 0.52 horses ha−1. Over that period, i (n = 79, each at 5 h values) and BD (n = 154, from depth ranges 0–10 and 30–40 cm) were measured multiple times and Ksat values were derived from infiltration measurements. Also, the standardized precipitation-evapotranspiration index (SPEI) was calculated with meteorological data from a nearby weather station. We found that: (1) i values inclusive of the largest pores tested (h = −1 hPa) were greater in rotationally- vs. continuously-grazed fields (geometric means ± GSE were 80.2 ± 1.15 and 42.3 ± 1.13 cm d−1, respectively), (2) Ksat values were consistent with those of infiltration at h = −1 hPa but were too variable to isolate the effect of pasture management, and (3) near-surface BD was similar under rotational and continuous grazing (arithmetic means ± SE were 1.32 ± 0.02 and 1.37 ± 0.02 Mg m−3, respectively). Further, during periods of water surplus (i.e., when SPEI was positive), infiltration was strongly reduced in the smaller soil pores (h = −10 and −15 hPa) of the rotationally-grazed fields. This reduction was likely the result of pore colonization and blockage by pasture grass roots growing in these fields. This study suggests that rotational management allows for a larger macropore system than continuous grazing, which could lead to a reduction of water deficits and contribute to the sustainability of grazed ecosystems, with positive effects accruing through time.

Influence of Tillage and Cropping Systems on Soil Properties and Crop Performance under Semi-Arid Conditions

Conservation agriculture helps to mitigate the adverse impacts of conventional practices and intensive cultivation, accordingly enhancing agricultural sustainability. Tillage management and the preceding crop impact the sustainable use of soil resources and ultimately crop growth and productivity. The present study aimed to assess the impacts of the tillage system, cropping system, and their different interactions on soil properties and agronomic performance. No-tillage (NT), reduced tillage (RT), and conventional tillage (CT) were combined with three cropping systems; continuous wheat (wheat/wheat/wheat, W/W/W), lentil/wheat/lentil (L/W/L), and oat/wheat/barley-pea (O/W/BP) during three years crop rotation. The results displayed that the conservative practices (NT and RT) recorded higher soil nutrient content (N, P, K, Ca, and Mg) than conventional tillage (CT). Moreover, NT and RT exhibited higher bulk density (BD) and lower water infiltration rates compared to CT. Besides, NT and RT tended to have higher soil moisture than CT. The cropping system W/W/W displayed higher magnesium content, while W/L/W had higher phosphorous and O/W/BP showed higher sodium values. The mono-cropping system under conventional tillage tended to have lower soil nutrient content compared to the other combinations. The highest wheat aboveground biomass, wheat grain yield, and lentil seed yield were produced by RT and CT compared to NT. Otherwise, the higher emergence of barley-pea was assigned for NT followed by CT and RT.

Modelling Water Consumption Efficiency Based on Perlis State Soil Series

Water is a limited resource for Perlis state. Domestically, meeting the water supply in the state requires improving the current supply facility and repairing water leakages in the supply system. However, an even more important aspect of water resources management is the water consumption from agricultural activities such as the over-irrigation in the crop field. This study identifies the soil series of Perlis state, determines its soil textures, estimates the field capacity, permanent wilting point, and plant available water. Additionally, the water infiltration studies were carried out. Results showed there were ten soil series present in the state, and this soil can be categorized by four soil textures that the clay soil texture dominates in seven soil series. Fully saturated soil in the Perlis state potentially losses 27-56% of its soil moisture content drains by gravity, which is unavailable to crop consumption, hence, wastage. An estimated 1.7 x 10-4 to 2.1 x 10-3 m/s water infiltration rate over the soil depths from 0.15-1.5 m. Knowing the soil surface area for the crop field allows the estimate of water volume needed in a unit time needed for storage tank estimation and distribution system designs. The water requirement increases by including the water evaporation rate into the water infiltration rate.

Keragaman Jenis Pohon dan Peresapan Air di Lahan Terbiarkan Setelah Kebun Tradisional

Ecological aspects of abandoned lands can be determine from many aspects, including the family diversity and the ability to absorb water. This study aims to determine the important value index based on tree family and the ability to absorb water (infiltration rate and permeability) on abandoned land after traditional gardens. The vegetation survey of trees with a diameter at breast height (DBH) >5 cm was carried out on 10 sub-plots each measuring 20 m × 20 m. Infiltration rate and permeability measurements were carried out 3 times with 3 repetitions each. The highest family significance values (FIV) were Euphorbiaceae (104.07), Moraceae (84.75), and Sapindaceae (20.94). The infiltration rates were 12.8 cm/hour in secondary forest (gentle slope), 6.0 cm/hour in secondary forest (a rather steep slope), 1.6 cm/hour in open land (gentle slope), and 1.2 cm/hour in open land (a slightly steep slope). Permeability in secondary forest (gentle slope), secondary forest (a rather steep slope), open land (gentle slope), and open land (a rather steep) were 15.45 cm/hour, 11.15 cm/hour, 9.82 cm/hour, and 8.93 cm/hour, respectively. Information about the diversity and water absorption can be used as a basis for consideration in managing abandoned lands in the future.

ZONASI KAWASAN RESAPAN AIR DAERAH CIJERUK, KECAMATAN CIJERUK, KABUPATEN BOGOR, PROVINSI JAWA BARAT

Cijeruk known as a strategic location that is still very close to the Mount Salak area, but also close to the urban area of Bogor itself. This causes the area to have the potential to have good water absorption, but it also has the potential to be disturbed by water absorption due to internal and external factors in the research area. For this reason, it is necessary to know the water absorption and infiltration rate in order to see the advanced conditions of the research area. In order to know this, researchers need to obtain primary data by processing in the field using a Double Ring Infiltrometer (Indonesian National Standard, 7752:2012); while secondary data were obtained from previous researchers, as well as official bodies in Indonesia. The rainfall at the nearest Citeko station per 5 years reaches more than 3000mm, namely 3168.8mm, indicating that the research area has a very high potential for rainfall. In addition, it can be concluded that the research area has a type of overburden in the form of loamy sand with flat to steep areas in 4 observation locations, while the other 5 observation locations are flat to very steep. Then, the results obtained in the Cijeruk area obtained 2 units of infiltration rate, namely sufficient infiltration rate with an infiltration rate of 0.192 m/day to 0.312 m/day and a high infiltration rate with an infiltration rate of 1.08 m/day up to 5.04 m/day. indicates that the water catchment area is classified as good.

Fuzzy system design for automatic irrigation of agricultural fields

One of the main challenges in arid and semi-arid regions is the lack of water for various purposes such as industrial and agricultural applications. The problem is even more significant in traditional agriculture. The geographical location, climatic conditions, average annual rainfall, vegetation, air pollution and turbidity, and canopy of plants are important and lead to different water consumption in plants. Therefore, proper water consumption in agriculture in most countries leads to food security and a better supply of crops. In this research, we propose a fuzzy system that has eight inputs and seven outputs. Inputs include soil moisture, relative humidity, air temperature, wind speed, soil permeability, daily rainfall, vegetation, and air pollution. The Fuzzy outputs are the reference and water stress evapotranspiration, water pump condition, duration of water pump operation, the volume of water requirements for crops, irrigation efficiency, and water losses. The main feature of the fuzzy system is the prediction of water consumption in different climates with high accuracy. To prove high efficiency and accuracy, we have performed many analyzes in various geographical locations. The geographical locations are tropical, semi-mountainous, and mountainous areas. In addition, we have performed three different analyses in four periods using our fuzzy system. In the first and second modes are used the average daily and hourly data, respectively. Finally, in the third mode, some data of the second method, such as the impacts of air pollution, soil moisture, vegetation, and water infiltration rate in the soil, are not considered because most of the proposed approaches do not consider the factors. The results show that the second mode is more efficient, and in some farms saves about 70% in water consumption. In addition, the results show that the water consumption in autumn and winter is lower than in spring and summer. The fuzzy system has high efficiency on all crops in different climates and can prevent water stress or waterlogging. It irrigates as much water as the plants need and prevents water loss. One of the main factors in increasing the accuracy of the fuzzy system is the use of vegetation level, soil moisture, air pollution, soil type, and plant canopy. The research results show that the proposed system can be used in different climates and significantly reduce water consumption in agricultural lands. Regression, correlation coefficient, and RMSE analysis have been used to validate the fuzzy system.

Macro-and/or microplastics as an emerging threat effect crop growth and soil health

Pollution caused by macro- and microplastics has become a global concern that is ubiquitous throughout the environment. The reported impacts of macro-and/or microplastics in soil were mixed without uniform conclusions. Here, we quantitatively analyzed the effects of macro-and microplastics on crop growth and soil health using a global meta-analysis, based on 2,226 paired field/ laboratory measurements from 141 papers published in the literature. The results show that the unabated accumulation of macro-and/or microplastics negatively impacts crop growth and soil health. Overall, there were no significant effects on crop-soil properties of macroplastics between 30 and 240 kg/ha excluding soil water infiltration rate, but the crop-soil properties were negatively impacted with time and macroplastics over 240 kg/ha excluding soil olsen-potassium. There were no significant effect on crop-soil animal properties of microplastics between 0.01 and 100 mg/kg excluding weight, but the crop-soil animal properties impacts were negative with time and microplastics over 10,000 mg/kg excluding plant chlorophyll. Using a random forest model (RF) trained with crop/ animal and macro-and/or microplastics factors, we found that the response of crop growth and soil health to macro-and/or microplastics was related to plastic content, plastic type, plastic size and crop/ animal type variables. Altogether, our findings of macro-and microplastics impacts on crop growth and soil health are crucial to policy-making related to agricultural sustainable development under global change.

Improved water and ions dynamics in a clayey soil amended with different types of agro-industrial waste biochar

Biochar is a beneficial amendment for fine-textured soils. In addition, the interaction of biochar particles with soil components influences the dynamics of water and ions, which is particularly important to remediate salt-affected soils. We investigated the effect of sugarcane bagasse (SB), orange bagasse (OB), and corncobs (CB) biochar on water movement and ion leaching in clayey soil. Non-amended soil (CT) column and soil amended with gypsum (CTG) served as controls. Water infiltration, water flow rate, cumulative leached cations, anions, and exchangeable cations (Ca2+, Mg2+, K+, and Na+) were determined. Biochar increased the water infiltration and water flow rate by 80% and 71%, respectively. The SB and CB treatments increased the ion removal from the soil by 48%, whereas the OB increased the removal by 19%. The OB´s lower surface area and water holding capacity likely influenced its performance. Biochar reduced the Ca2+ and Mg2+ concentration on the soil exchange complex by 44% and 76%, respectively, and increased K+ by 233%. However, the most exciting result was the reduction of exchangeable Na+, 90% in the SB and CB treatments and 50% in the OB treatment. Considering that a high concentration of Na+ on the exchange complex contributes to soil structural degradation, biochar application, especially SB and CB, can potentially improve soil quality and mitigate salt-affected soils.

An analytical approach to estimating electrostatic repulsion between soil particles

The electrostatic repulsion between soil particles has an important effect on the stability of soil aggregates and soil water movement. However, the electrostatic repulsive pressure is traditionally quantified through a complicated numerical method. In this study, the analytical expressions for calculating the midplane potential between soil particles in 1:1 and 2:1 electrolytes were derived respectively, consequently an analytical method for estimating the electrostatic repulsive pressure was obtained. The theoretical solutions of midplane potential between particles and electrostatic repulsive pressure are in good agreement with the numerical ones, and correctly predict the swelling pressure of montmorillonite. The surface potential, midplane potential and electrostatic repulsive pressure between soil particles calculated by the analytical method increase with increasing charge density, which depends on ionic polarization or/and polarization-induced covalent bond. For example, electrostatic repulsive pressure is the highest in non-polarized Li+, decreases in polarized Na+, and the lowest in K+ solution due to potassium’s relatively high polarization and polarization-induced covalent bond. The percentage of large soil pores (> 1 mm) and electrostatic repulsive pressure appear in a negative correlation, which is consistent with changes in the soil water infiltration rate, whereas the percentage of small soil pores (< 0.5 mm) has a positive relationship to electrostatic repulsive pressure. The ion polarization or/and polarization-induced covalent bond affect soil pore distribution and control soil water infiltration through significantly affecting the electrostatic repulsive pressure between soil particles. The analytical estimation of electrostatic repulsion is of great significance for understanding the physical/chemical processes in soils and quantifying the relations between mesoscopic processes and macroscopic phenomena.

Implications of crop residue removal on soil physical properties: A review

AbstractCrop residues are often removed for livestock and biofuel production, but how such removal impacts soil physical properties has not been widely discussed. The objectives of this paper were to discuss: (a) the impacts of crop residue removal on soil physical properties, (b) factors affecting residue removal effects on soils, (c) threshold level of residue removal, (d) strategies to offset the removal negative effects, and (e) research needs. We compiled 66 studies on crop residue removal and soil physical properties published prior to 17 Aug. 2021. Residue removal may not affect bulk density and water infiltration rate but increases penetration resistance by 55% and soil temperature by 1.8 °C in spring. However, it reduces wet aggregate stability by 31%, dry aggregate stability by 44%, and water retention at –33 kPa by 24% in most studies, indicating residue removal can increase erosion risks and reduce soil water storage. Residue removal rate is the leading factor that explains changes in soil physical properties. Residue removal at rates above 50%, in general, adversely affected soil physical properties, which correlates to retaining about 4 Mg ha–1 of residue. Cover crops and manure application may partially offset adverse effects of residue removal on soil physical properties, but studies are too few to make a strong conclusion. Consistency of soil sampling depths, accurate reporting of residue removal rates, and additional data from long‐term experiments are needed. Overall, high rates of residue removal can increase erosion potential and reduce soil water but have mixed impacts on other physical properties.

Thinning effects on forest production and rainfall redistribution: Reduced soil water deficit and improved sustainability of semiarid plantation forestlands

AbstractLarge‐scale planted afforestation worldwide has exacerbated soil desiccation and led to a serious shortage of water resources for forests sustainability in semiarid areas. Consequently, thinning is discussed as an important management approach to conserve water resources and to maintain plantation forestland sustainability. Here, we explored the effects of thinning intensity on semiarid forest production and soil water supply. Three artificial forests of Populus cathayana with an age of 15 yr were selected and thinned with different intensities [1/3 amount of trees removed (T1/3), 2/3 amount of trees removed (T2/3), and using no thinning (NT) as a control]. Results showed that thinning presented a significant impact on the above‐ground three‐dimensional structure of planted forests and increased forest gaps. Meanwhile, the rainfall redistribution pattern changed significantly. Thinning increased throughfall (T1/3, 43% ± 9%; T2/3, 79% ± 18%), reduced stemflow (T1/3, −44 ± 2%; T2/3, −71% ± 2%), and increased the soil water replenishment (T1/3, 34% ± 7%; T2/3, 64% ± 19%) of forest land. Meanwhile, the dead root channel caused by thinning effectively increased the water infiltration rate and groundwater replenishment, and effectively reduced soil water deficit (T1/3, 41% ± 33%; T2/3, 57% ± 33%). Through trade‐off analysis, we found that non‐thinning aboveground biomass yields were the highest, and T2/3 yields higher water yield, while T1/3 can maintain acceptable aboveground biomass while keeping better soil water. We conclude that thinning increased soil water supply, reduced soil water deficit and maintained forestland sustainability, and there are synergies of thinning on forest production and soil water supply through rainfall redistribution for maintaining the sustainability of semiarid plantation forestlands.

Strontium Peroxide-Loaded Composite Scaffolds Capable of Generating Oxygen and Modulating Behaviors of Osteoblasts and Osteoclasts.

The reconstruction of bone defects remains challenging. The utilization of bone autografts, although quite promising, is limited by several drawbacks, especially substantial donor site complications. Recently, strontium (Sr), a bioactive trace element with excellent osteoinductive, osteoconductive, and pro-angiogenic properties, has emerged as a potential therapeutic agent for bone repair. Herein, a strontium peroxide (SrO2)-loaded poly(lactic-co-glycolic acid) (PLGA)-gelatin scaffold system was developed as an implantable bone substitute. Gelatin sponges serve as porous osteoconductive scaffolds, while PLGA not only reinforces the mechanical strength of the gelatin but also controls the rate of water infiltration. The encapsulated SrO2 can release Sr2+ in a sustained manner upon exposure to water, thus effectively stimulating the proliferation of osteoblasts and suppressing the formation of osteoclasts. Moreover, SrO2 can generate hydrogen peroxide and subsequent oxygen molecules to increase local oxygen tension, an essential niche factor for osteogenesis. Collectively, the developed SrO2-loaded composite scaffold shows promise as a multifunctional bioactive bone graft for bone tissue engineering.