Available Water Capacity Research Articles

Impact of Soil Pore Size Distribution on Crop Growth in Relation to Plant Available Water (PAW) and Soil Organic Carbon (SOC) in Arid/Semi-Arid Regions

Soil structural status in relation to soil pore size distribution, soil water retention, and plant available water (PAW) influence crop plant growth. Also, soil organic carbon content (SOC) usually influence soil structural stability, soil pore size and may affect crop growth, especially in arid/semi-arid regions with low SOC. Our studies focused on soil structure under clay dispersion and conventional and no-tillage systems included cultivation of cover crop in arid/semi-arid region of north-eastern Iran, in 2020 and 2022, respectively. According to our findings, PAW directly depended on soil pore size distribution, the more micropores the more water retention. Consequently, smaller soil pores due to clay dispersion improved water retention in soils and crop growth increased with enhancing PAW. SOC usually is low in arid/semi-arid regions of the world, therefore, addition of soil organic matter by crop residue retention may help in improving soil condition. Based on our results, cover crop residue retention in no-till system increased SOC, and SOC positively influenced soil functions such as soil structural stability, soil pore size (using X-ray images), and root growth. Therefore, soil pore size distribution as influenced by soil structural status could be considered as a principal factor in crop growth in arid/semi-arid region of north-eastern Iran.

Flowering phenology differs among wet and dry sub-alpine meadows in southwestern China.

The effect of floral traits, floral rewards and plant water availability on plant-pollinator interactions are well-documented; however, empirical evidence of their impact on flowering phenology in high-elevation meadows remains scarce. In this study, we assessed three levels of flowering phenology, i.e. population-, individual- and flower-level (floral longevity), in two nearby but contrasting (wet versus dry) sub-alpine meadows on Yulong Snow Mountain, southwestern China. We also measured a series of floral traits (pollen number, ovule number, and the ratio of pollen to ovule number per flower, i.e. pollen:ovule ratio [P/O]) and floral rewards (nectar availability and pollen presentation) as plausible additional sources of variation for each phenological level. Floral longevity in the wet meadow was significantly longer than that for the dry meadow, whereas population- and individual-flowering duration were significantly shorter. Our results showed a significant positive relationship between flowering phenology with pollen number and P/O per flower; there was no relationship with ovule number per flower. Further, we found a significant effect of flowering phenology on nectar availability and pollen presentation. Our findings suggest that shorter floral longevity in dry habitats compared to wet might be due to water-dependent maintenance costs of flowers, where the population- and individual-level flowering phenology may be less affected by habitats. Our study shows how different levels of flowering phenology underscore the plausible effects of contrasting habitats on reproductive success.

Modeling Tillage Effects on Plant-Available Water by Considering Changes in Soil Structure

Highlights No-tillage improved plant-available water (PAW) as compared to conventional tillage, especially in dry years. Soil structure showed 4.5 times higher impact on PAW than surface disturbance due to tillage. Consideration of changes in soil structure is important in modeling the effects of soil management. PALMS was found to be an effective model to assess the effects of changes in soil management on soil water. Abstract. Management practices such as no-tillage (NT) have the potential to provide many benefits, such as reduced runoff and soil erosion and increased infiltration and soil water holding capacity. Most hydrological models that are used to simulate the effects of soil management are built based on empirical relationships between management and hydrology outcomes, and they tend to ignore or oversimplify the effects of soil structure. However, soil structure is management dependent and is a driver of water movement and storage in soil. The goal of this study was to better understand the effects of differences in soil structure between NT and conventional tillage (CT) on field-scale hydrology and plant available water (PAW). This study employed in-field measurements of soil structure in NT and CT fields in the Texas Blackland Prairies and used the Precision Agricultural-Landscape Modeling System (PALMS), which can simulate the effects of differences in soil structure. Regression analysis was performed on simulated soil water to understand the relative contributions of variations in surface roughness and macropore properties due to tillage on PAW. Results from this study showed that NT accumulated 44.8, 20.4, and 5.7 cm more PAW than CT in the top 150 cm of the soil profile during the summer growing season in the years 2006, 2008, and 2011, respectively, all of which encountered considerable dry spells. It was also found that the changes of soil structure due to tillage had about 4.5 times more impact on PAW than surface roughness. This study highlights the benefits of adopting NT over CT and showcases the importance of considering soil structure in modeling the effects of soil management on PAW. Keywords: Macropores, No-till, Preferential flow, Surface disturbance, Surface roughness, Texas Blackland Prairies.

Comparison of various sustainable amendments on soil cracking in semi-arid regions

Soil desiccation is an important process that happens mainly in semi-arid regions especially in Central Asia. Soil desiccation leads to higher loss of moisture at shallower depths and also deeper penetration of water, which ultimately reduces water availability and hence impacts the growth of plants for the application of agriculture and green infrastructures. Therefore, minimizing soil desiccation will help maintain higher water availability for plants for agricultural productivity and green infrastructure in Central Asian Region. In literature, various amendments such as natural fibers, cementation, lime, vegetation and biochar have been used to suppress cracking of soil. There is rarely any study that analyses and compares mechanism of crack suppression among the above-mentioned methods. The objective of this study is to explore various sustainable methods of minimizing soil desiccation and compare their mechanisms. Further, the aim is to analyse the feasibility of these methods by revealing their advantages and disadvantages. In order to achieve this objective, 1-D columns were prepared with control soil and amended soil (with fibers, vegetation and biochar). The review also provides insights into their mechanism of suppression of soil cracking by proposing a new factor (i.e., normalized CIF). Based on the proposed factor, the efficiency of biochar and fiber amendments are higher than that of vegetation. Vegetation may or may not have positive impact on cracking of soil depending on their shoot length. Among various amendments, wood biochar (10% content) and coir fiber (at 0.75 % content) seems to have highest efficiency in reducing cracking in soil. Overall, the study aims to develop preliminary guidelines suppressing soil desiccation in semi-arid regions such as Central Asia.

Flood Inundation and Streamflow Changes in the Kabul River Basin under Climate Change

The Kabul basin yields around 16% of the total annual water availability in Pakistan. Changing climate will alter the precipitation regime in terms of intensity and frequency, which will affect the water yield and cause flood hazards. Against this background, this study aims to quantify the impacts of changing climate on the water yield, its timings, and, more importantly, the associated flood hazards in the transboundary Kabul basin. For this, we used a rainfall-runoff inundation (RRI) model coupled with the snow and glacier melt routines and drove it for historical and future climates simulated by the atmosphere-only general circulation model (AGCM) at 20 km spatial resolution. The model simulations reveal that rainfall runoff contributes around 50% of the annual flows, and the rest is contributed by glaciers and snow melts. Annual precipitation is projected to increase by 14% from 535 mm, whereas temperatures will rise by 4.7 °C. In turn, the Kabul River flows will only increase by 4% to 1158 m3s−1 from 1117 m3s−1, mainly due to an increase in winter flows. In contrast to a minute increase in the mean river flows, the maximum flood inundation area is projected to increase by 37%, whereas its depth will rise between 5 and 20 cm.

Increased aridity and chronic anthropogenic disturbance reduce litter productivity in a Caatinga dry forest

Tropical dry forest productivity is thought to be driven by a combination of natural factors, particularly total water availability and seasonality. However, most of the world’s dry forests have been converted into forest successional mosaics by a combination of slash-and-burn agriculture and exploitation of forest products, which has potential impacts for forest productivity. Here, we examined litter production, nutrient concentrations and fluxes across regenerating and old-growth stands of a Caatinga dry forest during a 48-mo period, assessing the impact of annual rainfall, forest aboveground biomass, soil fertility, forest successional status, stand age and chronic anthropogenic disturbance. We found our sites to have low litter productivity, producing 0.193 ± 0.016 Mg ha−1 yr−1 (mean ± SE) of litter. Moreover, litter production was highly seasonal (> 90% during the dry season), and varied substantially across forest stands (from 0.0035 to 0.564 Mg ha−1 yr−1), but with no differences relative to forest successional status; i.e. similar litter production in regenerating and old-growth stands. Litter production was affected by precipitation, soil fertility and chronic anthropogenic disturbance. Litter nutrient concentration was highly variable across forest stands, but concentration responded very little to our focal drivers. Litter N-concentration was relatively high, while P was very low resulting in a small flux to the soil via litter decomposition. In contrast to litter nutrient concentrations, nutrient fluxes were more predictable, particularly considering forest successional status. Our results suggest that Caatinga dry forest on sandy soils is a low-productivity ecosystem, probably due to a combination of natural and anthropogenic drivers.

The Effect of Different Vegetation Restoration Types on Soil Quality in Mountainous Areas of Beijing

Soil quality is a very important indicator used to assess ecosystem restoration states in terms of vegetation recovery and establishment. Evaluating the soil quality of different vegetation restoration types in mountainous areas of Beijing and identifying their influencing factors would provide a scientific basis and be helpful for vegetation restoration in the future. Six vegetation types (or communities), including Platycladus orientalis (L.) Franco pure forest (POP), Pinus tabulaeformis Carr. pure forest (PTP), Platycladus orientalis–Pinus tabulaeformis mixed forest (PPM), Platycladus orientalis coniferous and broadleaved mixed forest (POCB), Pinus tabulaeformis coniferous and broadleaved mixed forest (PTCB), deciduous broadleaved mixed forest (DBMF), and one area of non-afforested land (NF), with similar stand conditions were selected and fourteen factors of soil physical and chemical characteristics were measured and used to establish a total data set (TDS), while a minimum data set (MDS) was obtained by using the principal component analysis (PCA) and Pearson correlation analysis methods. Two scoring methods, linear (L) and non-linear (NL), were used to calculate the soil quality index (SQI), and the key factors influencing soil quality by vegetation were identified by a general linear model (GLM), PCA, and correlation analysis. The results showed that: (1) The screened MDS indicators which showed good relationships with the SQIs in the study areas were total nitrogen (TN), sand content, total potassium (TK), pH, and available water capacity (AWC). The SQI–NLM method has better applicability. (2) The contribution rates of vegetation to different soil factors accounted for 28.644% (TN), 21.398% (sand content), 24.551% (TK), 16.075% (pH), and 9.332% (AWC). (3) TN showed a positive relationship with all vegetation types; the content of TN in PTCB and DBMF was obviously larger than in the other types in the 0–10 cm layer; PPM, PTCB, and POCB affected the sand content, which showed negative correlativity; and DBMF showed positive correlativity with AWC. The mechanism of how different species affect TN, sand content, and AWC should be focused on and taken into consideration in further studies.

Zonation of critical water distribution based on meteorological water balance in Coastal Areas of Pekalongan City

Water demand always increases, and its availability varies between regions and times. Pekalongan City is a city that faces water scarcity issues. This study aims to determine the critical water distribution zones in the coastal area of Pekalongan City by considering the critical water criteria based on the use of meteorological water balance during the wet and dry months. The research location includes eight sub-districts in the coastal area of Pekalongan City, specifically in North Pekalongan District. Water criticality is calculated by considering water availability and water demand. Water availability is influenced by rainfall, evapotranspiration, runoff, and infiltration. Water demand for domestic, industrial, and agricultural sectors is calculated based on their respective classification standards. Surplus and deficit values are obtained using the water balance. Water criticality is classified into four categories by comparing the total water availability with demand. All sub-districts experience a water deficit during the dry months, while during the wet months, all sub-districts except Padukuhan Kraton and Panjang Wetan sub-districts experience a surplus. All sub-districts are classified as highly critical in the dry month period. During the DJF period, all sub-districts are classified as not critical and near critical, while during the MAM period, one sub-district is classified as not critical.

Can agronomic options alleviate the risk of compound drought-heat events during the wheat flowering period in southeastern Australia?

The impacts of compound drought-heat (DH) events on crops are more devastating than a single extreme event of drought or heat. Previous studies mainly assessed the change of individual extreme climate events. However, studies quantifying the characteristics of DH events during crop growth periods are still lacking. To the best of our knowledge, there is no study that has quantified the potential of adjusting sowing time and changing cultivars to reduce the risk of DH events for wheat in Australia. We aimed to (1) develop a combined index to capture the DH events occurring during the wheat flowering period at six study sites in southeastern Australia’s wheat belt; (2) quantify the changes in the frequency (DHF), duration (DHD), and intensity (DHI) of DH events under future climate; and (3) identify feasible agronomic options to reduce the risk of DH events. We used the APSIM model driven by climate projections from 27 GCMs for the period of 1981–2100 to simulate the wheat flowering time and daily plant available water (PAW) at 0–100 cm soil layer. The wheat sensitive period (WSP) was defined as the period from 2 weeks before flowering to 2 weeks after flowering time. A DH event occurs when the daily maximum temperature is higher than 28 ℃ and daily PAW is less than 40% of plant available water capacity for three consecutive days or more. Then, we assessed the DHF, DHD, and DHI under projected climate change. Finally, we investigated the potential of changing sowing time and cultivars to alleviate DHF, DHD, and DHI under different climate scenarios. According to the average values across six sites, the DHF, DHD, and DHI during the WSP increased by 15%, 12%, and 0.9% in 2040 s, and 49%, 44%, and 5% in 2080 s, respectively, compared to 2000 s. Such increases in DH events were mainly due to enhanced heat events. Early sowing and planting better-performing wheat cultivars with early flowering had great potential to lower the risk of future DH events. They could reduce the DHF, DHD, and DHI by 15%− 100%, 18%− 100%, and 16%− 100%, respectively, compared to without adaptation options. However, the strategy may introduce an increased frost risk across six sites, especially in regions with climates that are less dry and hot, such as Mudgee and Wagga Wagga. We expect our modelling work can provide useful information for developing effective agronomic management practices to help Australian wheat growers better prepare for DH events under climate change. The newly proposed DH framework can be applied to other dryland wheat growing regions globally.

Effect of biochar and hydrochar of pistachio residues on physical quality indicators of a sandy loam soil

The carbonization of agricultural residues into carbon-rich biochars can be considered as one of the practical methods in sustainable management. The objectives of this study were to: (i) investigate and compare the chemical, physical and micromorphological properties of biochar and hydrochar produced from pistachio (Pistacia vera) residues, and (ii) compare the effects of these chars on the physical quality of a sandy loam soil (classified as Typic Haplocalcids) in pistachio orchards. The physical and chemical characteristics of the biochar and hydrochar were determined. Scanning electron microscopy images showed that hydrochar had a spherical pore structure while the biochar had elliptical pores. The chars were different in terms of functional groups, ratio of elemental composition, and electrical conductivity. Both chars were added at the rates of 0, 1 and 2%w/w to the soil and incubated for nine months under wet and dry cycles. Then, soil physical indicators including bulk density (ρb), dry and wet aggregate stability, water retention curve, saturated water content (θs), field capacity (θFC) and plant available water (PAW) were determined. The results showed that the hydrochar and biochar application had no significant effect on the ρb and dry aggregate stability. However, the percentage of water-stable aggregates larger than 0.25 mm increased at the rate of 1%w/w of chars in comparison with the control. The θs, θFC and PAW increased at both rates of chars when compared with the control. The residual water content (θr) increased at the rate of 1%w/w of chars compared to the untreated soil. It can be concluded that chars of pistachio residues can affect soil physical quality indicators and pore size distribution by the means of different mechanisms like the effect of morphological characteristics of chars, forming complexes between the soil particles, and creating hydrophobic coatings on the soil particles and aggregates.

Toward Optimal Irrigation Management at the Plot Level: Evaluation of Commercial Water Potential Sensors.

Proper irrigation practice consists of applying the optimum amount of water to the soil at the right time. The porous characteristics of the soil determine the capacity of the soil to absorb, infiltrate, and store water. In irrigation, it is not sufficient to only determine the water content of the soil; it is also necessary to determine the availability of water for plants: water potential. In this paper, a comprehensive laboratory evaluation-accuracy and variability-of the world's leading commercial water potential sensors is carried out. No such comprehensive and exhaustive comparative evaluation of these devices has been carried out to date. Ten pairs of representative commercial sensors from four different families were selected according to their principle of operation (tensiometers, capacitive sensors, heat dissipation sensors, and resistance blocks). The accuracy of the readings (0 kPa-200 kPa) was determined in two soils of contrasting textures. The variability in the recordings-repeatability and reproducibility-was carried out in a homogeneous and inert material (sand) in the same suction range. The response in terms of accuracy and value dispersion of the different sensor families was different according to the suction range considered. In the suction range of agronomic interest (0-100 kPa), the heat dissipation sensor and the capacitive sensors were the most accurate. In both families, registrations could be extended up to 150-200 kPa. The scatter in the readings across the different sensors was due to approximately 80% of the repeatability or intrinsic variability in the sensor unit and 20% of the reproducibility. Some sensors would significantly improve their performance with ad hoc calibrations.

Use of expanded shale, clay, and slate aggregates and biochar in the clear zone of road infrastructures for sustainable treatment of stormwater

A Clear Zone (CZ), the unobstructed roadside area with highly compacted soil, naturally accumulates high concentrations of pollutants from traffic activities. These pollutants are washed off by road runoff and enter waterways. In situ, treatment of polluted runoff from the CZ could not only protect water resources but also provide an opportunity to recharge groundwater. However, the soil in the CZ requires compaction, which limits the natural infiltration and treatment of road runoff. In this study, we examine whether and how amending the soil in the CZ with sand, a common bulking agent used in road design, and Expanded Shale, Clay, and Slate (ESCS) aggregates, a novel light-weight engineered bulking agent, could help treat stormwater in situ. ESCS-amended soil media infiltrated 220% more water than sand-amended soil under compaction, indicating that the addition of ESCS would make the CZ better at treating road runoff generated during high-intensity rainfall. Compared to sand-amended soil in the CZ, ESCS-amended soil provided 58% more plant-available water during prolonged drying, indicating that ESCS addition would help maintain vegetation, thereby minimizing maintenance needs. Finally, replacing sand with ESCS improved the soil capacity in the CZ to remove pollutants, including heavy metals and E. coli, indicating the performance life of ESCS-amended soil would be longer than that of sand-amended soil in the CZ. Collectively, these results indicate that the addition of ESCS as an alternative bulking agent to sand in compacted soil in the CZ could potentially treat road runoff in situ and prevent pollution originating from road infrastructure.

Nutrition quality response of orange‐fleshed sweet potato (Ipomoea Batatas L. Lam) varieties to deficit irrigation in Tanzania

AbstractMalnutrition in all its forms is a global problem, with the worst effects felt in developing countries. The importance of producing food to improve nutrition security is self‐evidently a promising approach to combating malnutrition. The present study assessed the nutritional quality response of orange‐fleshed sweet potato (OFSP) varieties to deficit irrigation (DI). The study's specific objectives were to (i) evaluate yield and root quality and (ii) assess the nutritional root yield and nutritional water productivity of selected OFSP varieties under full and DI. Beta‐carotene, iron, and zinc were the root quality parameters studied. A factorial arrangement of treatments was laid out in a randomized complete block design (RCBD). The irrigation rates used for scheduling were 100% (full irrigation), 60% (60 [DI]), and 30% (30 [DI]) of total available water (TAW). The test varieties were Naspot‐13 and Jewel of the OFSP crop. The beta‐carotene content of the Jewel cultivar was 27% higher than that of the Naspot‐13 cultivar. However, neither cultivar's root quality changed under DI. The results show that serving 125 g of boiled OFSP varieties provides more than 100% of vitamin A, sufficient iron, and minimal zinc dietary requirements for 4‐ to 8‐year‐old children and 10‐ to 50‐year‐old pregnant women. In general, the nutritional water productivity of root quality parameters increased with a decrease in water application. In conclusion, a positive water‐food‐nutrition nexus was established under the Naspot‐13 variety, suggesting a capacity for alleviating vitamin A, iron, and zinc deficiency health‐related problems, particularly in children and pregnant women in regions with limited water resources. Therefore, adoption of DI strategies for underutilized crops using smart pressurized irrigation systems could be significant in undertaking water management reforms.

Responses of plant sap flow rate to epikarst water availability under different karst water-bearing media

The water supply capacities of epikarst zones play an essential role in the restoration of vegetation and sustainable utilization of groundwater resources in karst areas. The permeability and water storage capacity of karst water-bearing media directly determines prospective water acquisition for plants. However, the degree to which karst water-bearing systems influence plant transpiration remains unclear. Consequently, this study selected three common karst water-bearing structures (pore and fissure (L1), fissure and conduit (L2), dissolution seam and pore (L3), to examine the sap flow rate (SF), infiltration rate, meteorological factors, soil water, and groundwater depth (GD) associated with the growth of Toona sinensis. The results revealed that: (1) Marked differences in the SF based on long term monitoring (2016/1–2022/6) were observed in three sample plots with the order of L2 > L1 > L3. Similar trends in the rock permeability coefficient were also found. (2) Groundwater depth and soil water are the major factors that determine the SF. (3) The threshold of GD (2.54 m for L1, 0.96 m for L2, and 3.56 m for L3) was identified, wherein the sensitivity of SF to GD (λn) was weakened with greater GD. (4) The fissure and conduit sample plot with a shallower GD and higher rock permeability provided more plant-available water, resulting in a larger SF. In contrast, the dissolution seam and pore sample plot with a more stable GD and media rock permeability hindered the absorption of water by plants, which translated to a lower SF. These results highlighted that the structures of karst water-bearing media determined the overall SF. This study provides useful information toward guiding the restoration of vegetation in subtropical karst areas with abundant rainfall and shallow groundwater reservoirs.

Selection of the best nitrogen fertilizer management scenario in wheat based on Palmer drought severity index with an environmental perspective

In arid and semi-arid regions, where winter wheat relies partially on precipitation for its water requirements, the timing and amount of precipitation play a pivotal role in nitrogen (N) losses. Given the extensive cultivation of wheat in these areas, farmers' oversight of N rates, N splitting, and the impact of precipitation patterns on N losses have led to water resources contamination. Therefore, tailoring N management to drought condition fluctuations can reduce N losses. The goal was to boost wheat yield while minimizing N losses. The CERES-Wheat model was meticulously calibrated and evaluated over three years, involving an experimental field and five farmer fields. The calibrated model simulated twenty-five N fertilizer scenarios, spanning various N levels (50–250 kg ha−1) and split patterns. This conesidered soil textures and meteorological data from 1992 to 2020. The model's outcomes, encompassing various yield indices and performance metrics such as water productivity (WP), irrigation water productivity (IWP), N residual in soil (NR), N leaching (NL), available N use efficiency (ANUE), N absorption efficiency (NAE), and N utilization efficiency (NUE), were categorized into four distinct groups based on the Palmer's Drought Severity Index (PDSI): Group A: Positive PDSI all season, Group B: Negative PDSI all season, Group C: Positive early, negative later, and Group D: Negative early, positive later. Indices underwent thorough Principal Component Analysis (PCA) to identify the optimal scenario. Model evaluation represented key parameters comprehensively. Simulated total biomass matched real-world conditions (NRMSE 12.44–26.08%, d-index 0.86–0.97). Soil moisture and N fell within specific ranges (NRMSE 18.79–25.60%, RMSE 1.98–4.95 mg kg−1). Comparing different drought and soil conditions, significant performance metric differences emerged. Specifically, in Groups A and D, WP, IWP, ANUE, and NAE increased by 3.38%, 11.53%, 5.86%, and 5.76% compared to C and B. Group B had an 8.55-fold NL increase over A, while Group A saw a substantial 50.64% NR surge compared to B. In overall assessment, the study has identified that the optimal N application rate for the study area is 150 kg ha−1. However, determining the most appropriate N split pattern hinges on the dynamic interplay between PDSI and soil available water content (AWC).

Holocene humid periods of the Levant – evidence from Dead Sea lake-levels

Water availability in the Levant is predicted to decline due to global warming in the upcoming decades and is expected to substantially impact the region. Determining the long-term natural rainfall variability in this region is essential for understanding the regional hydroclimatic response to external climate forcings and for contextualizing future hydroclimate changes. The Dead Sea (DS), located in the southern Levant, is a closed-basin lake whose size varies as a function of water availability. Reconstructing DS lake-level variations through time provides a quantitative measure of the natural hydroclimate variability and can inform on the local hydroclimate response to changes in global climate. Here, we constructed an updated lake-level history of the Holocene DS by: 1) studying lake high-stands derived from a series of new cores collected in the DS southern basin, 2) re-dating of the two major Holocene high-stand exposures, and 3) compiling all previously published ages of Holocene DS lake-level markers (n = 296 radiocarbon ages). The results show that the early (10–6.1 kyr cal BP) and late Holocene (3.6–0 kyr cal BP) in the DS were predominantly wet albeit punctuated by dry intervals, whereas the middle Holocene (6.1–3.6 kyr cal BP) was most likely relatively dry. This pattern of two Holocene humid intervals is also evident in distillation records derived from Levant speleothem caves (which represent the integrated magnitude of rainout from the vapor source to the caves), indicating that rainfall intensity and total water availability were correlated throughout the Holocene. These two humid intervals occurred during high and low summer insolation conditions, suggesting that they were modulated by different climatic mechanisms. The predicted future drying in the Levant is of similar magnitude to the natural hydroclimate variability and thus, it is crucial to assess whether the anthropogenic drying is in- or out-of phase with the natural climate variability.

Determination of water availability and long growth period of maize plant in Boalemo Regency, Indonesia

The lack of water availability and the short period of maize growth has the potential to be the main obstacles to achieving optimal production. Therefore, this research aimed to determine the water availability and long growth period (LGP) of maize plants in Boalemo Regency, which was included in the agrokilmat zone E2. Rainfall and temperature data from Saritani, Tangkobu, and Bubaa climate stations in Boalemo Regency were used over ten years, from 2012 to 2022. The soil profile moisture content data used pF 2.5 and pF 4.2 while the tool used Cropwat8.0. Furthermore, the determination of available water and LGP was conducted using a water balance table with the Thornwaite method. The results showed that the highest and lowest water availabilities were 556 mm and 118 mm at the Saritani and Tangkobu climate stations, with a maximum LGP of maize at 242 days and 181 days, respectively. Based on climate stations, the availability of water and the amount of LGP follow the pattern of Saritani climate station > Bubaa climate station > Tangkobu climate station.

No-tillage and rye cover crop systems improve soil water retention by increasing soil organic carbon in Andosols under humid subtropical climate

No-tillage (NT) combined with a cover crop is a climate-smart agricultural practice that eliminates nearly all physical disturbance of the soil surface and increases soil aggregation and soil organic carbon (SOC); however, the response of SOC and soil water retention (SWR) to long-term NT and cover crops systems in the volcanic ash Andosol soil of Japan has not been well addressed. This study aimed to evaluate the effect of NT and moldboard plow (MP) tillage systems combined with rye (RY) and fallow (FA) cover crop treatments on SOC, active carbon (AC), water-stable aggregates, aggregate stability index, mean weight diameter (MWD), bulk density, aggregate-associated carbon, and SWR. NT significantly increased the > 4 and 2 mm aggregates, aggregate-associated C at the 0–2.5 and 2.5–5 cm depths, field capacity, and SWR between 0 and 15 cm. RY cover crops significantly increased aggregate-associated carbon at the 2.5–5 and 5–10 cm depths in both NT and MP and SWR at the 10–15 cm depth. NT combined with RY significantly increased SOC and AC in the surface layer and volumetric water content at all soil depths. Path analysis revealed that SOC and MWD were correlated with easily plant-available water (EPAW) and field capacity under the NT system and is the primary reason for the observed increase in SWR. Thus, the NT system increased plant residue, reduced soil evaporation, increased SOC content and SWR, and bonded soil microaggregates into macroaggregates better than the MP system. The use of an RY-based NT system is an effective climate-smart agriculture practice that reduces the drought effects brought on by climate change.

Differences in mucilage properties and stomatal sensitivity of locally adapted Zea mays in relation with precipitation seasonality and vapour pressure deficit regime of their native environment.

With ongoing climate change and the increase in extreme weather events, especially droughts, the challenge of maintaining food security is becoming ever greater. Locally adapted landraces of crops represent a valuable source of adaptation to stressful environments. In the light of future droughts-both by altered soil water supply and increasing atmospheric water demand (vapor pressure deficit [VPD])-plants need to improve their water efficiency. To do so, plants can enhance their access to soil water by improving rhizosphere hydraulic conductivity via the exudation of mucilage. Furthermore, plants can reduce transpirational water loss via stomatal regulation. Although the role of mucilage and stomata regulation on plant water management have been extensively studied, little is known about a possible coordination between root mucilage properties and stomatal sensitivity as well as abiotic drivers shaping the development of drought resistant trait suits within landraces. Mucilage properties and stomatal sensitivity of eight Mexican landraces of Zea mays in contrast with one inbred line were first quantified under controlled conditions and second related to water demand and supply at their respective site of origin. Mucilage physical properties-namely, viscosity, contact angle, and surface tension-differed between the investigated maize varieties. We found strong influences of precipitation seasonality, thus plant water availability, on mucilage production (R 2= .88, p< .01) and mucilage viscosity (R 2= .93, p< .01). Further, stomatal sensitivity to increased atmospheric water demand was related to mucilage viscosity and contact angle, both of which are crucial in determining mucilage's water repellent, thus maladaptive, behavior upon soil drying. The identification of landraces with pre-adapted suitable trait sets with regard to drought resistance is of utmost importance, for example, trait combinations such as exhibited in one of the here investigated landraces. Our results suggest a strong environmental selective force of seasonality in plant water availability on mucilage properties as well as regulatory stomatal effects to avoid mucilage's maladaptive potential upon drying and likely delay critical levels of hydraulic dysfunction. By this, landraces from highly seasonal climates may exhibit beneficial mucilage and stomatal traits to prolong plant functioning under edaphic drought. These findings may help breeders to efficiently screen for local landraces with pre-adaptations to drought to ultimately increase crop yield resistance under future climatic variability.

Role of biochar on improvement of physical characteristics of re-vegetated ex coal mined soil and production of black corn (Zea mays L. var. Black Aztek)

Ex coal mined soil generally had problem for farming activities, even though it had been re-vegetated for few years. This research was aimed to determine the effect of biochar derived from corn cob to improve the physical characteristics of ex coal mined soil and production of black corn. A pot trial was conducted in Glasshouse at Andalas University, Padang. Soil was taken from re-vegetated of ex coal mined soil in Sawah Lunto, West Sumatra, Indonesia. The soil was mixed with biochar at 4 different doses (0; 0.5; 1.0; and 1.5%) of the weight basis. The experimental units were allocated based on Completely Randomized Design. Parameters analyzed were soil texture, bulk density (BD), total soil pore (TSP), hydraulic conductivity (HC), soil organic matter (SOM), and plant available water (PAT), as well as corn production parameters. The result showed that biochar significantly increased the SOM. SOM content at 1.5% biochar application increased by 32.4% compared to the OM content of the soil without biochar (0 T ha−1). Improving SOM due to biochar application, improved the soil physical properties, especially it decreased the soil BD (r=-0.71); increased HC (r=0.65); TSP (r=0.71); PAW (r=0.86); aeration pore (r=0.54); field capacity (r=0.83); and decreased wilting point (r=-0.66). Biochar application also improved production of black corn. It linearly increased crop height (r=0.76); corn stalk dry weight (DW) (r=0.75); grain yield DW (r=0.75); shoot DW (r=0.74); and root DW (r=0.76). Biochar derived from corn cob could be used to improve physical properties of ex coal mined soil.