High Rainfall Conditions Research Articles

Evaluation of climate conditions and ecological traits that limit the distribution expansion of alien Lolium rigidum in Japan

Invasive alien plants cause severe global problems; therefore, determining the factors that lead to the success or failure of invasion is a critical question in the field of invasion ecology. In this study, we aimed to determine the factors underlying differences in the distribution range of alien plants in Japan by investigating why Lolium multiflorum thrives in a wide range of habitats while L. rigidum is mainly distributed on sandy beaches. We initially evaluated environmental niche suitability through species distribution modelling and subsequently examined whether species traits influence the differences in range expansion between the two species. We used MaxEnt modelling to identify potential environmental niches for both species. The analysis revealed that L. rigidum was considerably less suited to the Japanese climate compared to L. multiflorum, with high summer precipitation in Japan identified as one of the climatic factors limiting the distribution of L. rigidum. Given that these winter annual plants remain dormant as seeds during summer, in subsequent experiments, we buried seeds in paddy field soil and sandy beach sand during summer and evaluated their survival rate in autumn. The survival rate of L. rigidum seeds was significantly lower than that of L. multiflorum, particularly in paddy soil. Factors contributing to seed mortality may include the decay or early germination of L. rigidum seeds under Japan’s high rainfall conditions. This study emphasises the importance of considering local environmental factors alongside climate niche modelling in the risk assessment of invasive species. Moreover, the integration of species distribution modelling for large-scale evaluations and manipulation experiments for fine-scale assessments proved effective in identifying climatic conditions and species traits influencing the success or failure of alien species invasion.

Exploitation of heterosis in chilli using genetic male sterile lines for red fruit yield with special reference to high rainfall conditions

High-quality red/dry chilli for spice, pharmaceutical and medicinal purposes is a major goal in chilli breeding. The male sterile lines have greater potential for the exploitation of heterosis in chilli to achieve this objective. Genetic male sterile lines with special traits like destalking and ability to withstand high rainfall were involved in heterosis breeding to identify hybrids for commercial and industrial purposes. Forty F1 hybrids were developed by crossing 4 diverse GMS lines with 10 testers using Line × Tester mating design to estimate heterosis, combing ability and gene action. The experiment involving 14 parents and 40 F1s, along with standard variety ‘CH-27’ was laid out in α-lattice square design in three replications during summer 2020 and 2021. The GMS lines MS 9-2 and MS 26-1 along with testers DPCh 10, VVG, DPCh 40 and Him Palam Mirch-2 showed significant GCA for marketable red/dry fruit yield and majority of their component traits. Ten F1 hybrids were identified with superiority for fruit yield based on mean performance, significant heterosis and SCA effects, providing an opportunity to utilize them in value-added products and dried spice purposes viz., MS 9-2 × HPM-2, MS 11-2 × DPCh 40, MS 9-2 × DPCh 40 and MS 9-2 × DPCh 101 with erect fruiting habit and that of MS 9-2 × DPCh 10, MS 26-1 × DPCh 10, MS 9-2 × PBC 535, MS 26-1 × VVG, MS 29-2 × DPCh 10 and MS 26-1 × DPCh 22- C with pendent fruits. The non-additive gene action was predominant in the expression of fruit yield, total red fruits/plant, oleoresin and capsanthin. A significant positive correlation among SCA, economic heterosis and per se performance is an indicative to identify superior hybrids. Multi-location testing of these hybrids shall pave way to exploit them commercially by making them available to the farmers.

Effects of Successive Top-Dressing Application of Lime on a Sweet Cherry Orchard in Southern Chile

Annual top-dressing application of agricultural lime is a common practice in fruit orchards on acidic soils in southern Chile, which could result in surface over-liming and base imbalances. A trial was performed in a cherry orchard with an 8-year history of surface liming to evaluate the effectiveness of lime materials in neutralizing acidity in the soil profile and the effect on the tree nutritional status. No-lime (NL), calcitic (AgL), hydrated (HL), and liquid (LL) lime treatments were applied on soil surface at commercial rates, and soil acidity variables were measured at depths of 0–5, 5–10, and 10–20 cm in samples collected at 0, 15, 30, 60, and 225 days after application. Tree nutritional status was evaluated through foliar analysis. Top-dressing application of AgL was ineffective in ameliorating subsoil acidity at depths >5 cm, even in high-rainfall conditions. HL did not exhibit greater alkalinity mobility compared to AgL, although it had a faster but shorter-lived reaction. At the manufacturer-recommended rates, LL application was ineffective. After 8 years of top-dressing liming with AgL, a significant stratification of soil pH, Al, and Ca was observed. However, foliar concentration of bases did not reflect the surface Ca accumulation in soil, discarding an antagonistic cation competition for tree uptake.

Analysis of Land Water Balance in Various Rainfall Conditions and Its Utilization to Determine Planting Patterns of Food Crops in the Eastern Part of Seram District of Seram Island

Soil water balance calculation is one of the methods used to estimate the dynamics of soil water content during plant growth. This study aims to describe rainfall conditions and analyze soil water balance as well as determine the growing season and composition of food crop combination patterns based on the available growing season in East Seram Island. This research uses rainfall data for 30 years of observation period 1992-2021 from Geser Meteorological Station (Data analysis with the following stages: (i) rainfall analysis (ii) calculation of average rainfall (iii) determination of rainfall with a 75% chance (iv) calculation of soil water balance using the Thornthwaite and Mather method (v) determination of the growing season and cropping pattern. The results showed that the average rainfall in East Seram was 2,194 mm/year with a water deficit (D) occurring in October and November, then the rainfall had a 75% chance of being exceeded at 1,439 mm/year with a water deficit of 228 mm/year which lasted for eight months, namely August - March. The growing season under normal rainfall conditions was available throughout the year, while under high rainfall conditions, a 75% chance of the growing season was available for five months, namely May and October. The cropping patterns and crop combinations used were monoculture, polyculture, and intercropping with combinations of cassava, maize, sweet potato, groundnut, mung bean, cassava-corn, cassava-peanuts/green beans, maize-peanuts, cassava-corn-peanuts/green beans, cassava-corn-horticultural crops.

A high-resolution perspective of extreme rainfall and river flow under extreme climate change in Southeast Asia

Abstract. This article provides high-resolution information on the projected changes in annual extreme rainfall and high- and low-streamflow events over Southeast Asia under extreme climate change. The analysis was performed using the bias-corrected result of the High-Resolution Model Intercomparison Project (HighResMIP) multi-model experiment for the period 1971–2050. Eleven rainfall indices were calculated, along with streamflow simulation using the PCR-GLOBWB hydrological model. The historical period 1981–2010 and the near-future period 2021–2050 were considered for this analysis. Results indicate that, over former mainland Southeast Asia, Myanmar will face more challenges in the near future. The east coast of Myanmar will experience more extreme high-rainfall conditions, while northern Myanmar will have longer dry spells. Over the Indonesian maritime continent, Sumatra and Java will suffer from an increase in dry-spell length of up to 40 %, while the increase in extreme high rainfall will occur over Borneo and mountainous areas in Papua. Based on the streamflow analysis, the impact of climate change is more prominent in a low-flow event than in a high-flow event. The majority of rivers in the central Mekong catchment, Sumatra, Peninsular Malaysia, Borneo, and Java will experience more extreme low-flow events. More extreme dry conditions in the near future are also seen from the increasing probability of future low-flow occurrences, which reaches 101 % and 90 %, on average, over Sumatra and Java, respectively. In addition, based on our results over Java and Sumatra, we found that the changes in extreme high- and low-streamflow events are more pronounced in rivers with steep hydrographs (rivers where flash floods are easily triggered), while rivers with flat hydrographs have a higher risk in terms of the probability of low-flow change.

Effects of water temperature on soil aggregate stability between soils developed from different parent materials in the subtropical hilly area of China

Water temperature has an important effect on soil aggregate stability. In this study, six soils derived from different parent materials in the hilly region of southern China were selected, and the mean weight diameter (MWD), geometric mean diameter (GMD), and soil erodibility (K value) were measured under different water temperature conditions. The aim of this study was to investigate the influence of water temperature on soil aggregate stability and erodibility. As the water temperature increased from 5 °C to 40 °C, the average content of >5 mm water-stable aggregates decreased by 57.13 %, while the average content of <0.25 mm water-stable aggregates increased by 214.41 %. The MWD and GMD of the six different parent soil types exhibited a decreasing trend with increasing water temperature. The trend of the K value was opposite to that of these values. The influence of water temperature on soil aggregate stability is mainly attributed to the thermal effect on the viscosity of soil water and the expansion of clay minerals. As the water temperature increases, the water viscosity coefficient, water density and water surface tension gradually decrease. Moreover, the response of soil aggregate stability and erosion resistance to water temperature varies with soil depth and parent material type. The topsoil exhibits greater sensitivity to water temperature than does the subsoil. Shale (SH) soils and quartz sandstone (QS) soils exhibited higher sensitivities, and Quaternary red clay (QRC) soils exhibited the lowest sensitivity to water temperature among the six soils. This difference is mainly attributed to differences in the contents of expansive clay minerals and organic matter. These results indicate that soil aggregate stability and erosion resistance decrease with increasing water temperature, which may be one reason for severe soil erosion under extremely high temperature and rainfall conditions in the southern red soil hilly region during summer.

Idealised Estuary Salinity-Morphology Effect Characterisation Investigation

Estuaries are bodies of water along the coasts that are formed when fresh water from rivers flows into and mixes with salt water from the ocean. The density of seawater is greater than fresh water and it varies with salinity and temperature. Fresh water tends to float on top of seawater because of its lower density. Human-induced activities like the dredging of shipping lanes along the bottom estuarine, the dumping of industrial wastes into the water system, and shoreline development influence estuarine dynamics which include the mixing process. These activities lead to salinity changes and further adversely affect the estuarine ecosystem. The purpose of this research is to verify how salinity-morphology relations change in an estuarine system under various rainfall patterns, more specifically under extremely high rainfall conditions. The experiment that has been conducted studied the salinity-morphology relationships for a variety of rainfall patterns, most particularly for exceptionally high rainfall conditions, using an idealised channel. In the first part of this research, the morphology changes of the mixing between salt water (estuary) and freshwater (river) for different rainfall patterns, had been investigated in laboratory experiments. Fresh water was released from one end of the flume channel and overflowing over the weir at the other end. Meanwhile, salt water was represented by the red dye tracer released slowly through a weir and intruded horizontally to the upstream as a gravity current. In this experiment, an artificial roughened bed section was used as morphology change. The salinity pattern is plotted using Microsoft Excel. The salinity levels were measured at selected stations along the channel/longitudinal (x-axis), and also in transverse (y-axis) and vertical directions (z-axis) within the time duration. The observed salinity profile showed the difference in salinity level between heavy and light rain conditions with morphology effect where during heavy rain, the salinity level will decrease, hence, the existence of an artificial roughened bed section will affect the time taken for the process of mixing between salt water and fresh water.

Flood Hazard Mitigation at Tarusan Watershed, South Pesisir District, West Sumatera Province

Floods are the most common natural disasters in Indonesia and have enormous potential. This study aims to determine the flood hazard zone and regional arrangement in the Tarusan Watershed, South Pesisir Regency. To determine the flood hazard zone using the GIS approach. The indicators used to determine flood hazard are slope, rainfall, soil type, landform, geology, and land use. Determine the direction of regional arrangement with an Interpretative Structural Modeling (ISM) approach. The results showed that the high flood hazard zone in the Tarusan watershed is about 22% of the total area, the medium index is around 58%, and the low flood hazard index is 20%. The high - hazard zone of flood disasters in the study area is caused by high rainfall and topographic conditions of the Tarusan Watershed. The main priority in the management of flood - hazard areas in the Tarusan Watershed is to find economic alternatives to reduce forest destruction. Increasing the economic value of the community can lead to reduced community activities in carrying out land conversion, especially in forest areas.

Calculation of Rice Farming Insurance Premium Price in Magelang City Based on Rainfall Index with Black-Scholes Method

Indonesia is a country with two seasons, the rainy season and the dry season. Unstable rainfall can affect rice production and may cause crop failure. The amount of rice production in Indonesia, one of which is in Magelang City, is quite large, so the losses that may be experienced are quite significant. Therefore, a way to reduce the impact of losses experienced by farmers is needed, one of which is through the rice farming insurance program. The purpose of this study is to determine the premium price of rice farming insurance based on rainfall index based on the exit value and trigger value in each growing season. Insurance using the rainfall index can provide protection to farmers due to too little rainfall or too much rainfall. Too much rainfall can cause damage to rice plants resulting in crop failure. The premium calculation method uses the Black-Scholes principle, while the exit value and trigger value are determined by the Historical Burn Analysis method. The result of this study is to obtain various trigger values and exit values as well as premiums that must be paid by farmers in each normal, high, and low (dry) rainfall condition. This value determines the premium price obtained for normal rainfall which is IDR 735,739.66 to IDR 871,698.64, for high rainfall the premium price obtained is IDR 1,404,184.75 to IDR 1,643,307.75, and for low rainfall (dry season) it is IDR 5,541,806.10 to IDR 6,689,629.88.

ROAD DAMAGE EVALUATION ON RIGID PAVEMENT WITH PAVEMENT CONDITION INDEX METHOD IN KLAKAH REJO-BENOWO ROAD, SURABAYA CITY, EAST JAVA

The research objective was to analyze the level and type of damage from every kind of damage on the Klakah Rejo Benowo road by calculating the rigid pavement condition index value and providing solutions. This study took the location of the Klakah Rejo-Benowo road section, Surabaya City—data analysis by calculating the Deduct Value, m, TDV, CDV, and PCI. The research results state it was concluded that five types of damage occurred in Jalan Klakah Rejo-Benowo, Surabaya City. The types of damage are Grooves, Patches, Alligator Cracks, Weathering and Loose Granules, and Pits. Damage caused by high rainfall conditions (&gt; 900mm/year) &amp; Daily Traffic Volume exceeds the provisions of the Binamarga. After analysis, it shows that the road pavement is in Moderate/Fair condition; field analysis results and values calculated using the PCI (Pavement Index Condition) method for damaged road conditions can provide recommendations for road repairs using the Asphalt Institute MS-17 method, namely patching and resurfacing. Based on the analysis of the road condition values obtained, the solution must be patched and re-coated so that water does not quickly seep into the road layer, which causes more severe road damage.

Performance assessment of furrow irrigation in two different soil textures under high rainfall and field slope conditions

Furrow irrigation systems have been widely evaluated around the world. However, there is no national data indicating how efficient furrow irrigation is under Uruguayan conditions. The objective of the present work was to evaluate the performance of a system of furrow irrigation in two different soils texture. Seventeen irrigation events were analyzed in sugar-cane cultivation in northern Uruguay during 2016-17 and 2017-18 irrigation seasons. The water advance and recess curves were determined; flow rate during irrigation and runoff were monitored. The maximum furrow length studied was 100 m and the average slope was 0.24%. Application efficiencies in both types of soils were observed above 75%. These field data were compared with data simulated by the WinSRFR model, where high correlations were observed in the results of water application efficiency, distribution uniformity and runoff. These first results encourage to continue working in the efficient use of water, not only thinking about a better use of the resource but also in less loss by run-off, and therefore, less possibility of contamination and lower cost of energy and labor.

The fishbone diagram analysis to know the factors that influence the decreasing interest of farmers in the cultivation of soybean

Soybean crop productivity in The Pracimantoro District ranked second in Wonogiri Regency in 2021. However, over time the stability of production has decreased. One thing that causes the decline in soybean production in Pracimantoro District is the decreased interest of farmers in cultivating. This study aimed to determine the factors causing the declining interest of farmers in planting soybeans. The research location was conducted in Pracimantoro District, Wonogiri Regency. The data in this study are primary data and secondary data. Primary data is data are taken directly from the research location through direct observation at the location, interviews with relevant stakeholders, and filling out questionnaires. Secondary data is obtained through agencies related to this research, tabulated and descriptive, and literature searches supporting this research. Analysis method of data using the fishbone diagram. The results showed that the factors that influence the decline in farmers' interest in cultivating soybeans are sources of plant pest and disease risks, sources of input risk and soybean production techniques and sources of risk in the business environment. Some pests and diseases that often arise and attack soybean commodities are leaf spot, whitefly, caterpillar/pod caterpillar, leafhopper, stink bug, bacterial wilt and javelin/ladybug. The Risks from nature is that high rainfall and changing climatic conditions also make it difficult for farmers to grow soybeans. The risk from the production input sector is the unstable quality, quantity, and price of seeds, pesticides and fertilizers. Moreover, other influencing factors exist, such as the entry of imported soybeans, price games at middlemen, the absence of a lower price limit for local soybeans, and post-harvest limitations.

Late Quaternary human-environment relationship in the Ganga Plain, India

Here, we present the first-ever attempt to combine palaeoenvironmental records (n = 17) from dated stratigraphic sequences with Geographic Information System (GIS) spatial modelling of archaeological sites (3 phases; n = 306 sites) in the Ganga Plain. The spatial modelling assesses the distribution of archaeological sites and phases on maps showing changing elevation, geology, geomorphology, biome, and rainfall variability within the Ganga Plain, aiming to evaluate the human-environment relationship during the Late Quaternary Period.The compilation of oxygen and hydrogen isotopic composition (δ18O and δD values) and pollen-based environment reconstructions for the last ∼100 ka indicates high rainfall conditions during ∼100–75 ka, ∼10–5 ka, and ∼3.6–1.3 ka. Fluctuating rainfall conditions were observed during ∼75–25 ka and ∼18–15 ka, while the period from ∼25 to 18 ka was the weakest monsoon phase, marking the Last Glacial Maximum. Arid conditions were also observed during ∼15–10 ka and ∼5–3.6 ka. The archaeological review suggests the presence of the Acheulian culture, diverse Mesolithic cultures, and the Neolithic phase marked by advanced agriculture and pottery production in the Ganga Plain. The past environmental analyses show changes in settlement areas correlating with rainfall variations. Frequent climate changes and increasing population density during the Late Pleistocene-Early Holocene boundary probably forced prehistoric humans to adopt agricultural practices. The distribution of archaeological sites representing different cultural phases on the modern spatial maps of landscape variability (e.g., elevation, rainfall, geomorphology, and geology) reflects an intricate relationship between prehistoric human settlements, monsoonal rainfall, and climate-driven landform processes.Our assessment suggests that the integration of archaeological sites, geological mapping, vegetation analysis, and palaeoclimate records has the potential to provide valuable insights into ancient human-environment interactions. Therefore, we recommend continued interdisciplinary research in these fields to further enhance our knowledge of prehistoric societies and their responses to changing landscapes and climates in the Ganga Plain.

Effects of Pre-Harvest Spraying with Salicylic Acid (SA) and Sodium Nitroprusside (SNP) on Storage Quality and Pathogenic Fungal Species in ‘Manaohong’ Cherries

Chinese cherries, with their delightful blend of sourness and sweetness, are highly favored for their taste and nutritional benefits. However, they mature in conditions of high temperatures and rainfall, making them vulnerable to fungal infections which compromise their post-harvest quality. Our research aimed to study the effects of pre-harvest spraying with salicylic acid (SA) and sodium nitroprusside (SNP) on the pathogenic fungi in Manaohong cherries and their subsequent storage quality. We discovered that using SA and SNP at varying fruit development stages preserved fruit hardness, texture, appearance, and respiratory rate during storage, although it did not significantly alter the fruit’s dimensions. Furthermore, this pre-harvest treatment preserved levels of titratable acids, total phenols, and other antioxidants in the cherries, bolstered the activities of certain antioxidant enzymes (SOD, APX), and inhibited the activity of PPO and POD enzymes.Notably, the SA treatment alone demonstrated superior storage performance compared to combined treatments. Our research also identified Alternaria alternata and Colletotrichum godetiae as the primary pathogens in Manaohong cherries. In in vitro experiments, neither SA nor SNP inhibited these fungi’s growth. Consequently, we evaluated 12 pesticides and determined that 5% hexaconazole and 50% benomyl were most effective against these pathogens. Thus, to enhance the shelf life of Manaohong cherries and ensure their post-harvest quality, we recommend a pre-harvest spray of a SA, and combined with 5% hexaconazole and 50% benomyl. This approach not only promises enhanced cherry longevity but also lays a foundational strategy for the flourishing Manaohong Cherry industry.

Assessing the impact of climatic factors on biosphere dose conversion factors in long-term safety assessment of radioactive waste disposal

Climate factors from different regions were employed to assess the impact on Biosphere Dose Conversion Factors (BDCF) in the biosphere assessment of radioactive waste disposal. Climate characteristics of tropical and subtropical regions were considered alongside diverse climatic regions, observing the influence of different radionuclides. Data on annual rainfall, monthly rainfall distribution, temperature, and sunlight were collected for various regions. The relationship between rainfall and the processes of flooding, as well as erosion, was also established. Furthermore, the Water Budget Model (WBM) was used to calculate the required surface water flow parameters for the biosphere model. The results indicated limited effects from flooding and erosion, which could be evaluated using simplified methods. Under conditions of high evapotranspiration, low rainfall, or uneven rainfall distribution, specific radionuclides exhibited higher BDCF values. For regions currently and prospectively aligning with these climate characteristics, a comprehensive investigation into climate factors and their correlation with surface and near-surface hydrology is recommended to mitigate uncertainty.

Formation mechanism and quantitative risk analysis of the landslide-induced hazard chain by an integrated approach for emergency management: A case study in the Bailong River basin, China

The landslide–debris flow–river blockage hazard chain is one of the most common types of geological hazard chain in mountainous areas, seriously threatening human life and property across an extensive geographical area. The development of approaches for the rapid investigation and prediction of multi-hazard chains can play a significant role in reducing the number of casualties and economic losses. Here, taking the Lijie landslide–debris flow–river blockage in the Bailong River basin as a case study, we used remote sensing methods, geophysical technology, numerical simulations and empirical formulas to develop an integrated approach for analyzing the mechanisms, multi-hazard prediction and quantitative risk assessment induced by this geological hazard chain. The reactivation process of the Lijie landslide is composite retrogressive sliding. The steep slopes and highly fractured bedrock with low strength are the principal internal factors, and heavy rainfall in 2020 and spring freeze–thaw effect are the principal triggering factors. The deposited landslide material is eroded and transformed into a channel-type debris flow under high rainfall conditions. The steep terrain and abundant fine-grained material provides favorable conditions for a viscous debris flow with a long runout, which is usually followed by secondary disasters associated with river blockage. Our results indicate that under rainfall conditions with a 100-year return period, the Bailong river will be completely blocked by the landslide-induced debris flow. And there will be an estimated 5.84 million CNY of economic losses caused by the multi-hazard chain, which is 2.6 times the losses directly caused by the landslide. Our integrated approach is practicable in an emergency context and useful for local administrators to rapidly develop strategies for multi-hazard chain prevention and mitigation, based on information about the transformation mechanisms of the multi-hazard chain, potential hazard-affected areas, damaged degree of elements at the risk, and incurred economic losses.

Magnesium Supplementation Concerning Soil Chemical Properties and Cowpea Yield in Ultisol of Kerala, India

Ultisol of Kerala faces high magnesium deficiency due to poor retention of magnesium to soil exchange surfaces under high rainfall conditions. Hence magnesium nutrition management is an important aspect of fertility improvement in these soils. We conducted a pot culture study to determine the influence of varying magnesium levels on soil chemical properties and yield of cowpea in Ultisols of Kerala. We used a completely randomized design. The study was carried out in the Radiotracer Laboratory, College of Agriculture, Vellanikkara, Kerala Agricultural University, in January-April 2019. Magnesium carbonate at levels 5 to 80 mg.kg-1 was provided along with recommended doses of fertilizers for cowpea maintained in pots. Rhizosphere samples were analyzed during flowering and at harvest of the crop following standard procedures. Yield and yield attributes are recorded at the time of harvest. Graded doses of magnesium introduced significant (P&lt; 0.05) variations in the soil available nutrients and yield of cowpea. Soil pH and available magnesium in rhizosphere soil during flowering and post-harvest increased with the increasing levels of magnesium carbonate, and using 80 mg kg-1 of magnesium recorded the highest pH, available phosphorus, potassium, and magnesium. In contrast, the gradation of magnesium could not produce significant variation in yield. The highest yield was recorded in treatment supplied with 10 mg kg-1 of magnesium and was on par with those of higher levels of magnesium supplement. Graded doses of magnesium introduced variation in available nutrients but a better yield response in cowpea was obtained from magnesium at 10 mg.kg-1.

Responses of Deep Soil Carbon and Nitrogen Contents to Long-Term Retention of Alfalfa Pasture on Infertile Loess: A Synthesis Study

Incorporating perennial pastures into annual crop systems is an efficient means of improving soil carbon (C) sequestration and reducing the application of nitrogen (N) fertilizer on farmlands. How the soil C and N at different soil depths respond to the length of pasture duration and rainfall conditions is still being determined. In this study, we conducted a meta-analysis of data from 63 published studies to investigate the impacts of the alfalfa pasture on the incorporation of soil organic carbon (SOC), total nitrogen (STN), and available nitrogen (SAN) contents in the 0–300 cm soil profile of the Loess Plateau. An annual crop field was taken as a reference. The results showed that the average SOC content at soil depths of 0–100 and 100–200 cm in the alfalfa pasture increased by 17% and 8% (p &lt; 0.001) compared to the crop field, respectively, while that at 200–300 cm decreased (p &gt; 0.05). The SOC content increased with pasture age; it was the highest when the alfalfa had been planted for 5–9 years and decreased thereafter. The STN content at soil depths of 0–100 and 100–200 cm increased by 19% and 14% (p &lt; 0.001), respectively; the content at depths of 200–300 cm only increased slightly (p &gt; 0.05). It also increased the most when the alfalfa was 5–9 years old. The increments in the SAN content at the 0–100 and 100–200 cm soil depths were higher than those of the STN, with values of 29% and 18%, respectively, while those at depths of 200–300 cm also changed insignificantly (p &gt; 0.05). The SAN content continuously increased with the age of the alfalfa, and the average increment in the 0–300 cm profile was as high as 21% when the alfalfa was ≥10 years old. The SOC and STN content increased the most under moderate rainfall conditions (350–500 mm), while the SAN content maintained the highest increment under high rainfall (500–650 mm) conditions. Therefore, ley farming with the alfalfa pasture contributed substantially to the soil C and N at depths of 200 cm in deep loess. Alfalfa should be removed in its middle ages to increase C sequestration while utilizing soil N efficiently.

Incentivizing sustainable fire management in Australia's northern arid spinifex grasslands

Fire management across Australia's fire-prone 1.2 M km2 northern savannas region has been transformed over the past decade supported by the inception of Australia's national regulated emissions reduction market in 2012. Today, incentivised fire management is undertaken over a quarter of that entire region, providing a range of socio-cultural, environmental, and economic benefits, including for remote Indigenous (Aboriginal and Torres Strait Islander) communities and enterprises. Building on those advances, here we explore the emissions abatement potential for expanding incentivised fire management opportunities to include a contiguous fire-prone region, extending to monsoonal but annually lower (<600 mm) and more variable rainfall conditions, supporting predominantly shrubby spinifex (Triodia) hummock grasslands characteristic of much of Australia's deserts and semi-arid rangelands. Adapting a standard methodological approach applied previously for assessing savanna emissions parameters, we first describe fire regime and associated climatic attributes for a proposed ∼850,000 km2 lower rainfall (600–350 mm MAR) focal region. Second, based on regional field assessments of seasonal fuel accumulation, combustion, burnt area patchiness, and accountable methane and nitrous oxide Emission Factor parameters, we find that significant emissions abatement is feasible for regional hummock grasslands. This applies specifically for more frequently burnt sites under higher rainfall conditions if substantial early dry season prescribed fire management is undertaken resulting in marked reduction in late dry season wildfires. The proposed Northern Arid Zone (NAZ) focal envelope is substantially under Indigenous land ownership and management, and in addition to reducing emissions impacts associated with recurrent extensive wildfires, development of commercial landscape-scale fire management opportunities would significantly support social, cultural and biodiversity management aspirations as promoted by Indigenous landowners. Combined with existing regulated savanna fire management regions, inclusion of the NAZ under existing legislated abatement methodologies would effectively provide incentivised fire management covering a quarter of Australia's landmass. This could complement an allied (non-carbon) accredited method valuing combined social, cultural and biodiversity outcomes from enhanced fire management of hummock grasslands. Although the management approach has potential application to other international fire-prone savanna grasslands, caution is required to ensure that such practice does not result in irreversible woody encroachment and undesirable habitat change.

Transformation of organic carbon through medium pressure (polychromatic) UV disinfection of wastewater effluent during wet weather events

An observed decrease in total organic carbon (TOC) and dissolved organic carbon (DOC) concentrations following wastewater disinfection with medium pressure (MP, polychromatic) ultraviolet (UV) irradiation during wet weather flows is investigated. When antecedent rainfall in the previous 7-days was >2 in (5 cm), TOC and DOC concentrations decreased dramatically following MP-UV disinfection. Organic carbon surrogate measurements of biological oxygen demand (BOD), TOC, DOC, turbidity, UVA – 254 nm, SUVA (specific UVA), scanning UV–Visible spectra (200–600 nm), fluorescence excitation-emission matrix (EEM) spectra, and light scattering data are presented for wastewater resource recovery facility (WRRF) influent, secondary effluent (pre-UV-disinfection), and MP-UV-disinfected (final effluent) samples. TOC and DOC in wastewater influent and secondary effluent (i.e., pre-UV disinfection) correlated with antecedent rainfall conditions. The percent TOC and DOC removal through secondary treatment (i.e., from influent to effluent pre-UV) and the percent TOC and DOC removal through MP-UV disinfection (i.e., from effluent pre-UV to effluent post-UV) were compared and the latter approached 90 % through MP-UV disinfection during high antecedent rainfall conditions. Spectroscopy (UV, visible, or fluorescence) was performed on samples after filtration through 0.45 μm filters, i.e., the operationally defined DOC fraction of aquatic carbon. Scanning UV–visible spectra indicated transformation of an unidentified wastewater component into light-scattering entities regardless of antecedent rainfall conditions. The types of organic carbon (diagenetic, biogenic, or anthropogenic) and the significance of wet weather are discussed. An organic carbon contribution via infiltration and inflow was attributed as a source-of-interest in this research.