Soil Drainage Research Articles

The Evolution of Hillslope Hydrology: Links Between Form, Function and the Underlying Control of Geology

AbstractForm and function are two major characteristics of hydrological systems. While form summarizes the structure of the system, function represents the hydrological response. Little is known about how these characteristics evolve and how form relates to function in young hydrological systems. We investigated how form and function evolve during the first millennia of landscape evolution. We analyzed two hillslope chronosequences in glacial forelands, one developed from siliceous and the other from calcareous parent material. Variables describing hillslope form included soil physical properties, surface, and vegetation characteristics. Variables describing hydrological function included soil water response times, soil water storage, drainage, and dominant subsurface flow types. We identified links between form and hydrological function via cluster analysis. Clusters identified based on form were compared in terms of their hydrological functioning. The comparison of the two different parent materials shows how strongly landscape evolution is controlled by the underlying geology. Soil pH appears to be a key variable influencing vegetation, soil formation and subsequently hydrology. At the calcareous site, the high buffering capacity of the soil leads to less soil formation and fast, vertical subsurface water transport dominates the water redistribution even after more than 10,000 years of landscape evolution. At the siliceous site, soil acidification results in accumulation of organic material, a high water storage capacity, and in podsolization. Under these conditions water redistribution changes from vertical subsurface water transport at the young age classes to water storage in the organic surface layer and lateral subsurface water transport within 10,000 years.

Dynamics of humus in field crop rotations on drained lands

The purpose of the research is to study the influence of different types of field crop rotation, fertilizers, drainage and hydrothermal conditions on the dynamics of humus in reclaimed soil. The studies were carried out on the experimental fields of the All-Russian Research Institute of Reclaimed Lands (reclamation sites “Kuzminskoye Boloto 2”, “Semenovskoye” and “Gubino” in the Tver region). Waterlogged soils were drained using closed drainage (inter-drain distance is 18–20 m, drain depth is 0.9–1.2 m). The soils of the experimental plots are soddy-podzolic, light loamy, gleyic, formed on a moraine or thin binomial. Observations of the dynamics of humus were carried out in the grain-grass-row, grain-grass, grain and grain-row types of crop rotation. The influence of crop rotation on the content of humus in the soil was determined, first of all, by the composition, the structure of the crops grown and agricultural technology of their cultivation. Due to plant residues, 56.6–76.5 % of the volume of mineralized humus were restored in grain-grass-row crop rotation, 51.8 % in grain, 26.4 % in grain-row crop rotation. The most significant qualitative changes in the composition of humus were observed in grain-grass-row crop rotation: with a positive humus balance, the ratio of humic and fulvic acids increased from 0.63 to 0.74. The use of organic and mineral fertilizers significantly changes the balance of humus in the arable layer of the soil. With an organic-mineral fertilizer system, the annual loss of humus (in kg/ha) on the drained plot was 6.8–11.4 times less, on the non-drained plot – 2.1–2.6 times less than in the variant without fertilizers. Drainage of waterlogged soils increases the role of fertilizers in the accumulation of humus, reduces its losses and improves the quality parameters of humus – the ratio of humic and fulvic acids in the composition of humus under the influence of drainage increased from 0.61 to 0.88. The impact on the dynamics of humus of hydrothermal conditions has been established. In years with a dry first half of the growing season, an increase in humus content is observed; in excessively wet years, on the contrary, a decrease is observed. The correlation coefficients of humus content with hydrothermal conditions in May-June were – 0.84 (in 1985–1993) and 0.95 (in 2014–2022).

Delineation of potential alternative agriculture region using RS and AHP-based GIS techniques in the drought prone upper Dwarakeswer river basin, West Bengal, India

Delineation of potential alternative agriculture region is an essential tactics of the drought prone to mitigate the harmful effect of drought for maintaining food security and sustainable economy. These alternatives can be integrated into existing cropping systems for providing additional income to farmers. The present study deals with site suitability analysis of alternative agriculture in the drought-prone upper Dwarakeswer river basin considering 15 parameters using Analytical Hierarchy Process (AHP) based Geographic Information System (GIS) techniques. The alternative agriculture zones are then delineated on the basis of 15 separate thematic layers such as Slope, landuse and landcover, soil depth, ground water, distance from roads, soil texture, distance from settlements, ruggedness index, drainage density, soil drainage, proximity to ponds, distance from vegetation, distance from streams, nitrogen and organic carbon. Finally, seven alternative agricultural zones are identified; these are plantation agriculture, integrated farming, fruit culture, folk rice culture, medicinal plant farming, mixed farming and horticulture covering an area of 96 km2, 234 km2, 295 km2, 341 km2, 298 km2, 199 km2 and 74 km2 respectively. This is also to note that the ‘Not Suitable Zone’ has been identified accounting 397 km2 area and covering 20.5% of total study area. A total of 350 alternative agricultural sites are identified for validation purpose and the computed kappa coefficient (k) of 95.34 denote a overall accuracy of 96%.

Sodium accumulation vs. nitrate leaching under different fertigation regimes in greenhouse soils in South Uruguay

In greenhouse conditions, soil salinity and N leaching depend on the provision of irrigation, the irrigation water quality and the application of fertilizers and organic amendments. The objective of this study was to quantify and analyze the accumulation and/or leaching process of NO3- and Na+ in greenhouse tomato production in the south region of Uruguay in fine-textured soil under different fertigation regimes. The study was conducted in four tomato crops during 2019/20/21 seasons. Three fertigation regimes were applied. Irrigation volume was the same for all treatments. Drainage was determined by using free drainage lysimeters. Concentration in soil solution and leaching of NO3- and Na+ was measured by monitoring soil solution and drainage solution. Yield, N uptake and N utilization efficiency were determined for each treatment. Soil total drainage was the main factor explaining N and Na+ leaching. The leaching of N ranges from 0 to 23.4 kg N ha-1 per tomato crop with total drainage between 0 and 46.2 % of total irrigation. Drainage necessary to avoid Na+ accumulation was 13 % of total irrigation. This drainage produced 8.4 kg of N leaching per ha-1 during tomato cropping period. Optimizing irrigation is the key factor to the salinity-nitrogen leaching paradox. Irrigation amount and timing should attempt: (1) to avoid excessive irrigation when NO3- concentration in soil solution is high, and (2) to apply leaching irrigation when Na+ concentration in soil solution is high. Soil solution monitoring with suction probes and rapid chemical analysis systems could be a useful tool to identify periods of high risk of N leaching and the right time for leaching irrigation.

Specifications of Sugar Cane Varieties Based on Land Characteristic and Typology

The productivity of sugarcane is decreasing and there are more and more varieties in circulation. The decrease in productivity is caused by the incompatibility of each variety of land typology. The purpose of this research is to arrange the right varieties in increasing the productivity of sugarcane. The research method is surveying and matching. Parameters used include soil texture, land type conditions, soil drainage conditions, and rainfall. Based on the research results, the total working area of 11,866.81 ha was divided into 4 land typologies, namely BHJ with an area of 2,910.95 hectares (24.53%), BPJ with an area of 2,047.44 hectares (17.25%), RHL an area of 471.12 hectares (3.97%), RPL area of 1,527.01 hectares (12.87%). Based on land typology the suitability of BHJ varieties of sugarcane suitable varieties PSMLG 1 AGRIBUN, VMC76-16, NX03, PS921, PSJT941, PSDK923; BPJ land typology of suitable varieties Cenning, VMC71-238, PA0218, NX01, Kentung, AASAgribun, PSJT 941, PSDK923, PSBK051, NX02; RHL land typology of suitable varieties PSKA 942, PA028, PSBK061, VMC76-16, AMS Agribun, ASA Agribun, PSJT941, NXI4T, MOJO01, Bululawang; RPL land typology of suitable varieties PS881, TLH02, PSKA 942, PSBK061, PS091, PSJK922, VMC86-550, PS862, PS851, PSCO902, Kidang Kencana, PS882, PS092, PS865, PS864, NXI4T, Bululawang. Keywords: Soil drainage, Soil texture, Soil type, Soil typology, Sugarcane varieties.

Contrasting effects of soil type and use of cover crops on nitrogen and phosphorus leaching in agricultural systems of the Argentinean Pampas

Agricultural systems of the Argentinean Pampas generally use rotations of summer crops under no-tillage and apply fertilization at rates that do not compensate nutrient exports with grain harvest, resulting in negative balances and soil fertility loss. However, the humid climate, long fallow periods and soil factors enhance nitrogen (N) and phosphorus (P) leaching, which has a negative impact on freshwater ecosystems. We propose to evaluate the effect of soil type and replacement of fallow periods with cover crops on drainage and N and P leaching. We used lysimeters containing two Mollisols of contrasting texture and porosity (a Typic Argiudoll and a Typic Hapludoll), and cultivated between 2014 and 2022 with a maize-soybean rotation with (M-CC-S) and without (M-S) cover crops under no tillage.The amount of drainage varied with rainfall (p<0.01), was similar between soils and higher in M-S than in M-CC-S during the intercropping period (148 vs 96 mm, p<0.05). The correlation between daily rainfall and drainage was higher for the Typic Argiudoll (r=0.46 and 0.42, for M-S and M-CC-S, respectively) than for the Typic Hapludoll (0.28 and 0.23 for M-S and M-CC-S, respectively) when considering same-day events, and it decreased for the Typic Argiudoll (r=0.31 and 0.26, for the M-S and M-CC-S, respectively) but not for the Typic Hapludoll (0.28 and 0.21 for the M-S and M-CC-S, respectively) with a 1-day lag between series. The amount of N and P lost through leaching varied with drainage (p<0.01). Cover crops reduced nitrate leaching to a greater extent in the Typic Hapludoll (from 30.4 to 3.3 kg ha−1 period−1) than in the Typic Argiudoll (from 17.6 to 2.0 kg ha−1 period−1) (p<0.05). Soil type modified P leaching in M-S (0.32 and 0.11 kg ha−1 period−1 for the Typic Argiudoll and the Typic Hapludoll, respectively) and M-CC-S had intermediate P leaching (0.17 and 0.16 kg P ha−1 period−1 for the Argiudoll and Hapludoll, respectively) (p<0.05).We conclude that: 1) water flows through different channels in each soil, the rapid flow of the Typic Argiudoll probably occurs through preferential flow channels (macropores) while the slower flow of the Typic Hapludoll is probably associated to matrix porosity, 2) P leaching is related to soil type (Typic Argiudoll > Typic Hapludoll) and drainage reduction by cover crops off-sets P leaching through macropores in the Typic Argiudoll, and 3) cover crops reduce N leaching, due to drainage reduction and N retention in cover crop biomass.

The diversity of epixylic bryophytes in relation to dead wood properties and forest management in New Brunswick, Canada

Rotting wood is widely recognized as an important feature for bryophyte diversity in forest ecosystems but forest management practices, focused on high yields, have led to widespread reductions in the quantity and quality of coarse woody debris (CWD). As a result, many epixylic specialists are now uncommon or threatened throughout much of their former ranges. How much CWD is required to maintain desirable biodiversity, and which qualities of CWD do this most effectively is still to be answered. To address this, we analyzed two datasets from mid-rotation and mature plantations from the same landscape to better understand how the epixylic community varies with stand age, wetness, silvicultural treatment, and the abundance and type of CWD. Mature stands were either partially cut with a strip-cut treatment or were untreated. Mid-rotation plantations had a higher richness of non-Sphagnum mosses and liverworts than mature plantations. Both plantation types had a similar Simpson’s diversity indices, but these were lower than those of treated and untreated mature white cedar stands and untreated mature softwood stands. While composition of both plantation types was similar, only mature plantations differed significantly from other stand types. We speculate that this discrepancy between mid-rotation plantations and mature plantations was due to better soil drainage and a longer duration of intensive management in mature plantations, leading to reduced CWD abundance, and therefore to reduced bryophyte diversity. Our results revealed a clear positive relationship between total CWD surface area and liverwort richness and diversity in xeric sites while no relation was detected in mesic sites. More CWD is better in the case of xeric sites, where apparent asymptote of diversity is near the maximum total CWD detected in these stands. Because canopy composition and humidity also had a significant influence on bryophyte diversity and composition, further studies are needed to clearly identify thresholds of CWD surface area that take into account different stand types, soil moisture, fertility regimes, or with regards to the ecosystem in which the managed stands occurs.

Temporal development of arsenic speciation and extractability in acidified and non-acidified paddy soil amended with silicon-rich fly ash and manganese- or zinc-oxides under flooded and drainage conditions

Oxides of silicon (Si), manganese (Mn), and zinc (Zn) have been used as soil amendments to reduce As mobility and uptake in paddy soil systems. However, these amendments are hypothesized to be affected differently depending on the soil pH and their effect on As speciation in rice paddy systems is not fully understood. Herein, we used a microcosm experiment to investigate the effects of natural Si-rich fly ash and synthetic Mn and Zn oxides on the temporal development of porewater chemistry, including aqueous As speciation (As(III), As(V), MMA, DMA, and DMMTA) and solid-phase As solubility, in a naturally calcareous soil with or without soil acidification (with sulfuric acid) during 28 days of flooding and subsequent 14 days of drainage. We found that soil acidification to pH 4.5 considerably increased the solubility of Si, Fe, Mn, and Zn compared to the non-acidified soil. Additions of Mn and Zn oxides decreased the concentrations of dissolved arsenite and arsenate in the non-acidified soil whereas additions of Zn oxide and combined Si–Zn oxides increased them in the acidified soil. The Si-rich fly ash did not increase dissolved Si and As in the acidified and non-acidified soils. Dimethylated monothioarsenate (DMMTA) was mainly observed in the acidified soil during the later stage of soil flooding. The initial 28 days of soil flooding decreased the levels of soluble and exchangeable As and increased As associated with Mn oxides, whereas the subsequent 14 days of soil drainage reversed the trend. This study highlighted that soil acidification considerably controlled the solubilization of Ca and Fe, thus influencing the soil pH-Eh buffering capacity, the solubility of Si, Mn, and Zn oxides, and the mobility of different As species in carbonate-rich and acidic soils under redox fluctuations.

Hydraulic Characterization of Permeable Materials Used for Filling Mole Drain Channels in Structurally Unstable Soils

Highlights Permeable materials can be used to fill mole drains and provide support to the cavity walls in structurally unstable soils. Permeable materials extend the lifespan and improve the hydraulic performance of mole drainage systems. Darcy’s law for nonlinear porous flow explained the hydraulic performance of the permeable materials used in this study. A numerical method was established to assess the suitability of permeable materials of unknown hydraulic performance. Design guidelines were developed to assist in the planning of filled mole drainage systems installed in structurally unstable soils. Abstract. Mole drainage in soils with low permeability is a cost-effective technique for managing soil drainage. Following installation, the satisfactory performance of the system will depend on having sufficient soil fissure development extending from the soil surface to the roof of the mole channel and mole channel stability to avoid its collapse. Permeable materials such as river-run gravel and crushed stone can be used to fill mole channels to prevent channel collapse in halomorphic and high-silt content (e.g., 50%–70%) soils and extend the lifespan of the system. The objectives of this work were to: (i) characterize a range of permeable materials that can be used to fill mole drains and provide support to the cavity walls in structurally unstable soils; (ii) verify the applicability of Darcy’s law to explain the hydraulic performance of such materials, and (iii) develop a set of design and planning guidelines aimed at improving the performance of mole drainage systems that are filled with permeable materials. Five permeable materials were characterized, namely: three types of river-run gravels, crushed baked mud bricks, and crushed stone. The materials were characterized for their mechanical and hydraulic properties, and the applicability of Darcy’s law was experimentally determined. Small- and medium-sized gravels are easy to handle and apply during field installation due to their shape and flowability properties and the reduced risk of clogging when placed in the mole channel. However, the hydraulic performance of these materials would not allow for system designs longer than about 100 m, which therefore would limit their utilization in practice. Large-sized gravel offered an intermediate solution with overall satisfactory hydraulic performance. Crushed brick and crushed stone offered good alternatives to gravel, allowing for longer (e.g., &amp;gt;120 m) system designs for all combinations of drain spacing and drain gradient. However, their angularity, poor uniformity, and size range distribution can compromise the efficiency of handling and delivery in current mole plough systems. For all materials, the hydraulic conductivity (Kh) decreased with an increase in the hydraulic gradient. For a given hydraulic gradient, Kh was dependent on aggregate size, such that a larger D50 value led to increased Kh. The nonlinear performance of Darcy’s law was verified for all materials, and potential equations were fitted to represent such relationships, all showing acceptable fits to the nonlinear models (P&amp;lt;0.001). A linear relationship (P&amp;lt;0.05) between the parameter m of the potential model and total porosity was established. The set of equations developed by this study will enable estimating Kh based on the aggregate size distribution or as a function of the total porosity of the material. Crushed brick and crushed stone could provide a cost-effective solution for the installation of filled mole drain systems in structurally unstable soils. Keywords: Darcy’s law, Extreme rainfall, Halomorphic soils, Hydraulic conductivity, Reynolds number, Silty soils.

Carbon stock changes of drained nutrient-rich organic forest soils in Latvia

Impact of drainage of organic soils in forest land on soil carbon (C) stock changes is of high interest not only to accurately estimate soil C stock changes, but also to provide scientifically based recommendations for forest land management in context of climate change mitigation. To improve knowledge about long-term impact of drainage on nutrient-rich organic soils in hemiboreal forests in Latvia, 50 research sites representing drained conditions (Oxalidosa turf. mel. (Kp) and Myrtillosa turf. mel. (Ks) forest site types) and undrained conditions as control areas (Caricoso-phragmitosa, Dryopterioso-caricosa and Filipendulosa forest site types) were selected. Soil C stock changes after drainage was evaluated by comparing current C stock in drained organic soils to theoretical C stock before drainage considering impact of soil subsidence. During the 53-years period after drainage, the peat subsidence was higher in nutrient-rich Kp forest site type compared to moderate nutrient-rich Ks forest site type (peat subsided by 37.0 ± 4.8 and 23.3 ± 4.8 cm, respectively). In nutrient-rich Kp forest site type, soil C stock decreased by 4.98 ± 1.58 Mg C ha–1 yr–1 after drainage, while no statistically significant changes in soil C stock (0.19 ± 1.31 Mg C ha–1 yr–1) were observed in moderate nutrient-rich soils in Ks forest site type. Thus, in Ks forest site type, the main driver of the peat subsidence was the physical compaction, while in Kp forest site type contribution of organic matter decomposition and consequent soil C losses to subsidence of the peat was significant.

Monitoring the performances of a geosynthetic-reinforced pavement during construction

Geosynthetic materials have been widely used to enhance engineering practice in buildings, bridges, and pavements. As a kind of popular stabilization product, geogrid can be used for pavement reinforcement by serving as an additional tensile element. It has been demonstrated by many laboratory studies and numerical simulations that the reinforcement could significantly extend the fatigue life and improve the rutting resistance in flexible pavement. Meanwhile, geotextiles can provide soil separation, filtration and drainage; therefore, mitigating the freeze-thaw disturbances in the subgrade underneath the pavement structure. To study the application of geosynthetics in pavement structures in a more comprehensive aspect, a full-scale study was performed. A fibreglass geogrid which is specifically designed to reinforce the asphalt layer; as well as a geogrid composite material made of bi-axial geogrid bonded to a continuous filament non-woven geotextile, were installed in two field test sections. The geogrid was installed in the middle of the binder course within the asphalt layer, while the geogrid composite was placed at the interface of the base layer and subgrade in another section. The stiffness of the pavement was tested on each layer of the pavement structure during construction. As one of the major criteria to evaluate the pavement condition in North America, the International Roughness Index (IRI) was assessed to investigate the performances of geosynthetic-reinforced pavement during construction on asphalt binder course and surface course.

ANALYSIS OF THE MORPHO-PEDOLOGICAL CHARACTERISTICS OF SOILS UNDER COCOA ORCHARDS AFFECTED BY SWOLLEN-SHOOT IN BOUAFLE (CENTRAL-WEST IVORY COAST)

The agricultural sector, in particular cocoa production, plays a key role in the socioeconomic development of Côte d'Ivoire. With climate change, soil impoverishment and diseases such as swollen-shoot, we are witnessing a drop in production, leading to the decline of many orchards. Since the various attempts to find solutions to this problem have all ended in failure, and even though these attempts have generally never overlooked the soil as a natural support for plants, the overall aim of this study is to diagnose the prevalence of swollen-shoot disease in the soil. A morpho-pedological study was carried out in the Bouaflé department in the Marahoué region, the main endemic area in Côte d'Ivoire, to compare the characteristics of soils under healthy orchards with those under infested orchards. The main differences observed were a higher load of ferruginous concretions and poor internal drainage of soils in diseased plots. While waiting to explore the chemical properties of soils, these results lead to the conclusion that the appearance of the disease in cocoa trees also depends on the quality of the cultivation soil.

ANALYSIS OF THE MORPHO-PEDOLOGICAL CHARACTERISTICS OF SOILS UNDER COCOA ORCHARDS AFFECTED BY SWOLLEN-SHOOT IN BOUAFLE (CENTRAL-WEST IVORY COAST)

The agricultural sector, in particular cocoa production, plays a key role in the socioeconomic development of Côte d'Ivoire. With climate change, soil impoverishment and diseases such as swollen-shoot, we are witnessing a drop in production, leading to the decline of many orchards. Since the various attempts to find solutions to this problem have all ended in failure, and even though these attempts have generally never overlooked the soil as a natural support for plants, the overall aim of this study is to diagnose the prevalence of swollen-shoot disease in the soil. A morpho-pedological study was carried out in the Bouaflé department in the Marahoué region, the main endemic area in Côte d'Ivoire, to compare the characteristics of soils under healthy orchards with those under infested orchards. The main differences observed were a higher load of ferruginous concretions and poor internal drainage of soils in diseased plots. While waiting to explore the chemical properties of soils, these results lead to the conclusion that the appearance of the disease in cocoa trees also depends on the quality of the cultivation soil.

Impact of Controlled Drainage on Crop Yield Including Within-Field Variability

Highlights A 10-m grid system was developed for spatial and temporal analysis of crop yield impacts of controlled drainage. Yields were analyzed by annual wetness classification, soil drainage class, and elevation within the field. Overall, controlled drainage significantly increased corn yield by an average of 2.3%, but not soybean yield. The grid-based analysis with a linear mixed model identified characteristics influencing CD yield effect. Abstract. Controlled drainage is the practice of using a water control structure to raise the outlet in agricultural fields during periods when drainage is unnecessary, with the primary purpose of reducing nitrate loss. The use of this practice may increase crop yields compared to free drainage because controlled drainage can capture water from precipitation as soil water and store it for crop use later in the growing season. However, results from published studies of controlled drainage have shown mixed impacts on crop yields, and the effects of field characteristics and annual weather variation on these impacts are not well understood. To analyze crop yield impacts, two controlled and two free draining plots in eastern Indiana were compared. A grid system consisting of 10 by 10 meter cells was created to obtain a balanced data set and used to analyze crop yield by year, annual wetness classification, soil drainage class, and elevation. Controlled drainage significantly increased the corn yield in six out of nine years, and the nine-year corn yield average increased by 2.3%. Soybean yield was significantly higher under controlled drainage in three out of four years, but there was no significant difference in the four-year soybean average. Years were further classified as wet, normal, or dry based on growing season precipitation, and results indicated controlled drainage had the greatest significant impact on corn yield in the dry years. Analyzing yield by soil drainage class determined that yield had the greatest response to controlled drainage on the very poorly drained soils. Controlled drainage had a significant yield benefit in corn during dry years in areas in which the elevation is more than 30 cm above the surface elevation at the outlet, and did not lead to significant differences in normal or wet years at any elevation. The grid-based analysis with a linear mixed model accounting for autocorrelation was useful for understanding within-field variability of yield response. Keywords: Controlled drainage, Crop yield, Drainage water management, Soil drainage class, Subsurface drainage.

Evaluation of Land Suitability for Sustainable Maize Crops in Popayato District, Pohuwato Regency

Utilisation of land resources requires information on the potential and limitations of land use so that commodities to be cultivated can achieve optimal results. This study aims to determine the suitability of land for corn (Zea mays L.) in Popayato District, Pohuwato Regency. This research uses a qualitative method that combines a statistical analysis approach with spatial analysis techniques. Results pH, texture, effective depth, organic C-C, clay CEC, temperature, rainfall, drainage, slope, altitude, and erosion. The maize crop requires an optimum temperature between 26°C and 807-1200 mm of rainfall annually, which is a uniform distribution of rainfall. The soil has a texture of loam, dusty loam, or sandy loam which is ideal for maize growth and development. Maize requires sufficient aeration so that the plant roots can absorb nutrients well. The soil drainage is good and the growth rate is quite fast.

The effect of drainage, fertilizers, and agro-reclamation techniques on spring wheat productivity

The current study was conducted at the agricultural site ‘Gubino’ of the All-Russian Research Institute of Reclaimed Lands (Tver Region) in 2011–2022. The purpose was to study the efficiency of drainage of waterlogged soils, fertilizers and agro-reclamation techniques when growing spring wheat in the conditions of the North-Western part of the Non-Blackearth region. The soil of the agricultural site was soddy-podzolic, light loamy and gleyic sandy loam, drained by closed drainage. The field trials have established the influence of drainage of gleyic soils, the use of fertilizers, volumetric slotting of the soil to a depth of 45–50 cm, ridge plowing and ridge belt-scattering method of sowing on spring wheat productivity. Drainage increased wheat productivity on the extensive background by 17.8 % (0.34 t/ha), on the medium-intensive and intensive background by 16.9–19.4 % (0.56–0.60 t/ha). Mineral fertilizers improved productivity more significantly, against a drained background, wheat productivity increase at medium fertilizer rates (N45Р15K45) was 1.20 t/ha (53.3 %) and at high fertilizer rates (N90Р30K90) it was 1.91 t/ha (84.9 %). The combined effect of drainage and fertilizers improved spring wheat productivity on waterlogged soil by 2.2 times (by 2.25 t/ha). The highest payback of 1 kg of fertilizers by a spring wheat yield was obtained on a drained plot with average fertilizer application rates of 9.8 kg of grain. A high effect was obtained from agro-reclamation techniques aimed at improving the water-air regime of soil. With volumetric slotting of the soil, spring wheat productivity raised by 0.50–0.97 t/ha (13.2–26.4 %), with ridge plowing by 0.36 t/ha (12.0 %), with ridge belt-scattering method of sowing with growing spring wheat on ridges 40–80 mm high by 0.45 t/ha or 13.7 %, in relation to the existing technology of row sowing. The study results can be used in the development of adaptive agricultural technologies for cultivating spring wheat on drained lands.

Prediction of Duration of Dry Bamboo Leaf Counting Using Fuzzy Logic

Dry bamboo leaves are selected as a planting medium for ornamental plants to enhance nutrient content and improve soil drainage. Before being processed into fertilizer, dry bamboo leaves need to be shredded first. The leaf counting process for planting ornamental plants in villages still relies on manual methods such as using knives and scissors, which can be time-consuming and less effective. In response to this issue, a device for shredding dry bamboo leaves has been developed to improve efficiency and facilitate the leaf counting process. The innovation created is a household-scale dry bamboo leaf shredder that is more affordable and easy to mobilize due to its compact dimensions and lighter weight. The device is also easy to operate, as the shredding occurs when it is closed, and the process stops when it is opened, ensuring safe use for various users. The manual control of bamboo leaf weight and counting duration results in inconsistent shredding outcomes. Therefore, development has been carried out on the dry bamboo leaf shredder with artificial intelligence capabilities, specifically using fuzzy logic to automate the counting duration based on the size and weight of the bamboo leaves being inputted.

Effects of Long-Term Management on Soil Organic Carbon in Tropical Peatlands

Objective: The aim of this study was to evaluate the effects of Histosols management on soil organic matter (SOM) characteristics. Theoretical framework: Histosols are soils that provide ecosystem services, especially carbon stocks. Among the environments in which these soils are formed, peatlands stand out. The conversion of these areas into agricultural systems requires soil drainage. This practice causes reductions in carbon content and changes in the structure of the SOM. Methodology: The study was conducted in the municipality of Rio de Janeiro, Brazil. The soils were classified as Histosols. Three areas were selected: a) cassava (Manihot esculenta) cultivation for 80 years; b) forest fragment for 20 years; c) consortium of coconut palm (Cocos nucifera) and cassava for 20 years. Total organic carbon (TOC); particulate organic carbon (COP); organic carbon associated with minerals (COam); fulvic acid fraction carbon (CAF); humic acid fraction carbon (CAH) and; humin fraction carbon (CHUM) were determined. Solid-state spectroscopy (UV-vis, ATR-FTIR and 13C NMR CP/MAS) was carried out to characterize the structure of the SOM. Results and conclusion: The results showed that management and drainage have an impact on the TOC content, fractions and chemical structure of the SOM. The management adopted in the cassava area had an impact on the labile and humified fractions of the SOM. Spectroscopy showed that labile structures were lost in the humic acids (HA), while in the forest area only recalcitrant structures were preserved. Research implications: The conversion of Histosols to agricultural production using the drainage technique promotes quantitative and qualitative changes in SOM in the long term. In order to reduce greenhouse gas emissions, it is necessary to use techniques that promote carbon stocks in the soil. Originality/value: This study uses spectroscopic and chemometric techniques to highlight the effects of long-term soil management on the chemical structure of the SOM and to quantify the total carbon content and SOM fractions.

SOIL ENGINEERING: MODERN CHALLENGES AND DEVELOPMENT PROSPECTS

The emergence of private ownership of land and the urgent needs of the developing practice of land use require a rethinking of some existing fundamental paradigms and the search for new technologies in the relationship between man and nature, as well as, for this purpose, the creation of new sections of knowledge. New ways of developing the surrounding landscape environment are not enough and the methods offered by traditional disciplines. Construction norms and rules need to be clarified for anthropogenically modified soils and soils. Soil engineering is a field of knowledge that studies the engineering properties of the soil and the possibility of using them for the design and construction of soilengineering structures in the soil and soil structures designed to solve specifi c soilengineering problems of environmental management and develop environmentally friendly engineering technologies for managing the properties of soils and landscapes. Such technologies are in urgent demand today in lowrise, communal, landscape, landscape gardening, agricultural, hydrological, forestry, urban, etc., construction. The objects of soil engineering are soilengineering structures and soil structures of various scales (from pedon to soil cover) created in natural and anthropogenically modified soils. Soilengineering structures mean a soil-technical complex that preserves or creates the basis for the sustainable existence of the natural environment. All soilengineering structures can be divided into inert structures (foundations, pipelines, road surfaces) and structures interacting with the soil (wells, fi ltrationfields, reservoirs, drainage and irrigation systems). Soil and landscape engineering is an integral part of environmental engineering, which is rapidly developing. Technologies of soil and landscape engineering have been one of the main driving forces of the progress of civilization throughout the existence of humanity, and they reached their peak in the Russian estate culture of the 19th century. However, the new socioeconomic phenomenon the «modern Russian estate» needs to be studied and norms and rules developed for organizing its interaction with the natural environment, which in many respects is similar to the influence of garden construction and is very similar to the influence of a city in space and time.

Controls on rapid rare earth element enrichment in sediments deposited by a continental-scale river system

Clay-hosted rare earth element (REE) deposits, generally considered products of extended subtropical weathering of REE-rich igneous protoliths, are a critical source of REEs globally.The Koppamurra deposit of southeast South Australia, in contrast, is developed in Pleistocene lacustrine clays overlying a REE-poor marine limestone. Here we examine the REE + Y (REY) sources and enrichment mechanisms of this unusual setting. We find that the greatest REY enrichment (up to 5000 ppm) occurs in lacustrine clays at the base of a ∼1–2 m thick contact zone with the underlying limestone. This zone features an increased proportion of leachable REYs (>50 %), increased smectite abundance and a sharp increase in pH from ∼5.0 to ∼8.3. Co-variation of HREEs with a suite of clay-specific elements demonstrates that HREEs are hosted mainly by Fe-rich smectite, with separate sorbed vs structurally bound HREE pools that are of similar magnitude. LREEs are mainly hosted in secondary LREE carbonates, these are preferentially intergrown with smectite but are only rarely present in kaolinite domains. Cerium occurs mainly as cerianite. The narrow range and overlapping εNd of samples within and above the REY enriched zone suggests that enrichment is related to internal redistribution within the clay unit. The clays are isotopically incompatible with local igneous or metasedimentary rocks, but 87Sr/86Sr and εNd isotopic fingerprinting shows that they were deposited by the Murray River, Australia’s largest river system. Murray sediments are enriched in REY due to the presence of material eroded from the Lachlan Orogen granites of southeast Australia. Deposition of these sediments occurred in a coastal lacustrine setting analogous to the modern-day Coorong, with tectonic uplift and shoreline progradation allowing the onset of subaerial weathering ∼1–2 Mya. We propose that vertical and lateral solute transport allowed for the concentration of REEs in local depressions in the karst-weathering surface which separates the limestone and overlying clay, facilitated by water table oscillation and pore water redox cycling driven by seasonally contrasted rainfall. Poor soil drainage, evaporative concentration of soil waters and alkaline pH adjacent to the limestone immobilized REEs in secondary carbonates and Fe-rich smectite. Our findings illustrate that REE mobilization and enrichment in clay deposits can occur more rapidly, over a larger area and in a broader range of host phases and geologic settings than is currently appreciated, with important implications not only for REE exploration but also for the use of REEs as tracers in the Earth Sciences.