Sandy Loam Research Articles

Influence of grazing intensity on organic carbon deposition in pasture soil

The study was conducted to study the effect of cattle grazing intensity on the deposition of organic carbon (Corg) in pasture soil. The work was carried out in 2010 on soddy-medium podzolic sandy loam soil in the Leningrad region. Three pasture areas were identified according to grazing intensity: weak (section 1), medium (section 2), strong (section 3). Corg and carbon in the clay fraction of the soil (Cclay) were determined according to the method of I. V. Tyurin. The sludge fraction (1 µm) was isolated using sedimentation and centrifugation. X-ray analysis of soil minerals was carried out in samples of the clay fraction of the soil on a DRON-3M diffractometer, Cu Kα tube mode 30 mA, 30 kV, from 3.5 to 75°, goniometer rotation speed 1° per minute. The soil of site 3 was distinguished by the minimum content of Corg in both periods of the survey (May – 16 C g/kg of soil; July – 27.8 C g/kg). The Corg value in the July samples was 1.3 times less compared to site 2 and 1.2 times less than site 1. Cclay values varied in the range: in May 40.8…108.9 C g/kg fractions, in July 99.7…140.9 C g/kg fraction. The content of Cclay in July samples from site 3 was 1.3 times higher than the content in samples from site 2 and 1.4 times from site 1. The variation in the enrichment coefficient (Esoc) was 1.78…3.50 in May, 2 in July .89…5.07. The highest Esoc was recorded for the soil of site 3 in July; its values exceeded the values in sites 1 and 2 by 1.75 times. The mineral depositing organic matter in the clay fraction of the soil of the site with high grazing intensity was mica with a deficiency of cations (r = 0.90). The increase in grazing intensity led to an increase in the content of Cclay.

Mineralogical Characteristics of Soils in Southern Taraba State Northeast, Nigeria

Mineralogy of fadama soils of southern Taraba state was carried alongside its influence on the soil’s physical and chemical properties. The three local government areas selected for this study were Ibi, Wukari and Donga. The mineralogical compositions of the soils were evaluated using the clay fraction. X- ray diffraction (XRD) analysis showed ibi had quartz (21%), microcline (47%) and kaolinite (25%), Wukari Tsukundi had quartz (17%), microcline (20%) and kaolinite (32%), phlogopite (15.4%) and gibbsite (23%) while Donga had mineral composition of quartz (20%), microcline (33%) and kaolinite (47%) and therefore the clay minerals are interstratified (mixed mineralogy). The soil textures in these mapping units (MUs) are sandy clay loam (SCL), loam sand (LS) and sandy loam (SL) in the Ap horizons of pedons I, 2 and 3 respectively. The subsurface horizons are Silt Loam, SCL and LS. The silt clay ratio (SCR) indicated that the soils are relatively young soils with reserved weatherable minerals, mean SCR were 1.40, 1.50 and 4.00 in pedons 1, 2 and 3 respectively. The acidity decreased as the profile depth increased and it was moderately acidic soil with pH(KCl) ranged from 5.92- 4.75 for pedons. The delta pH (\(\Delta\)pH) of the soils showed all negative values; this indicated that the soil colloids contained appreciable silicate clay minerals with relatively constant surface charge while C/N ratios indicated advanced stage of organic matter decomposition. Percentage Al saturation to the TEA stood at 15%, 19% and 9% for pedons I, 2 and 3 respectively, The exchangeable Ca constitutes above 70 % of the total exchangeable bases (TEB). The percentage base saturation (%BS), was largely dominated by exchangeable cations in moderately to very high rating and their mean values are 80%, 77% and 74% for pedons I, 2 and 3 respectively. The arrays of minerals are at different stages of weathering- quartz and phlogopite at moderate stage of weathering, microcline at minimal stage of weathering while kaolinite and gibbsite are at intense weathering stages. These minimally and moderately weathered soils are generally considered to be of good fertility status. The soils were classified as Alfisols/Entisols mix.

Physicochemical characterization of agricultural soils under a traditional system in the Mezquital Valley, Hidalgo

The study examines alkaline and sodic soils, characterized by a pH exceeding 7.5 and elevated exchangeable sodium, indicative of deficiencies in nitrogen, manganese, iron, zinc, and copper in crops. Its objective is to characterize agricultural soils under traditional and conventional systems using physical and chemical parameters to advocate for regenerative agriculture. Sampling and analysis adhere to Nom-021-RECNAT-2000 standards. Predominantly, the soils exhibit clay loam and sandy loam textures across Tula de Allende, Tezontepec de Aldama, Francisco I. Madero, and San Salvador municipalities. Organic matter percentages vary, classified as very high (Tula de Allende and San Salvador), high (Tezontepec de Aldama, Mixquiahuala de Juárez, and Francisco I. Madero), and low (Santiago de Anaya). The pH ranges from moderately alcaline to highly alkaline. Cation exchange capacity in irrigation zones varies from very high to high, and medium for Tezontepec and Santiago de Anaya, which rely on rainfed irrigation. Elevated nitrate (NO3-), phosphorus (H2PO4-), and potassium (K+) concentrations are noted across different municipalities. These findings prompt reconsideration of traditional tillage practices that exacerbate sodicity in agricultural soil.

One-time conventional tillage, crop diversification and mulching enhanced hydro-physical properties of a tropical sandy loam soil

One-time conventional tillage, crop diversification and mulching enhanced hydro-physical properties of a tropical sandy loam soil

Metabolomic Profiling and DNA-Fingerprinting of Newly Recorded White-Flowered Populations of Salvia lanigera Poir. in Egypt.

Salvia lanigera Poir. is a small herbaceous perennial species with violet flowers that grows in low-altitude deserts, and sandy loam. During the collection of S. lanigera, unusual populations with white flowers were found. Therefore, the two populations (violet- and white-flowered) were subjected to comparative investigations, including DNA fingerprinting, chemical composition, and biological evaluation. The two populations showed DNA variations, with 6.66 % polymorphism in ISSR and 25 % in SCoT markers. GC/MS and UHPLC/HRMS of aqueous methanol extracts, led to the tentative identification of 43 and 50 compounds in both populations. In addition, the structures of nine compounds, including four first-time reported compounds in the species, were confirmed by NMR. Furthermore, the total extracts exhibited weak radical scavenging activity against DPPH and a lower inhibitory effect towards acetylcholinesterase. In conclusion, the obtained data suggested that the white-colored flower could be an additional important character record for the Egyptian S. lanigera.

Comparison of the economic performance of organic and conventional corn–soybean–winter wheat rotations in southwestern Ontario, Canada

The economic viability of using summer-seeded legume cover crops (crimson clover, red clover, and hairy vetch) as a primary nitrogen (N) source for an organic corn ( Zea mays L.)–soybean ( Glycine max (L.) Merr.)–winter wheat ( Triticum aestivum L.) rotation was determined on a sandy loam soil in southwestern Ontario, Canada, by comparing gross profit for organic production (organic sources of N and phosphorus, no herbicides) to conventional production (no cover crops, synthetic fertilizers and herbicides added). Profits were determined for the initial 3-year transition period from conventional to organic production (2015–2017), and for 5 years of certified organic production (2018–2022). During the transition period when conventional crop prices applied to both production systems, organic production profits (CAD $1148–$1869 ha−1 per rotation) were lower than conventional profits (CAD $2126 ha−1 per rotation). During the certified organic period when price premiums were applied, organic soybean and corn profits (CAD $1995–$2274 ha−1 and $2819–$3195 ha−1 per year, respectively) were significantly greater than conventional soybean and corn profits (CAD $536 ha−1 and $1926 per ha−1, respectively). Winter wheat profits were slightly higher for organic production (CAD $426–$825 ha−1 per year) than for conventional production (CAD $371 ha−1 per year). During the certified organic production period, profits from the 3-year rotations were CAD $5533–$6153 ha−1 for organic production, and CAD $2860 ha−1 for conventional production. It was concluded that an organic rotation of corn–soybean–winter wheat/legume cover crop can be economically viable and more profitable than conventional production on sandy loam soil in southwestern Ontario.

Subsurface flow model for estimating 2D wetting pattern in drip irrigation

AbstractNumerical model using 2D Richard’s equation in cylindrical polar coordinate system was developed to assess the soil wetting patterns in a drip irrigation system. A fully implicit finite‐difference scheme was used to solve equations with suitable initial and boundary conditions. The developed model was validated with an experimental result available in the literature, which shows a high level of concordance with low values of RMSE and R2 greater than 0.93 for all discharge rates. Furthermore, the versatility and applicability of the model were demonstrated for complex subsurface conditions considering homogeneous and heterogeneous soil profiles. Water ponding on the surface was observed in clay loam soil, contrasting with deep percolation in sandy loam soil. This underscores the significance of adjusting both discharge rate and irrigation frequency in accordance with prevailing soil conditions.

Effect of Soil Texture on Agricultural Machine Performance in Sylhet, Bangladesh.

Soil texture is one of the primary soil physical properties that largely affects agricultural machine performance. Before implementing an agricultural machine at the farm level, it is important to test the machine to gain an understanding of its technical functionality and economic viability to get the best output from it. The research was carried out to assess how soil texture influences the performance of machinery, aiming to determine the effectiveness of agricultural equipment on a particular type of land. Soil samples were collected from nine different fields, and their textures were determined using hydrometer analysis. To correlate soil textural classes with machine performance, machinery data—effective field capacity, forward speed, and field efficiency—were calculated by operating a combine harvester on the study areas during the harvesting season of Boro rice. Two types of soil were identified: loamy sand and sandy loam. The findings of the study showed that machine efficiency has a positive correlation with sand proportion and a negative correlation with clay and silt fractions. It was observed that soil with loamy sand-type textural classes demonstrated better field efficiency, higher effective field capacity, and higher forward speed compared to sandy loam soil. Small and irregularly shaped fields also caused variation in performance. The study identified significant variation in speed between these two types of soils but no significant effect on effective field capacity or field efficiency at the 5% level of significance. The outcomes of this research will help farmers make informed decisions when selecting appropriate equipment for their agricultural operations.

Rice straw incorporation and Azolla application improves agronomic nitrogen-use-efficiency and rice grain yields in paddy fields

In paddy soils, excessive application of N fertilizer often results in substantial N losses due to low N utilization efficiency. However, this condition can be mitigated by enhancing soil organic carbon content. Two-year field experiment was carried out at Mkula Irrigation Scheme in Kilombero Valley, Tanzania with the aim of investigating the impact of Azolla, rice straw incorporation and reduced levels of nitrogen input from NPKS-containing fertilizers on N use efficiency, soil chemical properties and rice grain yield. Assuming that this technology will introduce a novel perspective to the research, shedding light on alternative and potentially more sustainable methods for nitrogen management in paddy soils, it will be particularly relevant in sub-Saharan Africa, where the annual cost of chemical fertilizers is expected to continue rising. The treatments involved absolute control, half dose N (50 kg N ha-1), full dose N (100 kg N ha-1), and combination of these N doses with PKS, dry Azolla (3.4 t ha-1) and rice straw (6.9 t ha-1) through omission approach. The soil of the experimental area was sandy clay loam in texture, very strongly acid (pH 4.8), normal electrical conductivity (0.06 dS m-1), low amounts of recorded organic carbon (1.35%), total nitrogen (0.33%), 0.68 mg kg−1 available P, exchangeable potassium (0.15 cmol(+) kg−1), calcium (0.19 mg kg−1) and sodium percentage (3.75%), with very low cation exchange capacity (1.6 cmol(+) kg−1). The results showed that combination of Azolla, rice straw +100 kg N ha-1 + 30 kg P ha-1 + 30 kg K ha-1 + 20 kg S ha-1 resulted in higher rice grain yield, nitrogen uptake and agronomic efficiency of N. Azolla, being an effective biofertilizer, significantly contributes to nitrogen fixation and soil enrichment. Interestingly, this study demonstrates that co-application of Azolla, rice straw, and 50% reduced N is effective for achieving high rice yields, minimizing over-dependence on chemical N fertilizer, sustainable agricultural development, and environmental conservation.

Studies in the Foliar Analysis of Sal (<i>Shorea robusta</i> Gaertn. F.) and the Physico-Chemical Status of the Underlying Soils in Madhya Pradesh

The paper describes the foliar analysis of sal (Shores robusta Gaertn. f.) and the physico-chemical status of soils under the respective sal forests of Madhya Pradesh.The soils are fresh, immature to leached down ones. The best growth of sal, as determined by Relative Growth Index (RGI-a new concept) is base poor, leached-down sandy loams. Coarse, fresh and thin soils under sal climate have poor growth of the species; and medium growth is registered in comparatively base richer soils.The soils are discussed to have been derived so by the process of 'laterisation' under the forest floor and the existing climate.Further, foliar analysis confirms the chemical status of the soils and reveals that sal is not a heavy demander of soil bases.

Evaluating the Physical and Chemical Characteristics of Soil from Several Blocks in Mirzapur District, Uttar Pradesh, India

An evaluation of the physical-chemical characteristics of soil was conducted in 2023–24 in several blocks within the Mirzapur district of Uttar Pradesh. This study's main goals were to assess the physico-chemical characteristics of soil in several blocks in Uttar Pradesh's Mirzapur District in ord`er to ascertain the soil's macronutrient availability. Samples of soil were taken at three different depths: 0–15 cm, 15–30 cm, and 30-45 cm. Sandy loam was the textural class of soil. 1.17 mg m-3 to 1.44 mg m-3 is the bulk density. Density of Particles (2.22 - 2.48 mg m-3). Pore Space Percentage (42.78% to 48.00%). It was evident that the soil had good physical conditions, an alkaline pH range of 7.43 to 8.15, a good water holding capacity (39.92 to 45.76%), and and all crops could benefit from the electrical conductivity (0.21 to 0.34 dSm-1). Organic carbon content in these soils is modest (0.27 to 0.38%). All villages have a medium nitrogen range (250 kg ha-1 to 380 kg ha-1). All villages have a medium phosphorus level (22.53 kg ha-1 to 37.49 kg ha1). (148.43 kg ha-1 to 282.4 kg ha-1) of potassium. is high in one place and medium in eight others.

Numerical modeling of PFAS movement through the vadose zone: Influence of plant water uptake and soil organic carbon distribution

In this study, we investigated the effects of soil organic carbon (SOC) distribution and water uptake by plant roots on PFAS movement in the vadose zone with a deep groundwater table under temperate, humid climate conditions. Two series of numerical simulations were performed with the HYDRUS computer code, representing the leaching of historical PFOS contamination and the infiltration of water contaminated with PFOA, respectively. We considered soil profiles with three distributions of SOC (no SOC, realistic SOC distribution decreasing with depth, and uniform SOC equal to the content measured in topsoil), three root distributions (bare soil, grassland, and forest), and three soil textures (sand, sandy loam, and loam). The SOC distribution had a profound impact on the velocity of PFOS movement. The apparent retardation factor for realistic SOC distribution was twice as large as for the scenario with no SOC and more than three times smaller than for the scenario with uniformly high SOC content. We also showed that the root distribution in soil profoundly impacts the simulations of PFAS migration through soil. Including the root zone significantly slows down the movement of PFAS, primarily due to increased evapotranspiration and reduced downward water flux. Another effect of water uptake by plant roots is an increase of PFAS concentrations in soil water (evapo-concentration). The evapo-concentration and the slowdown of PFAS movement due to root water uptake are more significant in fine-textured soils than in sand.

Evaluating the seasonal effects of whole orchard recycling on water movement and nitrogen retention for a newly established almond orchard: Simulation using HYDRUS-1D

Whole orchard recycling (WOR) is an emerging practice in perennial cropping systems and is an alternative to open or cogeneration burning. It is an orchard removal practice that incorporates large amounts of woody biomass back into the soil system. In this study, we utilized a soil hydrological model (HYDRUS-1D) to evaluate the seasonal effects of WOR on water movement and nitrogen (N) retention for a newly established almond orchard on a typical sandy loam soil in the Central Valley of California. Soil moisture and N content were monitored across the first five growing seasons from 2018 to 2022. The model was able to track seasonal moisture fluctuation nicely compared to observed data. Additionally, an increase in soil moisture was measured in the WOR treatments in surface soil (i.e., 0- to 15-cm depths) where biomass was incorporated, and N leaching was reduced when compared to the unamended control. Simulations suggest that with WOR, irrigation can be reduced by up to 20 % during the tree establishment stage with minimal effect on root water uptake. This reduction in applied water can increase farm water use efficiency and reduce operational expenses, e.g., cost of water and pumping. Likewise, the reduction in N leaching observed in both predicted results and laboratory analysis can further cut farm capital costs, e.g., fertilization, and lessen orchard environmental impacts. Overall, results from our simulation show a positive effect of WOR on soil ecosystem services and can potentially be a profitable strategy for orchard turnover. The results have important implications in reducing groundwater nitrate contamination in irrigated agriculture in the Central Valley of California and applicable to most parts of Southwestern United States.

Impingement of NPK and Rhizobium on Physico-chemical Properties of Soil under Cluster Bean (Cyamopsis tetragonoloba L.)

The study pertaining to the present topic under field investigation entitled “effect of different levels of NPK and Rhizobium on Physico-chemical properties of soil, growth and yield attributes of cluster bean” beginning from kharif seasons of the years 2023 at Research Farm, Department of Soil Science and Agricultural Chemistry. The excavated soil sample from experimental site before conducting research operation, mentioned that, the land topography range was nearly levelled with 1-3% slope, soil is of sandy loam texture with neutral to alkaline in reaction (7.140), electrical conductivity was non-saline (0.346 dS m-1) in nature, low organic carbon content (0.38%), low to medium available N (261.39 kg ha-1), available P (14.60 kg ha- 1) and available K (193.99 kg ha-1). Among nine treatments, during field experimentation, the conjunctive use of NPK and different Rhizobium levels, together come with best results significantly. However, the physical and chemical soil parameters, cumulative mean value for Bulk density (1.42 Mg m-3 and 1.45 Mg m-3),Particle density (2.64 Mg m-3 and 2.66 Mg m-3) and Soil pH (7.140 and 7.370) was found optimum in T1 (Absolute control) at 0-15 cm depth and 15-30 cm depth, respectively. Percentage porespace (45.17% and 43.17%), Water holding capacity (42.32% and 39.70%), Electrical conductivity (0.323 dS m-1 and 0.300 dS m-1), Percentage organic carbon (0.49% and 0.46%), Available N (284.41 kg ha-1 and 281.48 kg ha- 1 ), Available P (22.54 kg ha-1 and 21.29 kg ha-1 ), Available K (210.52 kg ha-1 and 203.98 kg ha-1 ) were found optimum in T9 consisting of (@ 100% NPK + @ 100% Rhizobium) in comparison to other NPK and Rhizobium levels application.

Impact of Various Levels of Nitrogen, Potassium, Phosphorus and Biochar on Soil Physico-chemical Properties and Yield of Black gram (Vigna mungo L.) Var: Shekhar-2

At the “Central Research Farm, Soil Science and Agricultural Chemistry Department, SHUATS, Prayagraj”, an experiment titled "Impact of various levels of Nitrogen, Potassium, Phosphorus and Biochar on Soil Physico-chemical Properties and Yield of Black gram(Vigna mungo L.)Var: Shekhar-2" was carried out during the Zaid season of 2023–2024. A randomized block design was used, consisting of three variables and three levels of NPK (at 0, 50, and 100% ha-1) and biochar (at 0, 50, and 100% ha-1). An excavated soil specimen from the experimental site prior to the start of study activities showed that the soil had a sandy loam texture, a neutral to alkaline reaction, and significantly higher treatment levels.

Effect of Varieties and Dates of Sowing on Seed Yield of Sunhemp

A field experiment was conducted at Agricultural Research Stattion, Amadalavalasa to identify a suitable sunhemp variety and sowing window during Khariff or obtaining higher yields in North Coastal Andhra Pradesh. The soil of experimental site was sandy loam in texture, medium in alkaline reaction (pH: 8.24), non-saline (EC: 0.22 dS m-1), low in organic carbon (0.5%), low in available nitrogen (219.3 kg ha-1), low in available phosphorus (22.18 kg P2O5 ha-1) and medium in available potassium (268.3 kg K2O ha-1). The experiment was laid out in a split plot design with four main plot treatments, three subplot treatments and with three replications. The main treatments comprised of four dates of sowing viz., D1: 1st may,D2:15th may,D3:1st june and D4: 15th june. The sub plot treatments comprised of three varieties viz., V1: K12 yellow, V2: K12 black and V3: SH 4. All the cultural practices were adopted as per the recommendations of University. The results of the experiment indicated that growth and yield of sunhemp was significantly influenced by variety as well as date of sowing. It was evident that sowing of sunhemp in North Coastal AndhraPradesh on 15th June was optimum as it recorded shorter plant height (224.8 cm), early flowering i.e flower initiation at 80 days, 50% flowering in 91 days, higher plant population and significantly higher seed yield (2.35 q/ha) was recorded. Among the varieties tested SH 4 produced taller plants exhibited early flowering and finally recorded significantly higher seed yield (2.16 q/ha). However, plant population did not vary significantly among the varieties. Interaction between dates of sowing and varieties indicated that for seed crop K12 black and SH 4 of sunhemp can be sown between 1st june to 15th June in North Coastal Andhra Pradesh for getting higher seed yield of sunhemp as the seed yield of the above two varieties and dates of sowing were atpar.

Response of Spring Maize to Different Sowing Schedules and Phosphorous Application

A field experiment was conducted at the Agronomy Farm, School of Agriculture, Lovely Professional University in 2023 to assess the performance of maize (Zea mays L.) under varying sowing schedules along with levels of phosphorus application. The experimental site featured sandy loam soil with pH of 7.34, 0.32% organic carbon content, and an electrical conductivity (EC) 0.423 ds m-1. An experiment comprised different phosphorus levels, including recommended diammonium phosphate (DAP), recommended single superphosphate (SSP), 10% increase in DAP, or 10% increase in SSP applied at three sowing dates. It followed a randomized block design with twelve treatments and three replications. The results indicated that the timing of sowings had a significant impact on all yield attributes, such as cob length (cm), number of rows/cob, number of cobs/m2 area, grains/cob, grain yield (q/ha), biological yield (kg/ha), and harvest index (%). However, levels of phosphorus application did not exhibit a significant effect on growth and yield attributes. The best results, including taller plants (213.8 cm), a higher number of cobs per m2 area (14), increased number of rows/cob (16), grains per cob (334.7), grain yield (45.2 q/ha), biological yield (97.8 q/ha), and harvest index (53.2 %), were achieved by sowing maize crop at the optimum sowing date (D2).

Developing novel ensemble models for predicting soil hydraulic properties in China’s arid region

Accurately quantifying the mass (water, nutrients, and carbon) and energy exchange processes between the Earth’s atmosphere, biosphere, and lithosphere requires the accurate parameterization of soil hydraulic properties (SHPs) and their spatial heterogeneity. Because direct measurements of SHPs are difficult, time-consuming, and impossible at larger spatial scales, various pedotransfer functions (PTFs) have been developed in the last few decades, providing divergent estimates of SHPs from readily measurable variables. However, existing PTFs are mostly developed for specific regions and may not be suitable for other pedoclimatic conditions. Here, PTFs were developed using multiple machine-learning algorithms to estimate SHPs and examined the weaknesses and strengths of each method in estimating the average and variability of SHPs across China’s arid region. The optimal PTFs were applied to a 1 × 1 km2 regional map of texture and bulk density, thus producing maps of the saturated hydraulic conductivity (Ks), the parameters of the van Genuchten (VG) formulation, field capacity (θfc), wilting point (θwp), plant available water (θpa), and soil macroporosity (ϕm) in the 0–2 m soil profile throughout the region. The results indicate that the ensemble model with the averaging method (EMA) is the most robust for estimating all SHPs. The EMA-PTFs for Ks yielded the best performance for sand textures, followed by sandy loam, loam, silty loam, silty clay loam, loamy sand, and clay loam textures. There were no significant differences in estimating soil water retention curve parameters among the different soil texture classes. Using the same observed data set, we demonstrated that the new EMA-PTFs outperformed those of existing PTFs, such as Rosetta and HYPRES, with RMSE values decreasing by 25–83 % depending on the SHPs. Furthermore, our SHP datasets exhibited significantly deeper soil profiles and higher accuracy than other available regional and global SHP products. The VG retention parameter α shows the greatest variation vertically throughout the 0–2 m soil profile, followed by ln(Ks), θr, θpa, θfc, θwp, ϕm, θs and n. All SHPs exhibit much lower variability in the desert than in other areas, likely due to the homogeneous particle size distribution of desert areas. This study provides more accurate SHP estimates in China’s arid region than the existing SHP products by developing advanced PTFs and highlights the inconsistency in SHPs among different global or regional products; the uncertainties induced by PTFs should thus be considered in future terrestrial biosphere modeling.

METHOD OF ACCOUNTING SOIL-AGROCHEMICAL POTENTIAL FOR OPTIMIZING THE STRUCTURE OF LAND USE OF THE VOLOZHINSK DISTRICT OF THE REPUBLIC OF BELARUS

The article discusses one of the ways to assess the condition of soil cover to improve the efficiency of land management using the example of the Volozhin region of the Republic of Belarus. A comprehensive assessment of the agrochemical and natural potential of the soil is proposed by means of typing the soil cover depending on agrochemical indicators (pHKCl, humus content, mobile compounds of phosphorus and potassium) and a quality score reflecting the natural state of the soil. Using geostatistical methods, the values of agrochemical indicators were interpolated from elementary areas into areas of soil varieties of agricultural lands and classified according to the degree of content of agrochemical elements that made up the agrochemical potential (AP). After crossing the AP with the bonitet score, 9 groups of soils were identified according to soil-agrochemical potential (SAP), of which the largest share (58,2 %) is occupied by soils with average potential (61,950 ha). Based on the results of a spatial assessment of the PAP, it was determined that sod-podzolic and sod-podzolic swampy soils developing on light loams and cohesive sandy loams have the greatest potential. It was also revealed that areas with low PAP gravitate towards the most dissected areas of the terrain with sandy and cohesive sandy soils. Based on the typification carried out, the main types of preferred land use in the Volozhin region were determined: more than half of the agricultural land can be used for intensive agricultural use for arable land (52,1 %) and meadows (12,5 %), traditional land use is possible for 29,3 % territories and only 6,2 % of lands require the use of soil protection farming systems, primarily focused on erosion-hazardous areas of the area.

A comprehensive analytical and computational assessment of soil water characteristics curves in Atlantic Canada: Application of a novel SelectKbestbased GEP model

For sustainable agriculture, irrigation is one of the most important management practices in a semi-arid climate. Determining the site-specific soil type-based irrigation water requirements requires the development of a soil water characteristics curve (SWCC). This study focuses on exploring the suitability of analytical SWCC models based on the observed data of SWCC developed using the pressure membrane apparatus. A novel SelectKbest gene expression programming (GEP) model is used to create the generalized machine learning SWCC model for Atlantic Canadian soils. The composite soil samples with representative soil textures of loamy sand, loam, and sandy loam are collected from the selected locations in Prince Edward Island and New Brunswick provinces of Canada. The suitability of models at three regions shows that at all sites, including PEI-1 (loam soil) 1, PEI-2 (loamy sand), and NB-3 (sandy loam) if SWCC data has four measured suction potential levels, then McBee & Bomb and Tani exponential models may be selected. Van Genuchten, double exponential, Ruso, Kosuki, and Gardner's four parameters models should be a good choice for five-section potential. Similarly, for six measured suction potential values, the Fredlund & Xing, Omuto, and Van Genuchten models having parameters should be selected for determining the optimum soil hydraulic parameters. The HydroMe program with Brooks and Corey, four, and five parameters Van Genuchten models performed well. The HydroMe program is calibrated and validated with standard RETC for selected regions of Atlantic Canada, which suggests that the HydroMe program is flexible in developing efficient agricultural water management algorithms. Various performance metrics like R2 and RMSE are employed to assess the robustness of the model. A generalized SWCC model (R2=0.976 and RMSE=0.04) is developed using a novel SelectKbest-based GEP modeling approach for Atlantic Canadian soils. These novel approaches can significantly improve site-specific agricultural water management and decision support systems.