Sandy Loam Research Articles

Physical and vegetation characteristics of soil cover on a liquefied land

Liquefaction is a phenomenon where a solid soil becomes liquid due to an earthquake or other vibrations and other sources of intense shaking, leading to a loss of soil strength and stiffness. Liquefaction can damage structures and condition of the land surface and may affect the state of the vegetation that grows on the land. Therefore, it is necessary to study the physical properties of the soil and the condition of vegetation after the liquefaction event. This study examines changes in the physical conditions of alluvial soil and vegetation cover on the land surface after the liquefaction disaster and future management strategies. This research was carried out from August to December 2022 by taking composite and representative soil samples from three land conditions, namely liquefied land consisting of eroded and piled up soil, as well as a control sample from ground that was not liquefied. Soil sample analysis was conducted at the Laboratory of Soil Science, Faculty of Agriculture, Tadulako University. The research used several observational variables: soil texture, permeability, bulk density, porosity, and organic matter. Observation of land surface cover and vegetation types was done using the quadrant method. The results indicated that, overall, areas affected by liquefaction experienced a substantial loss of soil mass, leading to a lower land surface, particularly in regions prone to erosion. Due to the erosion of surface soil, the remaining subsoil had a sandy loam texture, higher bulk density, increased permeability, and reduced organic matter content. As a result, the ground surface became undulating, with mounds of soil and irregular surface drainage in certain areas. For areas that experienced liquefaction up to four years after the disaster, the level of land cover only reached 60-61%. In contrast, the level of land cover by surface vegetation reached 93.7%.

Positive influences of the application of inoculated lignocellulosic waste compost on the agronomic potential of a sandy loam soil

Positive influences of the application of inoculated lignocellulosic waste compost on the agronomic potential of a sandy loam soil

Mechanical evaluation of soil and artisanal bricks for quality masonry product management, Limpopo South Africa

The selection of raw materials to produce quality artisanal bricks is imperative for sustainable building in rural regions. Artisanal brick-making process often employs traditional kiln to fire brick because it is an affordable, and applicable technology in the rural region. However, there are noticeable cracks, increasing among buildings constructed with artisanal bricks from the rural region in South Africa. In response, this study aims to evaluate the soil and artisanal brick specimens to understand the suitability of the raw materials and quality of products in the study area. A total of twenty soil samples and twenty-seven artisanal burnt bricks were collected from three different artisanal brick-making sites designated as Site A, B, and C. In all samples, the geotechnical tests revealed a sandy loam soil type with a predominance of chlorite clay minerals and non-clay minerals. Furthermore, the sand-size particles depict a relatively higher proportion compared to clay-size particles. Besides, Atterberg’s limit test plotted above the A-line of the plasticity chart indicates an inorganic clay of low plasticity with a low to medium compressibility property. Based on the empirical workability and mechanical tests, most of the studied soils are suitable for optimum and acceptable extrusion bricks and suitable for an on-site single-story construction based on SANS 227:2007 standards.

Soil Test Crop Response on Soil Health Parameters and Yield Attributes of Okra (Abelmoschus esculentus L.) var. Kuber

The investigation was conducted on Soil Test Crop Response (STCR) based Integrated Plant Nutrient System (IPNS) technology, where the fertilizer doses are customized according to the anticipated crop yield, considering the crop's nutrient requirements and the contributions from soil, fertilizers, and organic manures. The field trial took place at the Soil Science research farm of Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, during the zaid season of 2023. The soil under experimentation had a sandy loam texture. The setup followed a randomized block design with varying levels of NPK (0%, 50%, & 100%), FYM (20, 25, & 30 t ha-1), Fe and Zn (15, 20, & 25 kg ha-1) respectively. The outcomes from the T9 treatment - [115:112:75 Kg ha-1 + 25 t ha-1 FYM + 25 kg ha-1 Fe and Zn] exhibited superior plant height, number of branches plant-1, number of leaves plants-1, number of fruits plant-1, and overall fruit yield. No significant differences were noted in the yield and growth of okra under the control conditions. The application of organic manures alone or in combination with full NPK substantially enhanced the growth and total yield parameters of okra. Among all treatments, the simultaneous application of 100% NPK, 100% FYM, and 100% Fe & Zn displayed the most remarkable influence on the growth of okra.

Impacts of conservation agriculture on crop yield and soil carbon sequestration: a meta-analysis in the Indian subcontinent.

In the quest of achieving sustainable crop productivity, improved soil health, and increased carbon (C) sequestration in the soil, conservation agriculture (CA) is increasingly being promoted and adopted in the Indian subcontinent. However, because some researchers from different regions of the world have reported reduced crop yield under CA relative to agriculture based on conventional tillage (CT), a meta-analysis has been conducted based on published research from India to evaluate the effects of CA on the yield of crops, accumulation of soil organic C as an index of soil health, and C sequestration in the soil in different regions and soil textural groups in the country. The meta-analysis is based on 544 paired observations under CA and CT from 35 publications from India was carried out using Meta Win 2.1 software. The results showed an overall significant (p < 0.05) reduction of 1.15% crop yield under CA compared to CT. Yearwise data showed a reduction of yields under CA from 2009 to 2016, but an increase from 2017 to 2020. Yield reduction was observed in the eastern, north-eastern, and southern regions of India but in western, northern, and north-western regions of the country, an increase was observed under CA rather than CT. Sandy loam and clayey soils exhibited higher crop yield under CA than under CT. Compared to CT, soil organic C content and soil C sequestration under CA increased by 8.9% and 7.3%, respectively. Also, in all the regions and soil textural groups both soil organic C accumulation and soil C sequestration were higher under CA than under CT. Factors such as rainfall, soil depth, available nitrogen (N), and total N significantly influenced the extent of yield increase/decrease and soil organic C accumulation under CA. Overall, results of the meta-analysis suggest that the promotion of CA in India will have to be location-specific taking into consideration the crops, soil attributes, and climatic conditions.

Soil textural class modeling using digital soil mapping approaches: Effect of resampling strategies on imbalanced dataset predictions

In a digital soil mapping (DSM) context, machine learning (ML) algorithms are widely used to model soil textural classes (STCs). However, in the real world most soil class datasets exhibit imbalanced distributions. This poses a challenge as ML algorithms are designed to handle balanced classes, leading to a bias towards the majority classes while often overlooking the minority classes. Furthermore, within the DSM framework, two strategies can be employed to model STCs: direct and indirect approaches. In the direct approach, STCs are directly inputted into the model for prediction. In contrast, the indirect approach involves introducing soil texture fractions (i.e., clay, silt, sand) as initial inputs, then STCs are obtained from the outputs. Limited research has been conducted on the impact of data balancing on STC predictions, and there is a lack of comparative analysis between direct and indirect approaches in this context. Therefore, this study aimed to evaluate the efficacy of a resampling technique (SMOTE: synthetic minority oversampling technique) in handling an imbalanced soil texture dataset collected from the Kuhdasht region in western Iran. Additionally, the study sought to compare the performance of direct and indirect modeling approaches. Environmental covariates derived from Landsat 8 and Sentinel 2 images along with a digital elevation model (DEM) were used as input variables to a random forest (RF) model to model STCs and soil texture fractions. The results revealed that terrain attributes and Euclidean distances played a more significant role in modeling both balanced and imbalanced datasets compared to remotely sensed data. Kappa indices for balanced and imbalanced datasets, as well as for the indirect approach were found to be 89%, 68% and 38% respectively. In the same way, the overall accuracies were 91%, 79% and 68%, respectively. Among the imbalanced classes, clay loam and loam which accounted for the majority of observations showed the highest recall values, followed by sandy clay loam, sandy loam and silty clay loam. When employing the indirect approach, the RF model failed to capture the minority classes in terms of validation statistics. Additionally, modeling with the imbalanced dataset resulted in the exclusion of three minority STCs from the final map. Overall, this study showed the importance of balancing STCs prior to modeling to achieve more accurate estimates of STCs, as well as the superiority of employing the direct approach (using balanced data sets) over the indirect approach.

The Combination Between Super Absorbent Polymers (SAPs) and Biofertilizers Could be an Ecofriendly Approach for Soil Chemical Properties Improving and Sustainable Wheat (Triticum Sativum) Production in Sandy Loam Soil

Sustainable agriculture aims to provide food needs while improving soil health and protecting it from degradation and contamination from excessive chemical fertilizer use. Sandy-textured soils have low fertility and water-holding capacity. This study assessed the integrated impact of super absorbent polymers (SAPs) and biofertilizer application on the soil chemical characteristics and wheat growth parameters in sandy loam soil. Two super absorbent polymers (SAPs) included Barbary plant G3 (P1) and Aqua Gool polymer (P2), and four microbial inoculations (Trichoderma harzianum (T), Actinomycetes (Streptomyces rochei and Streptomyces atrovirens) (AC1 and AC2), and Bacillus subtilis (B)) as biofertilizers were used in our pot experiment. The SAPs were applied to soil at a level of 0.2% (w/w), while biofertilizers were applied in the form of microbial cell suspensions (50 ml per pot) in addition to treating wheat seed with these suspensions during cultivation. Wheat plants were irrigated every 8 days to field capacity level. Amending soil with super absorbent polymers and microbes either individually or in combination significantly reduced pH and EC, increased organic matter level, and the availability of macro- and micronutrients in soil. Wheat growth metrics, including shoot length, tiller number, biomass accumulation, leaf area, and grain yield, exhibited considerable enhancements relative to the plants of the control treatment. The interaction between P1 polymer and Streptomyces atrovirens (AC2) showed the highest performance in improving the almost studied parameters. The application of SAPs with microbial biofertilizers offers a promising eco-friendly method for enhancing soil health and wheat yield.

Versatile simplistic correction of T-higrow sensors for improved soil moisture measurement accuracy

The use of soil moisture sensors for irrigation can help reduce water and energy consumption and risks of groundwater contamination, which are essential aspects for pursuing sustainable development goals. However, increased adoption of this technology is limited by calibration requirements, technical complexities, and sensor costs. In this work, a simplified method for reducing the measurement error of a recently released low-cost soil sensor (T-Higrow) is presented. The method only requires measurements of a dry sample from the target soil, which are inputted into a simple correction formula to reduce the measurement error at higher moisture levels. The requirements of the proposed method are simple enough for most labs or extension services. This method was compared to the commonly used linear, polynomial, and logarithmic regression models based on repeated bench-scale experiments within 0%–35% moisture range in silt and sandy loam soils and in silica sand. Uncorrected sensor readings correlated well with soil moisture (r: 0.94–0.98), but with significant overestimation (25%–60% error). The simplified correction method showed comparable error reduction to regression models across all soil types. All methods reduced error down to 2%–10% (0.02–0.1 cm3 cm−3) and maintained high correlations (r > 0.94), except for logarithmic regression which reduced correlation by around 3%. Variability amongst sensor measurements was generally low (Standard Deviation: 0.01–0.03) particularly at moisture ranges below 20%, this was also the case for sensor-to-sensor variability (Standard Deviation: 0.01–0.03). Sensor evaluation and calibration works are needed to increase the accessibility to this technology for improved water and energy conservation.

Examining the Effects of Diverse Irrigation Regimens and Planting Timelines on Wheat Growth, Yield, and Yield Characteristics

In the Rabi season spanning 2021 to 2022, a field trial was carried out on sandy loam soil. at a research station near the Center for Advanced Studies on Climate Change, Dr. RPCAU, Pusa, Bihar (India). Positioned at a latitude of 25°98' N and a longitude of 85°66' E. the experimental plot ascended to an elevation of 52.3 meters above mean sea level. The primary objective was to assess the effects of different irrigation levels and planting dates on the development, yield, and yield characteristics of wheat. The investigation included four irrigation management protocols (irrigation at 0.6, 0.8, 1.0, and 1.2 IW/CPE) assigned to the main plot, along with four sowing dates (15 Nov, 30 Nov, 15 Dec, and 30 Dec) allocated to the sub plot. This layout was replicated thrice in a split-plot configuration. The results indicated that the maximum values of growth factors (specifically plant height), yield factor (effective tillers/m2), and yield (both grain and straw) were observed when irrigation was administered at 1.2 IW/CPE (I4). This method, statistically comparable to irrigation at 1 IW/CPE (I3), exhibited notable superiority over the other treatments. Conversely, the minimum values of plant height, effective tillers/m2, grain yield, and straw yield were documented under the irrigation regimen of 0.6 IW/CPE (I1).

Soil profile distribution of nutrients in contrasting soils amended with struvite and other conventional phosphorus fertilizers

AbstractPhosphorus (P) can be recovered from wastewater and used as an alternative fertilizer, namely, struvite [MgNH4PO4·6(H2O)]. However, the soil mobility of wastewater‐derived P and other nutrients needs to be evaluated. The objective of this study was to compare the vertical distribution of water‐soluble (WS) soil P and other nutrients from a synthetic‐wastewater‐derived electrochemically precipitated struvite (ECST) to that from a chemically precipitated struvite (CPST), triple superphosphate (TSP), monoammonium phosphate (MAP), and a control in six soils from Arkansas (AR; loam [L] and silt loam [SiL]), Missouri (MO; SiL 1 and SiL 2), and Nebraska (NE; sandy loam [SL] and SiL). A column‐leaching experiment was conducted with the six soils and five fertilizer‐P treatments. Water‐soluble (WS) P from the two struvite materials generally did not differ (p &gt; 0.05) and was similar to that of MAP in the depths of 0–3, 3–6, and 6–10 cm, but was greater than that of TSP in the top 6 cm in four of the six soils. WS P from CPST in the MO‐SiL 2 and NE‐SL soils (6.6 and 12.7 mg kg−1, respectively) was larger than that from ECST, MAP, and TSP. In the AR‐L and MO‐SiL 1 soils, TSP was the only fertilizer‐P source that had increased WS P concentrations in the top 6 cm relative to the other fertilizer‐P sources. Results showed that ECST‐derived, WS P had similar soil profile distributions in the top 10 cm, suggesting that ECST will be equally protective of environmental health and leachate quality across multiple soil textures as other common fertilizer‐P sources.

Influence of Different Rates of Nitrogen and Sulfur on Growth, Yield and Yield Attributes of Cabbage (Brassica oleraceae L.)

The field experiment was conducted at Lovely Professional University, Phagwara, during rabi season on the sandy loam soils to study the influence of different rates of nitrogen and sulfur on growth and yield attributes of cabbage (Brassica oleraceae L.). The experiment was laid in Factorial Randomized Block Design (FRBD) consisting of eight treatments and three replications viz. (N1: 0 kg N per ha, N2: 100 kg N per ha, N3: 125 kg N per ha, N4: 150 kg N per ha, S1: 0 kg S per ha, S2: 30 kg S per ha, S3: 60 kg S per ha and S4: 90 kg S per ha). The different growth and yield attributes viz. plant height (cm), number of unfolded leaves per plant, diameter of cabbage head (cm), weight of cabbage head (kg) and yield of cabbage (t/ha) were recorded at different growth stages and at the time of harvesting. The results revealed that the application of 150 kg nitrogen and 90 kg sulfur per hectare gave the maximum values in all the growth and yield attributes compared to all the other treatments as well as control.

Response of Zinc in Kharif Rice cv MTU-1010

A filed experiment was conducted during kharif season of 2016 and 2017 at Krishi Vigyan Kendra (KVK) Farm, Ashokenagar, West Bengal on a sandy loam soil to assess the effect of zinc on growth, yield attributing characters and yield of rice, cv MTU- 1010. The experiment was carried out in a Randomized Block Design with three treatments i.e. recommended NPK dose (60:30:30 kg/ha NPK), recommended NPK + 25 kg/ha of ZnSO4 as soil application, and recommended NPK + 20 kg/ha of ZnSO4 as soil application + 2.5 kg/ha as foliar application at 30 and 45 DAT with seven replications. The study revealed that most of the yield and yield attributing characters except a few were significantly influenced by the soil and foliar application of zinc. Application of zinc recorded 17.73% higher grain yield than soil application of sole NPK fertilizers. The maximum no. of effective tillers/hill (23.57), plant height (81.28 cm), no. of spikelet per panicle (89.57), yield (5.91 t/ha), starch content (75.28 %) and B:C ratio (1.87) were recorded in 20 kg/ha of ZnSO4 as soil application followed by 2.5 kg/ha as foliar application at 30 and 45 DAT, along with soil application of NPK.

Effect of Adding NPK-Chitosan Fertilizer and Organic Matter on phosphorus and potassium content of Corn (Zea mays L.)

A field experiment was conducted at the College of Agriculture, University of Basrah's research station in Garmat Ali during 2022 agricultural season. The study aimed to investigate the impact of three types of fertilizers (commercial NPK as a control and two types of prepared NPK-Chitosan organic fertilizers) at four addition levels (0, 1, 1.5, and 2 ton ha-1) and two levels of organic matter (0% and 2.5%) on the availability of nitrogen and potassium in loam sandy soil and yield of corn (Zea mays L.). The results indicated a significant effect of fertilizer type on increasing Phosphorus and Potassium Content of corn plant. The highest values of Phosphorus and Potassium Content for corn were 6.15 and 47.07 gm kg-1 respectively for the added fertilizer type. The NPK-Chitosan fertilizer in a 1:3 coating ratio achieved the, 3.62 and 31.01 kg ha-1, respectively, followed by the treatment of NPK-Chitosan fertilizer with a 1:3 mixing ratio and a fertilizer level of 2 tons/ha, which yielded The results showed a significant effect of fertilizer level on increasing Phosphorus and Potassium Content of the corn plants. Phosphorus and Potassium Content increased with higher levels of added fertilizer. The level 2 achieved the highest values of Phosphorus and Potassium Content for the vegetative part corn plants, reaching 2 tons per hectare.4.22 and 37.91 gm kg-1, and with a significant difference from level 1 and 1.5 tons per hectare, level 2 also outperformed level 0 tons per hectare (the control treatment). Similarly, the organic matter showed a significant effect the results indicated a significant interaction between the type and level of fertilizer, as well as the level of added organic matter to the soil, on Phosphorus and Potassium Content of the yellow corn plants. The NPK-Chitosan fertilizer with a 1:3 coating ratio added at the level of 2 tons per hectare outperformed the other treatments, yielding the highest phosphour contentand grain yield.

Effects of fertilization applications on soil aggregate organic carbon content and assessment of their influencing factors: A meta-analysis

Fertilizer application plays an important role in agricultural soil organic carbon (SOC) and its sustainable management. However, there is a lack of consensus about the mechanisms regarding fertilizer application in the soil on the procedure of carbon sequestration and sink enhancement in the aggregates. In this study, the extent by which various fertilization treatments, fertilization durations, climate conditions, soil texture, and land-use types affected the organic carbon (OC) content of different particle-size aggregates was quantitatively assessed using a meta-analysis of 696 treatment comparisons from 36 published studies. Based on the meta-analysis results, fertilization enhanced the OC contents of macroaggregates and clay and silt particles, particularly through replenishing organic material. Long-term fertilization increased the OC content of macroaggregates (>0.25 mm), while the OC content of the clay and silt particles (<0.053 mm) reached a maximum at 15.4 years of fertilization, after which it reached carbon saturation. Organic fertilizer effectively increased the OC content of small macroaggregates (0.25–2 mm) and microaggregates (0.053–0.25 mm) at lower temperatures and precipitation. Compared with inorganic fertilization, combined organic–inorganic fertilization increased OC contents of all sizes of aggregates in sandy or clay loam soils, but decreased OC contents of microaggregates and clay and silt particles in silt loam soils. All fertilization treatments increased the OC content of all particle-size aggregates in upland soils. In contrast, inorganic fertilization and mixed organic–inorganic fertilization reduced the OC content of microaggregates (0.053–0.25 mm) and clay and silt particles (<0.053 mm) in paddy field soils. In conclusion, the application of organic fertilizers is more conducive to the accumulation of OC in agricultural soil aggregates. Whereas the limiting factors for the accumulation of OC content in soil aggregates vary under different conditions, organic fertilizer inputs should be given more consideration, especially in dryland and coarse-textured soils.

Biochar influences soil health but not yield in 3‐year processing tomato field trials

AbstractBiochar can deliver many agronomic benefits, though effects may be greatest in suboptimal agricultural soils. The objective of this study was to investigate biochar in prime agricultural soils in a Mediterranean climate. In 3‐year irrigated processing tomato (Solanum lycopersicum) field trials, in which three biochars were amended to a sandy and silt loam, biochar did not influence yield. Given the global policy focus on biochar for climate change mitigation and adaptation, however, it is essential to measure more than just agronomic parameters. To this end, a soil health assessment was conducted 2.5 years after biochar amendment. In the fertile silt loam and more nutrient‐limited sandy loam, biochars had a variable but positive effect on pH, electrical conductivity, soil potassium, water stable aggregation, and permanganate oxidizable carbon. There was no effect on soil moisture nor potentially mineralizable nitrogen or carbon. In the silt loam, there was no change in microbial biomass or phospholipid fatty acid (PLFA) composition. In the sandy loam, almond shell biochars were associated with a slight increase in total biomass, an increase in the ratio of fungal to bacteria PLFAs, and reductions in multiple PLFA ratios were typically interpreted as indicators of environmental stress. Results of this study demonstrate that biochar may deliver soil health benefits in agricultural soils in a Mediterranean climate. However, increased soil health does not necessarily engender increased agricultural productivity within a 3‐year period. Furthermore, increases in soil health indicators were inconsistent across soil and biochar types, underscoring the need for site‐ and material‐specific investigation.

Economics of Fieldpea (Pisum sativum L.) as Influenced by Phosphorus Levels and Bio-fertilizers in Central Plains of Uttar Pradesh, India

A field experiment was conducted at the student instructional farm of CSAUA&amp;T, Kanpur, during the Rabi season of 2021-22 and 2022-23. Sandy loam was the texture of the experimental soil. There are twelve treatment involving combinations of phosphorus and biofertilizers with three replication of factorial randomized block design (FRBD). A fieldpea variety IPFD 6-3 was planted according to recommended agronomic practices. The results of these studies indicate that fieldpea cultivation over a two-year period is consistent with T12 (P90 R1 PSB1), the most economically effective treatment and also recorded the highest economics parametric values i.e., maximum cost of cultivation of ₹35850 &amp; ₹36700, gross return of ₹ 106055 &amp; ₹118535, net return of ₹70205 &amp; ₹ 81835 and benefit to cost ratios were 1.96 &amp; 2.23 followed by the treatment T11.

Habitat Characteristics and Morphology of Chlorophyta (Order Bryopsidales) on the Intertidal of Pandanan Hamlet, West Sekotong

Bryopsidales order macroalgae can be found on various substrates in marine waters. The Bryopsidales order has a morphological form that is shaped like a filament or shaped like a leaf and has pigments like land plants. The study aims to determine the habitat characteristics and morphology of the Bryopsidales order on the coast of Pandanan Hamlet. Sampling was carried out using the line transect method and 1x1 meter quadrant. A total of 5 transect lines were stretched from the shoreline to the point where macroalgae were found. Each transect is placed in quadrants every 20 meters in a zigzag manner. The Bryopsidales order found consisted of 13 species, 3 families and 4 genera growing in habitats with substrates of loamy sand, loam, sand, and sandy loam, rock, dead coral, coral fragments, and live coral. There are 3 types of holdfast were found, namely bulbous, fibrous, and sprawling growers. There are also three blade shapes in this order, namely creeping blades in the Caulerpaceae family, segmented blades in the Halimedaceae family, and blades that are neither creeping nor segmented that resemble sponges in the Codiaceae family.

Effects of Rainfall Intensity and Slope on Infiltration Rate, Soil Losses, Runoff and Nitrogen Leaching from Different Nitrogen Sources with a Rainfall Simulator

The combined effects of slope gradient, rainfall intensity, and nitrogen fertilizer source on infiltration, runoff, soil loss, and nitrogen (N) leaching in agricultural areas are not thoroughly understood, despite their critical importance in sustainable agriculture. Previous studies have focused on these factors individually, leaving a significant gap in knowledge regarding their synergistic impact. Investigating the interplay between slope gradients, rainfall intensities, and N fertilizer sources is vital to developing effective soil and water conservation strategies and implementing sustainable agricultural practices. This study is comprised of two experiments. Experiment 1 was designed as a 3 × 2 × 3 factorial arrangement, incorporating three levels of rainfall intensity (RI) (45, 70, and 100 mm/h), two slope gradients (5 and 8°), and three soil types (sandy loam, silt loam, and clay loam), aimed at assessing runoff, infiltration, and soil loss. Experiment 2, laid out as 3 × 2 × 3 × 3 factorial, expanded on this, adding N fertilizer source (urea, CaCN2, and limestone ammonium nitrate (LAN) at 130 kg/ha N) and assessing N leaching alongside the previous metrics. Both experiments used a rotating disc rainfall simulator and were replicated four times. Results revealed that steeper slopes (8°) led to increased runoff and soil loss, impeding infiltration, while gentler slopes (5°) facilitated greater infiltration and minimized soil loss. Rainfall intensity played a significant role, with 70 mm/h/5° combinations promoting higher infiltration rates (48.14 mm/h) and 100 mm/h/8° resulting in lower rates (37.07 mm/h for sandy loam and silt loam, 26.09 mm/h for clay loam). Nitrogen leaching varied based on N source; urea at 130 kg/ha N led to higher losses (7.2% in sandy loam, 6.9% in silt loam, 6.5% in clay loam), followed by LAN (6.9% in sandy loam, 6.7% in silt loam, 6.3% in clay loam) while CaCN2 at the same rate resulted in lower N losses (6.4% in sandy soil, 4.4% in silt loam, 4.2% in clay soil). This research highlights the critical need to consider both slope gradient and rainfall intensity in conjunction with appropriate nitrogen fertilizer sources when developing strategies to mitigate soil erosion and nutrient loss in agricultural settings.

Predictive modeling of green water availability: The role of annual plants as an ecological indicator in dryland ecosystems

Green water is primarily associated with the appearance of annual plants and plays a significant role in biomass production in both arid and semi-arid ecosystems. Herein, we aim to estimate the optimal threshold for determining the presence or absence of annual plants and use them as an ecological indicator to assess potential green water areas in Kuwait as a case study. We integrate remote sensing techniques and MaxEnt modeling. The AUC for the annual plant distribution with all examined factors is 0.847, and the standard deviation is 0.050. The results demonstrated that potential locations with high levels of green water cover <20% of the country. The annual plant distribution was significantly correlated with several types of perennial plants, maximum temperature, precipitation, and sandy soils. It was also found that annual plants are controlled by the spring and winter temperature decline and the timing of precipitation occurrence, especially the pattern and amount of rainfall received in November. Sandy loam and loam soils were found to be ideal for annual plants, although land depressions and soil types are crucial factors in determining annual plant distribution. Additionally, annual plants enhanced the growth of several perennial communities. To reiterate, our study's model helped to comprehend the significance of annual plants as an ecological indicator in sustaining soil moisture over a prolonged period, as well as factors controlling the distribution of annual plants. The developed model and indicators could support decision-makers in determining appropriate locations with adequate levels of green water for revegetation planning in arid landscapes.

Effect of Irrigation Regimes and Applied Nitrogen Levels on Growth and Physiological Responses of Ryegrass

A field experiment was conducted at the Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat. The experiment was laid out in split-plot design with three replications. The treatments consisted of five levels of irrigation in main plot viz., I0:Rainfed, I1: Irrigation at critical growth stages, I2: Irrigation at IW:CPE ratio of 1.0, I3: Irrigation at IW:CPE ratio of 1.2 and I4: Irrigation at IW:CPE ratio of 1.4 along with four levels of N- N0: 0 kg N/ha, N1: 30 kg N/ha, N2: 60 kg N/ha and N3: 90 kg N/ha in sub- plots. The soil of the experimental site was sandy loam in texture, medium in organic carbon, available N and available P2O5, acidic in reaction and low in available K2O. The result revealed that the highest leaf area index (LAI) recorded in irrigation at IW:CPE ratio of 1.4 at all the three cuts respectively during both the years. The crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) of ryegrass as influenced by different irrigation regimes were found to be non-significant at 30 DAS while at later growth stages i.e. 45 DAS, 60 DAS, 90 DAS and 120 DAS were significantly influenced during both the years. The application of irrigation at IW:CPE of 1.4 produced higher value of CGR, RGR but the highest NAR was recorded in rainfed treatment. The data on LAI as influenced by different N levels was found to be significant in all three cuts. Application of 90 kg N/ha recorded the highest LAI. The CGR, RGR and NAR as influenced by different N levels were found to non significant at 30 DAS but significantly influenced at later growth stage i.e. 45 DAS, 60 DAS, 90 DAS and 120 DAS during both the years. The highest data on CGR and RGR were recorded in 90 kg N/ha but the highest NAR was found in 0 kg N/ha.