Silty Clay Loam Soil Research Articles

Mechanisms of Cd immobilization in contaminated calcareous soils with different textural classes treated by acid- and base-modified biochars

Acid or base modification of biochars has shown promise for enhancing the immobilization of potentially toxic elements (PTEs) such as cadmium (Cd) in contaminated soils. However, limited information is available on the interaction between soil textural classes and modified biochar application for Cd stabilization in contaminated calcareous soils. Therefore, the objective of the study was to examine the extent of Cd immobilization in contaminated calcareous soils with diverse textural classes, utilizing both acid (HNO3) and alkali (NaOH) modified and unmodified biochars derived from sheep manure and rice husk residues. The modified or unmodified biochars were applied at a rate of 2% (w/w) to Cd-contaminated silty clay loam, loam, and sandy loam soils, followed by a 90-day incubation at field water capacity. Sequential extraction and EDTA-release kinetics studies were used to assess the effect of the treatments on the extent and mechanisms of Cd immobilization. Among the treatments, acid-modified manure biochar was most effective at reducing water soluble and exchangeable Cd fractions (-20.5%), by converting them into metal oxide and organic matter bound fractions. This effectiveness was primarily attributed to the significant increase in surface oxygen functional groups in the acid-modified biochar which could promote Cd complexation. However, the acid-modified manure biochar released more immobilized Cd during EDTA extraction than the base-modified manure biochar, suggesting that EDTA extraction of R-O-Cd complexes was easier than extracting Cd associated with insoluble compounds. This difference was likely due to the acidic pH and lower ash content of the acid-modified biochars compared to the base-modified manure biochars. Additionally, the extent of Cd immobilization was lower in sandy loam soil, highlighting the importance of immobilizing Cd in light-textured soils to prevent its transfer to organisms.

Impact of deficit irrigation and planting density on grain yield and water productivity of maize grown under temperate continental climatic conditions

Variable frequent drought periods in Vojvodina region (the southeastern part of the Pannonian Plain, Serbia), severely limit maize (Zea mays L.) production under rainfed conditions. A four-year field experiment was conducted to investigate the effects of sprinkler deficit irrigation and plant density on yield and water use efficiency of maize grown on silty clay loam soil under temperate continental climate. The experiment included fully irrigated crop (I1), three deficit irrigation treatments (I2, I3 and I4 corresponding to 80, 50 and 40 % of crop evapontranspiration, respectively) and non-irrigated treatment (I0), and three plant densities (LPD: 54,900 plants ha–1; MPD: 64,900 plants ha–1; HPD: 75,200 plants ha–1) in four replicates. The results showed that grain yield, CWP (crop water productivity) and IWP (irrigation water productivity) varied significantly with irrigation amounts, plant densities and seasons. The irrigation rates and plant density interact significantly. MPD and HPD differed significantly from LPD in almost all seasons. With increasing irrigation and plant density, yield and CWP showed an increasing trend. The relative values of IWP increased with the rise of plant density and decreased with the amount of irrigation. The highest four-year average yield (15.03 t ha–1) was obtained in the I1-HPD treatment, while the lowest (9.30 t ha–1) was obtained in the I0-HPD treatment. The highest average values of CWP and IWP were recorded at I3-HPD or/and I2-HPD. The lowest CWP and IWP values were determined for I4-HPD and I4-MPD, respectively. In the pedo-climatic conditions of Vojvodina and similar regions, we recommend growing maize under the I1-HPDtreatment to achieve high yields. Under the water shortage conditions, the application of I2-HPD treatment is a favorable strategy saving 37 % of irrigation water, while reducing maize grain yield by ∼10 %.

Performance of kharif maize under conservation tillage in silty clay loam soil

Maize is a major staple food as well as potential cash crop for millions of people, mostly grown in the winter season in Bangladesh under conventional tillage practice. But huge area of cultivable land remains fallow in kharif-1 season in Sylhet region as well as other parts of Bangladesh. Hence, we aimed to identify the best variety and tillage method to grow maize in silty clay loam soil in kharif season. An experiment was conducted to study the performance of six maize varieties in the Kharif-I season (summer) under three tillage methods in silty clay loam soil of Eastern Surma-Kushiyara floodplain (AEZ-20). The experiment was arranged in RCBD with three replications to observe yield contributing traits and yield performance of maize. Among the varieties, BARI Hybrid Maize-16 showed the highest yield attributes and grain yield followed by BARI Hybrid Maize-13 and BARI Hybrid Maize-9. Based on tillage, the maximum number of leaves per plant, cob length and diameter, kernel rows per cob, kernels per row, kernels per cob, highest grain yield, and stover yields were recorded in conventional tillage. Therefore, considering the yield and tillage methods, BARI Hybrid Maize-16 showed the best yield performance under conventional tillage in the kharif-I season in silty clay loam soil of Eastern Surma-Kushiyara floodplain of Bangladesh.

Potential of conservation tillage, cover crops, and digestate application as integrated C farming practices for processing tomato

Conventional soil management — based on intensive tillage and low input of organic material – negatively impacts soil quality via carbon (C) losses as carbon dioxide emissions (CO2), exacerbating the effect of climate change on agriculture. Carbon farming practices (CFPs), such as minimum tillage (MT) and strip tillage (ST), offer promising solutions to maintain soil fertility, sustain crop yields, and mitigate environmental impacts. However, applying CFPs in processing tomato (Solanum lycopersicum L.) cropping presents unique challenges due to specific crop and tillage characteristics. Our two-year field study investigated the effects of conservation tillage practices (i.e., MT and ST), both combined with cover crops and digestate application, on soil quality parameters and processing tomato yield. The field studies were conducted in fields with varying soil textures (i.e., clay and silty clay loam), and aimed to evaluate responses in terms of soil C sequestration, nutrient concentrations, soil structure, and abundance of earthworms. We hypothesized that both MT and ST would enhance soil quality parameters also in tomato cropping systems, with ST potentially outperforming MT in C sequestration. Results revealed that CFPs significantly increased soil organic matter, total nitrogen, and available phosphorous compared with conventional tillage. Both MT and ST increased soil C sequestration (up to 1.06 Mg C ha−1 y−1 and 1.21 Mg C ha−1 y−1, respectively) compared with conventional tillage (CT), which lost around 0.88 Mg C ha−1 y−1 under silty-clay loam soil, and had negligible C sequestration (+0.02 Mg C ha−1 y−1) under clay soil. We found no significant difference between MT and ST when using the equivalent soil mass method for calculating C sequestration. Noteworthy, CFPs enhanced fertility parameters without a negative impact on yields, underscoring their potential for enhancing soil C sequestration, improving nutrient availability, and supporting processing tomato yield under adaptation scenarios to climate change.

Effect of water regimes and weed-management practices on growth, yield and weed-control efficiency of rice under system of rice intensification

A field experiment was conducted during the rainy (kharif) seasons of 2012 and 2013 at Khudwani, Jammu and Kashmir, to evaluate the effect of water regimes and weed-management practices on growth and yield of rice (Oryza sativa L.) grown on silty clay loam soil. The treatments comprised 3 irrigations schedules, viz. alternate wetting and drying (AWD), saturated conditions (SC) and continuous flooding (FL), and 7 weed-management op tions including 4 herbicidal treatments, viz. pyrazosulfuron ethyl @ 20 g/ha at 3 days after transplanting (DAT, W1 ); cyhalofop butyl @ 80 g/ha at 15 DAT (W2 ); pyrazosulfuron ethyl 20 g followed by (fb) cyhalofop butyl 80 g/ha at 3 and 15 DAT (W3 ); butachlor @ 1.5 kg/ha at 3 DAT (W4 ); 3 cono weeding at 15, 25 and 35 DAT (W5 ) along with weedy check (W6 ) and weed free (W7 ). The experiment was laid out in a split-plot design with 3 replications under SRI. The data revealed that significant higher growth parameters like leaf-area index (LAI), dry-matter accumula tion and tillers/plant and yield attributes, i.e. panicle length, panicles/m2, grains/panicle, panicle weight, grains/ panicles, 1,000-grain weight, and higher grain yield were recorded in saturated water regime. On an average a yield superiority of 2.2 and 5.8% was recorded by saturated water regime over AWD and continuous flooding. Among the herbicides tested, pyrazosulfuron-ethyl @ 20 g/ha (3 DAT) fb cyhalofop-butyl @ 80 g/ha (15 DAT) re sulted in significantly higher panicle length, panicles/m2, panicle weight, grains/panicles, 1,000-grain weight and higher grain yield comparable to the weedy check. The mean yield advantage recorded by the use of pyrazosulfuron-ethyl fb cyhalofop-butyl was 19.3, 14.0 and 10.3% over cyhalofop-butyl, cono-weeding and butachlor, respectively, during both the years of experimentation.

Exploratory assessment of the SLAKES method to characterize aggregate stability across diverse soil types

AbstractClassical soil aggregate stability (AS) methods lack standardized protocols and require long measurement times. However, the fairly new SLAKES method purportedly allows for rapid AS estimation with minimal technical equipment. SLAKES has been tested on fine‐textured soils but its suitability for other soil types is unknown. This study investigated SLAKES’ suitability for AS measurements on silty clay, silt loam, and sandy loam soils. For each SLAKES test, three aggregates were immersed in distilled water and imaged for 10 min. SLAKES output includes disaggregation data per aggregate and three coefficients from a Gompertz function that describe slaking dynamics. Four AS descriptors obtained from SLAKES output were investigated: the averaged maximum slaking from a test (aSK), the maximum slaking for each measurement (aggregate) (aFT, from fitting a Gompertz function to SLAKES raw data), the averaged aFT for the measurements in a test (a̅FT), and the slaking index at 10 min per measurement (SI600). The aSK is a direct descriptor included in the SLAKES output, while aFT, a̅FT, and SI600 are indirect descriptors. The SI600 was the most preferred SLAKES AS descriptor since it is a calculated parameter and due to its sensitivity in detecting AS status among all soil types. The sandy loam soil was the most stable from both the raw SLAKES data and fitting, albeit counterintuitive. SLAKES default measurement time was sufficient for the silty clay and silt loam soils but not for the sandy loam soil. Overall, SLAKES was a useful tool for AS measurements on fine‐textured soils but was less suitable for AS measurements on the coarse‐textured soil.

The effect of tire inflation pressure and tillage systems on soil properties, growth and yield of maize and soybean in a silty clay loam soil

AbstractSoil compaction causes adverse effects on soil structure and the performance of crops. There is significant literature supporting the hypothesis that reducing tire inflation pressure can help to minimize compaction, but there is no data on the potential benefits of high flexion tires operating at reduced tire pressures in Midwestern United States agriculture. Hence, a field‐scale study was established in Illinois to determine the potential benefits of high flexion tires at low tire pressure (LTP) in comparison with those operated at standard tire inflation pressure (STP) on soil condition, crop growth and yield of maize and soybean for three tillage systems; deep tillage (450 mm), shallow tillage (100 mm) and no‐till. Two adjacent experiments were established in typical maize/soybean and soybean/maize rotations, respectively. The experiment used a 2 × 3 factorial design with five completely randomized blocks. The results showed that the use of LTP tires resulted in lower soil penetrometer resistance for three tillage systems in 2017 and 2018 in the maize field and 2018 in the soybean field. This improved plant establishment and the number of plants per hectare of maize in both 2016 (*p ≤ .05) and 2018 (**p ≤ .01) and plant establishment (***p ≤ .001) and the number of plants per hectare (***p ≤ .001) of soybean in 2018. The penetrometer resistance was higher in the no‐till plots compared to deep and shallow tillage plots in maize and was higher in the deep tillage plots compared to the shallow tillage in the soybean field. The use of LTP tires resulted in an increased grain yield of maize by 4.31% (15.02 Mg ha−1) and 2.70% (14.76 Mg ha−1) in 2017 (**p ≤ .01) and 2018 (*p ≤ .05), respectively, and soybean by 3.70% (4.25 Mg ha−1) in 2018 (*p ≤ .05). The depth of tillage had a significant effect on soybean and maize yields in 2017 (***p ≤ .001) and 2018 (***p ≤ .001), respectively, with higher yields of both soybean and maize in the deep and shallow tillage compared to no‐till plots. The study concludes that the use of the LTP systems can be a potential means of addressing soil compaction and maintaining soil porosity while increasing crop productivity in silty clay loam soils in Central Illinois.

Effect of irrigation interval on water consumption, water use efficiency, growth and yield of rice in two area of Sulaymani governorate

The different of locations (which has different in soil and water quality) and irrigation interval has an important influence on water use efficiency and rice crop yield to determine the effects of different irrigation water management on yield and water use efficiency of rice (Oryza sativa L.) in two different locations soils and water quality, the two-field experiments were conducted on silty clay loam and silty clay soil, in earthen and western Suleimani province of Kurdistan-Iraq The experiment was a complete randomized design with a factorial arrangement of treatments with three replications. The main treatment was Irrigation interval (full irrigation (D1), one day (D2), two days (D3), and three-day irrigation (D4)) The depth irrigation were 939, 811, 726 and 681 mm, respectively for qaragol, while for chalax the depth irrigation were 980, 821, 749 and 722 mm respectively. The sub- treatment was, Qaragol (L1) and chalax (L2) locations respectively, the results showed that the effects of irrigation interval and locations and their interaction on rice grain yield and water use efficiency were significant at 5%. The highest grain yield (6263 Kg ha-1) belonged to the (L2) location and the lowest grain yield (5823.3 Kg ha-1) belonged to (L1) in Qaragol location. And the highest water use efficiency 8.547 in Qaragol location belongs to the (D4) and the lowest water use efficiency 6.387 increasing of water use efficiency (D1 vs. D4) caused a 29.5% improvement in water use efficiency. The irrigation schedule can be planned to save water without considerable reduction of crop yield

Freeze-thaw effects on pore space and hydraulic properties of compacted soil and potential consequences with climate change

Freezing and thawing affect the pore-space structure in agricultural soils with implications for soil hydraulic properties and water flow. Previous studies have focused on the upper few centimeters of the tilled topsoil, where most freeze-thaw (FT) cycles occur, even though deeper soil layers are also subject to freezing and thawing in cold climates. Thus, little is known about how freezing and thawing affect untilled soil layers, which often show high bulk densities that restrict vertical water movement. Furthermore, it remains unclear how shifts in FT patterns with climate change may change the pore-space structure and water flow through these soil layers. Here we investigated the effects of freezing and thawing on X-ray imaged pore-space characteristics, water retention and near-saturated hydraulic conductivity (K) in untilled soil directly below plough depth. Intact cores were sampled at two sites in central Sweden under the same long-term reduced tillage management. The two soils, a silt loam and a silty clay loam, were subjected to three FT scenarios in a laboratory environment intended to represent FT patterns that are considered likely under current and future winter conditions for this region. The latter scenario was characterised by more FT cycles and a lower freezing temperature. Freezing and thawing increased K in the near-saturated range in both soils, which we attribute to observed small (<0.01 mm3 mm−3) increases in the volume of pores of diameters close to the X-ray resolution limit. Concomitant increases in pore network connectivity and critical pore diameter, especially in the denser silty clay loam soil, probably contributed to this increase in K. The water retention data suggested that changes in pore-space characteristics below X-ray resolution also occurred in both soils. Furthermore, our results indicate that both soils may show higher drainage rates due to shifts in FT patterns in the future, although longer-term changes in pore-space structure with an increasing number of FT cycles would mostly be limited to soils with relatively high clay contents. These soils are often more compacted below plough depth and, thus, benefits from improvements in soil structure such as improved root growth and plant water supply are also expected to be larger.

Influence of variable irrigation schedules and nitrogen levels on PAR (%) of rice (Oryza sativa L.) in temperate ecology of Kashmir

A field experiment was conducted at Faculty of Agriculture, Wadura, Sopore, SKUAST-Kashmir during Kharif 2021 and 2022 on silty clay loam soil. The soil of the experimental field was neutral in reaction, medium in available N, P and K and organic carbon. The experiment comprised of four irrigation schedules: I1 : Recommended Irrigation Scheduling, I2 :At field capacity (20 L m-2), I3 :10 % depletion from field capacity (20 L m-2) and I4 : 20 % depletion from field capacity (20 L m-2), assigned to main plots and four nitrogen levels including N0 : Control, N1 : 75 % RDN (Recommended dose of nitrogen), N2 : 100 % RDN and N3 : 125 % RDN assigned to sub-plots, replicated thrice. The test variety evaluated was Shalimar Rice-4 (SKUA-408) and the experiment was laid out in split plot design. The data revealed that recommended irrigation scheduling though at par with application of irrigation water at field capacity recorded significant increase in intercepted PAR (photosynthetically active radiation) (%) as compared to other irrigation schedules during both the years of experimentation. Among the different nitrogen levels, 125 % RDN treatment recorded significantly higher values of intercepted PAR (%)but was at par with 100 % RDN treatment during 2021 and 2022. Significantly lowest values of intercepted PAR (%) were observed when the irrigation water was applied at 20 % depletion from field capacity among irrigation schedules and control treatment among nitrogen levels during both the years of experimentation.

Assessing the effects of different tillage systems on selected physical and chemical properties of a silty clay loam soil under different field conditions in the Czech Republic

AbstractUnder the recent water‐limiting crisis on farmlands in the Czech Republic, more sustainable approaches to improve water infiltration and suction within the soil layer useful for plant growth is crucial. This study sought to explore changes induced by applied tillage system, and time after tillage (considering two field conditions; at crop maturity when the soil had consolidated long after tillage, and after tillage and seeding operations). The tillage systems investigated were reduced tillage (RT), occasional tillage (OT), no tillage (NT) and conventional tillage (CT). Soil properties at 0–30 cm depth analysed were dry bulk density, soil organic matter content, saturated volumetric water content and saturated hydraulic conductivity. After the tillage and seeding operations, soil organic matter increased on all conservation tillage plots (RT, OT and NT) but decreased under CT. Insignificant changes in dry bulk density were observed on the conservation tillage plots, whereas CT reduced dry bulk density by 15.3%. Saturated hydraulic conductivity fluctuated significantly under OT and CT, while remaining stable under RT and NT. Generally, significant variability in organic matter influenced changes in saturated volumetric water content and saturated hydraulic conductivity. Changes in dry bulk density on all the tilled plots (RT, OT, and CT) did not show any significant relationship with saturated volumetric water content. Likewise, no significant relationship between changes in bulk density and saturated hydraulic conductivity on all plots were observed. While organic matter improvements under OT positively correlated with saturated volumetric water content, its seasonal dynamics under saturated hydraulic conductivity can be further studied. CT causes high instabilities in both saturated volumetric water content and saturated hydraulic conductivity leading to impaired characteristics during the soil's consolidated state.

Enhancing soil resilience in Iranian Haploxeralfs: A study on the impact of two organic matters on aggregate stability and mechanical resistance

In arid regions around the world, erosion is a frequent occurrence due to low annual rainfall weakening plants, which in turn affects the concentration of soil organic matter (SOM). When the soil is exposed, sudden and heavy rainfall can lead to soil degradation, particularly in soil with high sodicity where unstable aggregates are easily ruptured, initiating the first phase of soil erosion. To investigate this phenomenon, soil samples were collected from an erosion‐prone area near Maharloo Salt Lake, specifically Chah‐angiri (soil 1) and Kamal-abad (soil 2), which are loam and silty clay loam soils with low SOM.&lt;strong&gt; &lt;/strong&gt;To evaluate the effect of organic matter sources on soil stability, cow manure (animal source) and wheat straw (plant source) were applied to both soil samples at four different rates (0.0, 10.0, 20.0, and 40.0 g kg&lt;sup&gt;−1&lt;/sup&gt;) and incubated for four months. The soil’s aggregate stability and mechanical resistance were then assessed using two different methods: mechanical resistance, which was measured as the module of rupture and penetration resistance, and aggregate stability, which was evaluated using the conventional and Le Bissonnais methods.&lt;strong&gt; &lt;/strong&gt;The application of organic matter resulted in a linear increase in aggregate stability in both soils, with the increase in Chah‐angiri (with lower sodicity) being greater than Kamal‐abad (with higher ESP). Both linear and exponential equations showed that organic matter treatment reduced soil mechanical resistance exponentially, with wheat straw proving more effective than cow dung at stabilizing aggregates against slaking and lowering soil mechanical resistance in both soils.&lt;strong&gt; &lt;/strong&gt;Furthermore, the stability of aggregates changed by mechanical breakdown (MWD&lt;sub&gt;stir&lt;/sub&gt;) was found to have the strongest relationship among three Le Bissonnais treatments (MWD&lt;sub&gt;slow&lt;/sub&gt;, MWD&lt;sub&gt;fast&lt;/sub&gt;, and MWD&lt;sub&gt;stir&lt;/sub&gt;) and the aggregate stability test using the usual technique (Kemper and Rosenau). The organic matter rate had a significant effect (&lt;em&gt;P &lt;/em&gt;&amp;lt; 0.001) on MWD&lt;sub&gt;stir&lt;/sub&gt;, which increased with rate in a linear relationship (&lt;em&gt;r&lt;/em&gt;&lt;sup&gt;2&lt;/sup&gt; = 0.957, &lt;em&gt;P &lt;/em&gt;= 0.022). Finally, the stability of soil aggregates in water was also investigated.

Determination of Residues and Degradation Kinetics of Oryzalin in Different Soils of Soybean Ecosystem

ABSTRACT Dinitroanilines group are persistent pesticides and important pollutants of soil and water. Their dissipation is needed to accurately predict the environmental risk entailing its use in different ecosystems. Degradation kinetics is not reported under subtropical conditions thus, kinetics of oryzalin under soybean field conditions at two application rate in texturally different Pantnagar soils were investigated for two cropping years. Oryzalin was extracted with acetone: methanol from soils followed by florisil SPE cleanup and residues were identified by HPLC-UV. Oryzalin persisted for more than 120 days in soils and slowly dissipated with biphasic first order kinetics. Dissipation was faster in sandy loam compared to silty clay loam soil. At 1.5 & 3.0 kg ha−1 initial half-life in silty clay loam and sandy loam soils were 5.892 & 5.675 and 6.015 & 5.770 days, while, in later phase it were 49.500 & 52.105 and 37.459 & 40.290 days, respectively. Recovery in soil, plant straw, seed husk, soybean oil, deoiled cake, and water samples varied from 77.50–88.85%, 79.50–89.25%, 78.05–88.20%, 75.45–83.92%, 77.40–84.75% and 81.75–93.75%, respectively. Minimum detection limit was 0.001 μg mL−1 and quantitation limit for soil, straw, oil, cake, husk and water were 0.007, 0.01, 0.04, 0.05, 0.03 µg g−1 and 0.005 µg mL−1, respectively. At harvest the oryzalin residues were below detection & MRL in all samples. Study revealed that under subtropical conditions oryzalin is safe for weed control in soybean fields and at harvest soybean crop could be used safely for human/animal consumption and would not create any residual/environmental problem.

Assessment of the Performance Efficiency of Eight-Purpose Compound Equipment in One

A field experiment was conducted to assess the performance of a locally developed and assembled eight-purpose compound equipment and determine its effect on some physical soil properties in a silty clay loam soil in one of the fields of the College of Agricultural Engineering Sciences / University of Baghdad / Jadriyah for the growing season 2022-2023. The experiment used two tractors, the (MF-650) MASSEY FERGUSON and the (MF-5640) MASSEY FERGUSON. The study included two factors: the first factor had three seed rates (3, 4, and 5 kg/donum), and the second factor had three tillage depths (15, 20, and 25 cm). Some performance indicators of the machinery unit were studied, including pulling force, fuel consumption, slippage percentage, and bulk density of the soil. The experiment was conducted using a randomized complete block design (RCBD) with split-plot arrangement and three replications. Seed rates allocated to the main plot, while the tillage depth treatments allocated to the sub-plot. The least significant difference (LSD) at a significance level of 0.05 was used to compare the means of the variables. The results showed significant differences in the performance indicators of the machinery unit due to the tillage depth and seed rate. The depth of 15 cm showed the lowest pulling force, which was 5 kilo Newtons, the lowest slippage percentage of 4.26%, and the lowest fuel consumption of 42.58 L ha-1. The results also confirmed the absence of significant differences in the performance indicators of the machinery unit due to the seed rate and the absence of significant differences in the performance indicators due to the interaction between tillage depth and seed rate.

Effect of organic manure, Biofertilizer and foliar spray of Ascorbic acid on vegetative growth and fruit quality of Basheqi cv. of Olive (Olea europaea L.)

ABSTRACT: This experiment was conducted in a private olive orchard located in the village of Kasara, Dohuk governorate, Kurdistan region, Iraq, during growing season 2021-2022 on 14 years old olive trees cv. Basheqi (Olea europaea L) planted at 4x8m apart in (silty clay loam) soil, under drip irrigation system. Three levels of Organic manure (poultry manure) at (0, 4 and 8) kg/tree was added to the soil at the second week of December in 2021 season, three levels of Bio-fertilizers (Bio Health) at conc. (0, 10 and 15) g.l-1 and three concentrations (0, 300 &amp; 600 mg.l-1 ) of foliar spray of ascorbic acid. Bio-fertilizers and ascorbic acid was carried out two times per season, First: Prior-Flowering, Second: After Setting in order to investigate there influence on growth and Fruit Quality of olive trees. A factorial experiment with three replications was carried out in a randomized complete block design (RCBD), using one tree for each experimental unit. Results indicated that soil application of organic manure (poultry manure) at 8 Kg/tree significantly increased all studied characters {average leaf area, chlorophyll content, Protein % in Leaves, Fruit Total Soluble Solids TSS %, Total Carbohydrates %, Anthocyanin Content, Ascorbic acid (Vit.C), Percentage of Oil}. Soil application of biofertilizer (bio health) at 15g.l-1 significantly increased all study characters except TSS. Foliar application of Ascorbic acid at 600 mg/l-1 significantly increased average leaf area, total chlorophyll content, Protein % in Leaves, Ascorbic acid, Percentage of Oil. In comparison to other interactions, the interaction of (8 kg O.M./tree, 15 g.l-1 bio fertilizer, and 600 mg.l-1 ascorbic acid) appeared to be more efficient in enhancing all characteristics studied in this experiment.

Reduction of nitrous oxide emission by using stearic acid combined zinc coated urea in silty clay and sandy loam soils under bare and planted conditions

Overuse of chemical fertilizers in agroecosystems leads to the increased economic burden, low crop production in terms of input and environmental pollution. Due to its improved nutrient management and degrading properties, synthetic slow release fertilizers have become a significant advancement in the fertilizer sector. In this study we evaluated the effect of slow release urea on nitrous oxide (N2O) emission, crop growth and crop nutrient contents. Measurements were carried out in two different texture soils (sandy loam and silty clay) under two different conditions (bare soil and planted). The N2O emission was measured for 15 days from bare soils and 48 days from planted soil. Plant fresh weight, dry weight, chlorophyll contents, N and Zn were measured in the end of the experiment. The results showed that N2O emission was reduced 33–39 % from coated urea as compared to conventional urea in bare soil. In planted soil, the coated urea reduced the N2O emission 29–33 %. The deep placement of urea in silty clay soil reduced the N2O emission up to 22.8 % as compared to surface placement. Plant fresh matter, dry matter, N and Zn contents were significantly (p ≤ 0.05) higher with coated urea as compared to conventional urea. It is concluded that the coating of urea with hydrophobic materials like stearic acid, along with Zn sources i.e. Zn fortified nano-bentonite or the ZnO nanoparticles (NPs) presents opportunities to overcome the environmental pollution and increasing the crop production and quality.

Soil carbon mineralization, enzyme activities, and crop residue decomposition under varying soil moisture regimes

AbstractIn the Lower Mississippi River Basin, farmlands are flooded in late fall and winter by impeding drainage to provide a habitat for migratory birds stopover. A laboratory incubation study was conducted to study the influence of temporary wetting of these soils on carbon (C) and nitrogen (N) mineralization from residue decomposition. Surface soils (0–15 cm) were collected from fields with clay and silty clay loam soils. Both soils were incubated with five crop residues—corn (Zea mays), soybean (Glycine max), cotton (Gossypium hirsutum), sorghum (Sorghum bicolor), and sweet potato (Ipomea batatus)—at 50% and 100% water holding capacity (WHC). Soil carbon dioxide (CO2) efflux was measured during 74 days of incubation. Soil moisture had the largest effect on soil CO2 efflux and most of the enzyme activities followed by residue and soil type. Cumulative soil CO2 efflux was reduced by 46% at 100% WHC compared to 50% WHC. Clay soil had higher cumulative CO2 efflux, aryl sulfatase, aryl phosphatase, and β‐N‐acetyl glucose aminidase activities than silty clay loam soil. Residue type had the largest effect on post‐incubation soil inorganic‐N, remaining biomass, and residue C and residue N. Sweet potato residue had the lowest remaining biomass, significantly lower than cotton, corn, and sorghum, but statistically similar to soybean. After incubation, residue N concentration had a positive association with cumulative CO2 efflux and a negative association with remaining residue biomass percentage. Winter flooding might limit the loss of soil C as CO2 depending on the crops grown and soil type.

Efficacy of Herbicide Mixtures for Transplanted Aman Rice in Silty Clay Loam Soil of Bangladesh

Weed management plays an important role in obtaining target yield. A field experiment was carried out at the Agronomy field of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh, from July to December 2019 to get the most effective weed control strategy for transplanted Aman rice. The soil of the study field was silty clay loam in nature. The study consisted of two factors i.e., variety (4: Chinigura, BR11(Mukta), BRRI dhan56, and BRRI hybrid dhan6) and herbicide (4) viz., Bispyribac-sodium WP @ 150 g ha-1, Acetochlor 14% + Bensulfuron methyl 4% WP @ 750 g ha-1, Pretilachlor 6% + pyrazosulfuron 0.15% WP @ 9.88 kg ha-1, and weedy check as a control. The experiment was laid out in a split-plot design with three replications. Thirteen weed species were found in the experimental plots, mostly broadleaf and sedge. Monochoria vaginalis was the most dominant weed species. The study noticed that the application of mixed herbicides offered better weed control over single herbicide application. Application of Acetochlor 14% + Bensulfuron methyl 4% WP @ 750 g ha-1 significantly reduced weed density and biomass and was the best way of controlling complex weed flora. The study marked out BR11 (Mukta) as the most potential aman rice variety to produce the highest yields at applying Acetochlor 14% + Bensulfuron methyl 4% WP @ 750 g ha-1. This treatment gave the highest gross return (Tk. 1,46,010), net return (Tk. 88,699), and benefit-cost ratio (2.55). Therefore, the study suggests the application of mixed herbicides and BR11 (Mukta) to get the optimum yield of transplanted Aman rice and maximum economic benefit.&#x0D; Bangladesh Agron. J. 2023, 26(1): 56-74

Soil health, microbial communities, and annual ryegrass yield under contrasting management practices

AbstractBiological indicators are often used to evaluate the effect of management practices on soil health. However, determining which indicators can detect changes in soil health after implementation of conservation practices and how these indicators relate to plant growth in grass seed production systems remains unclear. The goal of this study was to explore the relationships between management practice history, soil health metrics, plant growth, and soil microbial communities in annual ryegrass grown under greenhouse conditions. Soils were collected from 12 annual ryegrass [Lolium multiflorum (L.) Husnot] fields managed under conventional (till/bale) or conservation (no‐till/full straw) management practices, with three silt loams and three silty clay loams collected for each practice. Annual ryegrass was grown for 5 months on each of the 12 soils in a greenhouse. Soils with a history of conservation management improved the majority of the carbon cycling‐related metrics for the silt loam soils. Management practices had no effect on seed yield, however, conservation management significantly improved aboveground biomass in silty clay loam soils. Contrasting management practices resulted in distinct microbial communities, making them sensitive indicators of changes in soil conditions. Soil health and plant metrics were positively associated with the microbial communities in soils under conservation management. Total C and organic matter were positively correlated to plant parameters in silt loams, while few indicators were correlated to plant metrics in silty clay loams. These results highlight the complex interplay between microbial communities, soil health, and plant growth and the importance of considering inherent soil properties like texture.

An economic appraisal of the effect of tire inflation pressure for alternative tillage systems on a silty clay loam soil

AbstractCompacting soil has an adverse effect on soil properties, decreases crop productivity, and subsequently reduces farm income. Low tire inflation pressure (LTP) help in managing soil compaction and protecting the soil environment; however, there is scant economic data available on LTP in US Midwest farming systems. Hence, a 3‐year study investigated the effects of LTP, compared to tires inflated to the standard tire inflation pressure systems, on crop yield and farm economy for a typical maize/soybean rotation. The effect of the two tire inflation pressure systems was factorialized with three tillage systems: deep tillage (DT, 450 mm), shallow tillage (ST, 100 mm), and no‐till systems. The results showed that LTP systems increased maize (Zea mays) yield by 4.51% (2017) and 2.70% (2018) and soybean (Glycine max) by 3.70% in 2018. Annual earnings for both 200‐ and 800‐ha farms increased for all tillage systems with LTP tires based on a partial budget analysis. The payback periods for LTP tires were very short, ranging from 0.32 years for DT on an 800‐ha farm to 1.18 years for ST on a 200‐ha farm. The net present value of the higher returns with LTP tires was substantial, especially for the DT system. This study shows a strong economic benefit from investments in LTP tires on silty clay loam soils in the US Midwest.