Amendment Treatments Research Articles

Blended soil amendments: A viable strategy to reduce soluble phosphorus in soils.

Phosphorus (P) loss from soils can contribute significantly toward P enrichment in water bodies, impairing water quality. Application of soil amendments is a viable strategy to decrease soluble P in surface soils. Since soluble P is reduced through different mechanisms that are amendment-specific, blended amendments could be a better approach than single amendment applications; however, very little information is available on blended amendment effects in reducing P loss from soils. We compared the effectiveness of gypsum (CaSO4·2H2O), Epsom salt (MgSO4·7H2O), and alum [Al2(SO4)3·18H2O] applied singly or blended in different ratios in reducing water-extractable P (WEP) and Mehlich-3 P of two soils (0- to 15-cm depth) with contrasting P status (Mehlich-3 P of 7.1 mg kg-1 and 202 mg kg-1) from the Red River Valley region in MB, Canada. Ten treatments used for the laboratory incubation study were unamended control, gypsum or Epsom salt at 2.5 or 5 Mg ha-1, alum at 2.5 Mg ha-1, and four blended treatments of gypsum: alum or Epsom salt: alum at 1:1 or 2:1. Treated soils were saturated and incubated for 2 weeks and analyzed for WEP (an indicator of risk of P loss) and Mehlich-3 P (plant-available P) concentrations. All amendments significantly reduced the WEP concentrations compared to control in both soils. The blended amendments, particularly gypsum-alum blends, performed better than unblended amendments in reducing the potential risk of P loss. Mehlich-3 P concentration was not influenced by amended treatments, suggesting no significant decrease in plant-available P with amendments in both soils.

The Effect of Soil Amendments and Shading on the Yield of Red Chili (Capsicum annum L.) in a Sandy Dryland

Low nutrient along with intense sunlight levels in sandy drylands, often lead to poor crops yield. This study examined the effects of soil amendments and shading on the yield of red chili plants cultivated in a sandy (70% sand, 15% clay and 15% silt) dryland environment. The experiment was conducted in Gumantar Village, North Lombok Regency from May to September 2024. The C-organic content of the soil was 1.11% with only 0.09% of total nitrogen. The soil amendment treatments included no soil amendment, chicken manure, and seaweed biochar. The shading treatments consisted of two levels: no shading and shading using a 200-micron UV plastic with 14% diffusive ultraviolet ray. All treatments were arranged factorially using a randomized block design with three replications. The results indicated that soil amendments and shading did not significantly affect plant growth, certain soil chemical properties, or microbial populations, possibly due to its short time effect. However, both types of soil amendments and UV plastic shading increased the yield of red chili plants by approximately 6.0% compared to the treatment without any amendments or without shading. This study shows that soil amendment and shading with UV plastic improve tomato yield in sandy dryland soils.

Optimizing soil properties, water use efficiency, and crop yield through biochar and organic manure integration in organic soil.

Speedy decomposition of organic manure and efficient utilization of rice husk waste are two critical challenges for sustainable environment and soil health management. However, understanding the synergistic effects of rice husk biochar (B) and organic manure (OM) on soil properties and crop growth in subtropical conditions remains unclear. A field study was conducted to investigate the impact of sole and combined application of rice husk biochar (0tha-1, 3tha-1), farmyard manure (FYM), and vermicompost (VC) on soil aggregation, aggregate-associated carbon, water use efficiency (WUE), economic benefits, and yield of radish crop in sandy clay loam organic soil. Biochar application enhanced the macroaggregate stability and aggregate associated C contents. Soil moisture, infiltration rate (IR) and WUE were significantly improved by 9.2%, 20.8% and 13.6%, respectively, with addition of biochar, which might be related to improved aggregate-associated carbon and water retention in the soil. Similarly, improved soil properties, WUE were noticed in the treatment receiving combination of FYM+VC over the control. 16% and 30.9% higher radish yield was observed with biochar and FYM+VC amended treatments compared without B0 and manure OM0, respectively. The integrated use of biochar (3tha-1) and OM (FYM+VC) resulted in highest economic benefits of net return (₹ 138,325ha-1) and B:C (1:5) ratio and least in control plots. These results indicate that adding biochar in organic management practices considerably improved the soil properties, WUE which resulted in increased organic radish production.

Effect of Biochar Amendment on the Growth and Photosynthetic Traits of Plants Under Drought Stress: A Meta-Analysis

Biochar, as a soil improvement additive, is widely applied in field practices due to its excellent performance in improving soil conditions and promoting plant growth under drought stress. A meta-analysis was conducted, analyzing 283 pairs of non-biochar-amendment (non-BA) controls and biochar amendment (BA) treatments under drought stress. This study aims to (1) evaluate the effects of biochar on gas exchange and carbon accumulation in plants under drought stress; and (2) quantify the factors influencing biochar’s effects. The results showed that BA had a statistically significant positive impact on water use efficiency (WUE), yield, biomass, chlorophyll content, stomatal conductance (gws), photosynthetic rate (Pr), and transpiration rate (Tr). The extent of these effects was influenced by plant type, degree of water stress, soil type, and the duration of BA application. The response to BA varied across plant types, with significant effects on the WUE of legumes (32.4–37.7%) compared to modest effects on eggplants and other vegetables (8.1–9.4%). BA was more effective in improving plant growth and WUE in soils with extremely coarse or fine textures than in those with medium particle sizes. The duration of BA application was also a critical factor; as the application duration increased, the improvement rates of yield, chlorophyll content, gws, and photosynthetic rate showed a decreasing trend, while WUE and biomass did not exhibit significant declines. However, Tr increased sharply over time. These findings highlight the potential of BA to enhance plant growth, WUE, and photosynthetic traits, while identifying the conditions under which these benefits can be maximized.

Soil amendments alter tree growth and wood decay after forest thinning

AbstractForest soil amendments are increasingly used in western US forests to dispose of unmerchantable woody residues, reduce wildfire risk, and improve soil properties. Our objective was to determine the effect of fertilizer and organic amendments on tree growth and organic matter decomposition after thinning. Treatments were a control, three single soil amendments (wood chips, fertilizer, and biochar), and one combined soil amendment (biochar + fertilizer), each applied after thinning a ponderosa pine (Pinus ponderosa Dougl. ex. Laws) stand. After 10 years, amendment treatments had no effect on tree diameter increment (p = 0.600), but the biochar + fertilizer and wood chip treatments significantly increased height growth (p = 0.006). To estimate belowground biological changes, we used wood stakes made from aspen (Populus tremuloides Michx.) and loblolly pine (Pinus taeda L.) as an index of microbial activity. Stakes were placed: (1) on top of the litter/amendments, (2) at the interface between the litter/amendments and mineral soil, and (3) vertically inserted into the mineral soil, and stake mass loss was measured over 5 years. Stake mass loss of each species was least on the soil surface and increased with increasing depth. Aspen stakes generally had greater mass loss at all three soil locations in the fertilizer and biochar treatments. In contrast, pine stake mass loss was lower than aspen and less affected by fertilizer. Using thinned tree biomass to create amendments can improve forest productivity by enhancing soil conditions and mitigating wildfire. However, the impact of amendments on tree growth may take decades to be detectable.

Soil Aggregates and Organic Carbon Affected by Bio‑Fertilizer in Greenhouse Soil

ABSTRACT Bio-organic fertilizer exerts an important part in aggregate stability as well as carbon and nitrogen turnover. To investigate whether there is a synergistic effect of bio-organic fertilizer application on soil properties within the aggregates. In the present study, the field experiment was performed to examine soil organic carbon (SOC) contents, total nitrogen (TN) contents, stability, and the SOC and TN contents of aggregate fractions in 0–20 cm layer. The treatments comprised the application of no fertilizer (CK), chemical fertilizer alone (CF), bio-organic fertilizer alone (OF), and chemical fertilizer combined with bio-organic fertilizer (COF). Our study suggested that the OF and COF treatments evidently enhanced the stability of aggregates relative to other treatments. All bio-organic amended treatments elevated the SOC level in bulk soil and within each aggregate fraction by 0.67–153.62%. Small macro-aggregates and micro-aggregates made large the contribution to rate of SOC and TN under each treatment, relative to other aggregate fractions. Pearson’s correlation analysis revealed that both the significant positive correlation of SOC and TN with the composition of macro-aggregates and negative correlation with aggregates of <0.25 mm particle size. Further analysis using principal component analysis and comprehensive soil fertility index evaluation indicates that the combined application of bio-organic and chemical fertilizer was a favorable agricultural management practice for improving greenhouse soil quality and maintaining land productivity. This study evidenced that the COF treatment is more suitable for improving the greenhouse soil structure and enhancing carbon sequestration capacity, which is of great significance in ensuring the structure stability of greenhouse soil and maintaining the high yield of tomatoes.

Synergistic electrochemical performance of textile sludge based activated carbon with reduced graphene oxide as electrode for supercapacitor application

The procedure for disposing of textile waste sludge requires sustainable solutions due to numerous environmental issues associated with its disposal. The majority of textile manufacturers incinerate the waste sludge to meet their heating demands, which is harmful to the environment. It can also be used in soil amendment, biodegradable products, construction material and water treatment process as absorbent to remove the heavy metals etc. In this study we use the heavy metal containing textile waste sludge as a precursor for the fabrication of functional electrode material for supercapacitor applications. In this process the organic content within the textile sludge waste is treated at 900 °C and transformed into activated carbon, a vital component of supercapacitors electrodes. Through a series of pyrolysis and activation processes, it is further converted into porous activated carbon (AC) with a wide surface area and appropriate electrochemical properties. To enhance the overall conductivity of the electrode material for supercapacitor applications, the carbon content of the material is increased by loading of reduced graphene oxide (rGO) up to 4 wt%. It resulted in a significant increase in the surface area up to 128.68 m2/g. The effective conversion and relevance of the obtained material for supercapacitor applications is further reinforced by the excellent electrochemical performance of rGO@AC-900 °C which generated a specific capacitance of 362F/g with 4 wt% loading which is higher than the specific capacity achieved with lower rGO loading i.e., 83.2 F/g and 182.5 F/g for AC-900 °C and 2 wt% rGO@AC-900 °C, respectively. The 4 wt% rGO@AC900°C also represented improved stability with up to 82 % charge retention after 5000 charge–discharge cycles. The excellent EDLC behavior of 4 wt% rGO@AC900°C is also evident from the impedance data. The electrode material with 4 wt% rGO loading showed lower value of RCT i.e., 4.16 Ω as compared to 12.08 Ω with 2 wt% rGO loading. This novel approach offers a sustainable alternative for the handling of hazardous textile waste sludge through conversion into a potential electrode material for environmentally friendly energy storage devices.

Effect of salinity stress on the morphological parameters of &lt;i&gt;Hura crepitans&lt;/i&gt; L. ameliorated with &lt;i&gt;Calapogonium mucunoides&lt;/i&gt; DESV. and Biochar

Salinity is one of the most serious limiting factors for plant growth and production. This study assessed the effect of salinity stress on the morphological parameters of Hura crepitans ameliorated with Calapogonuim mucunoides Desv. and Biochar. Standard methodology was adopted to examine physicochemical properties of the soil and morphological parameters of the plant. The physicochemicalproperties of the experimental soils was significant at p=0.01. Morphological parameters of shoot length of H. crepitans at 1% non-amended saline soil for week 6 and 7 recorded 4.03±4.03cm which indicated a significant reduction (p=0.01) when compared to control 15.70±3.35 and 19.50±4.43cm respectively. The amelioration of the saline soil at 0.001% KI with biochar and C. mucunoides (21.80±0.05 and 22.43±3.52cm) of H. crepitans shoot length was significant when compared to the control 21.00±4.00cm. The higher the concentration of salinity, the lower the petiole length of H. crepitans for amended treatments. The photosynthetic pigment 56.70±2.47 of H .crepitans at 0.001% was significant (p=0.05) when compared to the control 51.36±2.99.This results showed that salinity causes a detrimental effect on some plant growth parameters. However, amelioration of saline soil with C. mucunoides and biochar recorded a satisfactory remediation effect on the growth of H. crepitans. Based on this research, amelioration treatment such as C. mucunoides and biochar can be use to improve crops planted in saline soil.

The Comprehensive Effects of Biochar Amendments on Soil Organic Carbon Accumulation, Soil Acidification Amelioration and Heavy Metal Availability in the Soil–Rice System

In recent years, biochar (BC) and biochar-based soil amendments (CSAs) have been widely used in agriculture and the environment. In the present study, a two-rice-season field study was conducted to explore the comprehensive effects of applying BC (1%) and CSA (0.5% and 1%) on soil organic carbon accumulation, soil acidification amelioration and heavy metal availability in a soil–rice system. The results show that soil pH was increased by 0.5–1.7 units and 0.3–1.0 units, respectively, in the early rice season and late rice season treated by the amendments compared with CK. Soil organic contents were increased by 18–30% in the early rice season and by 15–25% in the late rice season in the amended treatments. In addition, soil available phosphorus contents were largely increased as a result of BC and CSA addition. Soil CaCl2 extractable heavy metals (Cd, Ni, Cu and Zn) were simultaneously decreased by BC or CSA amendments. In addition, Cd contents in early rice grain and late rice grain were significantly reduced by 25–48% and 52–83% in amended treatments, while Zn contents were generally not affected. The uptake of Cu and Ni was also decreased by BC and CSA. This study demonstrates that biochar application alone or combinates with inorganic amendments (limestone, sepiolite and potassium dihydrogen phosphate) can significantly improve soil properties and nutrient content and decrease the heavy metal (especially for Cd and Ni) uptake and accumulation from soil to rice grain, where the combination application is more effective.

Enhancing phytoremediation of bauxite mine subsoil by Jatropha curcas L. using sewage sludge and poultry sludge

Phytoremediation is a sustainable technology for cleaning up heavy metal contamination at mining sites. However, degraded soils at these sites create a harsh environment for plants to survive and properly yield biomass. In this study, sewage sludge and poultry sludge were applied as soil amendments in bauxite mine subsoil to determine their impact on the growth and heavy metal uptake of Jatropha curcas L. Both sewage sludge and poultry sludge were applied at 25% and 50%. J. curcas was grown in the amended soils for 120 days under greenhouse conditions. Changes in soil physico-chemical properties, plant growth and heavy metal uptake of J. curcas were determined after that. An increase in EC, CEC, total C, total N, total available P and total extractable K was detected in the amended soils. These improvements enhanced the growth of J. curcas, particularly in the development of above-ground plant biomass. Increased plant biomass subsequently led to higher bioaccumulation and translocation efficiency of Al, Fe, Pb and Zn. As a result, higher heavy metal removal of up to 98.03% was detected in the amended treatments. The findings indicated that the application of sewage sludge and poultry sludge improves soil conditions for plant development.

Mitigating water deficit stress in lemon balm (Melissa officinalis L.) through integrated soil amendments: A pathway to sustainable agriculture.

Lemon balm (Melissa officinalis L.) is a valuable medicinal plant, but its growth can be significantly impacted by drought stress. This study aimed to mitigate the adverse effects of water deficit stress on lemon balm biomass by integrating poultry manure compost, poultry manure biochar, NPK fertilizer, Trichoderma harzianum, Thiobacillus thioparus, and elemental sulfur as soil amendments. The experiment was conducted in a greenhouse using a completely randomized design with a factorial arrangement, consisting of three replicates. It included a water deficit stress factor at three levels (95-100%, 75-80%, and 55-60% of field capacity) and a soil amendment treatment factor with eleven different fertilizer levels. Treatments included control (no amendment), NPK fertilizer, poultry manure compost, poultry manure biochar, and combinations of these with T. harzianum, T. thioparus, and elemental sulfur under various water deficit levels. Water deficit stress significantly reduced photosynthetic pigments, gas exchange parameters, chlorophyll fluorescence, relative water content, and antioxidant enzyme activity, while increasing membrane permeability and lipid peroxidation in lemon balm plants. However, the integrated application of organic, biological, and chemical amendments mitigated these negative impacts. The combined treatment of poultry manure compost, poultry manure biochar, NPK fertilizer, T. harzianum, T. thioparus, and elemental sulfur was the most effective in improving the morpho-physiological properties (1.97-60%) and biomass (2.31-2.76 times) of lemon balm under water deficit stress. The results demonstrate the potential of this holistic approach to enhance the resilience of lemon balm cultivation in water-scarce environments. The integration of organic, biological, and chemical amendments can contribute to sustainable agricultural practices by improving plant morphological and physiological properties and plant performance under drought conditions.

The Effect Addition of Soil Amandments and PGPR (Plant Growth Promoting Rhizobacteria) on the Growth and Yield of Cotton Plants Intercropped with Corn Plants in Dry Land of North Lombok Regency of Indonesia

This research investigates the effect of soil amendments in the form of cow, form goat manures and PGPR biofertilizer on cotton plants intercropped with corn in the dry lands of North Lombok Regency. The research aims is to determine the growth and yield response of cotton plants due to the application of soil amendments and PGPR in an intercropped system with corn in dryland areas. The research was conducted from December 2023 to June 2024 in Andalan Village, Bayan District, North Lombok Regency. The method used is an experimental method with field trials. The design used was Randomized Block Design (RBD), incorporating two factors: soil amendment treatment (P) as the main plot and PGPR (K) concentration treatments as the subplot. Soil amendments consisted of three levels: P0 (no cow manure and no goat manure), P1 (20 tons/ha cow manure), P2 (20 tons/ha goat manure). PGPR concentration consisted of four levels: K0 (without PGPR), K1 (20 ml/liter PGPR application), K2 (30 ml/liter PGPR application), and K3 (40 ml/liter PGPR application). The research results indicated that the application of 20 tons/ha of goat manure (P2) produced the highest average across all observed parameters (plant height, number of leaves, branch number, stem diameter, and plant yield). Similarly, the application of 40 ml/liter PGPR produced the highest average for these observed parameters. Based on the results of the land equivalent ratio (LER) analysis, this integration system shows highly suitable and relevant to be applied in the dry lands of North Lombok.

Effect of two amendments on seedling growth of two cashew varieties

Cashew, Anacardium occidentale L., is considered a promising crop for many regions in Colombia, requiring further research on new varieties and technologies. This study aimed to evaluate the effect of two organic amendments on two cashew varieties under nursery conditions in Puerto Carreño, Vichada department. A factorial experiment (3 organic amendment treatments x 2 varieties) with 4 replications was conducted. The treatments for the first factor were: chicken manure (30%), bovine manure (30%), and no amendment. The varieties used were Yucao and Mapiria. Emergence, survival, and morphometric variables such as stem length, stem diameter, and number of leaves were evaluated, as well as disease incidence and severity. Results showed that seedling emergence and survival were more influenced by the addition of organic amendments than by varieties. Stem length of cashew seedlings was influenced by the addition of bovine and chicken manure and their interaction with the two varieties until week 7, while stem diameter was influenced until the end of the nursery cycle. Neither variety nor treatment influenced the number of leaves. Anthracnose was primarily influenced by the variety factor, with Mapiria being more susceptible to both disease incidence and severity. Overall, both organic amendments had a significant effect on the development of cashew seedlings in both varieties studied.

Availability of Recycled Phosphorus on Biochar Reacted with Wastewater to Support Growth of Lactuca sativa

The use of biochar in water resource and recovery facilities (WRRF) shows promise for recovery of phosphorus (P) to use as a biochar-based fertilizer (BBF) that can replace conventional fertilizers, promote carbon sequestration, and improve soil quality. In this study, biochar was recovered after being dosed into secondary-treated discharge from a municipal WRRF. The value of the recovered biochar as a BBF was tested in a lettuce (Lactuca sativa) growth trial. The BBF was compared to an inorganic fertilizer, raw biochar, and controls that had either only nitrogen (N) fertilizer or no amendment. The ability of the treatments to support plant growth was determined by measuring plant height, biomass, leaf tissue total N and P concentration, and plant quality. Plant quality for the Fe-modified biochar used in the WRRF was 9.05 (±0.44) on a 10-point scale compared to 9.61 (±0.46) for the inorganic fertilizer treatment and 2.22 (±0.82) for the untreated control. Plant tissue P concentrations were 6.28 (±0.83), 9.88 (±0.90), 15.46 (±2.54), and 6.36 (±1.91) g plant−1 for the raw biochar, Fe-modified biochar used in the WRRF, inorganic fertilizer, and no amendment treatments, respectively. Soil P availability and P uptake amount in the leaves indicated that the BBF released P more slowly than the inorganic P fertilizer; however, it was sufficiently available for uptake to support plant growth to maturity. Results from these experiments show that Fe-modified biochar used in WRRF can supply adequate P to plants. The slow release will reduce P leaching into surface waters.

Unveiling the Implications of Organic Nutrient Management Protocols on Soil Properties, Economic Sustainability, and Yield Optimization in Fenugreek Cultivation in Acidic Soils of Northeast India

Utilizing yield, profitability, and environmental sustainability in terms of soil quality as the goal variables, we created a methodological protocol for a thorough assessment of nutrient management (NM) technologies for feasibility and optimized fenugreek production employing organic sources of nutrients in the acid soil of Northeast India. Five organic nutrient management technologies were tried and tested comprising T1: absolute control; T2: 2.5 t ha−1 vermicompost (VC) + 250 kg ha−1 lime; T3: 5 t ha−1 farmyard manure (FYM) + 250 kg ha−1 lime; T4: 10 t ha−1 FYM + 250 kg ha−1 lime; and T5: 5 t ha−1 VC + 250 kg ha−1 lime with four replications laid out in a randomized block design for two consecutive growing seasons during 2018–2020. Results indicated that across the differential levels of organic amendments (treatments) employed, the addition of maximum doses of VC and FYM, in general, excelled over the other treatments concerning fenugreek seed yield, its yield attributes, soil properties, and better economic returns. Thus, the overall findings elucidated that the addition of higher doses of organic amendments (VC and FYM) can sustainably improve fenugreek productivity, soil properties, and economic returns for fenugreek growers in the acid soil of Northeast India.

Halotolerant Microorganism-Based Soil Conditioner Application Improved the Soil Properties, Yield, Quality and Starch Characteristics of Hybrid Rice under Higher Saline Conditions.

Soil salinity represents a significant factor affecting agricultural productivity and crop quality. The present study was conducted to investigate the effects of soil conditioner (SC) comprising halotolerant microorganisms on the soil fertility, yield, rice quality, and the physicochemical and structural properties of starch in hybrid rice under saline conditions. The experimental treatments were composed of two high-quality hybrid rice varieties, i.e., 'Y Liangyou 957' (YLY957) and Jing Liangyou 534 (JLY534), and two soil amendment treatments, i.e., the application of SC at control levels and 2250 kg hm-2, or 'CK and SC', respectively. The crop was subjected to a mixture of fresh and sea water (EC 11 dS/m). The results demonstrated that the application of SC significantly enhanced the rice yield under salt stress conditions owing to an increase in the number of grains per panicle. Furthermore, SC was found to be effective in improving the organic matter and soil nutrient content. Furthermore, the application of SC resulted in an improvement in antioxidant defense, higher leaf SPAD values, and greater crop biomass, as well as the translocation of photo-assimilates at the heading stage. The application of SC not only improved the milling and appearance quality but also enhanced the taste value of rice by increasing the amylose and reducing the protein content. Furthermore, the application of SC also decreased the indentations on the surfaces of starch granules and cracks on the edges of the granules. The rice varieties subjected to SC exhibited excellent pasting properties, characterized by reduced proportions of amylopectin short chains and a lower gelatinization temperature and enthalpy of gelatinization. Overall, these findings serve to reinforce the efficacy of soil conditioner as a valuable tool to improve rice productivity and sustainability with improved rice grain quality under saline conditions.

Mathematical Modeling for Predicting Growth and Yield of Halophyte Hedysarum scoparium in Arid Regions under Variable Irrigation and Soil Amendment Conditions

Growing degree days (GDDs) and leaf area index (LAI) greatly influence the growth and yield of many crops grown in arid regions. Therefore, variation in LAI due to GDD can provide a theoretical basis for predicting crop growth, water consumption, plant development, and yield in arid agriculture via the development of mathematical growth models. This study described the relationship between plant biomass production and variation in LAI due to GDD in arid regions under different types of irrigation (fresh water and saline water) and soils amended with different substances (manure+sandy soil, compost+sandy soil, clay+sandy soil, and sandy soil). Mathematical models for LAI were established for GDDs. In addition, different water quality irrigation techniques were used as independent variables to calculate the LAI of halophytic plants (Hedysarum scoparium) in arid regions under different soil amendment treatments. Furthermore, mathematical models for plant biomass production were developed by using the LAI and GDDs. For this purpose, Logistic, Gaussian, modified Gaussian, and Cubic polynomial models were used. Modified Gaussian and Cubic polynomial models are the best among all developed models, but Cubic polynomial models are more suitable among all developed models because of their simple quadratic equations that can be solved by using the first derivative. It was observed that with increased salt concentration in the irrigation water, the growth of per plant production decreased. However, soil amendments like manure and compost enhance salt tolerance against salt stress and enable plants to sustain their growth. Furthermore, Hedysarum scoparium attains maximum LAI when its GDD is about 1117.5 °C under both irrigation regimes and in all soil amendment treatments. It was concluded that these predicted mathematical models can provide crucial insights for enhancing production in arid regions by using eco-friendly soil amendments to improve water use efficiency across diverse types of water irrigation.

Effect of biochar and iron ore tailing waste amendments on cadmium bioavailability in a soil and peanut seedling system.

Biochar and iron ore tailing waste have been widely separately applied for remediation of various contaminants, but the remediation effect of their combination on cadmium (Cd) pollution is unclear. In this study, the peanut biochar (BC), thermally activated iron ore tailing waste (TS), and the products of the co-pyrolysis of peanut shell and iron ore tailing waste (TSBC) were prepared for stabilizing Cd and reducing its bio-accessibility in soil and peanut seedling system. Present amendments enhanced soil pH, cation exchange capacity, electrical conductivity, and organic carbon content. The application of BC, TS, and TSBC led to decreases in acid-extractable Cd proportion of 2.2-8.81%, 2.43-7.20%, and 7.84-11.57%, respectively, and increases in the residual Cd proportion of 3.48-8.33%, 3.27-11.50%, and 9.02-13.45%, respectively. There were no significant differences in Cd accumulation in peanut roots due to three amendments treatments, especially at low Cd concentrations (i.e., Cd concentration of 0, 1, and 2mg·kg-1), and with a relatively small reduction (2.16-9.05%) in root Cd accumulation under the high Cd treatments of 5 and 10mg·kg-1. The Cd concentrations in seedling roots were significantly positively related to the acid-extractable Cd fraction, with a Pearson correlation coefficient of r = 0.999. The maximum toxicity mitigating effects were found in TSBC treatment, with increases in the ranges of 9.80-17.58% for fresh weight, 5.59-14.99% for dry weight, 5.16-10.17% for plant height, 5.96-10.34% for root length, 5.43-21.67% for chlorophyll a content, 17.17-71.28% for chlorophyll b content, and 13.11-39.60% for carotenoid content in peanut seedlings. Therefore, TSBC is a promising amendment for minimizing Cd contamination in peanut crops and utilizing industrial solid waste materials efficiently.

Organic soil amendment effects on soil hydrology in an almond orchard evaluated using time-lapse electrical resistivity tomography

Adding organic amendments to soils in orchards has been suggested as a climate-smart agricultural practice that can increase resilience to extremes such as drought. The benefits of adding almond hulls and shells to soil include releasing potassium into the soil, improving water infiltration, reducing soil water evaporation, and enhancing water-holding capacity. In this study, soil infiltration and root water uptake (RWU) patterns of almond trees in amended and control soil treatments were investigated. An almond orchard was mulched with a mixture of almond hulls and shells used as surface-applied organic matter amendments. The combined use of time-lapse electrical resistivity tomography (ERT), stem water potential (SWP) and leaf water potential (LWP) measurements were used to evaluate RWU, soil infiltration patterns, and tree water status at different times during the study. The results of the ERT showed that the RWU patterns for the almond trees are distinct between the amended and the control treatments after the irrigation was applied. Compared to the control treatment, the amended treatment allowed the soil to store more water. Regardless of treatment, the majority of RWU patterns were observed in the top 0.5–1 m root zone depth. Almond trees began to recover from stress, as indicated by the SWP and LWP values, four hours after the start of irrigation. In addition, this was demonstrated by the ERT measurements, which revealed the RWU activity four hours after the irrigation had been applied. This research reveals that time-lapse ERT surveys combined with soil and tree water status data can infer patterns of RWU in almond trees grown with organic soil amendments and under controlled conditions. Furthermore, it was concluded that using almond hulls and shells as organic matter amendments can help almond growers improve infiltration, making almond production more resilient to climate change-related extremes such as droughts.

Soil fertility and plant nutrition in an organic olive orchard after 5 years of amendment with compost, biochar or their blend

The agronomic use of compost and biochar as soil amendments may exhibit contrasting results in terms of soil fertility and plant nutrition. The effects of the biennial application of biochar, compost and a blend of compost:biochar (90:10; % dw:dw) on the agronomical performance of an organically managed and well established 25-year-old olive orchard was assessed 5 years after the initial application. The agronomical evaluation was based on the assessment of the soil physical, chemical, and biological characteristics, and the assessment of the soil fertility by both crop production and nutritional status of the orchard, and the bioassay with olive plantlets. Biochar mainly benefited the physical properties (bulk density, total porosity, aeration, water retention capacity) of soil, especially in the top 0–5 cm. Compost and its blend with biochar improved microbial activity, soil nutritional status (increasing the content of soluble organic C, N, and P) and favoured the formation of aggregates in soil. The bioassay conducted with young plantlets confirmed the enhanced soil fertility status in the three amended treatments, particularly in the case of biochar and its blend with compost. However, this effect was not significantly observed in the adult plants after 5 years of application, reflecting the slow response of adult olive trees to changes in fertilization. Based on these results, alongside the desirable long-residence time of biochar in soil and the ready availability of compost, the blend of biochar with compost assayed in this study is defined as a valid strategy for preparing high quality soil organic amendments.