Application Of Soil Conditioners Research Articles

Regulatory Effects of S-Abscisic Acid and Soil Conditioner on the Yield and Quality of Hybrid Rice Under Salt Stress

Salt stress significantly reduces rice yield and deteriorates rice quality. The present study was conducted to explore the regulatory effects of sole and combined application of S-abscisic acid (S-ABA) and soil conditioner on rice under high salt stress. The experimental treatments comprised 0.1% S-ABA alone (T1), the application of soil conditioner (T2), the combined application of both S-ABA and halotolerant microorganism soil conditioner (T3), and a control without any regulatory substance (CK). The treatments were arranged in a randomized complete block design in triplicate. To simulate high salinity stress, a 0.6% saltwater solution (by mixing natural seawater with freshwater) was used for irrigation. The results showed that T3 alleviated the phytotoxic effects of high salt stress and substantially improved rice yield. Furthermore, the numbers of effective panicles, grains per panicle, and 1000-grain weight under T3 treatment were 13.3–14.5%, 8.9–14.1%, and 4.9–5.5% higher than CK owing to improvement in dry matter accumulation, SPAD values, leaf area index, antioxidant enzyme activity, and reduced malondialdehyde and sodium ion content in rice. Moreover, the T3 treatment increased the output, output rate, and conversion rate of stem sheath matter after the heading stage; improved the milling yield, starch paste viscosity, starch stickiness, and gelatinization enthalpy; and reduced rice chalkiness. In addition, the T3 treatment also increased the amylose contents and decreased the total protein contents, thereby improving the taste of the rice. Overall, the results indicated that the application of exogenous S-ABA and soil conditioner is an effective strategy to alleviate the severity of salt stress in rice.

Effects of soil amendments and coverings on the kenaf yield and soil physicochemical properties in saline-alkali land

In order to investigate the effects of various treatments on the growth of kenaf in saline soil, this study employed a comprehensive experimental design incorporating a dual approach of soil amendment and mulching techniques. Soil treatment of saline and alkaline land, as well as biological material mulching treatment after sowing kenaf, were conducted. The growth dynamics of kenaf were assessed before the mid-term investigation, and the harvest period was examined. Soil physicochemical properties were measured and analysed at different periods. The results show that in the analysis of red sesame yield traits, the differences mainly appeared between soil treatments. There is no significant difference between the different mulching treatments within each soil treatment. In the mid-term study, significant differences were observed in kenaf plant height. Plant height was the most affected by soil conditioners, while other yield traits did not show significant variations. During harvest, only stem thickness and dry weight of a single plant did not show significant differences, whereas other yield traits did. The application of soil conditioners resulted in a 58.15% increase in dry hull yield compared to organic fertilizers and a 22.66% increase compared to regular fertilizers. Soil conditioners also led to higher levels of effective phosphorus, quick-acting potassium, organic matter, and total nitrogen throughout the kenaf growth period compared to organic and regular fertilizers. This is beneficial for enhancing soil quality and reducing soil alkalinity. Combined with the results of kenaf yield and soil physical and chemical properties analysis, it has been proven that the application of soil conditioner has the best effect, followed by the application of compound fertilizer, with organic fertilizer treatment being the least effective.

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.

Effects of Soil Conditioner (Volcanic Ash) on Yield Quality and Rhizosphere Soil Characteristics of Melon.

In this study, the effects of soil conditioners on the growth and development of melons and the rhizosphere soil environment were explored. The optimal amount of added soil conditioner was screened to solve the practical production problems of high-quality and high-yield thin-skinned melon. The melon variety "Da Shetou" was used as the material. Under the conditions of conventional fertilization and cultivation technology management, different soil conditioners were set up for potted melons. The effects of Pastoral soil (CK), 95% Pastoral soil + 5% volcanic ash soil conditioner (KT1), 85% Pastoral soil + 15% volcanic ash soil conditioner (KT2), 75% Pastoral soil + 25% volcanic ash soil conditioner (KT3), 65% Pastoral soil + 35% volcanic ash soil conditioner (KT4), and 55% Pastoral soil + 45% volcanic ash soil conditioner (KT5) on melon yield, quality, and rhizosphere soil characteristics were investigated. The soil microbial community was analyzed using Illumina MiSeq technology. Compared to CK, KT1, KT3, KT4, and KT5, the KT2 treatment could improve the single fruit yield of melon, increasing it by 4.35%, 2.48%, 2.31%, 5.92%, and 2.92%. Meanwhile, the highest contents of soluble protein, soluble solid, and soluble sugar in the KT2 treatment were 1.89 mg·100 g-1, 16.35%, and 46.44 mg·g-1, which were significantly higher than those in the control treatment. The contents of organic matter, total nitrogen, alkali-soluble nitrogen, nitrate nitrogen, ammonium nitrogen, available potassium, and available phosphorus in melon rhizosphere soil were the highest in the KT2 treatment. Through Alpha diversity analysis, it was found that the Chao1 index, Shannon index, and ACE index were significantly higher in the KT1 treatment than in the control, while, among all groups, the Simpson index and coverage were not significantly different. The dominant bacteria in the six treated samples were mainly Actinobacteriota, Proteobacteria, Cyanobacteria, Chloroflexi, Acidobacteria, Bacteroidetes, Myxomycota, Firmicutes, Gemmatimonadota, Verrucomicrobia, and Planctomycetes, which accounted for 96.59~97.63% of the relative abundance of all bacterial groups. Through redundancy analysis (RDA), it was found that the organic matter, electrical conductivity, available phosphorus, and nitrate nitrogen of melon rhizosphere soil were the dominant factors of bacterial community change at the dominant genus level. In summary, 15% ash soil conditioner applied on melon was the selected treatment to provide a theoretical reference for the application of soil conditioner in facility cultivation.

Wpływ zastosowania uzdatniaczów gleby na temperaturę i wilgotność środowiska glebowego

In cities, environmental and social impacts are increased every year due to high temperatures due to the heat island of the city. An effective struggle against the heat island of the city is the green infrastructure, where woody plants such as trees and shrubs play an irreplaceable role. Wood in the city is affected by a number of stress factors, especially high temperatures and lack of precipitation. In order for them to perform all their important functions and help reduce the negative impacts of the city's heat island, all requirements for their successful development and growth must be fulfilled. Soil conditions are an important factor affecting the condition of trees. Unsuitable soil conditions which include lack of water, compacted soil, result in insufficient development of the root system which directly affects the quality of the above-ground part of the plants. A possible treatment to improve the soil environment in the root zone of trees is the use of soil conditioners applied in the form of soil injection. The paper deals with the effect of soil conditioners (Hydrogel®, mycorrhizal mix Endomyk PROF + Trichoderma, and their combination) in the form of injection on the temperature and humidity conditions of the soil environment in a young plants of trees (species) Acer campestre L. in the city of Znojmo (South Moravia region). Plants without application of any preparation served as a Control variant. Before the actual application of conditioners MINILOG data loggers with temperature sensors and VIRRIB moisture sensors were placed in the soil which recorded changes in soil temperature and volumetric soil moisture in six-hour intervals every day in the period from February 2021 till December 2022. These changes were recorded in two profiles 0.1 - 0.4 and 0.4 - 0.7 meters. From the recorded results, it can be said that the application of soil conditioners had a significant effect on the temperature and humidity conditions of the soil environment. The variant with the soil conditioner Hydrogel® and the variant with the soil conditioner Hydrogel® in combination with the mycorrhizal mix in most cases show higher values of soil moisture and temperature compared to the Control variant. This trend is most evident in the soil profile of 0.4 - 0.7 m in the growing season.

Growth of cocoa seedlings affected by application of zeolite-cocopeat-manure mixture as soil conditioner enriched by Trichoderma sp.

The objective of this research was to study the effect of soil conditioner in different dosage levels enriched by Trichoderma sp. on cocoa seedling growth and biomass. This research was conducted in glass house Kaliwining,Experimental Station of Indonesian Coffee and Cocoa Research Institute (ICCRI), Jember, East Java, with rainfall type of D (Schmidt & Ferguson) with relatively flat topography at altitude 45 m above sea level. Complete Randomized Design using four treatments, i. e. no application of soil conditioner (control), the application of 200 grams, 400 grams, and 600 grams/polybags of soil conditioner, with 5 replications and 5 subsamples was engaged for this research. Trichoderma sp. as endophytic fungus has been detected highest in the soil conditioner that enriched with Trichoderma sp. The result of the research was the application of soil conditioner alone or combined with Trichoderma sp. could increase plant growth and plant biomass. This research finding was the addition of Trichoderma sp. with soil conditioner increased the plant growth doubled than soil conditioner alone.

Integrated Soil–Crop System Management Promotes Sustainability of Intensive Vegetable Production in Plastic Shed Systems: A Case Study in the Yangtze River Basin, China

Excessive fertilizer input, low nutrient use efficiency, soil quality, and environmental degradation hinder greenhouse vegetable production. Integrated agronomic strategies of soil, crop, and nutrient management are needed to sharply improve the vegetable yield and simultaneously maintain sustainable production. A three-season field experiment was conducted from 2015 to 2018, aiming to evaluate the effect of integrated soil–crop system management (ISSM) on the agronomy, environment, and economy of greenhouse vegetable systems in the Yangtze River Basin, China. Three treatments were included in the experiment: (1) farmers’ current practice (FP), based on a local farmers’ survey; (2) soil remediation treatment (SR), the application of soil conditioner and compost fertilizer instead of chicken manure; (3) ISSM, a combination of soil conditioner, reducing plant density, and using formula fertilizer as well as increasing the fertilization times. The results indicated that ISSM (47.7 Mg ha−1) improved the pepper yield by 17% relative to farmers’ current practice (FP, 40.7 Mg ha−1). Soil remediation (SR), as a single approach, mainly made a contribution to improving the yield (by 6.9%) and nutrient use efficiency while reducing apparent nitrogen (N) losses. Higher yields were mainly attributed to increasing the fruit number per plant. On average, apparent N losses were reduced by 245 kg N ha−1 per season for ISSM compared to FP. In addition, higher net profits were obtained under SR and ISSM relative to FP. Overall, both SR and ISSM have advantages for the agronomy, environment, and economy in greenhouse vegetable production, but ISSM would be the optimal choice to achieve higher yields with lower environmental impacts.

Preparation and application of soil conditioner using iron ore tailings-biochar composite material

Iron ore tailings (IOT) are industrial solid wastes that pose environmental threats. This study prepared IOT-biochar composite materials as multifunctional soil conditioners through an in-situ growth method. Biochar served as a carrier to improve the dispersity and reactivity of IOT in soil. The IOT-biochar composite (FeOT-BC) showed balanced impacts on soil properties, increasing pH, organic matter and available nutrients compared to IOT alone. This was due to the buffering effects of biochar. In pot experiments, FeOT-BC significantly promoted rice plant growth compared to IOT alone. The improvements were attributed to the improved soil fertility and increased microbial activities induced by biochar. The results suggest that integrating IOT with biochar can mitigate the negative effects of tailings and convert them into a value-added product. The biochar component can optimize the performance of IOT by moderating soil acidification, enhancing nutrient release from iron minerals, and stimulating microbial activities. The IOT-biochar composite materials integrate the functionalities of both components for optimized soil conditioning effects, providing a promising strategy for comprehensive tailings utilization.

Response of Cadmium in Soil-rice to Different Conditioners Based on Field Trials

A plot experiment was carried out to assess the applicability of soil conditioners on Cd-polluted acidic paddy fields. The effects of five soil conditioners[Tianxiang 1 Hao (TX1), limestone (Li), silicon fertilizer, Nuodikang (NDK), and calcium magnesium phosphate fertilizer (CaMg-P)] on Cd accumulation and transport between contaminated soil and rice plants and rice yield on the land were analyzed. The results showed that compared with that under the control, other tested methods increased soil pH by 0.41-0.68 units and decreased available Cd content in the soil by 11.2%-39.7%. The difference between Li- and NDK-treated soil available Cd reached a significant level (P < 0.05). ② Compared with that in the blank control, the application of soil conditioner could significantly reduce the total amount of Cd in rice, and the Cd content in roots, other leaves, rachises, chaffs, and brown rice were significantly lower than those in the CK treatment (P < 0.05). The Cd translation factor between various sites was shown as TFroots-other nodes > TFroots-first nodes > TFroots-rachises > TFroots-chaffs ≈ TFroots-flag leaves > TFroots-brown rice. The Cd content of brown rice met the national safety standard (0.2 mg·kg-1), in which the TX1, Li, and CaMg-P treatments showed significant Cd reduction effects, and ω(Cd) was 0.097, 0.094, and 0.134 mg·kg-1, respectively. ③ The application of soil conditioner could increase the yield by 9.9%-35.8%, and the yield of the CaMg-P and TX1 treatments was significantly higher than that of other treatments (P < 0.05). ④ Correlation analysis showed that the Cd content in brown rice was significantly positively correlated with available Cd content in soil, available Fe content in soil, and available phosphorus but negatively correlated with soil pH. In summary, TX1 and CaMg-P are recommended to be applied in farmland lightly polluted by the heavy metal Cd to ensure the safety of agricultural products.

Transcriptome analysis of growth and quality response of chrysanthemum to co-inoculation with Bacillus velezensis and Pseudomonas aeruginosa

The inoculation of plants with plant growth-promoting rhizobacteria (PGPR) has been increasingly discussed as a way to sustainably promote plant growth and soil health. Although some promising results have been achieved in the laboratory, the applications of microbial inoculants in chrysanthemum production greenhouses and co-inoculation with PGPRs in ornamental planting systems have been less investigated. Here, greenhouse experiments were conducted to study the integrated effect of bioagents (Bacillus velezensis and Pseudomonas aeruginosa) on chrysanthemum nutrient use efficiency, plant growth, and quality. The growth-promoting mechanisms were further elucidated by transcriptome analysis. Co-inoculation with the two PGPRs increased the absorption and utilization of nitrogen, phosphorus, and potassium. The quality and growth of chrysanthemum were significantly higher than those of single PGPR inoculation or soil conditioner application. Transcriptome analysis revealed that differentially expressed genes (DEGs) were co-expressed at 30, 60, and 90 days after chrysanthemum co-inoculation with the two PGPRs. DEGs were primarily enriched in metabolic and signal transduction pathways. PDC encoding pyruvate decarboxylase in the glycolysis pathway and SAUR32 and SAUR36 encoding auxin were upregulated in chrysanthemum during the PGPRs inoculation period. Notably, the transcription factors WRKY70 and BHLH35 belonging to signal transduction and defense responses were both upregulated, demonstrating that chrysanthemum system and disease resistance were activated. The results of this study could help to elucidate the mechanism of 2 PGPRs on chrysanthemum growth and development at the transcriptome level, which could lay a theoretical foundation for the highly efficient cultivation of cut chrysanthemum “Qinhuai Yulian”.

Dynamic response of cadmium immobilization to a Ca-Mg-Si soil conditioner in the contaminated paddy soil

Soil conditioners are often used to immobilize soil heavy metals. Understanding the transfer of Cd in soil-plant system to different application rates and modes of soil conditioners application is essential for food safety. The stabilization persistence of soil conditioners in immobilizing Cd, to date however, is still limited. In this study, the stabilization persistence of a Ca-Mg-Si soil conditioner (SC) was assessed based on a six-year Cd-contaminated paddy field study with growth of two rice local main varieties (Yongyou17-YY and Xiushui14-XS) and four application rates (1500 kg ha−1 (low), and 3000 kg ha−1 (high) for the first year only, and 1500 kg ha−1 and 3000 kg ha−1 every year). Results showed that continuous SC application with high rate increased soil pH, simultaneously with more water soluble and exchangeable Cd was transferred to Fe-Mn oxides bound and carbonate-bound Cd in the first 3–4 years; while the low rate was only effective with growth of YY that were applied for a shorter period of time. Statistical analysis indicated that the stability effect of SC was integratedly affected by soil pH, SC application rate, and meteorological factors (precipitation and temperature). Especially, soil fractionation contributed the most changes of Cd availability in soil, while meteorological factors, SC application rate and crop varieties altogether exhibited the great effect on Cd accumulation in grain. Our finding demonstrated the potential long-term stabilization of SC in soil Cd immobilization, with the performance needed for further verification on the basis of different soil types.

Effects of Biochar and Soil Conditioner on Coastal Barren Saline-alkali Soil

This study aimed to quantify the biological improvement and availability from a soil amendment substance for barren severe saline-alkali soils. A field experiment was conducted to apply biochar (B) and soil conditioner (C) rich in humic substances to pioneer crops and oil sunflower planted in the coastal barren severe saline-alkali area of the North China Low Plain. The six treatments included single or combined application of two-level biochar rates (0 and 1.25 kg·m-2) and three-level soil conditioner rates (0, 0.83, and 1.66 kg·m-2) at the start of the experiment. Soil samples were collected at 30 cm per layer and sampling from 0 to 90 cm after the oil was collected. The results revealed that the application of biochar increased the saline concentration of the 0-30 cm and 60-90 cm soil layers, whereas the soil conditioner significantly decreased the saline concentration of the 0-30 cm soil layers. Neither biochar nor conditioner showed a significant impact on soil pH. Biochar exhibited varying impacts on soil nutrients, that is, significantly inhibiting soil nitrification, which resulted in soil NO3--N decreasing while NH4+-N increased significantly, along with no significant impact on soil organic matter content (SOM) in the 0-90 cm soil profile. The application of soil conditioner exerted positive effects on improving SOM in the 0-30 cm layer and NO3--N in the 0-90 cm soil depth when the conditioner rate was at 1.66 kg·m-2. Either the sole application or the co-application of biomass and conditioner, along with their interaction, exhibited an increasing trend for the NH4+-N, available phosphorus (Olsen-P), and available potassium (Kex) contents, also seen in the 0-90 cm soil profile, although the increase effect for the three nutrients was primarily attributed to biochar. Soil conditioner was more effective in increasing SOM and reducing saline in the 0-30 cm soil layer. The application of a higher amount of conditioner accelerated soil nitrification, whereas biochar was applied essentially as a nitrification inhibitor. Therefore, the co-application of biochar with soil conditioner would be an effective practice for improving soil fertility, preventing soil nitrification, and deterring nitrate leaching, as well as reducing saline for topsoil, which would be a basis for developing soil amendments to control saline and a fertile soil environment for pioneer crops planted in coastal barren severe saline-alkali areas.

Effects of the Changes of Particle Surface Electric Field and Interaction Force on the Reclaimed Soil Aggregate Structural Stability under the Application of Different Soil Conditioners

Aggregate stability is a key factor in the evaluation of soil structure and erosion resistance, which is largely influenced by soil electric field and particle interaction. However, there are few studies on how different organic and inorganic soil conditioners change the surface electric field and interaction force of reclaimed soil to improve the aggregate stability. Therefore, a five-year field experiment was conducted to quantitatively study the effects of FeSO4 (TM), organic fertilizer (TO), fly ash (TF), maturing agent + organic fertilizer (TMO) and fly ash + organic fertilizer (TFO), compared with control (CK) treatment, on the reclaimed soil internal force and the aggregate crushing strength. The results showed that the reclaimed soil surface potential and electric field intensity increased after 5 years of application of organic and inorganic soil conditioners. Under the same electrolyte concentration and electric field conditions, the crushing strength of aggregates (<5 μm) treated with TFO, TMO, TO, TF and TM decreased by 43.70%, 35.51%, 25.97%, 8.28% and 5.49%, respectively, compared with the control treatment, and the combination of organic and inorganic treatment (TFO and TMO) had a better effect on improving the aggregate crushing resistance. With the application of soil conditioners, the reclaimed soil DLVO force and net resultant force gradually decreased, and the order of magnitude was TFO < TMO < TO < TF < TM < CK, indicating that the application of organic and inorganic soil conditioners enhanced the van der Waals attractive force and net attractive force between reclaimed soil particles, and reduced the net repulsive force between particles. The theoretical calculation results of the reclaimed soil internal force well explain the experimental results of aggregate stability against crushing, and the relationship between aggregate crushing strength and net resultant force is exponential (p < 0.01). Generally speaking, the soil conditioners increase the net attractive force between particles, reduce the possibility of violent crushing of aggregates due to the increase of electric field intensity and improve the aggregate structural stability, among which the combined application of organic and inorganic soil conditioners has a better improvement effect. The results of this study will lay a theoretical foundation for clarifying the improvement of different soil conditioners on the reclaimed soil structural stability and erosion resistance.

Interaction force mechanism for the improvement of reclaimed soil aggregate stability in abandoned homestead by different organic-inorganic soil conditioners

Reasonable application of organic-inorganic soil conditioners can effectively improve the structure and fertility of reclaimed soil in abandoned homestead. Aggregate stability is an important indicator to evaluate soil structure and fertility, and is largely influenced by soil internal forces (van der Waals attractive force, electrostatic repulsive force, hydration repulsive force) and particle surface properties. However, there are few studies on the influence of different soil conditioners on the reclaimed soil internal forces and its relationship with the aggregate stability. Therefore, we selected six different treatments of organic fertilizer (TO), fly ash (TF), maturing agent (TM), maturing agent + organic fertilizer (TMO), fly ash + organic fertilizer (TFO) and control (CK) to conduct a 5-year field experiment to study the effects of reclaimed soil particle interaction forces and surface characteristics on aggregate stability under the treatment of different soil conditioners. The results showed that with the application of soil conditioners, the soil organic matter (SOM), specific surface area (SSA), surface charge (σ0), cation exchange capacity (CEC), aggregate mean weight diameter (MWD) and Hamaker constant increased gradually, while the pH value decreased slightly. In particular, the MWD under the treatments of TFO and TMO increased by 150.3% and 65.6% respectively compared with that under the CK treatment. With the increasing application of soil conditioners, the electrostatic repulsive force and van der Waals attractive force between reclaimed soil particles increased constantly, but the net resultant force between particles decreased and the net attractive force increased continuously, thus improving the aggregate stability. Therefore, there is a significant negative correlation between the net resultant force among reclaimed soil particles and MWD and CEC. In addition, 10−2 mol L-1 is the critical concentration that affects the reclaimed soil internal force, and the organic-inorganic treatments of TFO and TMO can improve the net resultant force better. In a word, the particle interaction forces are important factors affecting the reclaimed soil structural stability, and this study provides a scientific reference for the rational selection of soil conditioners and its interaction force mechanism in the reclaimed soil improvement.

Microbial driving mechanism of soil conditioner on reducing cadmium uptake by rice and improving soil environment

Soil conditioners can reduce the transfer of heavy metal ions from the soil to crops and play a crucial role in safe food production. However, it remains unclear how soil conditioners reduce cadmium (Cd) accumulation in rice (Oryza sativa L.). In this study, five soil conditioners (U-, N-, T-, L-, and C-type) commonly used in China were selected, and the effects of soil conditioners on bacterial and fungal community diversity, soil enzyme activity, soil pH, and organic matter content were investigated through field experiments in two sites. The Cd content of rice was significantly reduced by 32.4–55.1 % in site I and 16.0–33.3 % in site II under the five soil conditioner treatments. The decrease in Cd content was related to the increase in soil pH, organic matter content, and Cd fixation-related flora caused by soil conditioner application. U-, N- and C-type conditioners increased soil pH, inducing an increase in the relative abundances of microbial populations related to Cd sorption and sequestration (Firmicutes, Nitrospirota, Actinobacteriota, and Methylomirabilota). U-, T-, and L-type conditioners increased soil organic matter, causing an increase in the relative abundance of microbial flora associated with macromolecule degradation, including bacteria (Acidobacteriota and Chloroflexi) and fungi (Ascomycota and Basidiomycota). Conditioner application reduced the availability of soil Cd; indirectly promoted the increased abundance of beneficial soil bacteria; and increased the activities of invertase, urease, dehydrogenase, catalase, and acid protease. In conclusion, soil conditioner reduces the effective soil Cd by adjusting soil pH and organic matter content, increasing Cd-passivating flora and Cd-tolerant flora. Soil conditioner also increases the abundance of other beneficial flora, enhances soil enzyme activity, promotes the microecological balance of soil under Cd stress, and finally reduces Cd accumulation in rice.

Correlation of secondary salinization and soil conditioning in vegetable production under irrigation with saline water

Secondary salinization is a main problem around the world due to climate change and intrusion of salts in the soil by improper irrigation. Our aim was to study the soil salinization process by simulating vegetable production under irrigation with saline water (total soluble salt content ⁓700 mg L-1). We tested 6 different technologies of soil conditioner application and 3 vegetable crops with different sensitivity to salinity in a small plot experiment set up on a meadow chernozem soil. During the irrigation season in 2020, we regularly measured the electric conductivity (ECa) and the soil moisture content (v/v%) in the topsoil (0.1 m) and analysed these parameters with Pearson’s bivariate correlation method. As our hypothesis, we expected that there is correlation (PCC) among ECa, soil moisture content, soil conditioning, and providing the possibility to quantify the secondary salinization process. We found that all the 4 biosynthetic soil conditioners technologies minimized the harmful effect of saline irrigation. In the case of the not salt tolerant (NT) peas, the PCC correlation was higher to compost application and control expressing more intense salinization. NT beans showed a weaker correlation with lower PCCs, which must be due to its higher root activity leading to intensive leaching resulting in a lower degree of salinization. In the case of chilli with low salt tolerance (LT), micro dosing of soil conditioners was not effective in mitigating the harmful effect of secondary salinization, only full doses decreased the PCC. The salt tolerance of the investigated vegetable crops was also manifested in the yields. We found that PCC is a suitable statistical method to understand and quantify the process of secondary salinization.

Effect of Some Soil Conditioners on Water-Use Efficacy, Growth, and Yield of Date Palm Siwi Grown in Sandy Soil under Different Irrigation Regimes to Mitigate Climate Change

A field experiment was carried out at Al-Bahariya Oasis, Giza, Egypt, during three successive seasons to find out the effect of application of bentonite (BN) as a natural clay deposit at either 6 or 12 kg/palm tree and humic substances (HS) as organic amendment at either 0.75 or 1.0 L/palm tree incorporated with Bacillus polymyxa (BP) as a biofertilizers at 14 and 28 mL/L rates on growth, yield, and fruit weight of 10-year-old Siwi date palm cv. (Phoenix dectylifera L.). Siwi trees were cultivated in sandy texture soil at a distance of 8 × 8 m and were irrigated with 100%, 85%, and 70% of ET crop. Effects of the previous treatments on growth, date palm crop, soil properties, water relations, water-use efficiency (WUE), and economic return were also studied. The obtained results showed that the mean values of leaf length, leaflet length and width, fruit set%, bunch weight, yield/palm, yield/fed, fruit weight, flesh weight, and fruit pulp weight were increased in response to the different individual and combined treatments used in this study with various significance levels compared to the control treatment means in the studied three seasons. However, the superiority was for combining between amending the sandy soil with either low concentrations of BN (6 kg/tree) + HS (0.75 Liter/tree) + BP (14 mL/L) or high concentrations of BN (12 kg/tree) + HS (1.0 L/tree) + BP (28 mL/L) and irrigation with 85% of ETc water level, as such combinations attained the highest values in most of the mentioned values over both the sole and combined treatments in the studied three seasons. Furthermore, the results indicated that the highest monthly ETc values occurred during June and July months, while the lowest values occurred during December and January months. Additionally, water productivity (WP) increased considerably by reduction of water quantity (70% ETc) associated with soil conditioner treatment (BN.12 kg +HS 1 L + BP. 28 mL/L), and values were 2.17, 2.25, and 2.27 kg fruit/m3 of water irrigation during the growing seasons, respectively. The highest net return was attributed to irrigation with 85% of ETc water level along with the application of soil conditioners at high rates. Accordingly, it is advisable to apply the soil conditioners of bentonite (at 6 or 12 kg/tree) and humic substances (at either 0.75 or 1.0 L/tree) with B. polymyxa (at either 14 or 28 mL/L) plus irrigation with either 85% or 70% of ETc water level to obtain the best growth, highest yield, (WP), and gross return from var. Siwi date palm grown under an oasis agro-system.

Biochar, Ochre, and Manure Maturation in an Acidic Technosol Helps Stabilize As and Pb in Soil and Allows Its Vegetation by Salix triandra

Past mining extraction activities still have a negative impact in the present time, the resulting metal(loid) contaminated soils affecting both the environment and human health. Assisted phytostabilization technology, combining soil conditioner application to immobilize metal(loid)s and plant growth to reduce erosion and leaching risks, is a useful strategy in the restoration of metal(loid) contaminated lands. However, contaminants will respond differently to a particular amendment, having their own specific characteristics. Therefore, in multi-contaminated soils, soil conditioner combination has been suggested as a good strategy for metal(loid) immobilization. In the present study, in a mesocosm experiment, organic (biochar and manure) and inorganic (ochre) amendments were evaluated in single and combined applications for their effect on metal(loid) stabilization and Salix triandra growth improvement, in an arsenic and lead highly contaminated soil. Specifically, the effects of these amendments on soil properties, metal(loid) behavior, and plant growth were evaluated after they aged in the soil for 6 months. Results showed that all amendments, except biochar alone, could reduce soil acidity, with the best outcomes obtained with the three amendments combined. The combination of the three soil conditioners has also led to reducing soil lead availability. However, only ochre, alone or combined with the other soil fertilizers, was capable of immobilizing arsenic. Moreover, amendment application enhanced plant growth, without affecting arsenic accumulation. On the contrary, plants grown on all the amended soils, except plants grown on soil added with manure alone, showed higher lead concentration in leaves, which poses a risk of return of lead into the soil when leaves will shed in autumn. Considering that the best plant growth improvement, together with the lowest increase in lead aerial accumulation, was observed in manure-treated soil, the addition of manure seems to have potential in the restoration of arsenic and lead contaminated soil.

Organic spelt production systems: Productive and financial performance in three orographic regions

A two-year field trial was conducted to study the effects of biohumus, biofertiliser, and soil conditioner application on spelt grain yield in different regions (plain, hilly, and mountainous regions) in Serbia. An analysis of economic efficiency indicators of spelt production in organic farming systems was also performed. The field experiment had a randomised complete block design with three replicates in each of the three regions. One winter spelt cultivar was also studied. The largest differences in spelt yield compared to control were found in the plain region in the biohumus + biofertiliser treatment (28.0%) and the hilly region in the organic fertiliser + zeolite treatment (28.8%). The differences in grain yield between control and treatment conditions in the mountain region were insignificant. Analysis of the economic effects of organic spelt production found a significantly lower gross margin in treatments with expensive organic fertilisers (3955.05 and 1104.75 € ha–1) than the control (5094.31 and 1833.85 € ha–1), leading to the conclusion that their application was not economically justified despite the increases in grain yield. The highest production costs (3569.71 € ha–1) were observed in treatments in the hilly region, resulting in the lowest benefit-cost ratio (0.1), while the greatest benefit-cost ratio was recorded in treatments in the mountainous region (2.1). Following the economic analysis results, a significant negative correlation between the benefit-cost ratio and the total production costs (r= –0.91**) was determined and a positive correlation between the gross margin and grain yield (r=0.66*). These results lead to the conclusion that the management strategy of spelt production in organic farming systems should be harmonised with the soil and agro-ecological characteristics of the region and directed at decreasing the costs and share of external inputs. In this case, organic spelt production can be economically profitable. Highlights - Organic fertilisers and soil conditioners affect spelt grain yield. - The analysis of the economic effects of organic spelt production concluded that fertiliser application was not economically justified despite the increases in grain yield. - Treatments in the plain region displayed the best production results compared to mountain region treatments, but these did not have the best benefit-cost ratio. - Knowledge of production costs is an important element in improving the economic efficiency of organic farming systems.

Performance of AquaCrop Model for Maize Growth Simulation under Different Soil Conditioners in Shandong Coastal Area, China

Evaluating the performance of AquaCrop models under the drip irrigation of maize with soil conditioners is of great significance for improving coastal saline–alkali land crop management strategies. This study aimed to evaluate the performance of an AquaCrop model for maize growth simulation under different soil conditions (humic acid (HA) and sodium carboxymethyl cellulose (CMC)) and dosages and different levels of irrigation in the Shandong coastal saline–alkali area, China, and to optimize the amount of irrigation. Three years of experiments were carried out in the growing season of maize (Ludan 510) in 2019, 2020, and 2021. The dosages of HA were 5, 15, 25, and 35 g/m2, the dosages of CMC were 1, 2, 3, and 5 g/m2, and the levels of irrigation from 2019 to 2021 were all 120 mm. The model was calibrated with data from 2019, and the model was verified with data from 2020 to 2021, according to the recommended corn parameters in the AquaCrop model manual. The results showed that the model had a good simulation effect on canopy coverage, with a root-mean-square error (RMSE) of less than 15.2%, and the simulated aboveground biomass and yield were generally low. The simulated value of soil water content was generally high, with some treatments having errors of more than 15.0%. The simulation effect of irrigated maize from 2019 to 2020 was better than maize in 2021. The simulation effect of HA was better than that of CMC, while the simulation effect of a low-gradient modifier was better than that of high-gradient conditioner when compared with CMC. In conclusion, the AquaCrop model could be a viable method for predicting maize development under different soil conditioners in this area. The suitable levels of irrigation under HA and CMC treatments were 47.0–65.9 mm and 61.0–92.4 mm, respectively, according to the principle of high yield and water use efficiency. The results provided a reference for optimizing the drip irrigation of maize under the application of soil conditioners in coastal saline–alkali areas.