Effects Of Organic Amendments Research Articles

An Investigation into the Effects of Organic Amendments in a Saline Environment on Soil Chemical Characteristics, Growth, and Yield of Rice in the South of Senegal

Context of the Study: The use of organic amendments could help increase the resilience of lowland rice in Lower Casamance to salinity. The aim of this study was to test the effect of different organic amendments (biochar and compost) on the salinity tolerance of lowland rice in Basse Casamance.
 Objective: The aim was to test the effect of different organic amendments on the salinity tolerance of rice in the lowlands of the villages of Selecky and Essyl in Lower Casamance.
 Methodology: A split-plot design was adopted with two factors: the type of organic amendment with 4 treatments (biochar, compost, compost + biochar and the control) and salinity with two treatments (salted and unsalted zones). These treatments were repeated 3 times in two consecutive years, 2020 and 2021, at the Selecky and Essyl sites. Physico-chemical characteristics as well as rice growth and production parameters were studied.
 Results: In the saline zone, soil amendments significantly increased the number of tillers and the height of rice plants compared with controls (p<0.05). Average rice yield and plant biomass were significantly higher in the amended plots at Selecky in both experimental years (p<0.05). At Essyl, on the other hand, height, number of tillers, rice yield and plant biomass were lower in the 2nd year of experimentation. Organic amendments had a significant effect (p<0.05) on rice production and yield parameters in the salt zone.

The effect of organic matter amendments on soil surface stability in conventionally cultivated arable fields

AbstractIn this study, new and traditional organic wastes (green waste compost, farmyard manure (FYM), anaerobic digestate or straw) were ploughed into an arable field experiment at a range of rates (1–3 t C ha−1) and under spring and winter cropping rotations for 5 years. The stability of the soil surface structure (<5 cm) was assessed in Years 3, 4 and 5 to guide the use of organic wastes in arable field management. Aggregate stability was determined by immersing each soil sample in water (fast‐wetting test, relevance to summer storms) and measuring the size distribution of the aggregates (mean weight diameter, MWD). The MWD value was compared with the different classes of aggregate stability (very stable, stable, medium, unstable or very unstable) to classify each result. All the arable field samples were classified as unstable, and there were no significant differences (p > .05) in MWD after any treatment. Potentially, this approach is too imprecise to detect differences, so pore‐scale analyses using CT scanning were used. There were no significant differences in porosity or pore shape (features associated with microbial activity) between the control and organic waste treatments. The results contradicted published data from the Broadbalk experiment (established in 1843), which was the basis for this study, so its soils were studied to understand this discrepancy. Broadbalk soils were classified as unstable, including soils treated with annual FYM applications. Instead, we found a significant relationship between MWD and clay content and previous interpretations had not taken this variable (23%–39% clay content) texture into consideration. In conclusion, to achieve a stable soil surface structure, a 150% improvement in aggregate stability would be needed here and ploughing in organic wastes was not a successful management approach on these arable field experiments.

Can Plant Nutrient Dynamics and Indian Mustard Yield Be Influenced by Addition of Organic Amendments Under Saline Sodic Soils?

ABSTRACT Arid and semi-arid regions are having huge potential for agricultural production but also have limitations of salinity and alkalinity. By mediating rhizospheric environment with the application of organic and inorganic nutrient sources, Indian mustard yield could be enhanced in these areas. For this, a field experiment was conducted to study the effect of organic (FarmYard Manure and vermicompost) and inorganic (urea) amendments with irrigation water of different sodium absorption ratios (SAR; 6, 10, 20 and 30). The experiment was laid out in a split-plot design (SPD) with 24 treatment combinations keeping different SAR in main plots and organic and inorganic nitrogen sources in sub plots. Experiment results revealed that increasing SAR levels reduced the availability of major plant nutrients, i.e. nitrogen, phosphorus and potassium. The soil organic carbon mineralization rate and Indian mustard seed yield were also deceased with increasing levels of SAR. Application of nitrogen through farm yard manure (FYM) and vermicompost decreased the electrical conductivity (EC), pH, and enhanced the cation exchange capacity (CEC) of soil solution. Application of 50% recommended dose of nitrogen (RDN) through urea and 75% through vermicompost produced maximum seed and stover yield of Indian mustard. Thus, supply of recommended dose of nitrogen as inorganic (50%) and organic (75%) sources improved the soil health and Indian mustard yield of arid lands with sodic irrigation water. The use of organic sources in place of sole application of N fertilizer may be a potential management option in sodic groundwater irrigated areas for enhancing mustard crop yield.

Positive Effects of Organic Amendments on Soil Microbes and Their Functionality in Agro-Ecosystems.

Soil microbial characteristics are considered to be an index for soil quality evaluation. It is generally believed that organic amendments replacing chemical fertilizers have positive effects on changing microbial activity and community structure. However, their effects on different agro-ecosystems on a global scale and their differences in different environmental conditions and experimental durations are unclear. This study performed a meta-analysis based on 94 studies with 204 observations to evaluate the overall effects and their differences in different experimental conditions and duration. The results indicated that compared to chemical fertilizer, organic amendments significantly increased total microbial biomass, bacterial biomass, fungal biomass, Gram-positive bacterial biomass and Gram-negative bacterial biomass, and had no effect on the ratio of fungi to bacteria and ratio of Gram-positive bacteria to Gram-negative bacteria. Meanwhile, land use type, mean annual precipitation and soil initial pH are essential factors affecting microbial activity response. Organic-amendment-induced shifts in microbial biomass can be predominantly explained by soil C and nutrient availability changes. Additionally, we observed positive relationships between microbial functionality and microbial biomass, suggesting that organic-amendment-induced changes in microbial activities improved soil microbial functionality.

Organic amendments perform better than inorganic amendments in reducing the absorption and accumulation of cadmium in lettuce.

The main purpose of applying organic or inorganic amendments is to guarantee crop safe production in heavy metal contaminated soil. However, previous studies showed that the effects of organic or inorganic composite amendments on the cadmium (Cd) concentration of lettuce (Lactuca sativa var. ramosa Hort) were inconsistent. Accordingly, a sixty-day pot experiment was carried out to examine the impacts of the inorganic materials (lime, L and zeolite, Z), organic materials (biochar, B and compost, C), and their combination on the immobilization of Cd in soil and its uptake by lettuce. The objective was to identify the most suitable soil amendment combination that promotes safe lettuce production. The results revealed that the combined application of BC, LZC, and LBC significantly increased the plant height by 11.09-28.04% and fresh weight by 183.47-207.67%. This improvement can be attributed to enhanced soil quality, such as increased dissolved organic carbon (DOC) by 70.19-80.42%, soil respiration (SR) by 29.04-38.46%, and soil microbial carbon content (SMC) by 36.94-46.63%. Compared to inorganic fertilizers and their combination with organic amendments, organic amendments had a significant impact on reducing shoot Cd concentration by 33.93%-56.55%, while increasing the activity of catalase by 138.87-186.86%. And soil available Cd measured by diffusive gradients in thin-films (DGT-Cd) decreased 24.73-88.13% in all treatments. Correlation analysis showed that plant Cd concentration was significantly correlated with soil pH, SR, cation exchange capacity (CEC), DOC and SMC. These results demonstrated that organic amendments, especially the combination of biochar and compost, have greater potential than inorganic amendments and inorganic-organic combinations for realizing safe production of lettuce and improving soil quality in the Cd moderately contaminated acid farmland.

Influence of organic amendments and different levels of nitrogen on production potential, economics and energetics of rice (Oryza sativa)–wheat (Triticum aestivum) cropping system

A field experiment was conducted during 2018–19 and 2019–20 at the Punjab Agricultural University, Ludhiana and Research Station, Dyal Bharang, Amritsar, to study the influence of organic amendments and nitrogen levels on rice (Oryza sativa L.)-wheat (Triticum aestivum L.) cropping system. In rice, main plot treatments were green manuring (GM), farmyard manure (FYM), poultry manure (PM) and control (NA). Nitrogen levels in sub-plots comprised control (N1), 50 kg N/ha (N2),75 kg N/ha (N3) and 100 kg N/ha (N4). In wheat, residual effect of organic amendments and nitrogen levels applied to preceding rice was evaluated. The statistically highest grain yield of rice was obtained with PM (8.29 t/ha), followed by GM (8.02 t/ha) which was at par with FYM (7.90 t/ha). The lowest rice grain yield was obtained with NA (5.16 t/ha) and its subsequent wheat crop recorded significantly higher grain yield with PM (6.14 t/ha), followed by FYM (5.88 t/ha) and GM (5.72 t/ha). Treatment N4 recorded significantly higher yield than N2 and was at par with N3. Maximum rice-equivalent yield (14.7 t/ha) was recorded with PM, while the highest energy-use efficiency of rice was recorded with green-manure (16.2) as compared to the other treatments. Treatment with the application of PM and N4 recorded significantly the highest economic parameters and system productivity for both rice and wheat crops compared to rest of the treatments.

Contrasting effects of different organic amendments on the microbial responses to extreme temperature changes

Soil organic amendments can change microbial communities, potentially impacting their resilience to environmental stresses and, consequently, their transformation of soil carbon and nitrogen. While several studies have investigated the impact of a few organic amendments on microbial resilience to stresses in the form of absolute change in environmental conditions, the potential stress effects of different rates of change have received much less attention. The rate of change in environmental properties such as temperature may induce different microbial stress responses, given the reliance of microbial defensive mechanisms on time-dependent signalling and activation processes. In this research, we explored the relevance of the rate of temperature change as a microbial stressor and evaluated the potential use of organic amendments in steering soil ecological response. We monitored the changes in microbial properties and concentrations of different carbon and nitrogen fractions to temperature change treatments of 2.5 and 30 °C/d after the application of three commonly available rural organic amendments to a podzol soil in a laboratory incubation study. Results showed significant effects of the temperature treatments on bacterial and total microbial DNA concentrations, as well as on dissolvable and insoluble carbon and nitrogen ratios regardless of the organic amendment treatment. Temperature impacts on respiration rates, priming rates and the concentration of soil hot water extractable carbon and nitrogen differed depending on the organic amendment treatment. Results demonstrated that compost-amended soils were least sensitive to the temperature treatments, while grasses and fermented grasses treatments were generally more sensitive while showing opposite responses. Our findings indicate that organic amendments might be utilized to manipulate the impact of environmental stresses on soil carbon and nitrogen concentrations, and highlight the need for future research to investigate the relevant ecological properties and mechanisms.

Temporal and spatial characteristics of paddy soil potassium in China and its response to organic amendments: A systematic analysis

Understanding the role of organic amendments on soil potassium (K) distribution characteristics in Chinese paddy fields, we conduct a meta-analysis to explore the effect of organic amendment under different climatic and management practices. The meta-analysis consisted of 376 published papers from which 1294 paired observations were collected to evaluate the response of exchangeable K (EK) to different organic amendments in Chinese paddy soils. The results showed that EK concentration presented great variations (coefficient of variation: 44.5 %) and followed a decreasing trend from North to South and West to East, while higher EK concentration was detected in Northeast China, in 2020 s. Compared to the 2000s, the soil EK concentration in the 2020s significantly increased for the Northeast, Southwest, and East China. The highest EK concentrations were observed in Northeast (164 mg kg−1) and lowest values were observed in South China (71 mg kg−1). In case of organic amendments soil EK significantly increased compared to chemical fertilizers (CF), whereas the total K showed no significant differences in CF plus manure (CFM). The effects of organic amendments on soil K concentration revealed significant difference under various soil textures, cropping systems, and organic material types. The boosted regression trees analysis confirmed that the difference in K input for CF and CFM, and available phosphorus (AP) for straw combined with CF were the most influential variables on the variation of soil EK concentration. The structural equation modeling illustrated that organic amendments can directly and indirectly affect soil EK variation through increased K input and the regulation of crop K uptake and soil properties (total nitrogen and AP), respectively. These findings indicate that the organic amendments presented great potential for solving paddy soil K deficiency, as well as the types of organic material and soil properties should be carefully considered for greatest K use efficiency and lowest resource waste.

Effect of Organic Amendments and Arbuscular Mycorrhizal Fungi on Plant Growth, Yield And Quality of Strawberry

An experiment was conducted at the research field and the laboratory of the Department of Horticulture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur-1706, Bangladesh from October 2018 to March 2019 to investigate the effect of organic amendments and arbuscular mycorrhizal fungi (AMF) on growth, yield and quality of strawberry var. BARI Strawberry-2. The experiment was laid out in RCBD design with three replications taking into eight treatments including control viz., T1: vermicompost (324 g/pot), T2: biochar (324 g/pot), T3: AMF (324g/pot), T4: vermicompost (162 g/pot) + biochar (162 g/pot), T5: biochar (162 g/pot) + AMF (162 g/pot), T6: vermicompost (162 g/pot) + AMF (162 g/pot), T7: vermicompost (108 g/pot) + biochar (108 g/pot) + AMF (108 g/pot) and T8: control (no manure or AMF). Results of the study revealed that the highest plant height (18.40 cm), number of leaves/plant (37.00), leaf area (578.60 cm2), root length (24.50 cm), fresh and dry weight of root (30.00 g and 12.5 g) and shoot (131 g and 41.00 g), number of flowers (32.67/plant) and fruits (22.33/plant), single fruit weight (21.60 g) and yield/plant (401.99 g) were recorded in T6 treatment which was significantly superior to all other treatments. Among the fruit nutrient and mineral contents, ascorbic acid (36.20 mg/100 g), total sugar (9.10 g/100 g), Ca (11.87 mg/100 g), Mg (36.67 mg/100 g) and K (73.33 mg/100 g) were also measured maximum in T6 treatment. On the other hand, TSS (8.49 %) and water percentage in fruit (66.95 %) were found significantly higher in T7 and T4 treatments, respectively while the lowest was estimated in the control. A significant influence of T6 treatment [vermicompost (162 g/pot) + AMF (162 g/pot)] on growth, yield and qualitative characters was observed. Therefore, vermicompost and AMF combination has reflected a positive impact on good quality strawberry production. However, it needs to be investigated under the open field condition before conferring recommendation to the end users. Ann. Bangladesh Agric. (2022) 26 (2) : 71-82

The effect of organic amendments on soil microbial activity and yield of faba bean (Vicia faba) inoculated with Rhizobium leguminosarum

A two year (2021 and 2022) field experiment was conducted to study the effect of organic amendments on soil microbial activity and yield of faba bean (Vicia faba L.) inoculated with Rhizobium leguminosarum at Savadkuh in the north of Iran as a factorial experiment based on a randomized complete block design with 3 replications. The treatments included seed inoculation at two levels (inoculation with Rhizobium leguminosarum bv. Viciae and non-inoculation) and fertilization at 5 levels [cattle manure (CM) @30 tonnes/ha, vermicompost of manure (VM) @20 tonnes/ha, vermicompost of Azolla (VA) @20 tonnes/ha, chemical fertilization based on soil analysis (NP), and control]. Present study found that the soil microbial biomass carbon (C) increased over time until 120 daysafter emergence (DAE). The maximum microbial biomass-C (441 mg/g soil) and bacterial count (545 × 105 cfu/ml) were obtained from the inoculated VA treatment. The highest yields of pods (14400 kg/ha) and seeds (1266 kg/ha) were obtained when the use of vermicompost was accompanied by inoculation of R. leguminosarum, so that in plants without inoculation, the use of vermicompost increased the yield of pods compared to the NP by 34% and compared to CM, it increased by 44%, but this increase was 39% and 19% for inoculated plants compared to NP and CM, respectively. Although the seeds of vermicomposted plants showed lower iron (Fe) content, they showed higher nitrogen (N), phosphorus (P), copper (Cu) and zinc (Zn) content than other plants. In total, the results showed a significant improvement in soil microbial activity, absorption of nutrients and bean yield by using vermicompost(especially VA) under R. leguminosarum inoculation. Therefore, in the low-fertile soils of Iran, the combined use of high-quality vermicompost together with R. leguminosarum can strengthen soil microbial activity and bean production and be a suitable alternative to chemical fertilizers.

Effect of Various Organic Amendments on Growth of Ginger (Zingiber officinale Rosc.) under Coconut Cropping System

Ginger is one of the most important spices which has been utilised for centuries as a food flavouring agent as well as a key ingredient in pharmaceutical products. Since organic food is considered to be healthy by the consumers, the demand for organic products are increasing and organic farming is gaining popularity worldwide. As ginger is a shade loving crop, it can be grown well under coconut ecosystem. Therefore, a study was undertaken to evaluate the effect of organic amendments on the growth and yield of ginger (IISR Varada) under coconut based cropping system. The results revealed that the maximum plant height (72.08 cm) was recorded in T8 - poultry manure + microbial consortium followed by T9 - goat manure + microbial consortium (71.86 cm), the number of leaves per plant were maximum (86.57) in the combined application of poultry manure and microbial consortium (T8) followed by T6 - FYM + microbial consortium (83.03), the largest leaf length (26.75 cm) was observed in T8 - poultry manure + microbial consortium followed by T9 - goat manure + microbial consortium (25.83 cm) and similarly, the largest leaf width was observed in T8 - poultry manure + microbial consortium (3.92 cm) followed by T9 - goat manure + microbial consortium (3.87 cm). The application of T8 - poultry manure + microbial consortium produced more number of tillers (9.48) followed by T6 - FYM + microbial consortium (9.23). Thus, the combined application of poultry manure and microbial consortium is considered as the best and effective organic amendment for ginger under coconut based cropping system.

Assessing the Effects of Organic Amendments on Soil Fertility

In light of the challenges posed by altering climate patterns and increasing population increase, soil degradation represents a substantial danger to the sustainability of agricultural practices and the safeguarding of food supplies. Traditional agricultural techniques, such as genetic modification and excessive chemical treatments, have been a contributing factor in the deterioration of soil health and production. In order to address this issue, soil amendments have emerged as an important intervention that can increase both the quality of the soil and the production of crops. An investigation of the many ways in which organic and inorganic soil amendments influence the chemical and physical characteristics of soil is presented in this article. Organic additions, such as compost and farmyard manure (FYM), improve the structure of the soil, the capacity of the soil to hold water, the pH balance, and the availability of nutrients, which in turn promotes the development of crops while maintaining their sustainability. Despite the potential advantages they offer, widespread adoption is hampered by obstacles such as competition for resources and expensive application costs, particularly in places that are still in the process of growing. A comprehensive approach to sustainable agriculture is presented by the combination of organic and inorganic fertilizers with efforts to conserve soil. When it comes to enhancing the effectiveness of soil amendments while simultaneously reducing their negative effects, quality control, and environmental management are very necessary. By implementing strategic soil management strategies, it is feasible to reduce the pace of soil deterioration and guarantee food availability for future generations.

Increasing the Efficiency of the Rice–Wheat Cropping System through Integrated Nutrient Management

The advancement of effective nutrient management strategies has been instrumental in enhancing crop productivity and economic viability. Thus, we investigated the effect of green manure and organic amendments at varying nitrogen levels in rice and their residual effect on wheat crops. A two-year research study (2018–2019 and 2019–2020) was conducted at two distinct locations: Punjab Agricultural University in Ludhiana and a Research Station in Dyal Bharang, Amritsar. The experimental design employed was a split-plot design. The main plot treatments consisted of four treatments (green manuring, farmyard manure, poultry manure, and no organic amendment (control)) and four subplot treatments (No N control, 50 kg N ha−1, 75 kg N ha−1, and 100 kg N ha−1), replicated four times in the rice crop, and its residual effect was studied in wheat. The study found that applying organic amendments at different nitrogen levels significantly increased rice–wheat productivity, growth, yield qualities, nutrient uptake, and efficiency (p < 0.05). Poultry manure increased rice grain yield more than other modifications. It significantly increased grain yield by 67.3% and 61.4% over the control in both years of the research. Poultry manure (41.9 kg, 60.0%) increased AE (kg grain kg−1 N uptake) and ANR (%) compared to control due to higher total N (177.4 kg ha−1), P (31.6 kg ha−1), and K (179.6 kg ha−1). Grain production was positively correlated with total nitrogen (N), phosphorus (P), and potassium (K) intake (r = 0.992**, 0.931**, and 0.984**, respectively). Total N uptake was positively correlated with P and K uptake (r = 0.963** and 0.991**, respectively). Poultry manure improved soil health by increasing total microbial count and alkaline phosphatase activity. In the subsequent wheat crop, rice grown with poultry manure yielded 24.3 and 24.4 percent more than no organic amendment control in rabi 2018–2019 and 2019–2020. The findings suggest that poultry manure and 100 kg N ha−1 or 75 kg N ha−1 afforded equivalent yields. This shows that even less nitrogen may be enough to boost rice and wheat yields.

Effects of organic amendments on soil bacterial community structure and yield in a saline‐sodic soil cropped with rice

AbstractOrganic improvement measures play a crucial role in the reclamation of saline‐sodic soil. However, there is still a limited understanding regarding the relationships between soil microbes and soil properties and crop yield in response to the application of these organic materials to saline‐sodic soils. In a field trial, the following treatments were carried out: no modifier input (CK) and compound lignite organic modifier 30 t/ha (LOM) with 2 years of rice cultivation, no modifier input (RF) with 5 years of rice cultivation, and the full amount of straw was returned to the field with rice‐duck farming (SW). Compared with RF and CK, the SOM content in the 0–20 cm soil layer of SW and LOM was significantly increased by 4.600 and 5.020 g kg−1, respectively, while the total alkalinity and pH were significantly decreased. In the 20–40 cm soil layer, the LOM treatment resulted in decreased pH and total alkalinity compared with other treatments. Overall, changes in soil microbial structure changes were significantly associated with SOM and pH levels. In the 0–20 cm soil layer, the LOM treatment significantly increased the relative abundance of Proteobacteria, while SW treatment significantly increased the relative abundance of Bacteroidetes and Firmicutes compared with CK. Moreover，the relative abundances of Longobacteriaceae of Bacteroidetes, Hydrogenaceae, and Xanthomonas of Proteobacteria were positively correlated with crop yield. The yields of SW and LOM were 6985.587 and 7879.910 kg ha−1, respectively. These results demonstrate that implementing comprehensive organic improvement measures can enhance the properties of saline‐sodic soil and increase crop yield, with lignite composite organic amendments may be more suitable for sustainable agricultural development.

Effective combination of arugula vermicompost, chitin and inhibitory bacteria for suppression of the root-knot nematode Meloidogyne javanica and explanation of their beneficial properties based on microbial analysis.

Root-knot nematodes (Meloidogyne spp.) are dangerous parasites of many crops worldwide. The threat of chemical nematicides has led to increasing interest in studying the inhibitory effects of organic amendments and bacteria on plant-parasitic nematodes, but their combination has been less studied. One laboratory and four glasshouse experiments were conducted to study the effect on M. javanica of animal manure, common vermicompost, shrimp shells, chitosan, compost and vermicompost from castor bean, chinaberry and arugula, and the combination of arugula vermicompost with some bacteria, isolated from vermicompost or earthworms. The extract of arugula compost and vermicompost, common vermicompost and composts from castor bean and chinaberry reduced nematode egg hatch by 12-32% and caused 13-40% mortality of second-stage juveniles in vitro. Soil amendments with the combination vermicompost of arugula + Pseudomonas. resinovorans + Sphingobacterium daejeonense + chitosan significantly increased the yield of infected tomato plants and reduced nematode reproduction factor by 63.1-76.6%. Comparison of chemical properties showed that arugula vermicompost had lower pH, EC, and C/N ratio than arugula compost. Metagenomics analysis showed that Bacillus, Geodermatophilus, Thermomonas, Lewinella, Pseudolabrys and Erythrobacter were the major bacterial genera in the vermicompost of arugula. Metagenomics analysis confirmed the presence of chitinolytic, detoxifying and PGPR bacteria in the vermicompost of arugula. The combination of arugula vermicompost + chitosan + P. resinovorans + S. daejeonense could be an environmentally friendly approach to control M. javanica.

Co-application of biochar and organic amendments on soil greenhouse gas emissions: A meta-analysis

Biochar has been shown to reduce soil greenhouse gas (GHG) and increase nutrient retention in soil; however, the interaction between biochar and organic amendments on GHG emissions remain largely unclear. In this study, we collected 162 two-factor observations to explore how biochar and organic amendments jointly affect soil GHG emissions. Our results showed that biochar addition significantly increased soil CO2 emission by 8.62 %, but reduced CH4 and N2O emissions by 27.0 % and 23.9 %, respectively. Meanwhile, organic amendments and the co-application with biochar resulted in an increase of global warming potential based on the 100-year time horizon (GWP100) by an average of 18.3 % and 26.1 %. More importantly, the interactive effect of biochar and organic amendments on CO2 emission was antagonistic (the combined effect was weaker than the sum of their individual effects), while additive on CH4 and N2O emissions. Additionally, our results suggested that when biochar is co-applied with organic amendments, soil GHG emissions were largely influenced by soil initial total carbon, soil texture, and biochar feedstocks. Our work highlights the important interactive effects of biochar and organic amendments on soil GHG emissions, and provides new insights for promoting ecosystem sustainability as well as mitigating future climate change.

Effects of organic amendments on soil hydraulic characteristics in the Mollisols of Northeast China

AbstractSoil degradation in the Mollisol region of Northeast China is ubiquitous partly due to poor soil hydraulic characteristics. Improving soil hydraulic characteristics thus delivers benefits to soil sustainability. In this study, the effects of organic amendments on soil hydraulic characteristics were explored at the laboratory scale. Soil samples were subjected to three low‐cost and eco‐friendly organic amendments, including corn straw juice (CSJ), fulvic acid (FA), and humic acid (HA). The soil infiltration capacity, soil water characteristic curve (SWCC) and soil water retention capacity were determined by using a steel‐ring method and a centrifuge method. The parameters of the SWCC were fitted by a van Genuchten (VG) model, and the specific water capacity [C(h)] was calculated. In addition, bulk density (BD), macroporosity, and soil organic matter (SOM) were measured, and the relationships between the variables and processes were evaluated. The results indicated that the soil infiltration capacity (i.e., initial infiltration rate, cumulative infiltration, and steady infiltration rate) was significantly increased in the CSJ and FA treatments (p < 0.05) but decreased in the HA treatment compared to the control (CK) treatment. All the selected organic amendments improved the soil water release and supply capacity, and the CSJ2 treatment showed the best effect. The incorporation of CSJ, FA, and HA significantly improved the soil water retention capacity by increasing the saturated soil water content, field capacity, and plant available water capacity (p < 0.05). Such changes were significantly associated with macroporosity and SOM (p < 0.05). In this sense, our results showed that the CSJ treatment with 4 L m−2 and 50% volumetric concentration could be an effective soil amendment to improve the soil hydraulic characteristics in Mollisols and deserves further research.

Effect of organic amendments on termite infestation in chickpea

The field experiment was conducted at the Research farm, Agriculture Research Station, Swami Keshwanand Rajasthan Agricultural University, Bikaner, during Rabi season in randomized block design with nine treatments, including the control. Out of the seven organic amendments, tested against termites in chickpea, the application of neem cake recorded the lowest 9.97 per cent termite damaged plants, followed by vermicompost (10.43). The highest termite damaged plants (19.53) were observed in plots treated with FYM followed by groundnut cake treated plots (19.47). The maximum grain yield (1325 kg ha-1) was obtained from the plots treated with neem cake, followed by vermicompost (1205 kg ha-1). The minimum yield (1060 kg ha-1) was obtained from the plots treated with FYM. The maximum profit (Rs 8790 ha-1) was obtained from the treatment of vermicompost, followed by poultry manures (Rs 7010 ha-1). The highest incremental cost-benefit ratio (ICBR) of 0.96 was obtained from vermicompost followed by poultry manures (0.69).

Biochar, manure and superabsorbent improve the physical quality of saline‐sodic soil under greenhouse conditions

AbstractThe increasing salinization and sodification of soils in drylands and irrigated systems present a great challenge to agricultural production and threaten soil quality. There is an urgent need to investigate potential strategies to remediate soils that are threatened by these processes. To address this challenge, the current study investigated the effects of organic and inorganic amendments and leaching fraction (LF) on physical and hydraulic properties including the soil water characteristic curve (SWCC), Dexter's index of soil physical quality (SDexter), bulk density (BD), saturated hydraulic conductivity (Ks), and water repellency index (RI) in a saline‐sodic soil. A greenhouse experiment was carried out in a completely randomized design with two factors (amendment and LF). The amendments included superabsorbent (1%) (SA), zeolite modified with CaCl2 (2%) (ZC), biochar (2%) (B), biochar + manure (2%) (BM), and a control (no amendment) (CT), and combined with two levels of LF (15% and 30%). Spring wheat (Triticum aestivum, ‘UG99’) was planted in the soil columns. After harvest, undisturbed samples were collected from each column for the determination of soil properties. The results demonstrated the effectiveness of the SA and organic amendments to enhance Ks and decrease BD. There was a significant (p < 0.01) positive effect of the amendments, particularly biochar and superabsorbent on the soil pore size distribution. The SA amendment significantly increased soil water retention, especially at high matric potentials (i.e., 0 to −80 hPa). The effect of organic amendments on the SWCC was in between those of the ZC and SA amendments. The SA and BM treatments were sub‐critically water repellent, while the ZC treatment increased soil water repellency. The SA, B, and BM15 treatments exhibited very good physical quality (SDexter > 0.05). The relative air and moisture capacities were optimal in the B‐amended soil at field capacity (matric potential –330 hPa). We conclude that B, BM, and SA are suitable amendments for reducing the adverse effects of salinity and sodicity via an improvement in soil physical quality.

Effect of organic and microbial amendments on the soil structure and properties of eroded Epicalcic Chernozem from northern Bulgaria

Effect of organic and microbial amendments on the soil structure and properties of eroded Epicalcic Chernozem from northern Bulgaria