Green Manure Treatments Research Articles

Modeling the Effect of Milk Vetch-Rice Rotation on N Runoff Loss in the Middle and Lower Reaches of the Yangtze River.

The winter planting of green manure (GM) is widely used in South China to reduce chemical nitrogen (N) fertilizer use, improve soil fertility, and maintain rice yields, but its effect on N runoff loss in paddy fields remains unclear. This study combines multi-site field experiments with a process model (WHCNS-Rice) to assess how GM with reduced N fertilizer impacts N runoff loss and its forms in the Yangtze River's middle and lower reaches, considering different rainfall years. The network field experiments included four treatments: conventional fertilization (FR), conventional fertilization plus straw return (FRS), GM with a 40% N reduction (MR), and GM-straw combined return with a 40% N reduction (MRS). Monitoring the results showed that compared to the winter fallow treatment, the GM treatments reduced the peak and average total N (TN) concentrations by 11.1-57.9% (average 26.9%) and 17.1-27.3% (average 22.3%), respectively. The TN runoff loss under the GM treatment decreased by 3.50-10.61 kg N ha-1 (22.5-42.1%). GM primarily reduced the runoff loss of dissolved inorganic N (DIN), with reductions at different sites ranging from 0.22 to 9.66 kg N ha-1 (8.4-43.4%), indicating GM effectively decreases N runoff by reducing DIN. Model simulations of ponding water depth, runoff, TN concentration in surface water, and TN loss in paddy fields produced the consistency indices and simulation efficiencies of 0.738-0.985, 0.737-0.986, 0.912-0.986, and 0.674-0.972, respectively, indicating that the model can be used to evaluate water consumption and N runoff loss in the GM-paddy system. The simulations showed that GM with a 40% N fertilizer significantly reduced N runoff loss under all rainfall conditions, with the greatest reductions in wet years. Under wet, normal, and dry conditions, the GM treatments significantly reduced average TN loss by 0.37-5.53 kg N ha-1 (12.77-29.17%), 0.21-5.32 kg N ha-1 (9.95-24.51%), and 0.02-3.2 kg N ha-1 (1.78-23.19%), respectively, compared to the winter fallow treatment. These results indicate that the combination of GM and a 40% reduction in N fertilizer can significantly reduce N runoff loss from paddy fields, demonstrating good effectiveness under various rainfall conditions, making it a green production model worth promoting.

Utilization of Diversified Cover Crops as Green Manure-Enhanced Soil Organic Carbon, Nutrient Transformation, Microbial Activity, and Maize Growth

Studying green manure in several returning methods to enhance soil fertility and crop benefits is a strong foundation for cropland nutrient management. However, how different types of green manures and their variable doses affect the efficacy of applied manures, either buried or mulched, remain overlooked. The objective of this study was to optimize green manure management to enhance soil fertility and maize biomass using five types of green manures (white mustard, forest rye, fiddleneck, sufflower, and pea) in two different doses (low, 5 g per pot, and high, 10 g per pot), which were either buried or mulched before and after maize sowing. Results revealed that total carbon content increased due to green manure treatments, representing a 10% increase over control, particularly through buried w. mustard (10% increase before maize cultivation) and mulched safflower and pea (12% and 11% increase after maize cultivation over control). Dry maize aboveground biomass yields also improved across all variants, with buried mustard yielding 18.4 g·plant−1 (compared to 8.6 g·plant−1 in the control), mulched mustard yielding 16.4 g·plant−1, and buried pea yielding 17.8 g·plant−1. Green mulching generally acidified the soil (pH 5.71 compared to 6.21 in the control), except for buried fiddleneck (pH 6.39 after maize cultivation) at a high dose of manures. Carbon-mineralizing enzyme activities (dehydrogenase and β-glucosidase) were significantly increased by green manures, with buried fiddleneck showing a 22.6% and 20.6% increase over the control, and mulched fiddleneck showing a 24.5% and 22.4% increase under high doses. The study suggests that partially decomposed and mineralized mulched biomass may induce a negative priming effect on carbon-mineralizing enzymes due to a decrease in the C/N ratio of the soil. It emphasizes that the nutrient content and stoichiometry of green manures, alongside soil characteristics such as the C/N ratio, are critical factors for sustainable soil management and carbon sequestration. These findings underscore the need for careful selection and management of green manures to optimize soil health and carbon-storage outcomes.

Effectiveness of Elephant Grass (Pennisetum purpureum) Green Fertilizer on the Growth of Soybean Plants (Glycine max L. Merrill)

Soybeans (Glycine max L. Merrill) After rice and corn, it is the third most important food commodity and occupies a strategic position in the country's food policy, It plays a very important role in the nutrition of the Indonesian population. The aim of this study was to investigate the effects of soybean plant (Glycine Max). The aim of this study is to investigate the effects of green manure Pennisetum purpureum on plant growth (Merrill). The study was conducted in Batu Melengangan Village, Langkat Regency, using an experimental method involving 2 treatments, namely P0 (without green fertilizers) and P1 (200 grams of green elephant grass fertilizer), and a completely randomized, non-evidence-based design (CRD). In analyzing the data from this study, the SPSS program used parametric tests, i.e. Anova and Duncan tests, and nonparametric tests, i.e. KRUSKAL-Wallis and Mann-Whitney tests. The results of the study show that there was effectiveness of elephant grass green fertilizer (Pennisetum purpureum) on the growth of soybean stem height with an average of 36.25 cm, number of soybean leaves with an average of 46,775 pieces, the age at which soybean flowers emerged with an average of 36.6 days, and the age at which soybeans emerge is an average of 43.2 days. The most effective green manure treatment for the growth of soybean plants (Glycine max L. Merrill) was in treatment P1 (200 gr grass green manure).

The Influence of Green Manure Planting on the Spectroscopic Characteristics of Dissolved Organic Matter in Freshwater-Leached Saline–Alkali Soil at Different Depths

This study investigated the influence of green manure planting on the spectroscopic properties of dissolved organic matter (DOM) in saline–alkali soil under freshwater leaching conditions at different soil depths. The UV254, UV253/UV203, α300, α355, SUVA254, SUVA260, and SR ultraviolet parameters indicated reductions in the content of large molecular substances, benzene ring substitution degree, colored dissolved organic matter, aromaticity, and hydrophobic components in the soil leachate DOM with an increasing soil depth. Compared with the non-green manure treatment control, green manure planting mitigated the leaching of dissolved organic matter in soil during saline irrigation, with rape green manure demonstrating superior effectiveness. Utilizing three-dimensional fluorescence combined with parallel factor analysis, this study analyzed three fluorescent components of soil leachate DOM: C1 (visible-light fulvic acid), C2 (humic acid), and C3 (tyrosine-like protein). The combined contribution of the two humic substance components (C1 + C2) was approximately 70%, indicating the dominance of humic substances in leachate DOM. The fluorescence parameters of soil leachate DOM included an average of the fluorescence index (FI) values between 1.4 and 1.9, low humification index (HIX) values consistently below 4, and biological index (BIX) values ranging from 0.8 to 1.0, suggesting a mixed source, low humification degree, poor stability, and moderate self-source characteristics. Compared with the non-green manure treatment control, both the green manure treatments exhibited a relatively higher proportion of biogenic sources and humification degree in soil leachate DOM. This suggests that planting green manure can reduce the relative DOM content under freshwater leaching conditions, increase the proportion of biogenic sources in soil leachate DOM, and enhance soil humification. Planting rapeseed green manure can diminish the leaching of DOM from land sources and augment soil humification.

Organic amendments increased Chinese milk vetch symbiotic nitrogen fixation by enriching Mesorhizobium in rhizosphere.

Symbiotic nitrogen fixation of Chinese milk vetch (Astragalus sinicus L.) can fix nitrogen from the atmosphere and serve as an organic nitrogen source in agricultural ecosystems. Exogenous organic material application is a common practice of affecting symbiotic nitrogen fixation; however, the results of the regulation activities remain under discussion. Studies on the impact of organic amendments on symbiotic nitrogen fixation have focused on dissolved organic carbon content changes, whereas the impact on dissolved organic carbon composition and the underlying mechanism remain unclear. In situ pot experiments were carried out using soils from a 40-year-old field experiment platform to investigate symbiotic nitrogen fixation rate trends, dissolved organic carbon concentration and component, and diazotroph community structure in roots and in rhizosphere soils following long-term application of different exogenous organic substrates, i.e., green manure, green manure and pig manure, and green manure and rice straw. Remarkable increases in rate were observed in and when compared with that in green manure treatment, with the greatest enhancement observed in the treatment. Moreover, organic amendments, particularly pig manure application, altered diazotroph community composition in rhizosphere soils, therefore increasing the abundance of the host-specific genus Mesorhizobium. Furthermore, organic amendments influence the diazotroph communities through two primary mechanisms. Firstly, the components of dissolved organic carbon promote an increase in available iron, facilitated by the presence of humus substrates. Secondly, the elevated content of dissolved organic carbon and available iron expands the niche breadth of Mesorhizobium within the rhizosphere. Consequently, these alterations result in a modified diazotroph community within the rhizosphere, which in turn influences Mesorhizobium nodulation in the root and symbiotic nitrogen fixation rate. The results of the present study enhance our understanding of the impact of organic amendments on symbiotic nitrogen fixation and the underlying mechanism, highlighting the key role of dissolved organic carbon composition on diazotroph community composition in the rhizosphere.

Sustainable basmati rice yield and quality enhancement through long-term organic nutrient management in the Indo-Gangetic Plains

Context or problemThe extensive use of chemical fertilizers and pesticides in modern agriculture, particularly since the green revolution, has led to profound consequences for agricultural ecosystems. This approach, while initially boosting yields, has disrupted soil health, biodiversity, and environmental balance. Moreover, it contributes silently to global climate change by releasing greenhouse gases. These challenges underscore the urgent need for a shift towards sustainable agricultural practices to safeguard soil health, biodiversity, and human nutrition while mitigating the impacts of climate change. Objective or research questionThe primary objective of this study is to assess the impact of the long-term (seventeen years) application of organic nutrient management on the physicochemical properties of basmati rice soil and its nutritional quality. The study aims to understand the effectiveness of different organic nutrient management practices in mitigating the negative consequences associated with conventional agricultural practices. MethodsThe experiment used a strip-plot design with three replications, assigning two cropping systems (basmati rice-wheat-green gram and basmati rice-wheat-sesbania) to vertical strips. Seven nutrient management practices, including control, farmyard manure (FYM), vermicompost, farmyard manure + crop residues, vermicompost + crop residues, farmyard manure + crop residues + biofertilizers, and vermicompost + crop residues + biofertilizers [nitrogen-fixing Azospirillum, phosphorus-solubilizing bacteria (PSB), potassium-solubilizing bacteria (KSB), and a cellulolytic culture (Aspergillus awamori, Trichoderma viride, Phanerochaete chrysosporium, and Aspergillus wululens)] were applied to the horizontal strips. ResultsThe findings show that the cropping system with sesbania green manure significantly improved soil physicochemical attributes, nutritional content, and basmati rice yield compared to the green gram-based system. Continued application of organic manures, crop residues, and biofertilizers notably enhanced soil fertility, grain quality, and basmati rice productivity. The combined use of vermicompost, wheat residue, biofertilizers, and sesbania green manure treatment increased organic carbon content by 78.7% over the control, and soil available nitrogen, phosphorus, and potassium by 38.3–54.9%, 57.6–143.8%, and 27.9–64.1%, respectively. Additionally, it augmented diethylenetriamine pentaacetic acid extractable iron, zinc, manganese, and copper content by up to 44.2%, 28.5%, 57.9%, and 71.0%, respectively. Co-application of the above organic sources also significantly enhanced grain and straw yields by 74.5–80.1% and 46.1–50.0%, respectively, compared to the control. ConclusionsEnhancing Basmati rice yield and quality in the Indo-Gangetic Plains can be sustainably achieved through sesbania green manuring and organic practices. Positive correlations with key soil parameters emphasize the significance of organic farming for long-term sustainability. Implications and significanceThe study suggests that adopting organic practices, including sesbania green manuring and combining organic inputs, can alleviate the adverse effects of conventional farming on soil health, biodiversity, and climate change. This aligns with the broader goal of establishing sustainable production and consumption in basmati rice-based cropping systems.

Growth and production of sweet corn (Zea mays saccharata Sturt.) as an intercrop in immature oil palm plantations (TBM 2) on dystrudepts soil given MB green manure (Mucuna bracteata) and NPK fertilizer

This research aims to examine the interaction, the main effects of Mucuna bracteata green fertilizer, NPK and obtain a combination that produces the highest production of sweet corn. The research was carried out in Kembang Damai Village, Pagaran Tapah Darussalam District, Rokan Hulu Regency from April to July 2023. The research was carried out experimentally using a factorial randomized block design, where factor I was the provision of Mucuna bracteata green fertilizer consisting of 3 levels, namely 4.18 . t.ha -1 , 8.36 t.ha -1 and 12.54 t.ha -1 . Factor II is the provision of NPK which consists of 3 levels, namely 0.1 t.ha -1 , 0, 2 t.ha -1 and 0.3 t.ha -1 , so there are 9 treatment combinations and they are repeated 3 times, so there are 27 experimental units. The parameters observed were the amount of chlorophyll, photosynthesis rate, transpiration rate, stomatal conductivity, and CO2 concentration in cells, plant height, time when female flowers appeared, harvest age, weight of cobs with husks, and weight of cobs without husks. The variance data was further tested using Duncan's multiple distance test at the 5% level. The results of the research showed that there was an interaction between Mucuna bracteata and NPK green manure treatment on the parameters of female flower emergence time, harvest age and husk ear weight, but not on other parameters . The application of Mucuna bracteata green fertilizer had a significant effect on the time the female flowers appeared, the age of harvest, and the weight of the husk cobs. NPK fertilizer has a significant effect on harvest age and husk cob weight. Providing Mucuna bracteata green fertilizer 12.5 t.ha -1 and NPK 0.2 t.ha -1 is a combination that provides higher production results in the weight parameter of husk cobs, namely 527,833 g per plant.

Evaluation of farmland soil health and optimization of evaluation system under different green manure applications in a semi‐arid irrigation area

AbstractHealthy soil is essential for maintaining food security and enhancing ecosystem functions. Green manure application improves soil fertility and is an alternative to chemical fertilizers; however, research on optimizing soil health assessment systems and providing comprehensive and accurate information for local farmland green manure management models remains limited. In this study, we used maize and potato intercropped with green manure farmland in the main crop production area of a semi‐arid irrigation area in Northwest China as the research object, integrated the regional soil environment characteristics, and used principal component analysis and other methods to establish a minimum index data set including physicochemical, biological, and yield indices. A soil health assessment system applicable to the study region was constructed and optimized by drawing the scoring curve. The results showed that green manure treatment exerted a positive effect on the soil bulk density, nutrient content, extracellular enzyme activity, and the yield of maize and potato fields. This evaluation method showed that both green manure treatments could improve the soil health index of two major crop fields, with scores of 6.9 (3.7–8.6) and 6.2 (4.5–7.0) for maize and potato farmland, respectively, with a greater positive effect caused on maize. This evaluation system can not only reflect the soil conditions of farmland accurately given the application of green manure in the semi‐arid irrigation areas of northwest China but also provide reference for the promotion of organic fertilizers such as green manure and the resolution of regional soil health differences.

Role of Organic Fertilizer Types on Nutrient Absorption and Soybean Yield in Teak-based Agroforestry Systems

Background: Indonesia’s soybean production is insufficient to meet the demand for domestic soybean consumption as 86.4% demand is met from imports. Climatic conditions strongly influence soybean production and its quality in Indonesia, so the agroforestry system are used to to boost soybean production. However, the weakness of the agroforestry system is the low light intensity resulting in lower production. This study examines the effect of various organic fertilizers on nutrient uptake and soybean yields in teak-based agroforestry systems. Methods: The study used a complete randomized block design with one factor, namely the type of fertilizer with seven levels, namely inorganic fertilizer (Urea 50 kg/ha, SP36 100 kg/ha and KCl 100 kg/ha), Indigofera tinctoria compost, corncob compost, peanut green manure, chicken manure, goat manure and cow manure (dose of 5 tons/ha) and repeated three times. Result: The type of fertilizer affects nitrogen and potassium uptake, root length and biomass, number of leaves, plant biomass and 1 ha soybean yield in a teak-based agroforestry system. Indigofera tinctoria compost produced the highest nitrogen and potassium uptake, 13.83g and 2.77g. Nitrogen uptake is positively correlated with root length and plant biomass. The highest soybean yield in the peanut green manure treatment was 1.6 tons. Organic fertilizers increased nutrient uptake and soybean yields under teak stands compared to inorganic fertilizers.

Impact of green manure and weeds on selected soil health indicators in an organic grain cropping system in Nova Scotia

The green manure residual effect on soil health 2 years later in crop rotation is understudied. Little is known about weed biomass impact on soil microbial communities or their interactions. A Colchester County, NS, Canada, organic grain research trial during 2016–2017 comprised 2 or 3-year rotations with or without green manure crop prior to wheat, and then soybeans. Fall soil sampling was conducted both years. The soybean phase of the crop rotation was managed as weedy or non-weedy. Weedy soil showed significantly increased soil respiratory activity and fungal microbial biomass. Green manure treatments did not significantly influence soil health indicators.

Response of nematode community structure to different restoration practices in two vineyard soils in Tuscany (Italy)

ABSTRACT Inappropriate land preparation before vineyard establishment can lead to soil degradation and vine health issues, with consequent reductions in the quantity and quality of the grapes. In the present short-term trial, the effects of dry mulching, green manure and compost treatments were evaluated as restoration strategies to enhance soil functionality in degraded vineyard areas at two Tuscan farms that had been under organic management for different lengths of time. Soil nematode community, soil physical and chemical properties were monitored as indicators of soil quality. The restoration treatments scarcely affected soil chemical or physical qualities; only the compost application increased soil total organic carbon (TOC). Bacterial feeder nematodes increased under dry mulching in response to the organic carbon inputs on the farm in conversion. Plant-parasitic nematodes decreased only after the first year of the restoration treatments and predators decreased during all 3 years. Nematode indicators showed only a few differences between the different management regimes; the diversity weighted abundance expressed as biomass indicated that the restoration practices sometimes represented a disturbing factor in ecosystem services regulation. The abundance of nematode taxa was differently affected by soil physico-chemical properties. On the farm that had been managed organically for longer, the higher proportion of large sized stable aggregates and greater soil porosity benefitted large nematodes such as predators, while the higher moisture levels were unfavourable for some plant-parasitic nematodes. However, on the farm still in conversion, increases in TOC and C/N ratio values were associated with a reduction in plant-parasitic nematodes.

Effects of Green Manures on Rhizosphere Fungal Community Composition of Cucumber Seedlings

Green manures are usually used to improve soil health and increase crop productivity. The activity and composition of the soil microbial community could be altered by green manures. High-throughput amplicon sequencing was used to assess the effects of green manures of wheat (Triticum aestivum) and Indian mustard (Brassica juncea) on the rhizosphere fungal community composition of cucumber (Cucumis sativus L). Results showed that green manures of wheat and Indian mustard altered the composition but not the diversity of rhizosphere fungal communities of cucumber Contents of inorganic N, Olsen P, and available K in bulk soil decreased by green manure treatments. Ascomycota, Zygomycota, and Basidiomycota were the predominant phyla in soil, and their relative abundance changed after treatment with wheat and Indian mustard. The relative abundance of Basidiomycota was increased in the green manure of wheat, while that of Zygomycota was decreased in the green manure of Indian mustard. The relative abundance of Ascomycota increased in both wheat and Indian mustard. Green manures of wheat and Indian mustard also increased the relative abundances of unclassified Sordariomycetes and Fusarium spp., whereas they decreased the relative abundances of Pseudallescheria, Mortierella, Kernia, and unclassified Chaetomiaceae spp. Compared with other treatments, green manures of wheat increased the relative abundance of Waitea sp. and decreased the relative abundance of Cephaliophora sp. Indian mustard increased the relative abundance of Humicola sp.

Green Manure Amendment Increases Soil Phosphorus Bioavailability and Peanut Absorption of Phosphorus in Red Soil of South China

Peanut (Arachis hypogaea L.) is one of the most important crops produced worldwide. Peanut is the dominant crop in the typical upland red soil areas of China; however, phosphorus bioavailability in red soil is very low, which severely affects peanut production. To improve the phosphorus bioavailability, which substantially promotes the green development of peanut production, a peanut–green manure rotation field experiment was conducted with six treatments (milkvetch; radish; brassica rape; mustard rape; winter fallow and no-tillage), commencing in September 2017 in the red soil area of Jiangxi province, China. The results show that compared with no-tillage (NT) treatments, different green manure returning treatments had significant effects on soil pH, soil phosphorus components and available potassium content. The particulate phosphorus and soil available phosphorus contents in the green manure treatments were significantly higher than those in the winter fallow (WF) treatment. Compared with the WF treatment, the content of particulate phosphorous in brassica rape (BR), radish (R) and milkvetch (MV) treatments was significantly increased by 6.55%, 3.66% and 2.50%, respectively; the available phosphorus content in mustard rape (MR), BR, R and MV was significantly increased by 20.93%, 25.60%, 23.76% and 18.10%, respectively. In addition, the total phosphorus content of peanut shell in the MV and R treatment was significantly higher than that in the WF treatment, increasing by 33.47% and 60.66%, respectively. Compared with the WF treatment, the peanut biomass of MR, BR and R treatments increased significantly by 19.51%, 29.83% and 19.77%, respectively. The total phosphorus accumulation in all green manure treatments was higher than that in the WF treatment, and the MV treatment reached a significant level at 18.83%. Based on these results, the particulate phosphorus (PP) and available phosphorus were significantly affected by different green manure treatments; green manure amendment improves peanut phosphorus uptake. The use of green manure (especially milkvetch and brassica rape) can be recommended to improve phosphorus bioavailability and yield of peanut in red soil areas.

Synergistic effects of diazotrophs and arbuscular mycorrhizal fungi on soil biological nitrogen fixation after three decades of fertilization.

Biological nitrogen (N) fixation (BNF) via diazotrophs is an important ecological process for the conversion of atmospheric N to biologically available N. Although soil diazotrophs play a dominant role in BNF and arbuscular mycorrhizal fungi (AMF) serve as helpers to favor BNF, the response of soil BNF and diazotrophic communities to different long-term fertilizations and the role of AMF in diazotrophs-driven BNF are poorly understood. Herein, a 33-year fertilization experiment in a wheat-maize intercropping system was conducted to investigate the changes in soil BNF rates, diazotrophic and AMF communities, and their interactions after long-term representative fertilization (chemical fertilizer, cow manure, wheat straw, and green manure). We found a remarkable increase in soil BNF rates after more than three decades of fertilization compared with nonfertilized soil, and the green manure treatment rendered the highest enhancement. The functionality strengthening was mainly associated with the increase in the absolute abundance of diazotrophs and AMF and the relative abundance of the key ecological cluster of Module #0 (gained from the co-occurrence network of diazotrophic and AMF species) with dominant diazotrophs such as Skermanella and Azospirillum. Furthermore, although the positive correlations between diazotrophs and AMF were reduced under long-term organic fertilization regimes, green manuring could reverse the decline within Module #0, and this had a positive relationship with the BNF rate. This study suggests that long-term fertilization could promote N fixation and select specific groups of N fixers and their helpers in certain areas. Our work provides solid evidence that N fixation and certain groups of diazotrophic and AMF taxa and their interspecies relationship will be largely favored after the fertilized strategy of green manure.

Green Manure Return Strategies to Improve Soil Properties and Spring Maize Productivity under Nitrogen Reduction in the North China Plain

In order to study the effect of green manure return for stabilized spring maize (Zea mays L.) grain yield (GY) we reduced nitrogen fertilizer input by regulation and examined effects on soil nutrients, enzyme activity, and fungal communities. This two-year field experiment was conducted in the North China Plain. The field experiment was undertaken with a split-plot design; the primary plots were winter fallow (WF) and green manure (GM), and the split-plots were five N application rates of 0 (N0), 189 (N189), 216 (N216), 243 (N243), and 270 (N270) kg ha−1. The results showed that, spring maize GY under GM treatments (GYGM) were significantly increased by 5.38–11.68% more than WF treatment (GYWF), and GYWF and GYGM significantly increased by 35.9–91.5% and 80.1–135.5% across all N treatments. By linear-platform model analysis, spring maize under GM treatments obtained higher GY, reaching 1270.5–14,312.2 kg ha−1 with optimized N application rate at 238–265 kg ha−1, which resulted in a GY higher than WF (11,820.0 and 13,654.2 kg ha−1) and N reduced 11.2% (238 vs. 268 kg ha−1). GM treatment significantly increased soil organic carbon by 3.90–12.23% more than WF over all N application rates, and total nitrogen and available nitrogen were significantly increased by 3.79–15.76% and 4.87–17.29%, with total phosphorus and available phosphorus for GM higher than WF by 6.1–13.6% and 9.6–5.3%, respectively. However, there were lesser effects of GM on total potassium and available potassium. Compared to WF, soil catalase, sucrose, urease, and alkaline phosphatase activity were significantly increased by 6.2–16.4%, 5.8–48.1%, 3.3–21.5% and 11.5–82.3%, respectively, over all N application rates under GM over two years. GM increased Zygomycota and Basidiomycota relative abundances significantly, and reduced Thielavia, unclassified fungi, and Podospora relative abundances by 35.35%, 52.92% and 52.77% more than WF treatment, respectively. In summary, due to the GM return into fields, increased soil nutrients were available, which were positively affected by soil enzyme activity and fungal communities, and reduced nutrient requirements, and so the farmers could obtain a spring maize grain yield higher than 14,000 kg ha−1 with a reduced 11.2% N application rate from 268 kg ha−1 to 238 kg ha−1 by sowing winter green manure for a long time period in the North China Plain.

Effect of Green Compost Processed Organic Fertilizer and Chlorella Microalgae Solution on Growth, Antioxidant and Phenolic Content of Tropaeolum majus under Drought Stress

Environmental stresses, especially drought, are the most important factors in reducing growth of the plant. The effect of processed organic fertilizer of green compost and chlorella microalgae solution on growth, antioxidant properties and some other physiological characteristics of Tropaeolum majus plant under control and drought conditions were investigated. The experiments were performed in pot with a completely randomized design with three replications. Green manure treatment included zero, 5% and 10% by volume of pots. Chlorella microalgae treatment had two levels in terms of zero cells and 368 million cells in each pot. Drought stress was applied based on lack of ten-day and seventeen-day irrigation. After two months, the samples were collected and the relative content of leaf water, fresh weight of aerial parts, phenol content and antioxidant were performed. The results showed that green compost of 10% alone and together with chlorella microalgae significantly reduced the effects of drought stress at 5% level. The use of 5% and 10% of compost with chlorella microalgae significantly increased the growth of the aerial part compared to the control. Microalgae treatments had a more positive effect on antioxidant content and phenol content than green compost in stress and control conditions. Tropaeolum majus plant with chlorella algae treatment with 5 and 10% green compost had the highest amount of proline amino acid under stress.

The effects of co-utilizing green manure and rice straw on soil aggregates and soil carbon stability in a paddy soil in southern China

The co-utilization of green manure (GM) and rice straw (RS) in paddy fields has been widely applied as an effective practice in southern China. However, its effects on soil aggregate and soil organic carbon (SOC) stability remain unclear. In the present study, the effect of GM, RS, and co-utilization of GM and RS on particle size distribution of soil aggregates and SOC density fractions were measured in a field experiment. The experiment included six treatments, i.e., winter fallow (WF) without RS return (Ctrl), WF with 50% RS return (1/2RS), WF with 100% RS return (RS), GM without RS return (GM), GM with 50% RS return (GM1/2RS) and GM with 100% RS return (GMRS). The results showed that the proportion of small macro-aggregates (0.25–2 mm) and the mean weight diameter (MWD) of aggregates in the GMRS treatment was greater (by 18.9 and 3.41%, respectively) than in the RS treatment, while the proportion of silt+clay particles (<0.053 mm) was lower (by 14.4%). The concentration of SOC in microaggregates (0.053–0.25 mm) and silt+clay particles was higher in the GMRS treatment than in GM and RS treatments individually. The concentration and proportion of free light organic carbon (fLOC) in aggregates of various particle sizes and bulk soil was greater in the GMRS treatment than the RS treatment, whereas the concentration and proportion of mineral-associated organic carbon in small macroaggregates, microaggregates, and bulk was lower in the GMRS treatment than in the RS treatment. The proportion of intra-aggregate particulate organic carbon (iPOC) was greater in the GMRS treatment than in GM treatment. The GMRS treatment had strong positive effects on iPOC in small macroaggregates, suggesting that SOC was transferred from fLOC to iPOC. In conclusion, co-utilizing green manure and rice straw cultivated the SOC pool by increasing the concentration of fLOC and improved soil carbon stability by promoting the sequestration of organic carbon in iPOC as a form of physical protection.

Effects of Fertilization on Morphological and Physiological Characteristics and Environmental Cost of Maize (Zea mays L.)

Maize (Zea mays L.) is one of the most important crops in the world and fertilization is the most important management practice which contributes to high yield. The objective of this study was to determine the effect of different fertilizers on maize crop and their contribution to the carbon footprint. The experiments were conducted in a commercial field in the area of Thessaloniki during the growing seasons of 2019 and 2020. During the experiment a number of physiological and morphological characteristics, and the energy output/input ratio, energy efficiency, and carbon footprint were determined. The results of the experiment showed that the inorganic fertilizers and manure improved the morphological and physiological characteristics that were studied compared to the green manure treatment and the control. In addition, it appeared most of the energy input of maize cultivation is from fertilizers (52%), followed by diesel (25%) and the use of machinery (14%). The treatments with the slow release fertilizers and the manure gave satisfactory results with an average of 42.1 Mg ha−1 in 2019 and 43.6 Mg ha−1 in 2020 for both fertilization treatments. Therefore, it is necessary to use the appropriate fertilizers in order to maintain the productivity of the crop and reduce the environmental costs.

Combined Use of Green Manure and Biological Agents to Control Meloidogyne javanica (Treub) Chitwood in Soybean

Root-knot nematode management requires the adoption of integrated practices. Biological agents and cultural control practices are the most widely used, but little is known about their combined effects. This study aimed to assess the interaction effects of the biological agents Trichoderma harzianum + Purpureocillium lilacinum and different green manures on the control of Meloidogyne javanica in soybean under greenhouse conditions. Green manures from white oat, Urochloa ruziziensis, Crotalaria spectabilis, millet, and buckwheat were grown separately and applied onto the soil surface. Subsequently, soybean seeds were treated with the biological agent and planted. The experiment was repeated twice to confirm the results. In Trial 1 and 2, application of green manure or biological treatment alone was efficient in reducing nematode populations. In Trial 1, there was an interaction between factors on total nematode number and number of nematodes per gram of root. Combined use of biological control with white oat and millet green manure produced great results, since when associated with the biological one, the reduction in the total number of nematodes was potentiated by 55 and 49%, respectively (Trial 1). There was no interaction between green manure and biological factors for Trial 2, and the best results were observed with green manures of C. spectabilis, U. ruziziensis and white oat, with a reduction in the population density of the nematode in 60, 59 and 44%, respectively. It is concluded that green manure application and T. harzianum + P. lilacinum were effective in reducing nematode populations when applied separately. White oat and millet green manures associated with T. harzianum + P. lilacinum increase thecontrol of M. javanica in soybean.

Performance of the single‐event wind erosion evaluation program (SWEEP) model in assessing the impact of crop rotation, green manure, fertilizer, and tillage on wind erosion

AbstractAgricultural land management strategies have been applied to minimize wind erosion in the inland Pacific Northwest (iPNW) due to their profound influence on various soil properties and crop residue characteristics. However, simulating soil loss in response to these treatment strategies remains a challenge. The objective of this study was to test the performance of the single‐event wind erosion evaluation program (SWEEP) in simulating soil loss from agricultural land under contrasting tillage, crop rotation, fertilizer, and green manure treatments in the iPNW. These management strategies appeared to impact residue characteristics but had little or no impact on soil properties except tillage treatments in the short term (&lt;2 years). Tillage appeared to have a greater impact on soil properties and residue characteristics than other treatments. As a result, the performance of SWEEP varied among disk‐tillage (DT), undercutter‐tillage (UT), and NT (no‐tillage/zero‐tillage) treatments. No or little difference was found in the performance of SWEEP between winter wheat‐summer fallow (WW‐SF) and WW‐oilseed‐SF (WW‐O‐SF) crop rotations and synthetic and biosolids fertilizer treatments. In addition, the performance of SWEEP was acceptable for both crop rotation and fertilizer treatments. In contrast, poor agreement between simulated and measured erosion was found for manure treatments in which SWEEP over‐estimated erosion by 313 and 210% for no manure and manure treatments, respectively. The over‐estimation of SWEEP may be due to the over‐estimation of abrasion flux from the fully crusted soil surface. Our results suggest that SWEEP can be used to identify control measures for windblown soil loss in the iPNW.