Effects Of Manure Application Research Articles

Soil health indicators reveal that past dairy manure applications create a legacy effect

AbstractUnderstanding the long‐term effects of manure applications on the soil microbial component in semiarid climates will be key to sustain essential processes that affect their productivity and soil health. In this paper, soil health indicators encompassed both selected chemical and biological indicators. From 2004 to 2009, solid dairy manure treatments were applied to plots at cumulative rates of 0, 134, and 237 dry Mg ha−1 (34–56 dry Mg ha−1 year−1) in a randomized complete block with three replicates. Soil samples were taken from each manure rate in the spring of 2020 at 0–15 and 15–30 cm. Eleven years after manure applications ceased, many of the soil chemical and biological indicators were different between the manure and control treatments. In general, soil organic carbon and biological indicators were significantly greater in the 134 and 237 Mg ha−1 treatments as compared to the 0 Mg ha−1 treatment.

Short-term effect of liquid organic fertilisation and application methods on N2, N2O and CO2 fluxes from a silt loam arable soil

AbstractThe absence of N2 flux measurements in liquid manure-amended soils has resulted in a poor understanding of the effect of manure application on gaseous N losses. The aim of this study was to quantify N2, N2O, CO2, N2O reduction to N2, depth distribution of moisture, water-extractable organic C, NO3−, NH4+, pH, and diffusivity in a laboratory incubation experiment with an arable silt-loam soil. To quantify N processes and gaseous fluxes, 15N tracing was applied. An artificial livestock slurry-mixture was added to the soil in various treatments (control, surface or injected application; slurry-application rate: 42.9 kg N ha− 1; soil water content of either 40% or 60% water-filled pore space (WFPS)). The soil was incubated for 10 days. The depth distribution of the control parameters was measured twice during the experiment on days 5 and 10. The average increase in N2 and N2O fluxes from denitrification was about 900% in slurry-amended soils. The highest N2 and N2O fluxes from denitrification were measured in the slurry injection, 60% WFPS treatment (7.83 ± 3.50 and 11.22 ± 7.60 mg N m− 2 d− 1, respectively). The hypothesis that injected slurry at a higher water content enhances denitrification was confirmed. This study provides important insights into the formation, spatial and temporal variation of the manure-soil hotspot and its impact on the denitrification process. The results will form part of a dataset to develop, improve and test manure application submodules of biogeochemical models and will help to understand in detail the effect of hotspots on N-cycling in manure-treated soils.

The Effects of Manure Application and Herbivore Excreta on Plant and Soil Properties of Temperate Grasslands—A Review

This review provides an overview of grassland studies on the effects of manure application and herbivore excreta on plant and soil properties in temperate grasslands. Grass biomass from grazing or mowing is mainly used for animal products such as milk or meat, as well as for energy or raw materials for biorefineries. Manure application or grazing has a significant impact on several plant and soil properties. There are effects on soil chemical properties, such as increased carbon sequestration, improved nutrient availability, and increased pH. Additionally, several physical soil properties are improved by manure application or grazing. For example, bulk density is reduced, and porosity and hydraulic conductivity are greatly improved. Some biological parameters, particularly microbial biomass and microbial and enzyme activity, also increase. The use of manure and grazing can, therefore, contribute to improving soil fertility, replacing mineral fertilizers, and closing nutrient cycles. On the other hand, over-application of manure and overgrazing can result in a surplus of nutrients over plant needs and increase losses through emission or leaching. The lost nutrients are not only economically lost from the nutrient cycle of the farm but can also cause environmental damage.

Grazing and fertilizer, compost or manure application effects on a meadow bromegrass pasture on a thick black chernozem I. Productivity and sustainability

Short duration, intensive grazing management with high stocking rates may result in sufficient turn-over of nitrogen (N) to compensate for production-limiting soil-N deficiencies for grass pasture. In central Alberta a 0.5 ha block was seeded to “Fleet” meadow bromegrass ( Bromus riparius Rehmann) in August 2002. Within this block, six fenced (9 m × 30 m) treatments were established in three replicates. They were (1) ungrazed—clip removal, (2) grazed—alone, (3) grazed—fertilizer, (4) grazed—fertilizer-compost, (5) grazed—hog manure, and (6) grazed—alfalfa ( Medicago sativa L.) grass. Measurements were conducted over a 4-year period between 2003 and 2006 and grazing occurred at identical times as vegetative mass permitted. Biomass was harvested before and after grazing for calculation of dry matter (DM) yield and biomass consumed. Sub-samples were used for determination of N concentration and in vitro digestibility. Mean herbage N-yield for grazed treatments was 131% of ungrazed and greatest for grazed-fertilizer and grazed-fertilizer plus compost. Grazed paddocks with no added N produced similar DM yield to those with added N. Estimated nitrogen fixation contributed an annual average of 82 kg ha−1 to herbage-N yield from the alfalfa-grass paddocks. Barley ( Hordeum vulgare L.) silage grown after termination of the grazed pastures produced 72% more herbage DM from grazed paddocks than ungrazed, but no significant ( P < 0.05) differences occurred among amendments.

Long-term manuring enhances soil gross nitrogen mineralization and ammonium immobilization in subtropical area

Manure amendments have been generally considered to enhance soil nutrient supply, thus improving soil fertility and crop productivity, especially in subtropical area. However, the underlying mechanisms of manure application effects on soil nitrogen (N) supply capacity and N transformation processes remain uncertain. Here, 15N isotope pool dilution techniques were used to determine the gross rates of N mineralization, ammonium (NH4+) immobilization and nitrification in red soil subjected to three decades of long-term fertilization regimes. Results showed that compared to treatments without manure, manure application alone or combined with chemical fertilizers significantly increased gross N mineralization rates by 4.55−8.31 folds, resulting from increased N-acquiring enzyme activity and decreased microbial N use efficiency (NUE). The decreased microbial NUE in the manure application treatments was due to alleviated imbalance of C:N between soil and microbial biomass. Gross NH4+ immobilization rates were 7.35−11.34 folds higher in the treatments amended with manure (1.51−2.23 mg N kg−1 d−1) relative to without manure, attributed to increased microbial biomass and bacterial abundance. Compared to chemical fertilizers application, manure application decreased gross nitrification rates by 38−55%, due to the decline in NH4+ availability via enhanced NH4+ immobilization. The significantly lower ratio of gross nitrification to NH4+ immobilization in the treatments with manure suggested that manure amendments could potentially mitigate the risk of soil N losses. Overall, long-term manuring has the potential to improve soil N supply and retention capacities by enhancing gross N mineralization and NH4+ immobilization accompanying with decreased gross nitrification.

The Composition of Dissolved Organic Matter in Arable Lands: Does Soil Management Practice Matter?

Dissolved organic matter (DOM) is a key soil quality property, indicative of the organic matter stored in the soil, which may also be a function of temporal variation. This study examines whether DOM is a robust property of the soil, controlling fertility, or if it may change with time. Altogether eight sets of soil samples were collected in 2018 and 2019 from the cultivated topsoil (0–10 cm) of cropland and from a nearby grassland near Martonvásár, Hungary. The study sites were characterized by Chernozem soil and were part of a long-term experimental project comparing the effects of manure application and fertilization to the control under maize and wheat monocultures. DOM was extracted from the samples with distilled water. The dissolved organic carbon (DOC), total dissolved nitrogen (DN), biological index (BIX), fluorescence index (FI), humification index (HIX), carbon nitrogen (C/N) ratio and specific ultraviolet absorbance at 254 nm (SUVA254) index were studied in the arable soils, and the results showed that all the DOM samples were humified, suggesting relevant microbiological contributions to the decomposition of OM and its conversion into more complex molecules (FI = 1.2–1.5, BIX = ~0.5, and HIX = ~0.9). Temporal variations were detected only for the permanent grassland where higher DOM concentration was found in spring. This increased DOM content mainly originated from humified, solid phase associated, recalcitrant OM. In contrast, there were no differences among fertilization treatments and sampling dates under cropfield conditions. Moreover, climatic conditions were not proven as a general ruler of DOM properties. Therefore, momentary DOM alone is not necessarily the direct property of soil organic matter under cropfield conditions. The application of this measure needs further details of sampling conditions to achieve adequate comparability.

Dairy Manure Application Effects on Water Percolation, Nutrient Leaching and Rice Yield Under Alternate Wetting and Drying Irrigation

Dairy Manure Application Effects on Water Percolation, Nutrient Leaching and Rice Yield Under Alternate Wetting and Drying Irrigation

Manure application effects on subsoils: Abundant taxa initiate the diversity reduction of rare bacteria and community functional alterations

Manure application is a significant agriculture practice that can affect the microbial community structure in both topsoil and subsoil. However, how the abundant and rare taxa in the soil profile respond to surface manure application and their ecological roles at different soil depths remain unknown. Based on a soil mesocosm experiment, we used amplicon sequencing and high-throughput quantitative-PCR array to characterize the bacterial community composition and functional traits across soil profiles. Results showed that the relative abundance and diversity of rare taxa increased in the topsoil but decreased in the 40–60 cm soil, where the relative abundance of abundant taxa increased after manure application. Evidence from network analysis, niche width and 16S rRNA operon (rrn) copy number suggest that abundant taxa in subsoils had a greater competitivity for resource mining than rare taxa. Regarding resource utilization strategies, microbial communities under manure treatment preferred to utilize recalcitrant carbon (C) and inorganic phosphorus (P) in the topsoil and labile carbon and organic phosphorus in the subsoil compared with non-manure application. Random Forest regression analysis indicated the relatively greater contribution of abundant taxa to C degradation and fixation in subsoils. These results imply that the manure application effect on microbial resource mining in subsoils is mainly driven by abundant bacteria due to the lower competitiveness of rare taxa for the C sources leached above. Overall, This study linked community functions with the ecological role of abundant and rare taxa in the context of environmental disturbances at different soil depths and shed light on the potential ecological risks of diversity reduction of subsoil rare bacteria.

Controlling AMR in the Pig Industry: Is It Enough to Restrict Heavy Metals?

Heavy metals have the potential to influence the transmission of antimicrobial resistance (AMR). However, the effect on AMR caused by heavy metals has not been clearly revealed. In this study, we used a microcosm experiment and metagenomics to examine whether common levels of Cu and Zn in pig manure influence AMR transmission in manured soil. We found that the abundance of 204 ARGs significantly increased after manure application, even though the manure did not contain antibiotic residuals. However, the combined addition of low Cu and Zn (500 and 1000 mg/kg, respectively) only caused 14 ARGs to significantly increase, and high Cu and Zn (1000 and 3000 mg/kg, respectively) caused 27 ARGs to significantly increase. The disparity of these numbers suggested that factors within the manure were the primary driving reasons for AMR transmission, rather than metal amendments. A similar trend was found for biocide and metal resistance genes (BMRGs) and mobile genetic elements (MGEs). This study offers deeper insights into AMR transmission in relation to the effects of manure application and heavy metals at commonly reported levels. Our findings recommend that more comprehensive measures in controlling AMR in the pig industry are needed apart from restricting heavy metal additions.

Effect of organic and mineral fertilizers applications in pasture and no-tillage system on crop yield, fractions and contaminant potential of Cu and Zn

Organic wastes, fertilizers, organominerals, and minerals contain nutrients essential to crops and contribute to increase productivity. However their use can also lead to the accumulation of copper and zinc, which changes the distribution of their fractions and enhances the risk of toxicity to plants and the environment, thereby working against the sustainable development goals. However, the effect of manure applications on clayey soils and the effects of increasing Cu and Zn contents over the years on crop productivity remain unknown. This study aimed to evaluate the distribution and the potential for contamination of heavy metals in clayey soil with a history of the application of different types and amounts of fertilizers under Cynodon spp. grazing and no-tillage system for soybeans. In Experiment 1, Cynodon spp. were cultivated for hay production and submitted to applications of the following treatments: 0, 200, and 400 kg ha−1 of total-N in the form of pig slurry and urea. In experiment 2, the soybean was grown and subjected to the following treatments: control, pig slurry, commercial granulated solid organic fertilizer, organomineral fertilizer blended with granules, and mineral fertilizer blended with granules. The dose of each nutrient source was determined based on the soil analysis and the recommendations of the liming and fertilization manual. The experiments were conducted for four agricultural crops where soil samples were collected in the layer of 0.00–0.10 m layer and submitted to chemical fractionation of Cu and Zn. The use of pig manure increased the availability of Cu and Zn in the soil, causing an increase in the distribution of copper organic (40.73% and 57.64% for PS200 and PS400 treatments, respectively, in Experiment 1; 67.33% for PS treatment, in Experiment 2) and residual fractions (10.01% and 7.60% for PS200 and PS400 treatments, respectively, in Experiment 1; 9.80% for PS treatment, in Experiment 2), while zinc was predominant in clay-mineral (61.04% and 92.01% for PS200 and PS400 treatments, respectively, in experiment 1; 278.90% for PS treatment, in Experiment 2) and residual fractions (2.36% for PS200 treatment in experiment 1; 9.90% for PS treatment, in Experiment 2). Additionally, the use of swine manure increased the Cu and Zn contents in the exchangeable fraction, which may potentiate the toxicity to plants and increase the potential for contamination of subsoil water. However, the increased bioavailability of Cu and Zn did not caused a loss of crop productivity but instead increased dry mass production and crop yield.

Insights into the associations between soil quality and ecosystem multifunctionality driven by fertilization management: A case study from the North China Plain

Recycling of livestock manure in agroecosystems has been shown to enhance the sustainability of food production and reduce adverse environmental consequences from intensive crop-livestock systems. However, the effect of manure application on the associations between soil quality and ecosystem multifunctionality still remains poorly understood. Hereby, we used a five-year field experiment to investigate the effect of mineral and manure fertilization on soil quality, enzymatic stoichiometry , and ecosystem multifunctionality for both topsoil and subsoil (i.e. 0-20 cm and 20–40 cm). Manure alone and combined with mineral fertilization increased soil quality index by 49.5% and 70.1% in the topsoil, and by 67.5% and 26.6% in subsoil compared to no fertilization. Moreover, the manure application increased the C, N, and P acquisition enzyme activities , especially those for C and P cycling. Fertilization regimes affect enzymatic stoichiometry in the subsoil rather than topsoil. Manure application increased soil ecosystem multifunctionality in both top and subsoil by 2.1 and 0.4 times, respectively. Interestingly, the soil quality index was positively correlated with ecosystem multifunctionality regardless of fertilization regimes. Furthermore, random forest analysis showed that soil organic C and N content, available P, and microbial biomass were the main drivers of soil ecosystem multifunctionality. Conversely, mineral fertilization did not affect soil quality and enzyme activity in both soil layers, and thus did not change soil ecosystem multifunctionality. In conclusion, manure application fosters soil quality and has the potential to improve the soil multifunctionality, thereby providing an effective way to sustainable soil management and cleaner crop production. • Manure addition increased soil quality and ecosystem multifunctionality. • Higher C and P enzyme activities promote ecosystem multifunctionality. • Fertilization regimes affect enzymatic stoichiometry in subsoil rather than topsoil. • Soil quality and ecosystem multifunctionality are co-driven by fertilization.

Copiotrophic taxa in pig manure mitigate nitrogen limitation of soil microbial communities.

Microbial nitrogen (N) limitation is a common problem in terrestrial ecosystems. Pig manure, a type of solid waste, is increasingly applied to improve soil N availability in agriculture through inputs of organic matter and inorganic N. Pig manure application also introduces a lot of exogenous microorganisms, which have distinctly different N requirements and metabolic properties, into the resident soil microbial community. However, the impacts of these manure-borne microorganisms on soil N cycling have not been well determined. Here, we investigated effects of manure-borne microorganisms on the N limitation of soil microorganisms using an ecoenzymatic stoichiometry analysis. We monitored microbial communities over a 90-day period in a laboratory-controlled experiment with four treatments: (1) non-sterilized soil mixed with non-sterilized manure (S-M), (2) non-sterilized soil mixed with sterilized manure (S-sM), (3) sterilized soil mixed with non-sterilized manure (sS-M), and (4) non-sterilized soil without manure addition (S, the control). The microbial N limitations were significantly mitigated in both S-M and sS-M. By contrast, the S-sM and S showed high levels of microbial N limitation, likely stemming from differences in the microbial functional composition. We found chitin-degrading bacteria were the dominant copiotrophic manure-borne bacteria associated with N mineralization, and they may improve soil N availability. We further identified several copiotrophic manure-borne bacteria in S-M and sS-M, and their abundances had significantly negative correlation with the level of N limitation and significantly positive correlation with the stoichiometric homeostasis. As these copiotrophic taxa can maintain homeostasis through regulating enzymatic activities, our results indicate that copiotrophic taxa in pig manure contribute to the mitigation of soil microbial N limitation. Our study also highlights the invasiveness capacity of manure-borne microorganisms in soil and evaluates the biotic effects of manure application on soil N cycling.

Erratum to: Long‐term manure application effects on nutrients and selected enzymes involved in their cycling

Erratum to: Long‐term manure application effects on nutrients and selected enzymes involved in their cycling

Understanding the Impact of Liquid Organic Fertilisation and Associated Application Techniques on N2, N2O and CO2 Fluxes from Agricultural Soils

The prediction of liquid manure effects on N transformations in soils and the associated N2O and N2 fluxes is poor because previous investigations have mostly excluded N2. The objectives of this study were thus to quantify N2, N2O and CO2 fluxes, the source processes of N2O, N2O reduction and the depth distribution of moisture, NO3−, NH4+, water-extractable organic carbon concentration and pH in a laboratory incubation study with sandy arable soil using 15N tracing to quantify N processes and gaseous fluxes. The soil was amended with and without artificial slurry in various manure treatments (control, surface and injected) and incubated for 10 days at varying moisture levels, where the depth distribution of control parameters was determined twice during the experiment. Manure application was found to increase N2 and N2O fluxes from denitrification, with the highest fluxes occurring in the wet manure injection treatment (33 ± 32 mg N m−2 d−1 and 36.1 ± 39.1 mg N m−2 d−1, respectively), confirming that manure injection under wet conditions enhances denitrification and possibly also N2O fluxes. This study concluded that the current dataset is suitable as a first step towards improving the capability of biogeochemical models to predict manure application effects, but further studies with more soils and refined experiments are needed.

The effect of intercropping and different dose of goat manure application on growth of Pogestemon cablin Benth

Patchouli (Pogostemon cablin Benth) is a perennial aromatic crop that can produceessential oil which is generally used as a mixture of ingredients for making cosmetics, pharmaceuticals, and aromatherapy which functions as a binder/fixative agent and pharmaceuticals. Although the production of patchouli increases year to year, the productivity per hectare of this plant showed a decreasing pattern. Efforts are needed to increase the productivity of patchouli, such as improving seeds quality and applying best management practices in planting. This study aimed to examine the optimum application of manure doses and intercropping practice on maximum growth of patchouli at first and two months after planting. The RCD (Randomize Complete Design) was conducted by using a cropping system and the application of goat manure in different doses. There were two levels of the cropping system: monocropping and intercropping with mung beans (Phaseolus radiatus) and four-level of manure in different doses were applied, 0 g, 500 g, 1000 g and 2000 g. ANOVA analysis shows that no interaction between cropping system and manure application on the growth of patchouli. All variables of patchouli growth in monocropping are better than in intercropping at two months after transplanting. Furthermore, there was no effect of manure application on canopy width, fresh and dry biomass of patchouli. The effect is only found on plant height and tree basal diameter, while without manure application and 500 g application is greater than 1000 g and 2000 g of manure application.

Quantifying water footprint of winter wheat – summer maize cropping system under manure application and limited irrigation: An integrated approach

Recycling of livestock manure in agroecosystems can promote resource utilization and reduce negative environmental consequences from intensive crop-livestock systems. However, the interaction effect of manure application and irrigation strategy on the water footprint (WF) of crop production still remains incomplete. Here, we estimated the WF of the winter wheat – summer maize cropping system based on a three-year field experiment under limited irrigation and manure application by combining the hydrological water balance and the life-cycle assessment. Four fertilization strategies were chemical fertilizer (Fc), manure (Fm), the combination of chemical fertilizer and manure (Fc+m), and no fertilizer input (F0). Two irrigation regimes were irrigation (W1) and no irrigation (W0) at the jointing stage of wheat. W1 increased the blue WF (groundwater consumption per unit of grain yield) of the wheat-maize system by 46–95% compared to W0. The annual blue WF of Fm was 6% lower than that of Fc+m under W0 in 2016–2017, while that of Fc+m was lowest under W1 in 2016–2017 and 2017–2018. Fm had a higher annual yield under W0, while Fc+m yielded better under W1. Notably, the combination of limited irrigation and manure application decreased annual blue WF by benefitting annual grain yield through improving soil water storage. The indirect water consumption per unit grain yield of Fc+m and Fm were 57% and 17% of Fc for wheat and maize, respectively. Our findings highlight the great reductions in blue water footprint and indirect water consumption through limited irrigation and manure application, suggesting an effective way to balance freshwater conservation and crop production.

A meta-analysis of arable soil phosphorus pools response to manure application as influenced by manure types, soil properties, and climate

Manure amendments to agricultural soils is an excellent opportunity for sustainable utilization of agricultural waste while providing multiple benefits to improve soil quality and increase the availability of nutrients to plants, including phosphorus (P). In this study, a meta-analysis of published data from 411 independent observations based on 133 peer-reviewed papers was performed for an in depth understanding of various factors affecting the transformation of soil P pools with manure application. Manure application increased all soil inorganic P (Pi) by 58.0%–282% and organic P (Po) by 65.0%–105%, while decreasing Po/total P (TP), compared to those in unamended soils. Manure types, soil TP, and manure application rates were the important factors that influenced soil P fractions. Elevation of soil labile Pi was more pronounced with compost application, while poultry and pig manure were more beneficial for promoting soil Pi fractions and stable Po contents compared with other manure types. The manure application rate had pronounced effect on increasing the stable Po fractions. The effects of manure application on increasing soil P fractions were greater in soils with lower TP contents as compared to that in high TP soils. Manure effects on enhancing soil labile Pi and moderately labile Pi were greater in acidic soil than that in neutral and alkaline soils. In addition, soil P fractions showed significant correlation with latitude and mean annual precipitation (MAP). By integrating the impacts of manure types, soil properties, and climate, this meta-analysis would help to develop the management of manure application in a specific region of agriculture as well as promote the interpretation of the interfering factors on the soil P fractions changes in the manure-amended soils.

Effects of Pig Manure and Its Organic Fertilizer Application on Archaea and Methane Emission in Paddy Fields

Paddy fields account for 10% of global CH4 emissions, and the application of manure may increase CH4 emissions. In this study, high-throughput sequencing technology was used to investigate the effects of manure application on CH4 emissions and methanogens in paddy soil. Three treatments were studied: a controlled treatment (CK), pig manure (PM), and organic fertilizer (OF). The results showed that the contents of Zn, Cr and Ni in paddy soil increased with the application of manure, but the contents of heavy metals gradually decreased with the growth of rice. The Shannon index and Ace index showed that the application of pig manure and organic fertilizer less affected the diversity and richness of soil Archaea. The results of community composition analysis showed that Methanobacterium, Methanobrevibacter, Methanosphaera, Methanosarcina and Rice_Cluster_I were the main methanogens in paddy soil after manure and organic fertilizer application. Soil environmental factors were changed after applied manure, among which total potassium (TK) and total nitrogen (TN) were the main environmental factors affecting methanogens in paddy soil. The changes of soil environmental factors affected the community composition of methanogens, and the increase of the relative abundance of methanogens maybe the main reason for the increase of CH4 emission flux. The relative abundance of methanogens and CH4 emission flux in paddy soil were increased by both pig manure and organic fertilizer application, and pig manure had a bigger impact than organic manure.

Cerium Oxide Salicylic Acid Nanoparticles’ (CeO2: SA-NPs) Foliar Application and In-Soil Animal Manure Use Influence the Growth and Physiological Responses of Aloe vera L.

Aloe vera is an economic crop due to the presence of a gel-like substance inside the leaves, which contains polysaccharides, vitamins, proteins, fats, and amino acids. There is an ongoing need for this plant and its products for diverse food and pharmaceutical industries. To meet good agricultural practices, we studied the effect of manure application (0%, 10%, and 20% of v/v of soil) and foliar application with distilled water, salicylic acid (SA, 13.8 mg L−1 equivalent to 100 µM), cerium oxide nanoparticles (CeO2-NPs, 50 mg L−1), and cerium oxide salicylic acid nanoparticles (CeO2: SA-NPs; 100 µM + 50 mg L−1) on the growth and physiological responses of Aloe vera, and a factorial experiment was arranged based on a completely randomized design with three replications at Azarbaijan Shahid Madani University, Iran. The results showed that foliar application of CeO2: SA-NPs with the soil-based application of 10% and 20% manure increased plant dry weight and aloin content. The highest harvest index, economic yield, shoots-to-roots ratio, gel dry weight, chlorophyll a and b content, phenolics content of gel, and leaf and gel flavonoids’ content, as well as potassium, magnesium, zinc, and iron content, were obtained by the CeO2: SA-NPs × 20% manure treatment combination. The 10% and 20% manure and foliar application with CeO2-NPs, SA, and CeO2: SA-NPs increased the phenolics content of leaves compared to the control. Manure application (20%) positively affected the plant’s phosphorus content. The results revealed that co-application of soil-based cow manure and foliar CeO2: SA-NPs stimulated the growth and physiological responses of Aloe vera, and the results would be helpful to the agricultural extension sections and pioneer farmers.

Reduction in net greenhouse gas emissions through a combination of pig manure and reduced inorganic fertilizer application in a double-rice cropping system: Three-year results

Manure amendment in croplands is common practice for soil carbon sequestration, and may also reduce greenhouse gas emissions. Few studies focus on the effects of manure application on the net greenhouse gas emissions (NGHGE, the global warming impacts of soil carbon sequestration and CH4 and N2O emissions) in double-rice cropping fields. Herein, a field experiment was conducted to analyze the effects of pig manure application in combination with reduced chemical fertilizers on the NGHGE, soil properties, and yields in a double-rice paddy field in 2012–2015. Four treatments were included: 0 N (no nitrogen fertilizer); 1/2 N (chemical nitrogen fertilizer reduced by 50%); N (100% chemical nitrogen fertilizer); and 1/2 N + PM (pig manure complemented with chemical fertilizer application). The average annual CH4 emissions for 1/2 N + PM were 53%, 50%, and 32% higher than those for 0 N, 1/2 N, and N treatments, respectively (p < 0.05). The soil organic carbon sequestration rates (SOCSR) for 1/2 N + PM were 224%, 208%, and 192% higher than those for 0 N, 1/2 N, and N treatments, respectively (p < 0.05). The average annual N2O emissions from 1/2 N + PM were 51% lower than those from the N treatment. Compared to 0 N, 1/2 N and N treatments, the average NGHGE for 1/2 N + PM decreased by 41%, 41%, and 52%, and the average greenhouse gas intensity (GHGI, the yield-scaled NGHGE) from 1/2 N + PM reduced by 67%, 52%, and 53%, respectively. The decreases in NGHGE and GHGI were predominantly due to increased SOCSR (contributions of 187–308% and 81–325%, respectively) in 1/2 N + PM. The average soil nitrate, microbial biomass carbon and nitrogen, soil organic carbon contents, and pH value for 1/2 N + PM treatment were higher than those for the 1/2 N and N treatments (p < 0.05). Compared to 0 N and 1/2 N treatments, 1/2 N + PM treatment significantly increased the average rice yield. However, no significant difference in average yield was observed between the 1/2 N + PM and N treatments. Gross margin analysis showed that the economic profit for 1/2 N + PM was higher than that for the other three treatments. Thus, the combined application of reduced chemical fertilizers and pig manure is an effective and economic way to neutralize greenhouse gas emissions and increase soil fertility in double-rice cropping systems.