Animal Manure Compost Research Articles

Enhanced tomato (Solanum lycopersicum L.) yield and soil biological properties through integrated use of soil, compost, and foliar fertilization under greenhouse conditions

This study investigates the combined effects of standard soil fertilization, composted animal manure, and foliar fertilization on tomato yield, soil nutrient content, and soil biological properties under greenhouse conditions. The experiment was conducted from March to October 2023 using a completely randomized block design with four replications. The treatments included: 1) Control (no fertilization), 2) Standard soil fertilization (30 kg N/da, 8 kg P2O5/da, 40 kg K2O/da), 3) Standard soil fertilization + composted animal manure (2 t/da), 4) Standard soil fertilization + foliar fertilization (1 kg 17-17-17/100 liters of water every 20 days), and 5) Standard soil fertilization + compost + foliar fertilization. Tomato seedlings (Solanum lycopersicum L. cv. Roma) were transplanted into pots filled with clay soil. Throughout the experiment, soil moisture content was maintained at field capacity. Plants were harvested on October 30, 2023, and data on fruit yield, soil nutrient content (NPK), and soil biological properties (microbial biomass C, CO2 production, and dehydrogenase enzyme activity) were recorded. The highest yield (4.5 kg/plant) was observed in the treatment combining standard soil fertilization, composted animal manure, and foliar fertilization, representing a 275% increase compared to the control (1.2 kg/plant). The standard soil fertilization treatment alone yielded 2.8 kg/plant (133.3% increase), while the combination with composted animal manure yielded 3.5 kg/plant (191.7% increase), and with foliar fertilization, 3.9 kg/plant (225% increase). Soil analyses showed significant increases in available nitrogen, phosphorus, and potassium in the combined treatments. The highest biological properties were also recorded in the combined treatment.

Study of Steroid Estrogen Loss in Soil after the Application of Composted Manure as a Fertilizer

Steroid estrogens (SEs) play a significant role as endocrine-disrupting substances, and one of their major sources is animal manure. However, there is limited information available regarding the loss of SEs in farmland soil after the application of commercial composted animal manure or fertilizers. To address this gap, our study aimed to simulate rainfall and flood irrigation scenarios and investigate the loss characteristics of SEs, as well as Chemical Oxygen Demand (COD), Total Nitrogen (TN), and Total Phosphorus (TP) in runoff from soil–manure mixtures. The results demonstrated that the loss concentrations of SEs (73.1 ng/L of the mean E2β active equivalent factor) presented a potential environmental risk. Additionally, substituting composted manure with commercial organic fertilizers lead to a significant reduction in TP (maximum 56%) and TN (maximum 24%) loss. Consequently, the application of commercial organic fertilizers offers considerable advantages in maintaining nitrogen and phosphorus fertilization efficiency while controlling SEs loss. Furthermore, our study explored the synergistic pollution mechanism among these pollutants and observed significant correlations between SEs and TN, TP, and COD loss concentrations, indicating the simultaneous occurrence and migration of these pollutants in agricultural non-point source pollution. These results provide valuable insights into the environmental risk associated with SEs from agricultural non-point sources.

Dynamics of antibiotic resistance genes and the association with bacterial community during pig manure composting with chitin and glucosamine addition.

In modern ecological systems, the overuse and misuse of antibiotics have escalated the prevalence of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), positioning them as emerging environmental contaminants. Notably, composting serves as a sustainable method to recycle agricultural waste into nutrient-rich fertilizer while potentially reducing ARGs and MGEs. This study conducted a 47-day composting experiment using pig manure and corn straw, supplemented with chitin and N-Acetyl-D-glucosamine, to explore the impact of these additives on the dynamics of ARGs and MGEs, and to unravel the interplay between these genetic elements and microbial communities in pig manure composting. Results showed that adding 5% chitin into composting significantly postponed thermophilic phase, yet enhanced the removal efficiency of total ARGs and MGEs by over 20% compared to the control. Additionally, the addition of N-Acetyl-D-glucosamine significantly increased the abundance of tetracycline-resistant and sulfonamide-resistant genes, as well as MGEs. High-throughput sequencing revealed that N-Acetyl-D-glucosamine enhanced bacterial α-diversity, providing diverse hosts for ARGs and MGEs. Resistance mechanisms, predominantly efflux pumps and antibiotic deactivation, played a pivotal role in shaping the resistome of composting process. Co-occurrence network analysis identified the key bacterial phyla Proteobacteria, Firmicutes, Gemmatimonadota, and Myxococcota in ARGs and MGEs transformation and dissemination. Redundancy analysis indicated that physicochemical factors, particularly the carbon-to-nitrogen ratio emerged as critical variables influencing ARGs and MGEs. The findings lay a foundation for the developing microbial regulation method to reduce the risks of ARGs in animal manure composts.

Root response and phosphorus acquisition under partial distribution of phosphorus and water‐soluble organic matter

AbstractUnderstanding how phosphorus and water‐soluble organic matter (WSOM) from animal manure compost contribute to root development is essential for enhancing phosphorus utilization efficiency under their combined application. This study aims to determine mechanisms underlying root responses and phosphorus acquisition based on the partially varying available phosphorus levels in root zone soil following WSOM. The plant growth test was performed using a specifically designed pot where the root elongation was guided into the soil of different root compartments with either phosphorus combined with WSOM or single phosphorus or WSOM. The results revealed high levels of available phosphorus in the root zone soil of individual plants in the presence of WSOM induced small root weight. Phosphorus concentrations in the root exhibited a negative correlation with root weight. Improved root structure development even in the presence of WSOM induced to increase uptake of phosphorus and other nutrients in the plant. Furthermore, a positive linear relationship was observed between nutrient uptake and aboveground dry weight. These findings provide pioneering experimental evidence demonstrating that root development varies to some extent depending on the level of available phosphorus induced by the combined application of phosphorus and WSOM, even within the root zone soil of individual plants. Given that plant growth varied based on partial root development even when phosphorus and WSOM were combined, this study suggests that implementing appropriate phosphorus fertilizer application while considering the augmented availability of phosphorus via the combined application of animal manure compost can promote root development and nutrient uptake, resulting in improved plant growth.

A Critical Overview on Recent Avenues in Co-Composting of Animal Manure with Other Organics of Varying Toxicity

Proper management of livestock invariably includes sustainable methods of reusing their manure. Considering the global scenario of animal manure handling and the need for sustained agricultural production, there is clear lack of a focused approach in achieving the environmental and economical resilience in small-scale farms. Present study reviews the possibility of employing co-composting as a suitable technology for safe and effective handling of animal manure along with other wasted materials of organic nature. The review identifies the scope of effective co-composting using different mixtures of manure, greens and bulking agents to achieve required stability and nutrient content of the product. The study highlights the state of the art in terms of (i) carbon and nitrogen transformation after composting, (ii) challenges in preparing ambient conditions, and (iii) feedstock selection to optimize the mix proportions. The study also highlights the challenges in preparation and application as well as the risks involved in handling emerging contaminants (toxins) such as hormones and antibiotics in manure in producing good quality compost, thereby breaking the chain of their reentry to the food cycles. The results of the study would impart sound technological interventions required to make the best use of animal manure compost in low fertile soils.

A Comparative Study on the Nutrients in Organic Fertilizers and Garden Soil in Tirunelveli

Organic fertilizers are natural compounds made from waste or by-products and human assistance is limited to physical extraction or processing steps. Examples of commonly used organic matter include sewage sludge, food processing waste, composted animal manure, and urban biosolids. In this study, an attempt was made to examine the nutritional value of Lyroderma lyra (giant pseudo-vampire bat) bat guano, garden soil, and earthworm compost. Essential elements (macro elements - N, P, K, NO3, NO2, Pi, PO3), trace elements (Na, C, Fe, Mn, Zn, Cl), meso elements (Mg, Ca, SO4)) from this study The identified non-essential elements (Al), toxic elements (Ba) and pH were analysed and compared. Earthworm compost is rich in No3, No2, Pi, PO3, Ca, Mg, SO4, C, Fe, Zn, Mn and Cl. On the other hand, bat guano is rich in N, K and Na. The garden soil was rich in Cl, Mg, Ca, N. No toxic element was found in the garden soil but found in very low levels in both vermicompost and bat guano. In summary, these elements improve soil health and gradually release necessary nutrients into the soil as essential elements. This study suggests the need for prior soil studies and the need to better balance the effects of different organic matter on plant growth.

Contribution of Soluble and Non-soluble Organic Matter Derived from Animal Manure Composts to Enhance Phosphorus Availability in Soil

Contribution of Soluble and Non-soluble Organic Matter Derived from Animal Manure Composts to Enhance Phosphorus Availability in Soil

Cattle-compost-soil: The transfer of antibiotic resistance in livestock agriculture.

Antibiotic resistance is a major global health threat. Agricultural use of antibiotics is considered to be a main contributor to the issue, influencing both animals and humans as defined by the One Health approach. The purpose of the present study was to determine the abundance of antibiotic-resistant bacterial populations and the overall bacterial diversity of cattle farm soils that have been treated with animal manure compost. Soil and manure samples were collected from different sites at Tullimba farm, NSW. Cultures were grown from these samples in the presence of 11 commonly used antibiotics and antibiotic-resistant bacteria (ARB) colonies were identified. Soil and manure bacterial diversity was also determined using 16S ribosomal RNA next-generation sequencing. Results showed that ARB abundance was greatest in fresh manure and significantly lower in composted manure. However, the application of composted manure on paddock soil led to a significant increase in soil ARB abundance. Of the antibiotics tested, the number of ARB in each sample was greatest for antibiotics that inhibited the bacterial cell wall and protein synthesis. Collectively, these results suggest that the transfer of antibiotic resistance from composted animal manure to soil may not be solely mediated through the application of live bacteria and highlight the need for further research into the mechanism of antibiotic resistance transfer.

Dose-dependent impact of compost on rhizosphere bacterial community in heavy metal-contaminated paddy soil

Different doses (1%, 5%, 10%, mass fraction) of animal manure compost were added into a multi-heavy metal contaminated paddy soil for 150 d, and the changes in microbial structure and composition were evaluated. Compost exhibited dose-dependent effects on the rhizosphere bacterial community. Low (1%) and middle (5%) additions of compost exerted more distinct influence on bacterial community structure in rhizosphere soil than in bulk soil. The bacterial diversity after addition of compost decreased in rhizosphere soils compared with that in bulk soil. Results of redundancy analysis (RDA) indicated that different responses of rhizosphere and non-rhizosphere bacterial community to the changed soil physicochemical properties (soil pH, Pb, Cd and Cu levels) might be one reason for the differences. Thus, in agricultural management practice, the influence of compost on rhizosphere microbes should be considered.

Phytotoxicity of farm livestock manures in facultative heap composting using the seed germination index as indicator

Static facultative heap composting of animal manure is widely used in China, but there is almost no systematic research on the phytotoxicity of the produced compost. Here, we evaluated the phytotoxic variation in compost produced by facultative heap composting of four types of animal manure (chicken manure, pig manure, sheep manure, and cattle manure) using different plant seeds (cucumber, radish, Chinese cabbage, and oilseed rape) to determine germination index (GI). The key factors that affected GI values were identified, including the dynamics of the phytotoxicity and microbial community during heap composting. Sensitivity to toxicity differed depending on the type of plant seed used. Phytotoxicity during facultative heap composting, evaluated by the GI, was in the order: chicken manure (0–6.6 %) < pig manure (14.4–90.5 %) < sheep manure (46.0–93.0 %) < cattle manure (50.2–105.8 %). Network analysis showed that the volatile fatty acid (VFA) concentration was positively correlated with Firmicutes abundance, and NH4+-N was correlated with Actinobacteria, Proteobacteria, and Bacteroidetes. More bacteria were stimulated to participate in conversions of dissolved organic carbon, dissolved nitrogen, VFA, and ammonia-nitrogen (NH4+-N) in sheep manure heap composting than that in other manure. The GI was most affected by VFA in chicken manure and cattle manure heap composting, while NH4+-N was the main factor affecting the GI in pig manure and sheep manure compost. The dissolved carbon and nitrogen content and composition, as well as the core and proprietary microbial communities, were the primary factors that affected the succession of phytotoxic substances in facultative heap composting, which in turn affected GI values. In this study, the key pathways of livestock manure composting that affected GI and phytotoxicity were found and evaluated, which provided new insights and theoretical support for the safe use of organic fertilizer.

Organic Amendments: Direct Application and Residual Effects on Vegetative and Reproductive Growth of Hot Pepper.

The high production potential of coffee and animals in the Gedeo zone that could produce huge amounts of coffee pulp and animal manure wastes has been polluting the environment. In this sense, this study was aimed at averting pollution and managing plant and animal wastes, focusing on the effect of coffee pulp and animal manure in the form of vermicompost, biochar, and ordinary compost on hot pepper vegetative and reproductive growth. A 15 ton per hectare of each treatment was applied in a randomized complete block design replicated three times. Vegetative and reproductive growth parameters (plant height, leaf number, number of branches, days to 50% flowering, total fresh biomass, number of fruits per plant, single fruit length, and fruit yield per hectare) were recorded, and the statistical difference was determined at 5% significance level using R-program. The result showed that there was a significant difference among treatments. Coffee pulp vermicompost prepared using Eisenia fetida earthworm had significantly (P < 0.05) higher results in plant height, leaf number, number of branches, total fresh biomass, number of fruits per plant, single fruit length, and total yield, while the minimum values were recorded in topsoil (control treatment) and animal manure compost. The direct and residual effects of vermicompost and biochar organic amendments were the potential organic fertilizers for hot pepper fast growth and to produce enormous yield, which might be due to their nature in improving soil physicochemical and biological properties as well as nutrient uptake.

Metagenomic assembly reveals hosts and mobility of common antibiotic resistome in animal manure and commercial compost

BackgroundAntibiotics and antibiotic resistance genes (ARGs) used in intensive animal farming threaten human health worldwide; however, the common resistome, ARG mobility, and ARG host composition in different animal manures and mixed manure composts remain unclear. In the present study, metagenomic assembly and cross-sample mapping were used to comprehensively decipher the common resistome and its potential mobility and hosts in animal manure and composts.ResultsIn total, 201 ARGs were shared among different animal (layer, broiler, swine, beef cow, and dairy cow) manures and accounted for 86–99% of total relative abundance of ARGs. Except for multidrug, sulfonamide, and trimethoprim resistance genes, the relative abundance of most ARGs in composts was significantly lower than that in animal manure. Procrustes analysis indicated that antibiotic residues positively correlated with ARG composition in manure but not in composts. More than 75% ARG subtypes were shared between plasmids and chromosomes in our samples. Transposases could play a pivotal role in mediating the transfer of ARGs between different phyla in animal manure and composting. Cross-sample mapping to contigs carrying ARGs showed that the hosts of common resistome in manure had preference on animal species, and the dominant genus of ARG host shifted from Enterococcus in manure to Pseudomonas in composts. The broad host range and linking with diverse mobile genetic elements (MGEs) were two key factors for ARGs, such as sul1 and aadA, which could survive during composting. The multidrug resistance genes represented the dominant ARGs in pathogenic antibiotic-resistant bacteria in manure but could be effectively controlled by composting.ConclusionsOur experiments revealed the common resistome in animal manure, classified and relative quantified the ARG hosts, and assessed the mobility of ARGs. Composting can mitigate ARGs in animal manure by altering the bacterial hosts; however, persistent ARGs can escape from the removal because of diverse host range and MGEs. Our findings provide an overall background for source tracking, risk assessment, and control of livestock ARGs.

Effects of Faba Bean Strip Cropping in an Outdoor Organic Tomato System on Soil Nutrient Availability, Production, and N Budget under Different Fertilizations

Crop diversification has been identified as a tool to improve both productive and environmental performances of organic horticulture. We tested the introduction of faba beans in a tomato cropping system—both as preceding crop and in strip cropping (SC)—under different fertilization strategies—faba residues, animal manure, and vegetable compost. We studied: (i) the tomato nutrient uptake and yield and quality; (ii) the soil-N and P, the N-budget, and the mycorrhizal colonization. SC did not provide consistent positive effects on tomato production and quality, namely the N-uptake, N in the tomato yield, the mean fruit weight, and the sugar accumulation in berries, regardless of the type of fertilizers applied. SC improved the tomato dry yield and P-uptake, especially in years when the faba growth and the subsequent yield were problematic. Faba residues could provide sufficient N to sustain tomato production but care should be given in balancing additional N-inputs. Organic fertilization increased the soil-N concentration but did not always translate into an increased yield and a higher quality production, with the risk of escalating N-losses. SC improved the soil-P availability and mycorrhizal colonization in tomato, due to the rhizobia–mycorrhiza-mycorrhiza association, especially when coupled with organic fertilization. Finally, introducing faba as SC holds potential to improve the productive and environmental performance of organic tomato production.

Aerosolization Behaviour of Fungi and Its Potential Health Effects during the Composting of Animal Manure

Compost is an important source of airborne fungi that can adversely affect occupational health. However, the aerosol behavior of fungi and their underlying factors in composting facilities are poorly understood. We collected samples from compost piles and the surrounding air during the composting of animal manure and analyzed the aerosolization behavior of fungi and its potential health effects based on the fungal composition and abundance in two media using high-throughput sequencing and ddPCR. There were differences in fungal diversity and richness between the air and composting piles. Ascomycota and Basidiomycota were the two primary fungal phyla in both media. The dominant fungal genera in composting piles were Aspergillus, Thermomyces, and Alternaria, while the dominant airborne fungal genes were Alternaria, Cladosporium, and Sporobolomyces. Although the communities of total fungal genera and pathogenic/allergenic genera were different in the two media, fungal abundance in composting piles was significantly correlated with abundance in air. According to the analysis on fungal composition, a total of 69.10% of the fungal genera and 91.30% of pathogenic/allergenic genera might escape from composting pile into the air. A total of 77 (26.64%) of the fungal genera and six (20%) of pathogenic/allergenic genera were likely to aerosolize. The influence of physicochemical parameters and heavy metals on the aerosol behavior of fungal genera, including pathogenic/allergenic genera, varied among the fungal genera. These results increase our understanding of fungal escape during composting and highlight the importance of aerosolization behavior for predicting the airborne fungal composition and corresponding human health risks in compost facilities.

Indigenous organic resources utilization, application methods and sowing time replenish soil nitrogen and increase maize yield and total dry biomass

Wise management of indigenous resources replenishes soil nutrients and improves crop productivity and soil sustainability. Three year consecutive experiments were performed in the framework of Farmers Field School (FFS) during 2012–2014. Organic nitrogen sources [animal-urine (AU), animal-manures (AM), and animal manure-compost (AMC) with two application methods [interior-application method (IAM) and exterior-application method (EAM)] and three sowing timing [early sowing (ES), late-sowing (LS), and timely sowing (TS)] were studied. One control plot in each replication was placed as a check. The results showed that among different sowing time, TS has higher grains year−1, 1000 grains weight, dry biomass, grain yield and harvest index (HI) than LS and ES. AM delayed silking and physiological maturation. A higher grains year−1, 1000 grains weight, grain yield, total dry biomass, and HI were observed with AMC than control plots. In application methods, the IAM has delayed the silking and physiological maturity as compared to EAM. Similarly, higher grains year−1, 1000 grains weight, grain yield, dry biomass, and HI were observed with IAM than EAM. In sowing timing, higher grain nitrogen (GN) was observed in TS. Higher GN produced by AMC and AU treated plots. AMC produced 10% higher GN than manures treated plots. The IAM produced higher GN than EAM. The AMC produced significantly higher soil N and statistically at par with AU treated plots. IAM applied AMC, maize grain yield was higher than the AU and AM. In conclusion, AMC and AU embedded in soil with TS can sustainably increase maize yield and soil productivity.

Deodorization of the off-gas from livestock manure aerobic composting tank using biotrickling filters and its mechanism

In this study, two biotrickling filters (BTFs) were fabricated to treat the off-gas produced during the aerobic composting of animal manure, namely: BTF-A (packed with volcanic rock) and BTF-B (packed with ceramsite). The results showed that the major contributors to the odor level of the off-gas were ammonia (NH3) and total volatile organic compounds (TVOCs). The removal efficiencies of BTF-B for NH3, TVOCs, and odor level (88.78 ± 5.03%, 70.25 ± 6.95% and 88.10 ± 13.21%, respectively) were superior to those of BTF-A. Partial nitrification was achieved in the circulating water with a pH of 7.0–8.2, dissolved oxygen (DO) content of 1–3 mg/L, and an average free ammonia (FA) content of 16.65 mg/L (without denitrification occurring). Ca. Nitrosoglobus was observed as the dominant ammonia-oxidizing bacteria in the BTF deodorization process. In addition, a deodorization mechanism based on Ca. Nitrosoglobus and Ralstonia sp. in the biofilm on packings was proposed.

Lagoon, Anaerobic Digestion, and Composting of Animal Manure Treatments Impact on Tetracycline Resistance Genes.

Increased demand for animal protein is met by increased food animal production resulting in large quantities of manure. Animal producers, therefore, need sustainable agricultural practices to protect environmental health. Large quantities of antimicrobials are used in commercial food animal production. Consequently, antimicrobial-resistant bacteria and the resistance genes emerge and are excreted through feces. Manure management is essential for the safe disposal of animal waste. Lagoons, with or without covers, and anaerobic digesters, with the primary purpose of methane production, and composting, with the primary purpose of producing organic fertilizer, are widely used methods of manure treatment. We reviewed manure management practices and their impact on tetracycline resistance genes. Lagoons are maintained at ambient temperatures; especially uncovered lagoons are the least effective in removing tetracycline resistance genes. However, some modifications can improve the performance of lagoons: sequential use of uncovered lagoons and the use of covered lagoons resulted in a one-log reduction, while post-treatments such as biofiltration following covered lagoon treatment resulted in 3.4 log reduction. Mesophilic digestion of animal manure did not have any significant effect; only a 0.7 log reduction in tet(A) was observed in one study. While thermophilic anaerobic digesters are effective, if properly operated, they are expensive for animal producers. Aerobic thermophilic composting is a promising technology if optimized with its economic benefits. Composting of raw animal manure can result in up to a 2.5 log reduction, and postdigestion composting can reduce tetracycline resistance gene concentration by >80%. In general, manure management was not designed to mitigate antimicrobial resistance; future research is needed to optimize the economic benefits of biogas or organic fertilizer on the one hand and for the mitigation of foodborne pathogens and antimicrobial resistance on the other.

Interactions between nitrogen release from organic fertilisers and organic horticultural soils

Mushroom compost has been one of the most commonly used fertilisers in organic greenhouse vegetable production in Iceland. However, mushroom compost contains conventional chicken manure. Therefore, the use of this fertiliser is prohibited in organic horticulture. In search of alternative nutrient resources, nine different substitutes for mushroom compost (plant compost, four composted animal manures, fishmeal, white clover residues, coarse meal of faba beans, ‘Pioner complete 6-1-3®’) were tested on two soils differing in organic matter in a pot experiment. Dry matter yield (DM) and the apparent N utilisation with the model plant perennial ryegrass was quantified in five cuts throughout 131 days. Both the DM yield and the apparent N utilisation was influenced by the fertiliser, the soil and their interaction. The N release of the tested alternative organic fertiliser resources was described by the N content and C:N ratio of the fertilisers, but was also affected by the soil. It was concluded that the composted animal manures provided an N release equal to mushroom compost and could therefore act as substitutes.

Phenology, growth, productivity, and profitability of mungbean as affected by potassium and organic matter under water stress vs. no water stress conditions

Pulses low yield in the arid and semiarid climates are imbalanced use of chemical fertilizers and no use of organic matter (animal and crop residues incorporation). The hypothesis was tested that integrated use of potassium (K) and animal manures could increase mungbean (Vigna radiata L. Wilczek) productivity and profitability in the semiarid climate of Peshawar. A field experiment was carried out to investigate the effect of organic matter (composted animal manures) (5, 10, and 15 t ha−1) and potassium (30, 45, and 60 kg ha−1) under irrigated (three irrigations, no water stress) and dryland or limited irrigated (one irrigation, water stresses before flowering and after pod formation) condition on mungbean (cv. Ramazan 92). The experiment was carried out in the summer of 2017 at Agronomy Research Farm, the results revealed that crop under no water stress had delayed phenological development (took more days to flowering, pod formation, and physiological maturity), better growth by producing taller plants with a more number of leaves, nodules, and pods plant−1, seeds pod−1, heavy 1000-grains weight, higher biological and grain yields than water stress condition. The experiment also confirmed that the combination of the highest rate of K and organic matter had improved the vegetative growth and development, and significantly increased yield and yield contributing parameters under both water stress and no stress conditions. It was concluded that mungbean yield and yield components increased with combined application of 60 kg K ha−1 + 15 t OM ha−1 under full irrigated (no water stress) and limited irrigated (water stress) conditions.

Compost and legume management differently alter soil microbial abundance and soil carbon in semiarid pastures

AbstractEstablishment of improved perennial pasture systems for livestock production has been demonstrated to improve soil health in the semiarid Texas Southern High Plains (SHP). Use of waste products from other components of the animal production chain, such as applying composted manure from feedlot operations to grazed pastures, may provide an additional means of improving soil health and sustainability of these systems. However, few studies have examined the impact of composted animal manure on the changes in soil microbial communities, although they are important indicators of soil health. We investigated the effects of a one‐time composted cattle manure application at 3.36 Mg ha−1 on soil microbial community size and structure, soil organic C (SOC), total N (TN), and soil organic matter (SOM) up to 1.5 yr after application. We compared pastures consisting of either WW‐B. Dahl Old World bluestem grass [Bothriochloa bladhii (Retz.) S.T. Blake] alone or in mix with alfalfa (Medicago sativa L.). Results showed that compost application significantly increased SOC by about 4.4 g kg−1 soil within 1.5 yr after application. In N‐fertilized grass‐only pastures, compost addition increased microbial phospholipid fatty acid abundance, SOC, TN, and SOM, but no significant differences were observed between compost treatments in unfertilized pastures containing legumes. Our results show that even a one‐time compost addition at a relatively low rate can augment SOC in this semiarid pasture system after 1.5 yr, and that stimulation of soil microbial abundance and soil C and N from compost is more pronounced in fertilized grass‐only pastures compared with those with legume establishment.