Influence Of Organic Amendments Research Articles

Effects of Organic Amendments on the Morphology and Chemical Composition of Black Mustard (Sinapis nigra L.) Grown on Soil Contaminated with Copper

The present study aimed to determine the influence of organic amendments (OAs) on neutralizing the harmful effect of copper (Cu) on black mustard (Sinapis nigra L.). In a pot experiment, three levels of copper pollution were used: 200, 400, and 600 mg Cu kg−1, against a control without Cu. The soil was amended with three types of OAs: pine bark (PB), peat moss (PM), and cattle manure (CM). Our research showed that plant condition depends on the Cu content in the soil. Increasing soil contamination significantly affected the plant yield, leaf greenness index, and dry matter content. The type of OA had no significant effect on the condition of black mustard (BM); however, each had a different effect on neutralizing the harmful effects of Cu. CM reduced Cu accumulation, PM showed no effect, while PB contributed to a significant increase in Cu content in BM plants. The chemical composition of BM depended on the Cu content in the soil. With increased soil contamination with Cu, the contents of Ntot, K, Mg, Ca, and Na in BM increased, while the content of P decreased. In terms of mitigating the harmful effects, CM was more beneficial than PM and PB. Among the analyzed OAs, CM, and PM contributed to Cu immobilization, while PB promoted Cu mobilization in contaminated soils.

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

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

Influence of organic amendments, PGPR and fermented folk liquid formulations on bell pepper in mid-hill conditions of Himachal Pradesh state of India

Bell pepper is an important cash crop of small farmers of Himachal Pradesh state of India. The present study was carried out in two consecutive years comprising seven treatments, as T1 being 100% recommended dose of nutrients alone and T2 to T7 included 90, 80, 70, 60, 50 and 40% RDN respectively; along with PGPR and fermented folk liquid formulations (panchagavya, jeevamrut and amritpani) which were replicated thrice in randomized block design. The recommended doses were given by vermicompost and poultry manure on nitrogen equivalence basis. Results of the study concluded that the application of PGPR with 90% RDN along with fermented folk liquid formulations significantly influenced bell pepper growth, quality, and yield parameters as well as soil organic carbon and available nutrient status including soil microbiological properties over the T1. The 90% RDN with PGPR and fermented folk liquid formulation also resulted in higher benefit cost ratio in comparison to T1 with 100% RDN, alone. Hence, it may be recommended to use conjoint application of PGPR, bulky manures and fermented folk liquid formulations to boost sustainable bell pepper production, higher economic returns and maintaining soil fertility status.

Influence of Organic Amendments Based on Garden Waste for Microbial Community Growth in Coastal Saline Soil

Garden waste compost (GWC) has been applied as an amendment to improve the desalination efficiency, nutrient availability and diversity of the microbial community in coastal saline soil. Understanding the response of the microbial community to garden waste compost application is of great significance in coastal ecological restoration. Four treatments were established: CK, nonamended control; T1, application of 68 kg·m−3 garden waste compost; T2, application of 15 kg·m−3 bentonite; and T3, a mixture of garden waste compost and bentonite. In addition, soil physicochemical properties, soil enzymes, microbial biomass carbon and the soil microbial community were measured. The results show that T3 had a more significant effect on increasing soil enzymes, as well as microbial biomass carbon and nitrogen, urease, sucrase and dehydrogenase activities. Based on the relative abundance, microbial diversity and linear discriminant effect size (LEfSe) analyses, the amendments can be seen to have increased the microbial abundance and alpha diversity of the bacterial structure and also altered the microbial community structure. RDA and Pearson correlation analysis at the phylum level indicated that available nitrogen, total porosity, hydraulic conductivity, bulk density and EC were the primary determinants of microbial communities associated with this amendment. In conclusion, the application of garden waste compost enables more microorganisms to participate in the soil material cycle, indicating that garden waste composting is beneficial to the restoration of coastal soils.

Effects of straw incorporation and straw-burning on aggregate stability and soil organic carbon in a clay soil of Bangladesh

The clay soil of Bangladesh is typically low in soil organic carbon (SOC) and generally has poor soil aggregate stability (measured as mean weight diameter, MWD). The addition of organic amendments in the field has the potential to increase soil organic matter (SOM) and MWD. However, the influence of organic amendments on aggregation in the clay soils of Bangladesh is largely unknown. A short-term (105 days) field study has been conducted to evaluate the effects of straw incorporation and straw-burning treatments on MWD and SOC in clay soil under eggplant (Solanum melongena L.). This study consisted of three treatments: (i) control (no amendments), (ii) rice straw (straw applied at 21 t ha−1), (iii) rice straw-burning (ash retained after burning at 7.4 t ha−1). Soil samples were collected after plant harvest, and then MWD, SOC, glomalin-related soil protein (GRSP), microbial biomass carbon (MBC), Fe-oxides, and available soil nutrients (e.g., N, P, K, S, Na, Ca, and Mg) were determined. Our results showed that MWD in straw addition treatment was on average 2 times higher, whereas SOC was 1.3 times higher compared to the control and straw-burning treatments, respectively (P < 0.05). Conversely, the straw-burning treatment reduced the MWD by 19% and the SOC by 20% compared to the control treatments (P < 0.05). Significant improvements in the available K, S, and Mg content of soil were found in the straw incorporation treatment (P < 0.05). We did not find any significant influence of the treatments on the MBC and GRSP content of the soil. Soil organic carbon had a significant correlation with MWD (R2 = 0.80**, P < 0.01), while GRSP and Fe-oxides did not show any relationship with MWD (P > 0.05). Our study demonstrates that the incorporation of rice straw has the potential to increase soil aggregation and SOC stock, at least for the short term in the clay soils of Bangladesh.

Influence of Organic Amendments and Fertigation on Growth, Yield, Quality of Watermelon (CitrulluslanatusThunb.) and Available Nutrient Status in Their Land (Red Sand Dune) of Southern Tamil Nadu

The present investigation was carried out at Thirumaraiyur village, Sattankulamtaluk, Thoothukudi district, to study the effect of organic amendments with the recommended dose of fertilizers on the growth and yield of watermelon in Ther isoil (red sand dunes) during the year 2017 and 2018. The experiment was laid out in Randomized Block Design with Factorial concept (FRBD). There were three factors as organic amendments with 6 treatment combinations for each factor, which were assigned at random in each plot with three replications. The recommended dose of fertilizers in treatments was two levels 75 and 100 percent. Among the treatment combinations, the tank silt application @ 100 t ha-1 with 100 per cent recommended fertilizer as 200:100:100 kg of NPK ha-1 through Fertigation at 7 days interval (A1N5) produced the maximum number of branches (10.67), longest vine (362.0 cm), number of fruits plant-1 (2.57), the weight of fruit (5.27 kg), fruit yield (68.77 t ha-1), total soluble solid (TSS) 10.94%), ascorbic acid (8.08 (mg 100g-1), gross return ( 4,09,320/ha), B:C ratio (2.45), uptake of NPK 41.51, 3.93 and 31.94 kg ha-1, respectively) compared to other treatments. Significant built-up of organic carbon (0.52%), available N (253.47 kg ha-1 ), P (16.40 kg ha-1) and K (218.40 kg ha-1) were registered with the application of tank silt application @ 100 t ha-1 with 100 per cent recommended fertilizer as 200:100:100 kg of NPK ha-1 through Fertigation at 7 days interval (A1N5).

Influence of Organic Amendments on Soil Carbon Sequestration Potential of Paddy Soils under Two Irrigation Regimes

Soil organic carbon (OC) is one of the most important soil components regulating soil quality, fertility and agronomic productivity as well as the global carbon (C) cycle. Soil acts as a sink for global C, which can be influenced by the water regime and organic matter (OM) management in field. The aim of this study is to evaluate the effect of the application of different organic amendments on C sequestration in paddy soils under contrasting irrigation regimes. A 4-month pot experiment was conducted under net house conditions and the treatments were composed of two organic amendments: rice straw (RS) and poultry manure (PM); four application rates of amendment: 0 g (control), 2.5 g, 5.0 g and 15.0 g kg−1 soil; and two irrigation regimes: (i) continuous waterlogging condition (CWL) and (ii) alternate wetting and drying (AWD). After the incubation period, soil samples were collected from the pot and isolated into labile (&gt;53 µm) and mineral-associated (&lt;53 µm) OM. Bulk (before and after incubation) and fractionated soil samples were analyzed for OC, total nitrogen (N), C:N ratio; and C sequestration percentage was calculated. Relatively higher amounts of soil OC were present in CWL condition (1.23%) than AWD (1.13%). The C sequestration potential also showed the similar trend (CWL: 47% &gt; AWD: 35%). This was explained by the induced aerobic condition in between the anerobic condition in AWD and the continuous anaerobic condition in CWL which resulted in a difference in OM decomposition. The mineral-associated OM fraction (&lt;53 µm) was higher in the CWL condition than AWD condition which also indicated the importance of the chemical stabilization of OC (OC bound to minerals) in the CWL condition. The application of PM led to a significant increase (45%) in C sequestration potential than RS (37%). This could be attributed to C:N ratio and probable biochemical composition of amendments which resulted in lower decomposability of PM than RS, and also in line with the higher distribution of OC in mineral-bound OM than labile fraction. The application of higher organic amendments did not increase OC content, and declined C sequestration potential in soils as the microbial activity presumably did not match with the amendment amount. Overall, C sequestration potential was higher with 5 g PM kg−1 soil application under CWL-irrigated paddy soil. The findings indicated the need to pay more attention to the selection of the proper type and rate of organic amendments for higher C sequestration in soil under a specific irrigation system for sustainable agriculture.

Influencia de las enmiendas orgánicas en el suelo y el comportamiento agronómico de Chenopodium quinoa Willd. en el Altiplano peruano

Quinoa has high nutritional value and its consumption has increased worldwide. The objective of the research was to determine the influence of organic amendments on the soil and the agronomic behavior of the crop. It was evaluated in two localities (Cruz Mayo and Cahualla), two organic amendments with the control. A randomized Complete Block Design (DBCA) with six treatments and four repetitions was used. Chemical characteristics of the soil and agromorphological characteristics of the crop were evaluated. Data was subjected to analysis of variance, Tukey test, and principal component analysis. A greater increase in pH was found with T2 (6,87), the highest electrical conductivity with T5 (0,20 mmhos/cm). Regarding the values of organic matter, nitrogen, phosphorus and potassium, T3 was higher with values of 3.05, 0.16, 12.99 and 592.16 respectively. Regarding theyield, the T5 was higher (2036.13 kg/ha). Finally, regarding plant height, length and panicle diameter, the highest values were with T3 with 143.75,26 and 19.75 cm respectively.Correlation was found between the chemical characteristics of the soil with the yield and agromorphological characteristics. Organic amendments significantly improve the chemical characteristics of degraded soils.

Influence of Organic Amendments and Moisture Regime on Soil CO2-C Efflux and Polycyclic Aromatic Hydrocarbons (PAHs) Degradation

In this study, a 30-day incubation experiment was performed to investigate the interactive effects of soil moisture content and two types of organic manure (animal manure: M and wheat straw: WS) on organic C mineralization and the degradation of PAH compounds. Specifically, washed sandy soil sample free from PAHs was treated with combined standard solution containing six different PAHs; pyrene (Pyr), fluoranthene (Flt), benzo[a]pyrene (BaP), benzo[g,h,i]perylene (BghiP), benzo[k]fluoranthene (BkF), and indeno[123-cd]pyrene (IP). The soil samples treated with PAHs were amended with M or WS and then, the soil samples were incubated and subjected to two levels of moisture content (50% and 100% field capacity, FC). The results indicate that CO2–C rates were the highest at day 1, but they tended to be decreased sharply when incubation time increased. The results showed that the higher rate of CO2-C efflux rate and cumulative were observed in M and WS treatments at 100% FC. Applying organic amendments at 50% FC increased the total cumulative CO2-C from 21.6 mg kg−1 to 228 mg kg−1 for M and to 216 mg kg−1 for WS. Meanwhile, applying organic amendments at 50% FC increased the total cumulative CO2-C from 30 mg kg−1 to 381 mg kg−1 for M and to 492 mg kg−1 for WS. The highest increases at 100% FC could be explained by the optimum water content at field capacity. PAHs concentrations decreased significantly in the presence of organic amendments in relation to enhance CO2-C efflux (soil respiration) and to decrease soil pH. It could be concluded that applying organic amendments might be a useful technique to remediate soil PAHs through mineralization.

Organic amendments enhance soil microbial diversity, microbial functionality and crop yields: A meta-analysis

Fertilization plays an important role in changing soil microbial diversity, which is essential for determining crop yields. Yet, the influence of organic amendments on microbial diversity remains uncertain, and few studies have addressed the relative importance of microbial diversity versus other drivers of crop yields. Here, we synthesize 219 studies worldwide and found that organic amendments significantly increased microbial diversity components (i.e., Shannon, richness, and phylogenetic diversity) and shifted microbial community structure compared to mineral-only fertilization. The performance of microbial alpha diversity varied substantially with organic amendment types, microbial groups and changes in soil pH. Both microbial diversity and community structure exhibited significantly positive relationships with microbial functionality and crop yields. In addition, soil abiotic properties and microbial functionality had a much stronger impact on crop yields than microbial diversity and climate factors. Partial least squares path modeling showed that soil microbial diversity was an important underlying factor driving crop yields via boosting soil microbial functionality. Overall, our findings provide robust evidence for the positive diversity-functions relationships, emphasizing that substituting mineral fertilizers with organic amendments is a promising way to conserve microbial diversity and promote soil microbial functions and crop yields.

Influence of organic amendments on acidic soil responsive crop groundnut (Arachis hypogaea L.)

AbstractThe present study evaluated the comparative effects of organic amendments on physiology, growth, and yield of acidic soil responsive crop groundnut and soil physicochemical and biochemical (dehydrogenase, acid phosphatases, and glucosidase activity) parameters. The treatments comprise of control (recommended dose of fertilizer or RDF), lime at 25% (L25 + RDF) and 100% lime requirement (L100 + RDF), farmyard manure+ RDF, compost+ RDF, poultry manure+ RDF, and pig manure+ RDF. The impact of organic amendments was also investigated on root exudation and crop parameters in a controlled growth chamber. At active growth stage, organic amendment application especially poultry and pig manures maintained higher leaf cell membrane integrity, chlorophyll content and stomatal frequency/or density compared to other treatments. Soil available P under organic manure (particularly pig and poultry manure) or lime was significantly higher over control. In contrast, exchangeable acidity and readily soluble Al were significantly lower under pig and poultry manure. Increased soil P availability was due to P availability from manure, increased soil pH, exchangeable Ca + Mg, organic carbon and enzyme activities, and reduction in exchangeable acidity and readily soluble Al as evident by their significant correlation with soil available P. In conclusion, pig and poultry manures seems to be effective substitute of lime for amelioration of soil acidity by maintaining favorable soil pH, organic carbon and microbial biomass carbon, available nutrients, exchangeable Ca and Mg, enzyme activities, and thereby improved plant physiological condition. These findings confirmed the applicability of poultry and pig manures as recyclable low‐cost farm wastes as alternative liming materials in acidic soils.

Influence of Organic Amendments on Soil Fertility and the Growth of Maize (Zea Mays)

In recent years, the application of poultry manure and compost as a soil amendment has generated huge interest for the preservation of soil fertility by improving the physicochemical and biological properties of soil, and for the reduction of the negative effects of greenhouse emissions. In this study, we investigated the effect of two soil amendments, namely poultry manure and compost, on soil parameters and their influence on maize growth performance. The experiment was conducted at the nursery site at the University of Energy and Natural Resources where organic amendments were applied to the soil at different application rate compost (10 t/ha and 5 t/h) and poultry (10 t/ha and 5 t/h, respectively). The results show that organic amendments increased the NPK content of the soil. Plant growth parameters are also increased by the application of the organic amendment. There was no significant improvement in plant height, plant girth, and the number of leaves with the application of both poultry manure and compost. However, biomass yield and leaf area of plants significantly increased in soils amended with poultry manure and compost. Poultry manure was found to contain higher nutrients and contributed to higher maize growth than compost and the control. This study showed that organic amendments increased soil fertility and crop growth.

Fate of pendimethalin in soil and characterization of non-extractable residues (NER)

One important route of degradation of herbicide pendimethalin in soil leads to formation of non-extractable residues (NER). To investigate NER nature (irreversibly, chemically bound, including possible biogenic NER, or strongly sorbed and entrapped) residues of 14C-labelled pendimethalin in soil were investigated after conventional extraction with organic solvents by silylation. After 400 days of incubation, 32.0% of applied radioactivity (AR) was transformed into NER, 39.9% AR remained extractable. Mineralization reached 26.2% AR. Additionally, 14C-pendimethalin was incubated in soil amended with compost for 217 days to investigate the influence of organic amendments on NER formation. NER amounted to 37.8% AR, with 57.9% AR remaining extractable. Mineralization was negligible (1.4% AR). For all sampling times only low amounts of radioactivity were entrapped (<5% AR) in soil without compost amendment. Pendimethalin was present only in trace amounts (ca. 0.4% AR), other released residues consisted of undefined fractions (sum ≈2% AR). In soil amended with compost, silylation overall resulted in release of higher amounts of radioactivity (19% AR). Addition of compost led to an increase in potential entrapment and sorption sites for pendimethalin, forming higher amounts of strongly sorbed, entrapped residues. Furthermore, potential release of non-extractable pendimethalin residues was investigated by incubation of solvent-extracted soil (without compost amendment) mixed with fresh soil for additional 3 months. NER were partly mineralized (7% AR) and 20% became extractable with organic solvents. However, no pendimethalin or any known metabolites were found.It can be concluded that no parent pendimethalin was found and NER of pendimethalin in soil are mainly formed by covalent binding to organic matrix with only low potential of remobilization under natural conditions.

Influence of Organic Amendments on Growth and Lead Uptake of Spinach (Spinacia oleracea L.) Grown in Lead-Contaminated Soil

Influence of Organic Amendments on Growth and Lead Uptake of Spinach (Spinacia oleracea L.) Grown in Lead-Contaminated Soil

Influence of organic amendments on dissipation and leaching potential of penoxsulam under laboratory conditions

ABSTRACTApplication of organic amendments to soil is a frequent agricultural practice for avoiding the irreversible soil degradation. However, this practice could modify the behaviour of applied herbicide. This study evaluates the impact of organic matter (OM) amendment on dissipation and leaching of penoxsulam. The addition of OM amendments enhanced the degradation rate of penoxsulam and 91.27, 89.46, 89.05 and 81.03% degradation was observed in press mud (PM), farmyard manure (FYM), poultry manure (POM) and vermicompost (VC)-amended soils after 30 days in comparison to 67.31% degradation in unamended soil. PM OM amendment was most effective in enhancing the degradation of penoxsulam. Three metabolites of penoxsulam were detected and depending upon the type of amendment there was variation in appearance and persistence of these metabolites in soil. The analysis of penoxsulam at different soil depths showed that it leached up to the depth of 30–40 cm in unamended and VC and FYM amended soil whereas to a depth of 20–30 cm in POM and PM-amended soil. The residual amounts of penoxsulam at lower depths were lesser in the amended soils than in unamended soil. None of the leachate fractions showed the presence of penoxsulam residues. The use of OM amendment in soil is an effective management practice for controlling potential pollution caused by penoxsulam to the environment.

The influence of organic amendments on the consumer features of jelly products

New products development improving human nutritional status and increasing the ingredients use efficiency with high functional properties in the production are key components of the State Policy Concept of the Russian Federation in the field of population healthy nutrition. Pectin containing raw materials with detoxifying and radioprotective properties belong to the main group of biologically active substances. Recently, natural products from fruit and vegetable raw materials without the artificial improvers use have become very popular, despite the short shelf life and higher cost. Among the sugary confectionery products, marmalade takes special place. Although it has low energy values, it has a low micronutrients amount. Moreover, in order to reduce the cost and extend the shelf life of the product, manufacturers often use synthetic additives, which negatively affects the consumers health. Therefore, the main direction of optimizing the nutritional value and developing a new range of marmalade is the infusions introduction of medicinal plants, fruit and vegetable raw materials into the recipes. The article considers the possibility of expanding the range of marmalade products using quince, the natural raw material. The high number of vitamins, minerals, organic acids, polyphenols, and aromatic substances in quince fruit indicates that it is promising for the prescription composition development for functional confectionery products. Given the availability, good preservation, low cost and high nutritional value, the researchers can recommend the quince use in marmalade technology, which will expand the range of jelly-fruit products and increase its biological value. The authors selected the structure forming agents of plant nature as substances that provide the desired structure of products; and determined the optimal concentration of each structure-forming agent. The thesis consists of mutual complex influence study of product components on consumer characteristics.

The role of organic amendments to soil for crop protection: Induction of suppression of soilborne pathogens

AbstractApplication of external organic inputs to soils can be considered as one of the most ancient strategies in agriculture, and it has been commonly used since the very beginning of human‐based agricultural practices. During all this time, application of several organic matters to agricultural soils has demonstrated their benefit to plants and soils. Organic amendments have proved to be useful in recovering soil properties, improving soil quality and, in some cases, can be directly involved in providing beneficial effects to plants. All these obtained effects finally lead to an increase in crop protection and sustainability. One most expected effect caused by the application of organic amendments, is the suppression of a wide range of soilborne pathogens (mainly bacterial and fungal pathogens) due to the induction of physicochemical and biological changes in soils. In order to get insight into the nature of the induced soil suppression of soilborne plant pathogens, the analysis of the physical, chemical and the microbial changes, pointed to the key role of beneficial activities produced by soil microorganisms finally adapted to the environmental changes produced by the influence of organic amendments. As shown in the case studies reported here, participation of soil microbes specifically selected after organic amendment is crucial in the control of fungal soilborne diseases. Moreover, the development of “omics” approaches allowed these recent studies to go one step further, revealing the main actors involved in the induced soil suppressiveness and their activities. Thus “omics” techniques will help to understand the soil and its microbiome as a whole system, and to assign the important roles of its biological components.

Understanding how long-term organic amendments increase soil phosphatase activities: Insight into phoD- and phoC-harboring functional microbial populations

In context of the use of organic materials as alternatives for mineral fertilizer, it is important to understand how organic amendments influence soil extracellular phosphatase activities which accelerate the mineralization of organic phosphorus (P). To address this, the current study investigates the influence of organic amendments on acid (ACP) and alkaline (ALP) phosphatase activities in soils and how organic amendments influence these activities from the perspective of microbially-mediated pathways. Herein, a comprehensive meta-analysis of 599 measurements from 106 published studies around the world was performed as well as a field component sourced from a 30-year-old field experiment on fertilization. Based on meta-analysis, organic amendments increased average extracellular ACP and ALP activities by 22% and 53%, respectively, in comparison to the mineral-only fertilization. Observed increases in activities were consistent with significant increases in soil organic carbon (C), total nitrogen (N) and available P contents, and microbial biomass C and N pools. According to the data from the long-term field experiment, we found phoD-harboring species encoding ALP were more closely correlated with phoC-harboring species encoding ACP in organically amended soils, and more network hubs were also observed by organic amendment. Soil C:P and N:P ratios, and microbial biomass C were the main predictors of the abundance, diversity, and composition of the phoC- and phoD-harboring populations. Further analysis revealed that the soil C:P ratio was identified as the dominant predictor of potential ACP and ALP activities. Our work highlights the importance in understanding how soil C:N:P stoichiometry mediates phosphatase-harboring populations in order to determine the downstream consequences of using organic amendments for increasing phosphatase activities.

Influence of Organic Amendment on Soil Respiration and Maize Productivity in a Semi-Arid Environment

Soil degradation and C emissions are a threat to sustainable agriculture in many arid and semi-arid areas. For sustainable agriculture, the influence of soil amendments on crop production and soil respiration has been a key focus of research. A three-year field study to assess how soil amendments influence soil properties, soil respiration (Rs), and yield of maize (Zea mays L.) was conducted. Treatments were: no amendment (NA), chemical fertilizer (CF), swine (Sus scrofa L.) manure (SM), maize stover (MS), and swine manure + chemical fertilizer (SC). Soil amendment (CF, SM, MS, and SC) consistently produced greatest grain yield and aboveground biomass, which averaged 38 and 34% greater than NA, respectively. No amendment reduced Rs by an average of 12% compared to amendment treatments. Enhanced grain yield with soil amendment resulted in increased carbon emission efficiency (CEE) with SC&gt;MS&gt;CF&gt;SM&gt;NA. Across years, SC decreased soil bulk density by 13% and increased CEE, soil total C, and soil hydraulic conductivity by 52, 19, and 21%, respectively, compared to NA. These results demonstrate the viability of swine manure + chemical fertilizer at 200 kg N ha−1 as a soil amendment for improved CEE and advancing sustainable maize production in semi-arid rainfed environments.

Influence of organic amendments used for benz[a]anthracene remediation in a farmland soil: pollutant distribution and bacterial changes

Organic amendments are usually carried out at field-scale for efficient remediation of organic pollutants; however, their effects on pollutant distribution and the corresponding microbial mechanisms were rarely discussed. The main aim of this study was to compare the fate of benz[a]anthracene in soil amended by several bioremediation materials and underlying microbial mechanisms. In this study, the potential for biotransformation of polycyclic aromatic hydrocarbon in a farmland soil was investigated in microcosms spiked with 14C-benz[a]anthracene as the tracer. A series of organic amendments including lignin, straw, mushroom culture waste, and cow manure, as well as a fungal inoculum of Pleurotus ostreatus, were compared. Illumina sequencing was introduced to reveal the bacterial community in different amendments. The metagenomic function was predicted with the bioinformatics tool of phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). From the results, the lignin-contained substrates (lignin, straw, mushroom culture waste) showed increase trend in the dissipation of benz[a]anthracene, while Pleurotus ostreatus and cow manure resulted in opposite trends. Specifically, mushroom culture waste mainly increased 14C to the formation of humin-bound residue (39.5 ± 6.8%); lignin amendment significantly (P < 0.05) enhanced the mineralization to CO2 (7.38 ± 0.89%) and humic acid–related nonextractable residue (9.77 ± 0.45%). The influence of straw on the environmental fate of benz[a]anthracene was marginal. High-throughput sequencing of 16S rRNA genes demonstrated that mushroom culture waste and lignin significantly changed bacterial community composition, leading to increases in the relative abundance of Pseudomonadaceae, Methylophilaceae, Bacillaceae, and Burkholderiaceae. Moreover, the result of PICRUSt showed that the genes-encoding bacterial cytochrome P450 enzymes were significantly increased in the lignin treatment, suggesting a possible co-metabolism between lignin degradation and PAH mineralization. These findings suggest lignin-containing organic amendments could be promising soil remediation agents of benz[a]anthracene by stimulating mineralization and sequestration of pollutants.