Crop Field Soil Research Articles

Estimation of evaporation of different cover types using a stable isotope method: Pan, bare soil, and crop fields in the North China Plain

The North China Plain (NCP) is one of the major crop production areas in China. However, severe water shortage is the primary limiting factor in this area. Quantifying evaporation loss under different cover types will make a huge contribution to reduce water consumption. This research estimated the evaporation from pan, bare soil, and irrigated winter wheat–summer maize field in the NCP using the isotope method. The results showed that the evaporation from the pan was the highest, followed by bare soil, while that from the soil surface with crop cover was the lowest. Water loss associated with soil particles and crop cover was decreased for 9 %∼77 %. The source of soil moisture was primary groundwater during the wheat season (April–June) and precipitation in the maize season (July–September). The crop field soil evaporation depth was 0–30 cm, which will be beneficial in determining the subsurface drip irrigation depth. This research will provide a scientific basis for developing an agricultural water-saving strategy for the NCP.

Assessing GHG cycling in agricultural and riparian soils using a uniform reactive transport modeling approach

Agricultural drainage ditches are necessary for regulating moisture contents in fields for crop production, and moreover, they can provide and regulate important ecosystem services. Drainage ditches and their associated riparian zones can be significant sources of enhanced N2O, CH4 and CO2 emissions, since they receive nutrient laden runoff and drainage from adjacent fields, while providing moisture conditions suitable for the production of greenhouse gases (GHGs). In this study, a uniform reactive transport model with up-scaled rate parameters was used to assess the dynamics of GHG cycling and biogeochemical processes in a crop field and riparian soils adjacent to a drainage ditch (i.e., located on the shoulder and midslope of the ditch) in eastern Ontario, Canada. Simulations adequately reproduced observed spatial variations in pore gas GHG concentrations in the cropped field and the monitoring locations near the drainage ditch. Spatial variations can be attributed to differences in environmental factors (i.e., soil moisture content and temperature), soil nutrient supply (i.e., NH4+, NO3–), and organic C availability. Simulation results also showed that at this site, GHG emissions did not vary significantly between monitoring locations, suggesting that the ditch slopes are not significant GHG emission hotspots. Both major rainfall events and warmer summer temperatures led to the development of hot moments for CO2 and N2O emissions and corresponding soil gas concentrations. Although the uniform model was successful in reproducing long-term trends in observed data, the model was not able to fully capture in-season temporal variability of fluxes and concentrations related to acute precipitation events (i.e., hot moments). Nevertheless, the modeling approach presented shows promise for future studies comparing the effect of management styles for agricultural soils and drainage ditch zones on GHG emissions and uptake.

Context Aware Evapotranspiration (ETs) for Saline Soils Reclamation

Accurate Evapotranspiration for saline soils (ETs) is important as well as challenging for the reclamation of saline soils through an effective leaching process. Evapotranspiration (ET) by FAO-56 Penman-Monteith standard method is complex, especially for saline soils. Moreover, existing studies focus on the use of the Internet of Things (IoT) and machine learning-enabled smart and precision irrigation water recommendation systems along with the ET estimation by limited parameters. The ETs for saline soils are also equally important for the reclamation of saline soils, which is ignored by the existing literature. The study proposed IoT and machine leaching-based architecture of context-aware monthly ETs estimations for saline soil reclamation with the effective leaching process. The IoT-enabled crop field contexts in terms of crop field temperature, soil salinity, and irrigation water salinity are used as input features to the Long Short-Term Memory (LSTM) and ensembled LSTM models for monthly ETs predictions. The performance of the proposed solution is observed in terms of the accuracy of the machine learning models along with the comparison against the FAO-56 PM-based standard method. The implementation of the proposed solution reveals that the ensembled LSTM-based approach for ETs is more accurate as compared to the LSTM model with accuracies of 92 and 90% for the training and validation datasets, respectively. The predictions made by the ensembled LSTM are more in line with the FAO-56 PM-based method with a Pearson correlation of 0.916 as compared to LSTM models. The implementation of the proposed solution in real-time environments reveals that the proposed solution is more effective in reducing the soil salinity as compared to the traditional method.

Spatiotemporal distribution and human health risk assessment of potential toxic species in soils of urban and surrounding crop fields from an agricultural area, Córdoba, Argentina.

The spatiotemporal distribution of potentially toxic species was studied in the topsoil of parks, playgrounds, and surrounding crop fields of Marcos Juarez City in Córdoba province, Argentina. The content of available metals and of some pesticides used in the region was determined. The mean values of available metal concentrations in all samples, expressed in mgkg-1, were 7.99 ± 6.58, 0.89 ± 0.71, 0.35 ± 0.26, and 1.50 ± 1.40 for Pb, Cr, Cd, and Ni, respectively. Pearson's correlation coefficients, coefficient of variation (%), and principal component analysis were used to explore whether variations in metal content were associated with anthropogenic factors. Agrochemicals such as lindane, chlorobenzilate, endosulfan, endrin, permethrin, and chlorpyrifos were found in crop field soil samples. In turn, chlorothalonil, chlordanes, methoxychlor, DDT, permethrin, and chlorpyrifos were detected in park and playground soil samples. The degree of pollution with possible effects on environmental health was evaluated using the Nemerow integrated pollution index (NIPI) and the modified degree of contamination (mCd). In some campaigns, the values obtained from crop fields ranged from low to high pollution levels during periods of agrochemical application. Noteworthy, in periods of low agrochemical application in crop fields, a high level of pollution was observed in parks and playgrounds. For children, the hazard index (HI) values were higher than the threshold value of 1, suggesting a potential health risk. This study provides valuable information regarding land management practices and highlights the importance of monitoring and implementing policies to reduce human health risks.

Antibiotic resistance gene dissipation in soil microcosms amended with antibiotics and swine manure.

The use of antibiotics in animal agriculture has exacerbated the presence of both antibiotic resistance genes (ARGs) and residual antibiotics excreted in animal manure. Field application of this manure is a common practice because its nutrient rich material can benefit crop growth. However, this practice can also introduce antibiotics and ARGs into nonagricultural settings. The integration of prairie buffer strips within and at the edge of crop fields is a potential management solution to reduce concentrations of ARGs commonly transported via water runoff and infiltration. An incubation experiment was conducted to investigate the fate of ARGs in directly manured crop field soils and the surrounding affected prairie strip soils. Row crop and prairie strip soils sampled from three sites received either an antibiotic spike and swine manure addition or a control water addition. The concentrations of select ARGs were then monitored over a 72-d period. Although soil vegetation and site location were not observed to influence ARG dissipation, the select genes did display different half-lives from one another. For example, tetM demonstrated the fastest dissipation of the genes quantified (average half-life,5.18 d). Conversely, sul1 did not conform to the first-order linear regression kinetics used to describe the other investigated genes and was highly abundant in control prairie strip soils. The quantified half-lives of these select ARGs are comparable to previous studies and can inform monitoring and mitigative efforts aimed at reducing the spread of ARGs in the environment.

Microbiome of abandoned agricultural and mature tundra soils in southern Yamal region, Russian Arctic

AbstractSoil microbiome plays a significant role in the development of the soil profile and the implementation of key soil biochemical processes. Observed Arctic warming creates significant environmental risks, since permafrost soils contain a huge amount of organic matter, which is in potential risk to be released in the form of greenhouse gases. This work is aimed to investigate the microbiomes in soils of mature tundra and anthropogenically affected areas of the Yamal region using a high-throughput sequencing approach. The taxonomic analysis of the soil microbiomes revealed 33 bacterial and archaeal phyla, among which the dominant wereProteobacteria,Acidobacteria,Actinobacteria,Bacteroides,Chloroflexi,Cyanobacteria,Firmicutes,Gematimonadetes,Patescibacteria,Plantomycetes,Thaumarchaeota,Verrucomicrobia, andWPS-2. The analysis of alpha and beta diversities revealed that undisturbed soil is completely different from anthropogenically affected ones in terms of microorganism biodiversity. Soils of the urban zone of Salekhard were found to be different with regard to the number of operational taxonomic units and beta diversity. Herein the microbiome in the upper and lower layers of soil developed under strong technogenic influence (M19) was unequal both in quality and in quantity. At the same time, soils developed in the recreational zone of Salekhard showed less differentiation profile of microbiome (former crop field and former vegetable garden soils). Microbial communities in the mature tundra soil showed less differentiated microbiome composition.

Potential of Atoxigenic Aspergillus flavus Vegetative Compatibility Groups Associated With Maize and Groundnut in Ghana as Biocontrol Agents for Aflatoxin Management.

Increasing knowledge of the deleterious health and economic impacts of aflatoxin in crop commodities has stimulated global interest in aflatoxin mitigation. Current evidence of the incidence of Aspergillus flavus isolates belonging to vegetative compatibility groups (VCGs) lacking the ability to produce aflatoxins (i.e., atoxigenic) in Ghana may lead to the development of an aflatoxin biocontrol strategy to mitigate crop aflatoxin content. In this study, 12 genetically diverse atoxigenic African A. flavus VCGs (AAVs) were identified from fungal communities associated with maize and groundnut grown in Ghana. Representative isolates of the 12 AAVs were assessed for their ability to inhibit aflatoxin contamination by an aflatoxin-producing isolate in laboratory assays. Then, the 12 isolates were evaluated for their potential as biocontrol agents for aflatoxin mitigation when included in three experimental products (each containing four atoxigenic isolates). The three experimental products were evaluated in 50 maize and 50 groundnut farmers’ fields across three agroecological zones (AEZs) in Ghana during the 2014 cropping season. In laboratory assays, the atoxigenic isolates reduced aflatoxin biosynthesis by 87–98% compared to grains inoculated with the aflatoxin-producing isolate alone. In field trials, the applied isolates moved to the crops and had higher (P < 0.05) frequencies than other A. flavus genotypes. In addition, although at lower frequencies, most atoxigenic genotypes were repeatedly found in untreated crops. Aflatoxin levels in treated crops were lower by 70–100% in groundnut and by 50–100% in maize (P < 0.05) than in untreated crops. Results from the current study indicate that combined use of appropriate, well-adapted isolates of atoxigenic AAVs as active ingredients of biocontrol products effectively displace aflatoxin producers and in so doing limit aflatoxin contamination. A member each of eight atoxigenic AAVs with superior competitive potential and wide adaptation across AEZs were selected for further field efficacy trials in Ghana. A major criterion for selection was the atoxigenic isolate’s ability to colonize soils and grains after release in crop field soils. Use of isolates belonging to atoxigenic AAVs in biocontrol management strategies has the potential to improve food safety, productivity, and income opportunities for smallholder farmers in Ghana.

De novo genome assembly and comparative annotation reveals metabolic versatility in cellulolytic bacteria from cropland and forest soils.

Cellulose, the most abundant polysaccharide in nature, is a rich source of renewable energy and sustains soil nutrients. Among the microorganisms known to degrade cellulose, bacteria are less studied compared to fungi. In the present work, we have investigated the culturable bacteria actively involved in cellulose degradation in forest and crop field soils. Based on clear zone formation and enzyme activity assay, we identified 7 bacterial strains positive for cellulose degradation. Of these, two most efficient strains (Bacillus cereus strains BHU1 and BHU2) were selected for whole genome sequencing, annotation, and information regarding GC content, number of genes, total subsystems, starch, and cellulose degradation pathways. Average nucleotide identity (ANI) showed more than 90% similarity between both the strains (BHU1 and BHU2) and with B. cereus ATCC 14579. Both the strains have genes and enzyme families like endoglucanase and β-glucosidase as evident from whole genome sequence. Cellulase containing gene families (GH5, GH8, GH1), and many other carbohydrate-degrading enzymes, were present in both the bacterial strains. Taken together, the results suggest that the strains were efficient in cellulose degradation, and can be used for energy generation and production of value-added product.

Degradation of Metal-Organic Framework Materials as Controlled-Release Fertilizers in Crop Fields.

The behavior of a metal-organic framework (MOF) compound synthesized in hydrothermal reaction conditions and rich in N, P, and Fe nutrients was explored in the field. The attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and laser induced breakdown spectroscopy (LIBS) characterization results showed that the chemical structures changed during the degradation process in crop field soil. The scanning electron microscope images showed that the micro-rod of the MOF peeled off and degraded in layers. During the growth period of wheat, the MOF degraded by 50.9%, with the degradation rate being closely related to soil temperature. It was also found that the degradation rate increased with soil temperature. Moreover, the nutrient concentration of the soil indicated that the MOF had stable nutrients release efficiencies and could provide a continuous supply of nutrients throughout the wheat growth period, which showed a great alternative for MOF as a fertilizer both benefiting agricultural production and environmental protection.

New Records of Aspergillus allahabadii and Penicillium sizovae from Crop Field Soil in Korea

Two new records of Trichocomaceae, namely Aspergillus allahabadii and Penicillium sizovae, were isolated in 2016 during a survey of fungal diversity in different crop fields locations in Gyeongnam, Korea. These species were identified based on morphological characters and phylogenetic analysis using internal transcribed spacer region and β-tubulin-encoding gene sequence data. A. allahabadii and P. sizovae have not yet been reported in Korea. Thus, this is the first report of these species in Korea, and their descriptions as well as details of their morphological characters are presented.

輪作の土壌学的研究(第3報) : 田畑転換牧草地土壌について

輪作の土壌学的研究(第3報) : 田畑転換牧草地土壌について

Profenofos Degradation Potential of Bacillus cereus and Aneurinibacillus migulanus Isolated from Paddy Crop Field Soil

The indiscriminate application of pesticides to increase crop production could have adverse impact on the biota. Profenofos is an organophosphate pesticide used to kill flying, crawling, chewing and sucking insects in paddy cultivation. The present research was designed to isolate the bacteria prevalent in profenofos exposed paddy crop field soil and to evaluate their potential to degrade profenofos in soil under laboratory conditions. Bacillus cereus and Aneurinibacillus migulanus were the dominant bacteria. Among them, Aneurinibacillus migulanus accelerated the degradation of profenofos within 36 hour when compared to the control. 1,3- dimethyl benzene and 4-phenyl but-3-ene-lyne were obtained as degraded products of profenofos in control, which were not detected in soil exposed to Bacillus cereus and Aneurinibacillus migulanus. On the other hand, n-propyl benzene was obtained as degraded metabolite in soil exposed bacteria, which were not detected in the control. Isopropyl benzene was detected in soil exposed to Bacillus cereus and 1,2,3-4-tetra methyl benzene was detected in soil exposed to Aneurinibacillus migulanus as byproducts of profenofos degradation when compared to the control. Thus, these bacteria could play a vital role in degrading profenofos in soil.

Two New Records of Ascomycetes from Crop Field Soils in Korea

In the ongoing survey of fungal diversity in Korea, two Ascomycetes species, namely Rhinocladiella similis and Toxicocladosporium irritans, were isolated in 2016. These species were identified based on the internal transcribed spacer region and morphological characteristics. This is the first report of these species in Korea, and the morphological characteristics and images of the fungi are presented.

Aphanoascus fulvescens: A New Record from Crop Field Soil in Korea

Aphanoascus fulvescens: A New Record from Crop Field Soil in Korea

Sixteen New Records of Ascomycetes from Crop Field Soil in Korea

The present study reports 16 species of Ascomycota that were previously unknown in Korea, namely Acremonium cellulolyticus (KNU14-25), Acremonium zonatum (KNU14-15), Chaetomium madrasense (KNU14-9), Cladosporium silenes (KNU 14-18-1), Humicolopsis cephalosporioides (KNU15-3), Leptosphaerulina chartarum (KNU14-16), Paecilomyces marquandii (KNU14- 8), Paecilomyces tenuis (KNU14-18-2), Paraphaeosphaeria sporulosa (KNU15-2), Penicillium rubidurum (KNU14-12), Pochonia suchlasporia (KNU15-6), Sporothrix inflata (KNU15-8), Thielavia hyrcaniae (KNU15-1), Thielavia terricola (KNU14-23-1), Xylogone sphaerospora (KNU15-7), and Zopfiella longicaudata (KNU15-5). These fungal species were isolated from soil samples collected from various regions of Korea and identified based on their morphological characteristics and rDNA internal transcribed spacer sequence data. Full descriptions and illustrations for each species are provided.

A New Record of Pseudeurotium bakeri from Crop Field Soil in Korea

A New Record of Pseudeurotium bakeri from Crop Field Soil in Korea

Discovery of Two New Talaromyces Species from Crop Field Soil in Korea

Two new fungal species of the genus Talaromyces, Talaromyces purpurogenus and Talaromyces trachyspermus from the Trichocomaceae family, were recovered during an investigation of fungal communities in soil collected from the Gangwon-do and Jeollanam-do provinces of Korea. These two species have not been previously officially reported from Korea. In this study, detailed descriptions of internal transcribed spacer rDNA and beta-tubulin gene regions of these two fungi are presented. Morphological features of the two fungi in five agar media, potato dextrose, oatmeal, malt extract, czapek yeast extract, and yeast extract sucrose, are also reported. The species were identified on the basis of molecular and morphological analysis, and herein we present data with detailed descriptions and figures.

Three New Records of Mortierella Species Isolated from Crop Field Soil in Korea

Three new fungal species of the genus Mortierella, Mortierella zychae, Mortierella ambigua, and Mortierella indohii, have been reported in Korea. The fungi were encountered during a study on the fungal community of soil samples collected from different locations in Korea. The species were identified based on molecular and morphological analyses. This study presents detailed descriptions of the morphological observations and molecular phylogenetic analysis of these three fungi. All three species were found to be sensitive to triphenyltetrazolium chloride staining. M. zychae demonstrated the highest intensity of mycelial staining, indicating that this species has the highest potential to produce arachidonic acid of the three species. The staining results indicated that the newly recorded species could potentially be useful for arachidonic acid production.

A New Record of Gongronella butleri Isolated in Korea

We report the isolation of a Gongronella butleri species and describe it based on the analysis of the internal transcribed spacer region of rDNA and morphological characteristics. G. butleri has been reported as a high chitosan producer in the literature. This is the first record of G. butleri isolated from crop field soil in Korea.

A New Record of Volutella ciliata Isolated from Crop Field Soil in Korea

During a survey of fungal species in South Korea, a species of Volutella ciliata was isolated and described based on the analysis of the internal transcribed spacer region of its rDNA and its morphological characteristics. This is the first record of Volutella ciliata isolated from crop field soil in Korea.