Orchard Soil Research Articles

Apple Root Microbiome as Indicator of Plant Adaptation to Apple Replant Diseased Soils.

The tree fruit industry in Nova Scotia, Canada, is dominated by the apple (Malus domestica) sector. However, the sector is faced with numerous challenges, including apple replant disease (ARD), which is a well-known problem in areas with intensive apple cultivation. A study was performed using 16S rRNA/18S rRNA and 16S rRNA/ITS2 amplicon sequencing to assess soil- and root-associated microbiomes, respectively, from mature apple orchards and soil microbiomes alone from uncultivated soil. The results indicated significant (p < 0.05) differences in soil microbial community structure and composition between uncultivated soil and cultivated apple orchard soil. We identified an increase in the number of potential pathogens in the orchard soil compared to uncultivated soil. At the same time, we detected a significant (p < 0.05) increase in relative abundances of several potential plant-growth-promoting or biocontrol microorganisms and non-fungal eukaryotes capable of promoting the proliferation of bacterial biocontrol agents in orchard soils. Additionally, the apple roots accumulated several potential PGP bacteria from Proteobacteria and Actinobacteria phyla, while the relative abundances of fungal taxa with the potential to contribute to ARD, such as Nectriaceae and plant pathogenic Fusarium spp., were decreased in the apple root microbiome compared to the soil microbiome. The results suggest that the health of a mature apple tree can be ascribed to a complex interaction between potential pathogenic and plant growth-promoting microorganisms in the soil and on apple roots.

Pistachio Male Inflorescences as an Alternative Substrate for the Application of Atoxigenic Strains of Aspergillus flavus.

Aflatoxins are carcinogens mainly produced by Aspergillus flavus and A. parasiticus in susceptible crops, including pistachio. The primary inoculum sources of these pathogens are plant debris in the orchard soils. In Californian fields, one approach to controlling aflatoxin contamination is based on releasing the atoxigenic strain of A. flavus AF36 in inoculated (coated) sorghum grains (AF36 Prevail). However, this control method can fail due to poor sporulation of the AF36 strain or sorghum grain losses due to predation. In 2008 and 2018, we showed that toxigenic and atoxigenic isolates of Aspergillus spp. frequently colonized fallen inflorescences of male pistachio trees. Under controlled conditions, strain AF36 profusely colonized pistachio male inflorescences when humidity was higher than 90%. However, there were significant differences between types of inflorescence (aerial > fallen). In 2016, we considerably (P = 0.015) increased the population of AF36 on the canopies of trees when fallen inflorescences were inoculated with AF36, compared with untreated trees. In 2017 and 2018, these differences were not detected (P > 0.05) due to cross-contamination of strain AF36 between seasons and neighboring plots. In any case, the density of AF36 spores on the canopy of the inflorescence-treated trees was similar (P > 0.05) to that on trees treated with the commercial product. Here, we present a new method for applying strain AF36 based on using a natural, abundant, and uniformly distributed substrate in pistachio fields, and we discuss how it can be improved. Furthermore, our results indicate that, in pistachio orchards where biocontrol practices are not conducted, eliminating this important source of toxigenic Aspergillus inoculum is recommended.

Dissipation Kinetics of Imidacloprid and Thiamethoxam in a Sweet Lime Orchard Soil Near Pulivendula using Ultra-Hplc Coupled with a Photodiode Array Detector (PDA)

Imidaclopride (IMI) and Thiamethoxam (THI) were the neonicotinoids that were most frequently used in Andhra Pradesh in sweet lime orchards to control Helicoverpa armigera and Marucavitrata. Despite the frequent use of these insecticides, little is known about their behaviour and interaction in the soils of sweet lime orchards. The main objective of this study is to estimate the degradation of IMI and THI in soils from sweet lime orchards collected in and around Pulivendula, near Kadapa, using established kinetic models. A new, rapid, sensitive, precise, and validated "Ultra High Performance Liquid Chromatography Coupled with a Photodiode Array Detector" (UHPLC-PDA) is developed for the quantification of IMI and THI individually in agricultural soil samples by the QuEChERS extraction technique. The IMI and THI were sprayed on the sweet lime trees at a rate of 2 ml/l and 1.5 ml/l respectively. Soil samples were collected for analysis at 0 (within 1 hour), 1, 3, 5, and 10days time intervals after spraying on soil soils. Quantification was carried out utilizing a 40:60 (v/v) methanol/water mobile phase and a validated reverse-phase HPLC with a "PDA" detector at 272nm wavelength. Within the measured range of 0.05 to 1 ppm concentration, the calibration graphs of IMI and THI in methanol solvent were linear with an index of correlation greater than 0.996. Sprayed soil recovery ranges from 95% to 110% respectively, in respect of IMI and THI. The dissipation kinetics of IMI and THI was studied in logarithmic first-order kinetic models, for which the R2 was 0.948 and 0.997 respectively. The IMI residues were 1.91, 0.45, 0.31,

PRESENCIA DE HONGOS ENTOMOPATÓGENOS ASOCIADOS A SUELOS CULTIVADOS CON AGUACATE (Persea americana Mill.) EN COLIMA, MÉXICO

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Entomopathogenic fungi (EF) play a key role in the regulation of arthropod populations and biotransformation in natural systems, as well as biological pest control agents in different agroecosystems, including avocado cultivation (&lt;em&gt;Persea americana&lt;/em&gt; Mill.), where Mexico is a leader in production and export worldwide.&lt;strong&gt; Objective&lt;/strong&gt;: Determine the presence of EF in soil in commercial avocado orchards in the state of Colima, Mexico. &lt;strong&gt;Methodology&lt;/strong&gt;: Sampling was carried out in three avocado orchards (Piedra rajada, El Guardián, and Montitlán) located in Comala and Cuauhtémoc in the state of Colima, Mexico, from July 2016 to June 2017. Soil samples were collected around avocado trees. Isolation of entomopathogenic fungi was performed using the &lt;em&gt;Galleria mellonella&lt;/em&gt; Linnaeus insect trap technique. The isolates were identified considering their micro- and macroscopic characteristics with the taxonomic keys of Humber (2012). &lt;strong&gt;Results&lt;/strong&gt;: A total of 108 samples were collected, of those, 120 isolates were obtained, of which 112 belong to the genus &lt;em&gt;Metarhizium&lt;/em&gt; and eight to &lt;em&gt;Beauveria&lt;/em&gt;. &lt;strong&gt;Implications&lt;/strong&gt;: The recovered fungi have a great value for the avocado-growing areas of the state of Colima, either for the conservation of natural enemies of soil pests or for their potential use as an alternative to synthetic insecticides. &lt;strong&gt;Conclusion&lt;/strong&gt;: Knowing the native micro-biota of the soil should be considered within biological pest control strategies, since it allows selecting the best adapted species, and including sustainable alternatives for the environment. &lt;/p&gt;

Illumina MiSeq sequencing investigation on the contrasting rhizosphere soil bacterial community structures in tea orchard soil under different content of aluminium

The rhizosphere of grown tea (Camellia sinensis (L.) O. Kuntze) becomes acidic, and aluminium (Al) toxicity has been identified as a key constraint on plant development in acidic soils. The current study investigated the composition and functions of rhizosphere bacteria as well as soil enzyme activity under different Al stress conditions. The effect of soil pH, soil enzyme activities, the diversity and structure of the rhizosphere bacterial population under various Al concentrations were studied by the pot experiment. All analyses demonstrated that substantial alterations in the activity of soil enzymes and the composition of the bacterial communities in the rhizosphere could only be seen under conditions of extreme Al stress. Soil enzymes were more concentrated in Al concentrations of 100, 150 and 250 µM, respectively. More than 82,000 valid reads were obtained for each replicate, and the abundance of certain genera in the aluminium treated groups were greater than the control group. Lower Al stress attracted Al-tolerant bacteria such as Burkholderia to increase Al stress resistance. These findings revealed that soil enzyme activities and the structure of the rhizosphere bacterial population in tea orchard soil provided tolerance or resistance capability to tea plants for their development under Al stress.

QUALITATIVE AND QUANTITATIVE COMPOSITION OF MYCOFLORA OF GRAY FOREST SOIL UNDER DIFFERENT DIRECTIONS OF AGRICULTURAL LAND USE

This article presents the results of research on the quantitative and species composition of soil fungi, including pathogenic, gray forest soils in the conditions of the Right Bank Forest Steppe. The mycoflora of the soil was considered for different directions of agricultural land use including soils under intensive apple orchards, intensive crop cultivation and fallow. The condition of soil micromycetes was studied based on the indicators of the abundance of the main ecological and trophic groups. In soils, fungi are determined to be critical players in the ecosystem and play a huge role in agriculture and soil microbiome. The results of research showed certain changes in the content and composition of mycobiota in soils, as a result of their fourteen-year use under fallow, garden and field crop rotations. The difference in the intensity of micromycete colonization of soils of different agricultural lands was revealed: fallow 125.7 thousand CFU/g, intensive gardening 130.5 thousand CFU/g, field crop rotation 191.2 thousand CFU/g. The negative influence of intensive horticulture on quantitative and qualitative indicators of soil mycoflora was established. It was investigated that the lowest percentage of saprotrophic fungi, the highest percentage of pathogenic fungi and toxin-producing species of fungi from the total number of isolated species were observed in the soils of the apple orchard under intensive horticulture, compared to the soils of fallow and field crop rotation. A common feature of all soils of various uses is the presence of representatives of genera Penicillium, Gliocladium and Trichoderma in the soil. Fallow soils were not represented by species from the genera Rhizopus, Arthrinium and Cladosporium, compared to the other soils. However, only they contained representatives of genera Mucor and Absidia. Common to all the three presented soils was the presence of representatives of the species Trichoderma viride Pers. and Gliocladium roseum Bainier.

Research of Soil Biome of a Young Apple Orchard of Intensive Type

Fungi are one of the main sources of biotic inducers of plant immunity, but among this group of microorganisms, the largest number of phytopathogens is also noted. A two-year study was carried out on the dynamics of the composition and structure of the fungal community in the soil and the agrochemical characteristics of the soil of a young apple orchard of intensive type. The study of the fungi pool in the control (background, without plants) showed that the content of soil saprotrophs and cellulolytics was two times higher than the abundance of these groups in the root zone of a young apple tree. The importance of the role of plant exudates for the formation of the root zone mycobiota, its participation in the differentiation of the soil microbial community and the formation of the “phytogenic region” where root exudates affect the activity and distribution of ecological-trophic groups of fungi, is demonstrated. In the zone of intensive root growth in the 10–20 cm layer, a sharp decrease in the content of macroelements (nitrogen, phosphorus, potassium) was noted.

Study of Soil and Crop Parameters of Coconut Orchard for Design of Tractor Operated Coconut Basin Lister Cum Fertilizer Applicator

Aims: To study the soil and crop parameters of coconut orchard for the design of tractor operated coconut basin lister cum fertilizer applicator.&#x0D; Place and Duration of Study: The study was conducted in Instructional Farm, KCAET in the Year 2021.&#x0D; Methodology: Soil parameters such as moisture content, bulk density, cone index and shear strength; crop parameters such as trunk diameter and root zone depth of coconut palm were studied using standard procedures to design tractor operated coconut basin lister cum fertilizer applicator.&#x0D; Results: The soil moisture content varied from 13.2 to 15.6% with mean of 14.66%. The soil bulk density ranged from 1615 to 1865 kg m-3 with mean of 1696.6 kg m-3. The soil cone index varied from 0.428 to 1.506 N mm-2 with mean of 1.041 N mm-2. The soil shear strength varied from 1.47×10-3 to 3.13×10-3 N mm-2 with mean of 2.31×10-3 N mm-2. The trunk diameter of coconut palm varied from 32.3 to 38.1 cm with mean of 34.74 cm. The root zone depth of coconut palm varied from 13.4 to 15.2 cm with mean of 14.3 cm.&#x0D; Conclusion: Soil moisture content, bulk density, cone index and shear strength helped in the design of power requirement, rotor shaft, cutting blades, main shaft etc. of the machine. The trunk diameter of the coconut palm aided in deciding the working width of the machine while the root zone depth assisted in finalizing the operational depth of the machine.

Identifying the effects of cropping with different pear cultivars on microbial community composition and networks in orchard soils.

The role of plant genotype in determining the assembly of soil microorganisms is widely accepted; however, the effects of cropping with different cultivars of perennial crop plants on the composition of soil microbial communities are not fully understood. In the current study, high-throughput amplicon sequencing and real-time PCR were used to investigate the major features of bacterial community composition, ecological networks, and soil physicochemical properties in three replicate pear orchards, each planted with monocultures of pear cultivars Hosui (HS) or Sucui (SC) of similar ages. A distinct difference in the composition of microbial communities was observed between soils of HS and SC orchards. A significantly greater relative abundance of Verrucomicrobia and Alphaproteobacteria whereas a significantly lower relative abundance of Betaproteobacteria were found in soils of HS cropped orchards than that in SC orchards. Sphingomonas sp., belonging to the Alphaproteobacteria, was recognized as a key species in the co-occurrence network of the microbial interactions. Moreover, redundancy analysis, the Mantel correlation test, and random forest analysis showed that soil pH was the dominant driver in determining microbial community composition in HS soils, whereas soil organic matter was the primary factor determining microbial community composition in SC soils. Altogether, we provide evidence that soils in HS orchards harbor unique microbial communities enriched with respect to microbial groups associated with nutrient cycling, whereas soils in SC orchards are dominated by a group of beneficial microbes exhibiting plant growth promotion. These findings have implications for science-based guidance for manipulation of the soil microbiome to achieve sustainable food production.

Distribution of potassium, calcium, and magnesium ions from potassium fertilizers in columns of orchard soils

AbstractPotassium (K) in fruit and nut orchards affects productivity, water relations, and crop quality; however, information about K, calcium (Ca), and magnesium (Mg) dynamics in orchard soils is limited. This study evaluates the distribution of K, Ca, and Mg in 30‐cm soil columns following four wetting events over 70 days. Soils were a Hillgate sandy loam, a San Ysidro loam, and a Yolo loam applied with muriate of potash (KCl), microfine sulfate of potash (SOP; [K2SO4]), polyhalite (POLY; [K2SO4·MgSO4·2CaSO4·2H2O]), and an unfertilized control. Soil solution K concentrations measured at 5 cm using a porewater sampler were greater than 1400 mg K L−1 in the Hillgate sandy loam POLY treatment after the first two wetting events. Ca and Mg in soil solution were also greater for POLY when averaged across all four wetting events, likely due to greater Ca and Mg inputs. Extractable K using ammonium acetate, significantly increased after the wetting events resulting in 88% and 75% of the extractable K in the top 0–10 cm of the San Ysidro and Yolo loams, respectively. Leached K accounted for 6.2% of the SOP inputs in the Hillgate sandy, whereas only 0.3% and 1.1% in the San Ysidro and Yolo loams, respectively. Higher K leaching as well as Ca and Mg is likely due to higher cation exchange capacity in loam soils and great porosity in sandy loam soils. Our results show differences in the distribution of K, Ca, and Mg and provide insights into K fertilizer availability for orchard soils.

Dynamic Monitoring of Nutrition Inputs and Fertility Evaluation during a Decade in the Main Peach-Producing Areas of Shandong Province, China.

The main peach-producing area in Shandong is an important peach fruit-producing area in China. Understanding the nutritional properties of the soil in peach orchards helps us to understand the evolution of soil properties and adjust management methods in a timely manner. This study focuses on 52 peach orchards in the main peach-producing area in Shandong as the research object. The spatiotemporal changes in soil traits and their influential factors were studied in depth, and the changes in soil fertility were effectively evaluated. The results showed that the input of nitrogen, phosphorus and potassium from organic fertilizer in 2021 was significantly higher than that in 2011, while the input of fertilizer in 2011 was significantly higher than that in 2021. Compared with traditional parks, both organic fertilizer inputs and chemical fertilizer inputs in demonstration parks showed a significant downwards trend. There was no significant change in pH values between 2011 and 2021. In 2021, the soil organic matter (SOM) contents of the 0-20 cm and 20-40 cm layers were 24.17 g·kg-1 and 23.38 g·kg-1, respectively, an increase of 29.3% and 78.47% over the values measured in 2011. Compared with 2011, the content of soil alkaloid nitrogen (AN) decreased significantly in 2021, and the contents of available phosphorus (AP) and available potassium (AK) in the soil increased significantly. According to the calculation results of the comprehensive fertility index (IFI) value, we found that in 2021, compared with 2011, the quality of soil fertility improved, most of which was at the medium and high levels. The research results show that the fertilizer-saving and synergistic approach in peach orchards in China significantly improved the soil nutrition. In the future, research on suitable comprehensive technologies should be strengthened in the management of peach orchards.

Paclobutrazol Biodegradation of Native Bacteria in Mango Orchards in Mekong Delta, Vietnam

Background: Paclobutrazol (PBZ), a plant growth regulator, is usually used to promote off-season flowering in mango orchards in the Mekong Delta, Vietnam. Several studies demonstrated that PBZ degradation in the soil takes several months and its residue effects to the soil environment and consequently to the plants and microorganism community. The objective of this study was to identify native bacteria that can biodegrade PBZ in the soil of mango orchards. Methods: Soil samples were collected in thirty mango orchards in Vietnam’s Mekong Delta. One gram of soil was mixed with distilled water and injected into a PBZ culture medium. After culturing, bacterial colonies were isolated and transferred onto the TSA medium in order to characterize morphological and biochemical assays and to evaluate PBZ biodegradation ability. Four strains of bacteria, which had high PBZ biodegradation, were identified and evaluated PBZ biodegradation ability. Additionally, 16S rDNA region was sequenced. Result: The results of identification indicated that the four high PBZ biodegradation bacterial strains related to Pseudomonas fluorescens, Pseudomonas nitroreducens, Burkholderia cepacia, Acinetobacter seifertii. After 30 days, the content of paclobutrazol biodegradable by these bacteria was 36.51%, 36.23%, 34.19% and 33.56%, respectively, at an initial concentration of 60 ppm.

Natural occurrence of Metarhizium in agricultural avocado soils (Persea americana Mill.) in Colima, Mexico

Avocado (Persea americana Mill.) has become one of the most important fruits in the world, being Mexico the main producer and exporter worldwide, it has led to an accelerated growth in the establishment of monoculture avocado plantations, promoting the increase of insect and mite pests, which has led to the need for biological control strategies for integrated pest management. The objective of this study was to isolate entomopathogenic fungi from the soil of a conventional avocado orchard and identify them by translation elongation factor 1-α (5’TEF). During the sampling, a total of 34 isolates were obtained, belonging to the genus Metarhizium, 23 isolates identified as Metarhizium robertsii and 11 as Metarhizium guizhouense. These results show the low diversity of entomopathogenic fungi species associated with the rhizosphere of the avocado crop and suggest that their occurrence could be associated with their ability to survive agronomic practices that induce their endophytic activity. It is necessary to understand the role of Metarhizium in the rhizosphere, this will allow the development of biological control programs specific for each crop, and thus guarantee its success in pest control.

Intercropped Amygdalus persica and Pteris vittata applied with additives presents a safe utilization and remediation mode for arsenic-contaminated orchard soil

Intercropping the arsenic (As) hyperaccumulator Pteris vittata with fruit trees can safely yield peaches in As-polluted orchards in South China. However, the soil As remediation effects and the related mechanisms of P. vittata intercropped with peach trees with additives in the north temperate zone have rarely been reported. A field experiment was conducted to systematically study the intercropping of peach (Amygdalus persica) with P. vittata with three additives [calcium magnesium phosphate (CMP), ammonium dihydrogen phosphate (ADP), and Stevia rebaudiana Bertoni residue (SR)] in a typical As-contaminated peach orchard surrounding a historical gold mine in Pinggu County, Beijing City. The results showed that compared with monoculture (PM) and intercropping without addition (LP), the remediation efficiency of P. vittata intercropping was significantly increased by 100.9 % (CMP) to 293.5 % (ADP). CMP and ADP mainly compete with available As (A-As) adsorbed to the surface of Fe-Al oxide through PO43−, while SR might activate A-As by enhancing dissolved organic carbon (DOC) in P. vittata rhizospheres. The photosynthetic rates (Gs) of intercropped P. vittata were significantly positively correlated with pinna As. The intercropping mode applied with the three additives did not obviously affect fruit quality, and the net profit of the intercropping mode (ADP) reached 415,800 yuan·ha−1·a−1. The As content in peaches was lower than the national standard in the intercropping systems. Comprehensive analysis showed that A. persica intercropped with P. vittata applied with ADP is better than other treatments in improving risk reduction and agricultural sustainability. In this study, a theoretical and practical basis is provided for the safe utilization and remediation of As-contaminated orchard soil in the north temperate zone.

Role of silt and clay fractions in organic carbon and nitrogen stabilization in soils of some old fruit orchards in the Nile floodplain, Sohag Governorate, Egypt

PurposeStudy the effect of both silt and clay fractions on stabilizing organic carbon and total nitrogen in soils of some old cultivated fruit orchards in Sohag, Egypt.MethodsEleven surface soil samples (0–15 cm) were collected. Silt (63–2 μm) and clay (< 2 μm) fractions were separated from soils and analyzed for cation exchange capacity (CEC), organic carbon (OC), total nitrogen (TN), specific surface area (SSA), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopic analysis were determined using the standard analysis methods.ResultsThe silt and clay were responsible for 77.49 to 93.34% of soil CEC. The SSA of clay was twice the silt, and the phyllosilicates (%) average was 29.83% and 62.70% in silt and clay. Other minerals, such as quartz, feldspar, and carbonate minerals, were detected in these fractions. The phyllosilicate species of clay were smectite-illite mixed layers (44.4–88.9%), Smectite (1.0–6.4% except one sample recorded 45.7%), Kaolinite (3.7–10.5%) and kaolinite/smectite mixed layers (2.0–8.2%). The average OC-silt and clay were 6.79 and 8.96 g OC kg−1 soil (38.01 and 50.28% of soil OC). On average, the total nitrogen (TN) in silt and clay particles was 0.817 and 1.156 g N kg−1 soil (35.88 and 50.66% of soil TN). The OC and N content significantly and positively correlated with CEC, SSA, and phyllosilicates in the fine fractions.ConclusionResults showed that the soil's capacity to sequester OC and N is affected significantly by its fine particles' content, characteristics, and mineralogy.

Isolation and characterization of Priestia megaterium KD7 for the biological control of pear fire blight.

Erwinia amylovora is a plant pathogen that causes fire blight disease in Rosaceous plants, such as pear and apple. To develop an effective biocontrol method to suppress E. amylovora, a total of 16 bacteria were isolated from pear orchard soil in China and screened for antagonistic activity in vitro. Among them, 9 isolates that exhibited antagonistic activity against E. amylovora were identified, including Bacillus atrophaeus, Priestia megaterium (previously known as Bacillus megaterium) and Serratia marcescens based on the partial 16S rDNA sequence analysis and similarity search. The plate confrontation experiments showed that strain 8 (P. megaterium strain KD7) had strong antagonistic activity against E. amylovora. The methanolic extract from cell-free supernatant of strain KD7 displayed high antibacterial activities against E. amylovora. Furthermore, the active compounds of strain KD7 were separated by thin layer chromatography (TLC) and the amino acids were detected by the presence of a spot with retention factor (Rf) of 0.71. Next, three lipopeptides were identified with high-resolution mass spectrometry (HRMS), including C13-surfactin [M+H]+ at m/z 1008.14, C15-surfactin [M+H]+ at m/z 1036.50, and C14-iturin A [M+H]+ at m/z 1043.17. Strain KD7 showed multiple antibiotic resistance, such as ampicillin, erythromycin, penicillin and tetracycline. The detached pear leaves, twigs and fruits assay showed that both protective and curative action with strain KD7 had the ability to decrease the development of fire blight. Taken together, P. megaterium strain KD7 is a potential effective biocontrol agent against fire blight.

Litter Decomposition Characteristics and Variety Differences in a Kiwifruit Orchard in Subtropical Climate Zone of China

The aim of this study was to reveal the decomposition dynamics of kiwifruit litter and verify the variety differences and provide a scientific basis for rational fertilization in orchard. Kiwifruit litters of two varieties (‘Hongyang’ and ‘Jinyan’) were taken as the objects; the litter decomposition rate, the dynamics of macro-elements and micro-elements, and soil enzyme activities during the decomposition process were analyzed. The results showed that the litter decomposition rate of ‘Hongyang’ kiwifruit was faster than that of ‘Jinyan’ kiwifruit, because of the higher initial N and P content in the litter of the ‘Hongyang’ kiwifruit. The dynamic trends of macro-elements and micro-elements during litter decomposition of two varieties were similar. The C content was relatively stable, the P content was fluctuant, and the K content was decreasing. The contents of N, Fe, Mn, Cu, and Zn were increasing. The contents of Ca, Mg, and B increased first and then decreased. After 180 days of the decomposition experiment, more than 75% of the initial contents of C, N, P, K, Ca, Mg, and B were released. The dynamic trends of the soil enzyme activities of two varieties were generally similar. Due to the slow decomposition rate, the dynamic trends of soil enzyme activities of ‘Jinyan’ kiwifruit litter each showed hysteresis. The contents of Ca, Mg, and Mn were significantly correlated with some soil enzyme activities. In conclusion, the litter substrate quality of the two kiwifruit varieties is different, which leads to the difference in the decomposition rate. The litter decomposition of kiwifruit is an important supplement to the macro-element in orchard soil.

ВЗАИМОСВЯЗЬ ГРАНУЛОМЕТРИЧЕСКОГО СОСТАВА ПОЧВ С ИХ НАИМЕНЬШЕЙ ВЛАГОЁМКОСТЬЮ В ЯБЛОНЕВЫХ САДАХ ООО «ТИМИРЯЗЕВСКИЙ» ЛИПЕЦКОЙ ОБЛАСТИ

The research was carried out in 2018-2021 in the old fruit-bearing, but not yet uprooted apple orchards of Timiryazevo LLC in the Lipetsk region. The lowest moisture capacity was determined by the method of gypsum casts, the granulometric composition was determined by the pyrophosphate method. The most moisture - intensive genetic horizons of soils were the following: in leached chernozem – A1+A1B (0-170 cm), in podzolized chernozem – A1 (0-42 cm), B (140-167 cm) and B +C (178-230 cm), in chernozem-meadow podzolized soil – B (110-160 cm). All types of soils in apple orchards differed significantly in the lowest moisture capacity of all genetic horizons located deeper than humus. The moisture capacity of hu-mus horizons (A) of all four soils is the same. In the profile of leached chernozem, the predominant frac-tion is silt and coarse dust, in the profile of podzolized chernozem – fine sand, coarse dust and silt, in the profile of podzolized slightly glued chernozem – medium and fine dust and silt, in the profile of cherno-zem meadow podzolized soil - fine sand, coarse dust and silt. The highest content of physical clay was ob-served in the humus horizon and the parent rock of the slightly frozen podzolized chernozem, as well as in the leached chernozem parent rock and the illuvial horizon of the podzolized chernozem. The lowest mois-ture capacity of soils increases as the silt content in the soil increases (r= 0.61-0.9), as the percentage of fi-ne dust in them decreases (r= -0.59...-0.97), medium dust (r= -0.67), fine sand (r= -0.61), medium sand (r= -0.75...-0.8) and coarse sand (r= -0.67...-0.92). The relatively low moisture capacity of transitional horizons (A1B) in podzolized chernozems is due to the presence in these layers of a large amount of dust and sand, but a small amount of silt.

Evaluation of Fertilizer Inputs and Soil Nutrient Status in Apple Orchards in China

Apple is an important horticultural crop in China and its production consumes large amounts of Chemical fertilizers. In a survey of more than 300 Chinese apple growers, we found that small farmers’ fertilizer inputs are blind. Current research lacks a comprehensive evaluation of fertilizer inputs and soil nutrient status for apple production in China, but the evaluation work will play a supporting role in the macro management decision of nutrient resources. In this study, a database of fertilizer inputs and soil nutrients in five major apple producing areas in China was constructed by means of data integration. Two main conclusions can be drawn from the analysis of the database. Firstly, the chemical N and P fertilizer inputs exceed the recommended use in all five production areas, and secondly, the organic matter content of orchard soils in the five production areas only reaches a maximum of level 3. The research shows that China’s agricultural authorities should carry out macro management of nutrient resources in apple orchards, so as to guide different producing areas to adjust fertilizer input according to their soil environment, so as to improve the utilization rate of fertilizer.

Target and suspect screening of pesticide residues in soil samples from peach orchards using liquid chromatography quadrupole time-of-flight mass spectrometry

Agricultural soil contamination by pesticide residues has become a serious issue of increasing concern due to their high persistence and toxicity to non-target species. However, as the world’s largest peach producer, national scale surveys on pesticide residues in peach orchard soils are scarce in China. In this study, a target and suspect screening method covering over 200 pesticides commonly used in peach orchards was developed using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in MSE. An identification strategy using different data processing parameters was developed to identify the pesticide occurrence in soil. The method was applied to soil samples from typical peach orchards in 12 regions across China. The present work also discusses in detail the frequency of occurrence, concentration of pesticides, spatial distribution of multiresidues, and relationship between pesticide occurrence and soil properties. In the tested soil samples, 21 herbicides (level 1), 31 fungicides (level 2a), 24 insecticides (level 2a), and 3 growth regulators (level 2a) were identified. The total concentrations of quantifiable herbicides in the soil samples ranged from 1.05 to 327 ng/g. Only in 5.4% of the soil samples, no pesticide residues were present. By contrast, more than 86% of the total contained multiple residues. This study represents the first large-scale survey of pesticides in soil from peach orchards and provides comprehensive and accurate information on the pesticide residue status for risk assessment.