Soil Nutrient Characteristics Research Articles

Statistical and machine learning methods for crop yield prediction in the context of precision agriculture

It is of critical importance to understand the relationships between crop yield, soil properties and topographic characteristics for agricultural management. This study’s objective was to compare techniques to quantify the relationship between soil and topographic characteristics for predicting crop yield using high-resolution data and analytical techniques. The study was conducted on a multiple field dataset located in Southwestern Ontario, Canada, where few studies have assessed the impact of applications for precision agriculture and machine learning (ML) to the soil property-yield relationship in this region. The dataset included 145,500 observations of corn and soybean yield, topographic and soil nutrient characteristics. The attributes considered for this study included pH, soil organic matter (OM) content, cation exchange capacity (CEC), soil test phosphorus, zinc (Zn), potassium (K), elevation and topographic wetness index. Multiple linear regression (MLR), artificial neural networks, decision trees and random forests were compared to identify methods able to relate soil properties and crop yields on a subfield scale (2 m). Random forests were the most successful at predicting yield with an R2 value of 0.85 for corn and 0.94 for soybeans. MLR was the least successful with an R2 of 0.40 for corn and 0.45 for soybeans. Cross-validation experiments showed that random forest models in most cases could predict low- and high-yield areas from fields excluded from training datasets, but this was not possible in all cases. Techniques tested the models and identified significant soil and topographic attributes when predicting yield, though the identification was subject to some uncertainty. These results suggest that ML techniques might be used to predict high yield areas of fields without existing yield maps, if those fields have similar relationships of soil properties to yield.

Freeze\u2013thaw cycle frequency affects root growth of alpine meadow through changing soil moisture and nutrients

Alpine meadows grow in alpine regions and play an important role in the production and life of alpine regions. As a unique feature of alpine regions, freeze–thaw cycles (FTCs) affect the growth of alpine meadows. However, with climate change, the change in the freeze–thaw cycle frequency (FTCF) has become obvious. These changes affect the content and distribution of soil moisture and nutrients, as well as the growth of roots in the alpine meadow. Therefore, based on the analysis of FTCF in the Nagqu River Basin, the characteristics of soil moisture, nutrients, and alpine meadow roots are analyzed, thus revealing the influence mechanism of FTCF on the root growth of alpine meadows. The results highlight three major findings. (1) Compared with the low-frequency mode (LFM), the moisture at 0–20, 20–40, and 40–60 cm in the high-frequency mode (HFM) has decreased by 30.74%, 52.89%, and 47.52%, respectively. Additionally, in HFM the contents of soil hydrolysable nitrogen (HN), available K (AK), and microbial biomass carbon (MBC) at the same depth are lower than those in LFM. (2) The original distribution of soil moisture at 0–60 cm has gradually increased from the surface to the bottom. However, with the increase in FTCF, the distribution of the soil moisture now means that the soil moisture at the surface (0–20 cm) and the deeper layers (40–60 cm) is higher than that in the middle (20–40 cm). (3) With the increase in FTCF, the growth mode of alpine meadow roots has changed from vertical extension to horizontal divergence; the distribution range of roots has changed from 0–40 cm to 0–20 cm; the length, surface area, and volume of 0–0.5 mm roots have increased by 20.95 cm, 1.90 cm2, and 0.014 cm3; and the corresponding specific gravity has increased by 9.09%, 13.50%, and 12.14%, respectively. This study provides a theoretical basis for predicting the growth mode of alpine meadow roots in the Nagqu River Basin under the influence of climate change and provides guidance for protecting the ecology of alpine regions and mitigating and solving global climate change.

Effects of Warming and Increased Precipitation on Soil Respiration of Abandoned Grassland in the Loess-Hilly Regions

Clarifying the changing trends and driving factors of soil respiration in fragile habitats under the background of climate change is of great significance for understanding the regional carbon cycle and the conversion of ecosystem carbon source and sink functions. This research focused on grasslands that had been naturally abandoned and restored for 12 years in the loess hilly region of northern Shaanxi, using an open top chamber (OTC) and artificially increased natural rainfall to simulate climate warming and precipitation increase and their interaction. Furthermore, we used a combination of field monitoring and indoor analysis to explore soil water content, temperature, and nutrient characteristics and the response characteristics of soil respiration rate to warming and increased precipitation and further analyzed the key factors driving changes in soil respiration. The results showed that:① warming (W) significantly increased the 5 cm soil temperature, with an average increase of 1.34℃ throughout the sampling year, whereas the increased precipitation (P50%) treatment significantly reduced the 5 cm soil temperature, reducing the average 5 cm soil temperature during the entire sampling year by 0.88℃ and increasing the soil water content (SWC) at the same time. The SWC was 13.12% and 16.45% higher than that in the control (CK), respectively. In addition, compared with that in the CK, the treatment of warming and increased precipitation (WP50%) not only increased soil temperature but also increased SWC; in general, the increase in temperature and precipitation played an antagonistic effect on the influence of soil temperature and humidity. ② P50% significantly increased the content of soil organic carbon, dissolved organic carbon, and labile organic carbon, causing changes in the soil stoichiometric ratio and the distribution characteristics of labile-recalcitrant carbon components, whereas W did not have a significant impact on organic carbon. In addition, soil total nitrogen and phosphorus and available nitrogen and phosphorus nutrients were not significantly different between treatments. ③ P50% significantly increased the Rs rate, and the effect of W on the soil respiration rate mainly depended on the seasonal precipitation and temperature. It was demonstrated that warming in winter and seasons with abundant rainfall had a significant promotion effect on the soil respiration rate. The exponential fitting of soil respiration rate and 5 cm soil temperature found that the soil respiration temperature sensitivity (Q10) was the highest under the precipitation treatment, reaching 1.68, whereas the Q10 was the lowest under the warming treatment (1.50). ④ Linear regression analysis showed that soil organic carbon, dissolved organic carbon, and labile organic carbon were all significantly positively correlated with soil respiration rate. Variation partitioning analysis showed that soil temperature, SWC, and nutrient characteristics explained 64.43% of the variation in soil respiration rate. The soil temperature and SWC were the main controlling factors of the change in soil respiration rate, with an explanation degree of 31.16%. Correlation analysis also showed that there was a significant correlation between SWC, soil temperature and respiration rate, soil organic carbon, dissolved organic carbon, labile organic carbon, C:N, and C:P. In summary, the climate prediction of abandoned grassland tending toward warm temperatures and high humidity in the loess hilly region will significantly affect the regional hydrothermal environment and nutrient characteristics, change the distribution ratio of soil labile and recalcitrant carbon, and promote regional soil carbon emissions. The analysis results showed that the key factor driving the change in soil respiration rate of abandoned grassland in the loess hilly region was soil temperature and SWC characteristics.

Distribution and enrichment characteristics of soil nutrients in the nebkhas profile of Nitraria tangutorum in Gahai Lake Area, Qaidam Basin.

As a special bio-geomorphic landscape in the Qaidam desert area, Nitraria tangutorum nebkhas play a critical role in fixing quicksand, improving soil quality, and maintaining the stability of regional ecological environment. Taking the N. tangutorum nebkhas with coverage of approximately 15%, 25%, 45% and 60% in Gahai Lake area of Qaidam Basin as the research objects, we analyzed the vertical distribution and enrichment characteristics of soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the contents of SOM, TN, TP, TK, AN, AP and AK varied in the range of 1.67-10.22 g·kg-1, 0.05-0.42 g·kg-1, 0.31-0.54 g·kg-1, 15.87-18.84 g·kg-1, 2.26-11.68 mg·kg-1, 0.80-15.00 mg·kg-1 and 45-161 mg·kg-1, respectively. Vertically, soil nutrients in the N. tangutorum nebkhas with 15% coverage showed a decreasing trend first then increased, and then decreased again with the increase of soil depth, except for TP, which did not show any significant change. In the nebkhas with 25%, 45% and 60% coverage, SOM, TN, AN, TP and AP all showed a decreasing trend with increasing soil depth ,whereas TK and AK did not change significantly with soil layer. Above the nebkhas ground level of N. tangutorum, SOM, TN, TK, AN, AP and AK were all enriched, especially in the surface layer.Aamong all the nutrients, the enrichment rate of AN reached 5.19. In addition, below the nebkhas ground level of N. tangutorum, TN, AN, TK, AK and AP also showed enrichment. SOM, TN, AN, TP, AP, TK and AK were all significantly positively correlated with soil water content, and negatively correlated with altitude. All nutrients except TP were mainly affected by altitude. In conclusion, soil nutrient content of N. tangutorum nebkhas was the highest in the surface layer, the enrichment effect of which was not only reflected in the interior of the nebkhas, but also below the ground level of the nebkhas. Our results could provide reference for the scientific utilization of N. tangutorum nebkhas and ecological environment protection in Qaidam Basin area.

Effects of Long-term Fertilization on Soil Nutrient Characteristics and Microbial Resource Restrictions in a Terrace on the Loess Plateau

Long-term fertilization has an important effect on soil fertility and soil microbial activity. In order to explore the effects of long-term fertilization on soil extracellular enzyme activities and nutrient characteristics in a terrace on the Loess Plateau, we based our investigation on the long-term nutrient localization plot of Ansai Soil and Water Conservation Experimental Station, Chinese Academy of Sciences. We measured the soil physicochemical properties, microbial biomass, and extracellular enzyme activities of six fertilization treatments, which included no fertilization (CK); manure and nitrogen fertilization (MN); manure and phosphate fertilization (MP); manure, nitrogen, and phosphate fertilization (MNP); manure (M); and nitrogen and phosphate fertilization (NP). The results showed that all fertilization treatments significantly increased soil nutrient content and soil extracellular enzyme activities compared with that in CK. Correlation analysis showed that extracellular enzyme activity and soil physicochemical properties had an extremely significant correlation. The redundancy analysis indicated that soil nutrient and soil microbial biomass could explain 79.66% and 74.87% of the variation in soil extracellular enzyme activity and its stoichiometric ratio, respectively. Thus, the effects of fertilization on soil fertility were primarily through influencing soil extracellular enzyme activities indirectly. M, MN, MP, and MNP significantly improved soil organic carbon (SOC); soil total nitrogen (STN); and carbon (C), nitrogen (N), and phosphorus (P) source enzyme content; however, MNP changed the soil pH, which had an inhibitory effect on microbial activities. Vector analysis showed that the microbial communities of all treatments were in the condition of P limitation. Although MNP could alleviate the extent of P limitation, there was no significant difference between M and MP. Our study indicated that long-term application of manure[7500 kg·(hm2·a)-1]could meet the nutrient requirements of dryland crop growth, and long-term application of manure combined with phosphorus fertilization could alleviate the resource constraints faced by microorganisms. Consequently, our results provide a new insight into improving regional nitrogen excess.

Retracted] Spatial‐Temporal Variation Characteristics of Soil Moisture and Nutrients Based on Nanomaterials in the Root Zone of Haloxylon ammodendron Seedlings

Haloxylon ammodendron is the main constituent species in the desert area of Junggar Basin, which plays a key role in biodiversity protection and regional ecological balance. Replenishment and settling capacity of seedlings determine population regeneration and community stability, and soil moisture and nutrients are the main limiting factors of natural regeneration. In view of the serious degradation and low seedling survival rate of Haloxylon ammodendron forest in Junggar, typical degraded Haloxylon ammodendron population was selected in Gurbantunggut Desert. The effects of soil moisture on soil nutrients were explored, and the temporal and geographical fluctuations of soil moisture and nutrients in the root zone of Haloxylon ammodendron seedlings were clarified. The results showed that soil moisture and nutrient content in the root zone of seedlings had obvious temporal and spatial variation characteristics. With the advance of the growth period, it decreased at first and then increased, reaching the maximum in April and the minimum in August. In the soil horizontal space (0~40 cm), with the extension of the horizontal distance, the soil moisture content has an obvious “wet island” effect, and the soil moisture content at the 10 cm level is 1.99 times that at the 40 cm level in August, when the growth period is the driest. The nutrients available in the soil were clearly “poor on the inside and high on the outside.” The degrees of soil natural matter, soluble hydrolyzable nitrogen, accessible phosphorus, and accessible potassium in August were 57.97%, 44.37%, 75.46%, 19, and 55% higher at the 40 cm level of the sapling spine, 10 cm level each. The soil moisture content increased first, then declined, and the soil nutrient content gradually fell in the vertical (0.50 cm) space of soil as soil depth increased. The soil moisture content in the 20~30 cm layer is the highest, reaching 11.04%, 7.90%, 2.92%, and 4.29%, respectively, in each period. Soil water content in 0~30 cm was significantly affected by habitat rainfall (P < 0.05), and soil water had a higher effect on soil organic matter, alkali‐hydrolyzable nitrogen, and available potassium (P < 0.05).

FACTORS INFLUENCING THE USE OF LOCAL RICE VARIETIES AND ITS INFLUENCE ON PRODUCTIVITY IN THE LWAFI-KATONGOLO IRRIGATION SCHEME, NKASI DISTRICT, TANZANIA

Performance of rice production in the Lwafi-Katongolo Irrigation Scheme is influenced by both environmental and non-environmental factors. Despite introduction of improved rice varieties in irrigation schemes for increased production, farmers still choose to use local rice varieties. The factors that determine farmers’ choice of local and improved varieties have not been studied and used as a basis to improve productivity in the scheme. Such an analysis has wider implications on improvement of performance of rice irrigation schemes. This study was done to determine: (1) socio-economic factors influencing use of local rice varieties (2) other non-socio-economic factors influencing rice production (3) factors influencing productivity in the scheme. A sample of 120 farmers from 4 purposely selected villages of Katongolo, Masolo, Kamwanda and Mpata were surveyed using standard socio-economic survey approaches. Data on soil chemical and nutrient characteristics for the irrigation scheme were obtained from ARI- Uyole database. Quantitative data were analyzed using SPSS and Stata computer programs. Qualitative data were analyzed by content analysis. Multinomial Logistic Regression model was used to determine factors influencing the adoption of different rice varieties. The results show that education level had significant positive influence on the use of local varieties (p<0.1). Other major economic activities influence use of local varieties for farmers who grow both varieties (p = 0.05). For most farmers prior experience on growing local varieties and investment capital greatly influenced adoption of new rice varieties. Constraints of using local rice varieties are poor appearance, poor taste and low production with implications on markets, economic performance and consumer preferences. Understanding farmer preferences based on quality of rice is prerequisite in introducing new rice varieties for improvement of productivity in irrigation schemes. Research on the most favorable rice varieties especially from socio economic and soil condition points of view is imperative. Concerted extension education to promote the use of improved rice varieties and measures to ameliorate possible saline condition of the soil will augment productivity.

Long-Term Effects of Different Soil Tillage Practices on Stoichiometric Characteristics of Soil Nutrients, C Sequestration, and Crop Productivity Based on a 17-Year Experiment in a Semi-Arid Area of Northern China

Long-Term Effects of Different Soil Tillage Practices on Stoichiometric Characteristics of Soil Nutrients, C Sequestration, and Crop Productivity Based on a 17-Year Experiment in a Semi-Arid Area of Northern China

Cover cropping and conservation tillage improve soil health in the southeastern United States

AbstractConservation agricultural systems have a long history of development and use in the southeastern United States, but they are still not the norm on the landscape. Literature from the region suggests that a diversity of soil properties can be improved with cover cropping and conservation tillage, but results are not always consistent. Our objectives were to (a) review recent research on conservation tillage and cover cropping in the region and (b) compile and synthesize recent data from a diversity of farms along a conventional to conservation gradient. As part of recent on‐farm trials focused on soil N availability, we analyzed soil organic C and N fractions and routine soil nutrient characteristics from a total of 196 fields in corn (Zea mays L.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.) production in three physiographic regions of the Coastal Plain (n = 71 fields), Piedmont (n = 77 fields), and Appalachians (n = 48 fields) in North Carolina, South Carolina, Pennsylvania, and Virginia. These data allowed us to establish first estimates of threshold optima for soil organic C and N fractions and other inorganic nutrients. On‐farm data confirmed the literature review that conservation tillage resulted in greater stratification of soil organic C and N and nutrient concentrations. Soil health improvement could be inferred along the gradient from inversion tillage to no tillage without cover cropping to no tillage with cover cropping. This collection of recent literature and on‐farm data can be a useful starting point for establishing target limits and assessing soil health conditions on farms in the region.

Soil nutrient evolution under different vegetation types in semiarid loess area

The soil nutrient characteristics under three vegetation types of arbor ( I ), shrub ( II ) and herb ( III ) were studied by mathematical statistics method combined with field investigation and indoor detection analysis. The change characteristics of soil nutrients under different land use patterns were discussed. The results showed that the average contents of soil organic matter, total nitrogen, available phosphorus and available potassium were 21.30 and 0.65 g/kg, 3.67 and 67.61 mg/kg, respectively. Compared with grassland, woodland has better effect on fertilizer conservation in the Loess Plateau. In the process of soil nutrient improvement, the nutrient indexes such as organic matter, total nitrogen, available phosphorus and available potassium increased synchronously, and the soil alkaline environment that was not conducive to plant growth was also gradually improved. In the correlation between soil nutrients, available phosphorus and available potassium have good relative independence. In the future, organic fertilizer should be applied in this area, and nitrogen and phosphorus fertilizers should be supplemented to improve soil organic matter, nitrogen and phosphorus content, and to ensure soil nutrient balance by optimizing fertilization methods. In addition, in the case of uneven distribution of soil nutrients in the soil profile, it is recommended to take appropriate soil ploughing and reasonable human management measures to improve soil nutrient status, achieve high-quality sustainable development of soil, and promote the positive succession of vegetation communities. Bangladesh J. Bot. 50(3): 969-976, 2021 (September) Special

Distribution characteristics of soil water and nutrients in pear orchard and their relationship with yields in loess hilly region

We analyzed soil water, nutrients, and yields in three different slope sites in the sloping farmland under Yuluxiang pear planted in the loess hilly region of Western Shanxi, across the growth periods and different soil depths. The results showed that: 1) The yield of pear was in the order of high slope site > middle slope site > low slope site. In high slope site, the yield was significantly correlated with soil water content (SWC), soil organic matter (SOM), available potassium (AK), with AK showing the most significant effect. The yield of pear in middle and low slope sites was significantly correlated with SWC, SOM, and total nitrogen (TN), with SWC having the most significant effect on yield. The contents of SWC, SOM, available phosphorus (AP) and TN in high slope site were higher than in middle and low slope sites, while AK was the highest in middle slope site. 2) Among different soil depths, soil nutrient contents were the highest within 0-20 cm soil layer, but the lowest within 20-40 cm soil layer. The SWC was significantly lower within 0-20 cm than the other soil layers and was the highest within 20-40 cm soil layer. 3) Among different growth periods, the contents of SOM, AP, and TN were the highest in flowering period, the SWC was the highest in fruiting period, and AK content was the highest in maturing period. It was suggested that in the future management of pear water and fertilizer in the region, more K fertilizer should be applied in the high slope sites in the flowering period, while N and P compound fertilizer should be applied in the fruiting period, to enhance irrigation in middle and low slope sites to decrease the limitation of water with 300 m3·hm-2. Our results could provide theoretical support and data refe-rence for planting precision irrigation and scientific fertilization of pear planted in loess hilly areas.

Soil Nutrient Characteristics of Phoebe zhennan Plantation at Regional Scale

To analyze the effects of regions and age groups on soil properties of Phoebe zhennan plantation, the soil characteristics of P. zhennan plantation on regional scale were discussed from soil nutrients perspective, which could provide a basis for the accurate evaluation of sustainable forest management and site quality. Different regions and age groups of P. zhennan plantation in Sichuan province were selected as the research objects. The soil samples were collected by S-shaped sampling method and the nutrients were analyzed at two soil depths (0—20 cm and 20—40 cm). The general linear model, correlation analysis, principle components and other multivariate statistical methods were combined to explore the differences and relationships of soil nutrient factors of P. zhennan plantation in different regions and different age groups. The results showed that there were significantly differences of soil total nitrogen, total phosphorus, total potassium, calcium and magnesium contents in P. zhennan plantation in different areas of Sichuan (P<0.05), and there was no significantly difference in soil organic carbon. There was no significant difference in all nutrient factors among different age groups. With the increase of soil depth, the nutrient content represented a decreasing trend, and showed surface accumulation. There was a positive correlation between organic carbon and total nitrogen content, while other nutrient properties had no significant correlation. According to the results of principle components analysis, the top three comprehensive scores of soil nutrient of P. zhennan plantation were Yingjing county of Ya'an city, E’meishan of Leshan city, and Yucheng district of Ya'an city, respectively, Therefore, sustainable management of P. zhennan plantation should be carried out base on the characteristics of soil nutrients in different regions.

Impact of Different Biochars on Microbial Community Structure in the Rhizospheric Soil of Rice Grown in Albic Soil.

The purpose of this study was to clarify the effects of biochar on the diversity of bacteria and fungi in the rice root zone and to reveal the changes in soil microbial community structure in the root zone after biochar application to provide a scientific basis for the improvement of albic soil. Rice and corn stalk biochar were mixed with albic soil in a pot experiment. Soil samples were collected at the rice maturity stage, soil nutrients were determined, and genomic DNA was extracted. The library was established using polymerase chain reaction (PCR) amplification. The abundance, diversity index, and community structure of the soil bacterial 16SrRNA gene V3 + V4 region and the fungal internal transcribed spacer-1 (ITS1) region were analyzed using Illumina second-generation high-throughput sequencing technology on the MiSeq platform with related bioinformatics. The results revealed that the biochar increased the soil nutrient content of albic soil. The bacteria ACE indexes of treatments of rice straw biochar (SD) and corn straw biochar (SY) were increased by 3.10% and 2.06%, respectively, and the fungi ACE and Chao indices of SD were increased by 7.86% and 14.16%, respectively, compared to conventional control treatment with no biochar (SBCK). The numbers of bacterial and fungal operational taxonomic units (OUT) in SD and SY were increased, respectively, compared to that of SBCK. The relationship between soil bacteria and fungi in the biochar-treated groups was stronger than that in the SBCK. The bacterial and fungal populations were correlated with soil nutrients, which suggested that the impacts of biochar on the soil bacteria and fungi community were indirectly driven by alternation of soil nutrient characteristics. The addition of two types of biochar altered the soil microbial community structure and the effect of rice straw biochar treatment on SD was more pronounced. This study aimed to provide a reference and basic understanding for albic soil improvement by biochar, with good application prospects.

Coupling of different plant functional group, soil, and litter nutrients in a natural secondary mixed forest in the Qinling Mountains, China.

Soil and litter play important roles in ecosystem nutrient storage and cycling, which both affect plant growth and ecosystem productivity. However, the potential linkages between soil and litter nutrient characteristics and nutrient characteristics of different plant functional groups (PFGs) remain unclear. In this study, we investigated the carbon (C), nitrogen (N), and phosphorus (P) concentrations and stoichiometric ratios in different organs of three PFGs (trees, shrubs, and herbs), litter, and soil in nine natural secondary mixed forests in the Qinling Mountains. Leaves N and P concentrations and N:P ratios, varied from 15.6 to 18.97 mg·g-1, 1.86 to 2.01 mg·g-1, and 7.34 to 8.72, were highest at the organ level, whereas the C:N and C:P values were lowest in leaves. At the PFG level, N and P concentrations of herbaceous were 1.23 to 3.69 and 1.42 to 1.93 times higher than those in same organs of woody species, while the N:P ratio was significantly lower in herb leaves than in tree and shrub leaves. Tree organs had significantly higher C concentrations and C:N and C:P ratios than shrub and herb organs. The leaf N:P ratios of all PFGs were less than 14, suggesting that plant growth was limited by N in the study region. The nutrient contents and stoichiometric ratios in plant organs had different degrees of linkages with those in litter and soil. Soil nutrient characteristics mainly affected (23.9 to 56.4%) the nutrient characteristics of the different PFGs, and litter nutrient characteristics also had important contributions (4.5 to 49.7%) to the nutrient characteristics of PFGs, showing the following order: herbs > trees > shrubs. Our results indicate that the functional difference in plant organs resulted in diverse nutrient concentrations; and varied nutrient connections exist among different ecosystem components. Furthermore, nutrient characteristics of litter and soil can together affect the nutrient characteristics of PFGs.

Spheres of Influence: Host Tree Proximity and Soil Chemistry Shape rRNA, but Not DNA, Communities of Symbiotic and Free-Living Soil Fungi in a Mixed Hardwood-Conifer Forest

Host and symbiont diversity are inextricably linked across partnerships and ecosystems, with degree of partner reliance governing the strength of this correlation. In many forest soils, symbiotic ectomycorrhizal fungi coexist and compete with free-living saprotrophic fungi, with the outcomes of these interactions shaping resource availability and competitive outcomes for the trees aboveground. Traditional approaches to characterizing these communities rely on DNA sequencing of a ribosomal precursor RNA gene (the internal transcribed spacer region), but directly sequencing the precursor rRNA may provide a more functionally relevant perspective on the potentially active fungal communities. Here, we map ectomycorrhizal and saprotrophic soil fungal communities through a mixed hardwood-conifer forest to assess how above- and belowground diversity linkages compare across these differently adapted guilds. Using highly spatially resolved transects (sampled every 2 m) and well-mapped stands of varying host tree diversity, we sought to understand the relative influence of symbiosis versus environment in predicting fungal diversity measures. Canopy species in this forest included two oaks (Quercus agrifoliaandQuercus douglasii) and one pine (Pinus sabiniana). At the scale of our study, spatial turnover in rRNA-based communities was much more predictable from measurable environmental attributes than DNA-based communities. And while turnover of ectomycorrhizal fungi and saprotrophs were predictable by the presence and abundance of different canopy species, they both responded strongly to soil nutrient characteristics, namely pH and nitrogen availability, highlighting the niche overlap of these coexisting guilds and the strong influence of aboveground plants on belowground fungal communities.

Trace Metal Levels and Nutrient Characteristics of Crude Oil-Contaminated Soil Amended with Biochar–Humus Sediment Slurry

Biochar utilization for environmental remediation applications has become very popular. We investigated the trace metal levels and soil nutrient characteristics of a biochar–humus sediment slurry treatment of a simulated crude oil-contaminated soil in the present work. The results revealed that biochar prepared at moderate pyrolysis temperature (500 °C) could still retain a significantly higher nutrient content than those prepared at high temperatures (700 and 900 °C). Despite the suitability for soil treatment, one-pot treatment studies seem not to be very effective for monitoring trace metal sorption to biochar because trace metals do not biodegrade and remain in the system.

Effects of biomass conditioner on soil nutrient and microbial community characteristics of alpine desertified grassland in northwest Sichuan, China

Biomass conditioner made from agricultural and animal husbandry waste for resource disposal could be used to improve desertified soil, which is one of the effective ways of ecological management on desertified grasslands in northwest Sichuan. To clarify the effects of different raw material conditioners on alpine desertified grassland in northwest Sichuan, we analyzed the effects of three conditioners on soil nutrients and microbial community characteristics. With no conditioner as the control (CK), three different biomass conditioners were set up with an application rate of 12 t·hm-2, including mushroom dregs (JZ), straw (JG) and biochar (SWT). The results showed that all biomass conditioners could significantly increase soil available nutrients and active organic carbon by 23.0%-521.6%. Among the three conditioners, JG had the best effect, with an improvement range for soil nutrient and organic carbon of 65.1%-521.6%. Because biomass conditioner was only applied in the first year, soil available nutrients and active organic carbon in the second year decreased by 4.5%-92.3% compared with that of the first year, while soil organic carbon and microbial biomass carbon content of the second year increased by 5.6%-458.0%. The biomass conditioners changed the relative abundance of the dominant bacteria in the microbial community. JG significantly affected bacterial flora, while JG and JZ affected fungal flora. Compared with CK, JG significantly reduced the diversity of soil bacteria and fungi. The Shannon index was decreased by 2.9% and 31.8%, while the Simpson index was increased by 175.0% and 320.9%, respectively. Results of the redundancy analysis showed that the contents of soil available nutrients and active organic carbon were important factors affecting microbial community composition. The contents of soil nitrate and microbial biomass carbon had greater impacts on bacterial community composition, explaining 65.9% of community variations. The contents of soil available potassium and microbial biomass carbon had a greater impact on fungal community composition, explaining 83.2% of community variation. According to the comprehensive comparison, straw conditioner could significantly increase soil available nutrients and active organic carbon, and benefit the growth of beneficial bacteria and fungi, which could be used as a promotion measure to improve soil quality of alpine desertified grassland in northwest Sichuan.

Statistical variation in Soil Nutrient Characteristics near Industrial Area of Mayiladuthurai Taluk of Mayiladuthurai District in Tamilnadu, India

Surface soil samples were collected from the 0-50 centimeter depth and assessed the soil statistical variation in physico-chemical parameters. The soil grain class of the surface layer is (0-58 centimeter) of the shape. Soil samples of the experimental field were clay loam while it was clay for the subsurface (25-100 Centimeter) layers of the profile. The soil samples were air-dried, crushed and passed through a 2 mm sieve before analyzing it for Nitrogen, Phosphorus, Potassium, Organic Carbon, Organic Matter, pH and exchangeable bases. Soil pH was measured electrometrically with a glass electrode pH meter, EC was determined are by using Conductivity meter. Alkaline permanganate method, colorimetric method and Flame Photometer method is used to determine Macronutrients like N P and K. Walkley and Black method is used to determine Organic Carbon (OC) and Organic Matter (OM). While the SAR, ESP% and Cation Exchange Capacity (CEC) were calculated. Micronutrients like Zinc(Zn), Copper(Cu), Iron(Fe) and Manganese(Mn) were determined by using Atomic Absorption Spectrophotometer (AAS). Available Soil pH ranged between 7.3 to 7.9. The available Electrical Conductivity (EC) values ranged from 0.18 to 0.5dsm-1 within the range for optimal growth of plants. The ranges of available Organic Carbon are ranged between 0.23% and 0.36%, Organic matter content ranged between 0.46 and 1.11 %. Nitrogen 39.2 kg/ha-1 and 72.8 kg/ha-1 are lower than that of the control soil. Available Phosphorus is ranged between 30.00 kg/ha-1 and 67.5 kg/ha-1 and is slightly higher than that of the control soil and potassium 169 kg/ha-1 and 370 kg/ha-1 content were high respectively. Cu is available between 0.72 – 0.92 ppm and Cu was found in 100% sufficient in study area. Zn is noticed between 0.62-0.82 ppm and Zn was found in 100% deficient in study area. Mn is available between 1.18-3.92 ppm and Mn was found in 70.0% deficient and 30.0% sufficient in study area. The available concentration of Fe ranged between 3.09-4.88 ppm and Fe was found in 100% sufficient in the study area. Where all below the recommended limits. Our aim is to support the farmers to characterize the soil based on their nutrition status for best suited crops which can be used effectively for crop production and enhanced productivity [1]. The statistical variation in soil nutrition is focused in Mayiladuthurai taluk in the present study at industrial based agriculture land area of Mayiladuthurai taluk in Mayiladuthurai district. The recommendations of fertilizer can be made for the crops to enhance the productivity. Soil test assessed and recommends the application of balanced fertilizers would go a long way in enhancing soil fertility and productivity.

Assessment of Potato Farmland Soil Nutrient Based on MDS-SQI Model in the Loess Plateau

Soil nutrients are essential nutrients provided by soil for plant growth. Most researchers focus on the coupling effect of nutrients with potato yield and quality. There are few studies on the evaluation of soil nutrients in potato fields. The purpose of this study is to investigate the soil nutrients of potato farmland and the soil vertical nutrient distributions, and then to provide a theoretical and experimental basis for the fertilizer management practices for potatoes in Loess Plateau. Eight physical and chemical soil indexes were selected in the study area, and 810 farmland soil samples from the potato agriculture product areas were analyzed in Northern Shaanxi. The paper established the minimum data set (MDS) for the quality diagnosis of the cultivated layer for farmland by principal component analysis (PCA), respectively, and furthermore, analyzed the soil nutrient characteristics of the cultivated layer adopted soil quality index (SQI). The results showed that the MDS on soil quality diagnosis of the cultivated layer for farmland soil included such indicators as the soil organic matter content, soil available potassium content, and soil available phosphorus content. The comprehensive index value of the soil quality was between 0.064 and 0.302. The SPSS average clustering process used to classify SQI was divided into three grades: class I (36.2%) was defined as suitable soil fertility (SQI &lt; 0.122), class II (55.6%) was defined as moderate soil fertility (0.122 &lt; SQI &lt; 0.18), and class III (8.2%) was defined as poor soil fertility (SQI &gt; 0.186). The comprehensive quality of the potato farmland soils was generally low. The proportion of soil nutrients in the SQI composition ranged from large to small as the soil available potassium content = soil available phosphorus content &gt; soil organic matter content, which became the limiting factor of the soil organic matter content in this area. This study revolves around the 0 to 60 cm soil layer; the soil fertility decreased gradually with the soil depth, and had significant differences between the respective soil layers. In order to improve the soil nutrient accumulation and potato yield in potato farmland in northern Shaanxi, it is suggested to increase the fertilization depth (20 to 40 cm) and further study the ratio of nitrogen, phosphorus, and potassium fertilizer.

Content characteristics of mineral elements and its correlation with soil nutrients and effective components in Chrysanthemum morifolium from different producing areas in Macheng

In this study, 24 copies of samples of Chrysanthemum morifolium and soil from two main production towns in Macheng city were collected, and the contents of 13 mineral elements, 5 effective components and 14 soil nutrient factors in Ch. morifolium were determined. The enrichment characteristics of available soil nutrients by mineral elements were analyzed and the dominant factors affecting the effective components of Ch. morifolium were screened. The results showed that the content of mineral elements and soil nutrients and effective components are very different, and variation of soil fertility was much greater than that of inorganic elements in chrysanthemum plants. In general, the level of element content in Ch. morifolium from different producing areas is K&gt;N&gt;P&gt;Mg&gt;Ca&gt;Fe&gt;Mn&gt;Zn&gt;Cu&gt;Ni&gt;Cr&gt;Pb&gt;Cd. The content of K, N and Mg is higher than that of common crops, and the content of Cu, Cd and Pb in Ch. morifolium from various producing areas does not exceed the relevant standards. The N, P and K enrichment capacity in soil was stronger than that of other elements, and the Ca enrichment ability was the worst. The content of AvCu in the soil was positively correlated with the contents of N, Mg, K, Fe and Cu elements in Ch. morifolium. The contents of chlorogenic acid, luteolin, 3,5-O-dicaffeoylquinic acid reached the pharmacopoeia standard. The percentage of chlorogenic acid and 3,5-O-dicaffeoylquinic acid in Ch. morifolium that from Huangtugang town in the active components were generally higher than that from Futianhe town, and the diffe-rences of luteolin contents in the two producing areas were relatively small. The correlation and regression analysis showed that the contents of Cu, Zn and Cr in Ch. morifolium were positively correlated with the active components, while the contents of Fe, Mn and Ni were negatively correlated with the contents of AvP, AvK, TK, AvMn and AvCu in soil. In general, Zn and Ca fertilizer should be added to the ecological planting of Ch. morifolium, K fertilizer should be added, and N and P fertilizer should be applied appropriately.