Soil Fertility Indicators Research Articles

Integrated effects of vermicompost, climatic factors and soil mixing on selected soil fertility indicators

A field experiment was carried out to investigate the effects of vermicompost (0, 10, and 15 tha-1), climatic elements i.e. soil moisture (50%, 70%, and 100%) and elevation of soil temperature (1 to 20C) on the physico-chemical properties and nutrient availability of post-harvest calcareous-acid mixed soils after rice production. A total of 18 treatments assembling the afore-mentioned doses was applied. The analyses of the soils demonstrated significant variation in effects (p ≤0.05) of the treatments on both the available nutrient status and the physicochemical properties of soils. Except for available sulfur; soil pH, EC, organic carbon (OC), available nitrogen, phosphorous, potassium, calcium, and sodium were detected in the higher amounts in 1:1 (calcareous : acid-soils) mixed soils than those of 1:3 mixed counterpart both in initial and post-harvest soil conditions. The highest levels of soil pH, OC, available P and Zn were determined in the treatment T13. Whereas, treatment T6 proved to be the best dose for the highest availability of Ca and Mg. The treatments T1, T2, T11, and T16 were recorded to have the lower OC, available N, P, Ca, Mg, Zn and S contents in soils. In particular, the availability of Na was found to be in lesser amounts in all the subplots. In a nutshell, most of the treatments exerted favourable influence in maintaining a healthy level of soil physico-chemical parameters owing to their inherent characteristics. Dhaka Univ. J. Biol. Sci. 32(1): 119-134, 2023 (January)

Efficiency of Methods of Bioconversion of Fertilizer Nutrients into Green Fodder in a Peat Bog

In a two-factor field experiment, the effectiveness of the use of mineral fertilizers in combination with direct sowing of grass seeds in the turf of a cultivated peat bog was studied for the development of low-cost methods of bioconversion of nutrients of mineral fertilizers into green feeds. During the agro-economic and energy assessment of the agricultural practices used, it was established that the combination of sowing and application of mineral fertilizers was effective and contributed to obtaining the highest profit, which amounted to 24-53 thousand. rub/ha, reducing the cost of 100 k.e./ha by an average of 41-46%, increasing the energy efficiency of costs by 1.8 times compared to the control. The highest payback of a feed unit of 1 kg of NPK was noted in variants with cultivated fertilized phytocenosis, this indicator increased by an average of 1.2-1.6 times compared with variants of natural phytocenoses. Taking into account the indicators of soil fertility and the payback of the costs of carrying out a complex of agricultural practices, it was concluded that the optimal dose of mineral fertilizers in the natural phytocenosis (without sowing) was the dose of N60P90K120, in the cultivated phytocenosis - doses of N60P60K90 and N60P90K120.

Results and prospects of optimization of agrochemical indicies of arable soils fertility in Belarus

A critical overview of dynamics of agrochemical indices of arable soils fertility over 50-year period is presented. The low-yield sod-podzol and swampy soils of Belarus were relatively poor in available plant nutrients. As a result of the largescale water engineering, liming and the intensive use of fertilizers over the period of 1965–2020 the productivity of arable land increased from 1.5 to 4.6 tons per hectare in grain equivalent. The significant improvement of soil fertility status was also achieved. Data of soil fertility status are based on the large-scale soil test monitoring conducted by State Agrochemical Service every 4–5 years. The share of strongly and moderately acid soils with pH < 5.0, that are harmful for the main crops, decreased from 66.8 % in 1970 to 4.5% of total area of arable land in 2004. However, the share of acid arable soils increased up to 9.8% in 2020, due to insufficient volume of liming that will be increased in the forthcoming years. The average organic matter (O.M.) content had been strongly increased from 1.77 to 2.28 % during the period of 1970–2000, due to high share of perennial grasses in cropping structure and manure application up to 14–15 t/ha per year. About 1 million ha of drained soils with the high O.M. content was also involved to arable land. The average O.M. content in the last two decades had been in mobile equilibrium of 2.23–2.27 % with a tendency to decline in some districts. The average contents of mobile Phosphorous and Potassium in arable soils increased up to 2.4–3.2 times during the experimental period and they are in the optimal range for cultivated crops. Currently balanced fertilization is the most important, with differentiation of fertilizer rates that would be most suitable to crop requirements and soil tests on each field. Formation and maintenance of optimal soil fertility indices, especially pH and mobile Р2О5 and К2О contents, are strictly controlled as protective measures on the land contaminated with radionuclides 137Cs and 90Sr after Chernobyl accident. Measures to improve the efficiency of capital investment at fertility reproduction and use of arable soils are discussed currently.

Humus and nitrogen content of sod-podzolic soil under the influence of biopreparations for potato cultivation

In organic potato cultivation technologies, various biopreparations are used, which have a considerable impact on both the growth and development of crops, and on soil fertility indicators, which is especially important for sod-podzolic soils characterised by low potential fertility. The purpose of the study is to establish the changes in humus content and mineral nitrogen in sod-mediumpodzolic loam soil under the influence of biopreparations for the decomposition of white mustard as a cover crop and for the treatment of potato tubers and vegetative potato plants. In a two-factor experiment, the following factors were examined: factor 1: control without a destructor and “Ecostern” destructor at a dosage of 1.2 litres per hectare; factor 2: nine options of biopreparations application, including Agat, Regoplant, Mycohelp, Phytohelp, and Stimpо. Soil samples were collected from the 0-30 cm layer of sod-medium-podzolic sandy loam soil on water-glacial deposits. In them, the total humus content was established by the Tyurin method, and the mineral nitrogen content was calculated as the sum of ammonium and nitrate nitrogen determined potentiometrically. The application of the destructor on the green biomass of the cover crop contributed to an increase in the humus content in the 0-30 cm soil layer, where it ranged from 1.135% to 1.24%, compared to 1.025% to 1.15% in the options without the use of the bio-destructor. A reverse dependence was observed in terms of mineral nitrogen content. In the options with the use of the Ecostern destructor, the mineral nitrogen content was on average 2.09 mg/kg lower compared to the options without the application of the destructor. The highest humus content was observed in option 8, which involved the use of “Phytohelp” for treating potato tubers at a dosage of 1.0 litre per ton and three-fold treatment by “Phytohelp” at a dosage of 1.0 litre per hectare during the vegetation period. In the option without the destructor, the humus content was 1.15% and 1.24% with the application of the Ecostern bio-destructor. It slightly lagged behind option 9 with the “Phytohelp” biopreparations. The materials presented in the study may have practical value for agricultural enterprises engaged in growing organic potatoes to ensure the preservation and reproduction of organic matter in soils

Examining the influence of bare soil UAV imagery combined with auxiliary datasets to estimate and map soil organic carbon distribution in an erosion-prone agricultural field

Soil organic content (SOC), an indicator of soil fertility, can be estimated quickly and accurately with remote sensing (RS) datasets; however, the issue of vegetation cover on the field still remains a major concern. In order to minimize the effects of vegetation cover, studies relating reflectance spectra to SOC may require bare soil. However, acquiring satellite images devoid of vegetation is still an enormous challenge for RS techniques. This is because the area that may have been accurately predicted at a targeted date is sometimes limited since many pixels are covered by vegetation. The study goal was to assess the impact of using UAV-borne imagery coupled with auxiliary datasets, which include spectral indices (SPIs) and terrain attributes (TAs) (at 20 cm and 30 m resolution), singly or merged, to estimate and map SOC in an erosion-prone agricultural field. Both field samples and UAV imagery were acquired while the fields were bare. Using a grid sampling design, 133 soil surface samples were collected. The models used include partial least square regression (PLSR), extreme gradient boosting (EGB), multivariate adaptive regression splines (MARS), and regularised random forest (RFF). The models were evaluated using the root mean squared error (RMSE), the coefficient of determination (R2), ratio of performance to interquartile distance (RPIQ), and the mean absolute error (MAE). For prediction, the three merged datasets (R2val = 0.86, RMSEval = 0.13, MAEval = 0.11, RPIQval = 4.19) outperformed the best separate dataset (R2val = 0.82, RMSEval = 0.15, MAEval = 0.10, RPIQval = 2.08). Though all datasets detected both low and high estimates of soil SOC, the three merged datasets with EGB showed a less extreme prediction error. This study demonstrated that SOC can be estimated with high accuracy using completely bare soil UAV imagery with other auxiliary data, and it is thus highly recommended.

Effects of land‐use changes on soil organic nitrogen fractions in the black soil region of Northeast China

AbstractSoil organic nitrogen (SON) accounts for more than 90% of the total nitrogen (TN) in black soil and is one of the most important indicators of soil fertility. However, the effect of land‐use changes on SON fractions is still unclear in black soil. Hence, natural grassland (uncultivated), farmland (converted from natural grassland), and artificial forestland (grain plots converted into forests) in the black soil region of Northeast China were selected for research. TN, available nitrogen (AN) and SON fractions (ammonia nitrogen (AMN), amino acid nitrogen (AAN), hydrolysable unknown nitrogen (HUN), acid insoluble nitrogen (AIN)) in the topsoil (0–20 cm), and subsoil (20–40 cm) were analysed and compared with elucidate the effects of land‐use changes on SON fractions. The results showed that compared with natural grasslands, the contents of TN and AN in farmlands were 49.1%–67.4% and 48.0%–67.7% less, respectively, and the content of AAN decreased the most in SON fractions, by 52.2%–76.7%, followed by the content of AMN, which decreased by 46.9%–70.7%. The contents of TN and AN in the artificial forestland increased by 18.8% and 30.6%, respectively, compared with those in the farmland. Other than AAN, the content of the SON fractions in the artificial forestland soils was greater than that of the farmland, and the content of HUN increased the most in the SON fractions, by 29.6%, followed by the content of AIN, which increased by 25.8%. The proportions of AMN and AAN in the TN of the natural grassland were 1.2 and 1.7 times those of the artificial forestland, respectively. In conclusion, after natural grassland is converted to farmland, it will destroy the original soil structure, change the physical and chemical properties of the soil, significantly reduce the soil nitrogen supply potential, and significantly decrease nitrogen accumulation. The conversion of grain plots into forestland significantly improved the soil nitrogen storage capacity, but the potential nitrogen supply did not reach the levels of the uncultivated lands. Changes in land use types lead to changes in soil structure and vegetation cover, which in turn alter soil nitrogen cycling. These results provide a scientific basis for evaluating the nitrogen supply capacity of different land‐use types. The study suggests that the land use structure in the area should be properly matched to restore soil nitrogen reservoirs and maintain and improve soil fertility, taking into account local environmental conditions.

Unearthing soil-plant-microbiota crosstalk: Looking back to move forward.

The soil is vital for life on Earth and its biodiversity. However, being a non-renewable and threatened resource, preserving soil quality is crucial to maintain a range of ecosystem services critical to ecological balances, food production and human health. In an agricultural context, soil quality is often perceived as the ability to support field production, and thus soil quality and fertility are strictly interconnected. The concept of, as well as the ways to assess, soil fertility has undergone big changes over the years. Crop performance has been historically used as an indicator for soil quality and fertility. Then, analysis of a range of physico-chemical parameters has been used to routinely assess soil quality. Today it is becoming evident that soil quality must be evaluated by combining parameters that refer both to the physico-chemical and the biological levels. However, it can be challenging to find adequate indexes for evaluating soil quality that are both predictive and easy to measure in situ. An ideal soil quality assessment method should be flexible, sensitive enough to detect changes in soil functions, management and climate, and should allow comparability among sites. In this review, we discuss the current status of soil quality indicators and existing databases of harmonized, open-access topsoil data. We also explore the connections between soil biotic and abiotic features and crop performance in an agricultural context. Finally, based on current knowledge and technical advancements, we argue that the use of plant health traits represents a powerful way to assess soil physico-chemical and biological properties. These plant health parameters can serve as proxies for different soil features that characterize soil quality both at the physico-chemical and at the microbiological level, including soil quality, fertility and composition of soil microbial communities.

The tempo-spatial changes of soil fertility in farmland of China from the 1980s to the 2010s

The grain yield level is closely related to soil fertility. To clarify the status and variations of soil fertility in Chinese farmland, soil sample profile data from the Soil Species of China in the 1980s and the Soil Series of China in the 2010s were collected. And surface soil data of fertility indexes (pH, soil organic matter, total nitrogen, total phosphorus, and total potassium) were calculated. The tempo-spatial variations characteristics of both soil fertility indexes and soil comprehensive fertility of Chinese farmland were analyzed with descriptive statistics, comparative analysis of paired sample points, and Integrated Fertility Index method. The results showed that: 1) The farmland soils in southern China were acidic and those in northern were alkaline. From the 1980s to the 2010s, the pH mean decreased by 0.34, and the acidification of soils in the southern region was more significant; 2) SOM and TN contents showed similar spatial patterns, with higher contents in southern and northeastern regions. Compared with the 1980s, the SOM mean and TN mean in the 2010s increased by 2.72 g/kg and 0.06 g/kg, respectively, with a decreasing trend in some areas; 3) The spatial distribution of TP and TK contents showed significant variability, with change range of the mean values was 0.15 g/kg and −1.51 g/kg during the three decades, respectively; 4) In general, the soil fertility in Chinese farmland was poor, with the most sample points at Grade IV (Mid-low) in the 2010s (22.38 %). During the three decades, the IFI mean increased by 0.01. The number of sample points with increasing IFI in eastern China was more than that in western China. And the soil fertility in eastern China showed a trend of ameliorating. This study would have great scientific significance for guiding agricultural fertilizer application and improving fertility in farmland soils.

Novel Weighting Method for Evaluating Forest Soil Fertility Index: A Structural Equation Model.

Understanding nutrient quantity and quality in forest soils is important for sustainable management of forest resources and maintaining forest ecosystem services. In this study, six soil nutrient indicators, including soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) were measured in five different aged stands of Chinese fir forests in subtropical China. A structural equation model (SEM) was developed based on these soil nutrients indicators in order to better evaluate the soil fertility index (SFI) in these studied forests. The results show that soil nutrient contents changed with the soil depth in different age groups. The SOM decreased in a specific order: over mature > mature > near mature > middle > young stands. The TN content of the soil gradually decreased with increased soil depth throughout all age groups. The SEM indicated that the TN had the highest weight of 0.4154, while the TP had the lowest weight at 0.1991 for estimating the SFI. The weights of other indicators (AN, SOM, AP, and AK) ranged 0.2138−0.3855 in our study. The established SEM satisfied the fitness reference values and was able to accurately describe the forest soil nutrient status through the SFI. The overall SFI values were significantly higher in over mature stands than in young-aged stands and in topsoil than in deeper soil in all examined forests. Soil TN, AP, and AK were the most important nutrient indicators to the evaluation of the SFI in the study sites. The results confirmed that the SEM was suitable to estimate the weights of the SFI and better describe the soil nutrient status in forests. Our research provides an innovative approach to assess a soil nutrient status and soil fertility and provides a scientific basis for accurate implementation of soil nutrient assessment in forest ecosystems.

The effectiveness of the use of organic fertilizers in the link of crop rotation on light gray forest soil of the south of the Volga-Vyatka region

Relevance. The issues of reproduction of fertility of light gray forest soils of the forest-steppe zone and utilization of poultry industry waste as organic fertilizers are interrelated and are very relevant. Methods. The experiments studied the effect of one-time application of various doses (15, 30, 50 t/ha) of chicken manure, chicken manure compost and local organic fertilizers (sapropel and peat) on crop yields, and the aftereffect of fertilizers on the main indicators of soil fertility — amount of humus, nitrate nitrogen, phosphorus and potassium. The variants of the experiments were investigated sixfold. The Federal State Center of Agrochemical Service "Chuvashsky" was involved in laboratory analyses of soils and crop production. Mеthods of analysis of soil samples and crop production are generally accepted in agrochemical science.Results. Organic fertilizers for three years of research were introduced into the soil only once at the beginning of the experiment in doses of 15, 30 and 50 t/ha, and their effect on the yield and quality of crop production (potato tubers, spring wheat grains and peas) in 2020–2022 was positive. The agrochemical properties of the arable soil layer in the variants with the use of organic fertilizers have significantly improved. The nitrate content in the products in variants with doses of chicken manure and compost of 50 t/ha or more approached the critical level. Local fertilizers (sapropel and peat) at a dose of 30 t/ha, chicken manure and compost at a dose of 15 t/ha are good organic fertilizers with a long aftereffect.

Analiza comparativă a cernoziomurilor tipice din zona de nord a Moldovei după diferiți indicatori

The purpose of this presented paper is determining the main indicators of soil fertility of typical chernozems in the Northern part of Moldova, by the Near Infrared Reflectance Spectroscopy method, used as a rapid and cost-effective analytical tool for the assessment and monitoring of their quality over time. The study was carried out in the fields of 10 districts in the northern area of Republic of Moldova. For the analysis of the agrophysical and agrochemical soil properties, a total of 16 soil profiles cultivated with different agricultural crops (winter wheat, corn, winter barley, sunflower, soybean, peas, sugar beet) and a soil profile from a fallow land were taken. Data on soil texture (clay, silt and sand fractions) do not show large differences between the sampling regions and the depth of the soil layer. On average, physical clay content is 53-64%, and fine clay content is 35-44%. The humus content varies between 3.48-4.85% in the arable soil layer and between 2.69-4.80% in the 25-50 cm sub-arable layer. The total nitrogen content in the investigated soils correlates with the humus content. The higher the humus content, the higher the total nitrogen content. Total N content ranges from 0.28% (chernozem under fallow) to 0.13% (chernozem grown with maize) in the 0-50 cm soil layer. The C:N ratio is equal to 10-11 in the 0-50 cm soil layer and 8-11 in the 50-100 cm layer. The pH values vary between 5.9-7.2 in the 0-50 cm layer and 6.8-8.1 in the 50-100 cm soil layer. Carbonates are accumulated throughout the soil profile. Comparing the results previously obtained on the typical chernozems under fallow land with the results obtained on the arable chernozems investigated in this study, showed that there is a tendency of the humus content decrease by about 2%, especially in the 0-50 cm soil layer, as a result of applied agricultural practices. Simultaneously, degradation processes are amplified, especially through erosion. In this context, the main issue is the need to monitor soil fertility to assess the impact of agricultural management applied by farmers.

The Effect of Enzyme Activity on Carbon Sequestration and the Cycle of Available Macro- (P, K, Mg) and Microelements (Zn, Cu) in Phaeozems

The study objective was to determine the relationship of selected enzyme activities with carbon sequestration and N, P, K, Mg, Zn and Cu contents in Phaeozem soils. Soil samples were taken from a 10 ha area. A selection of their physical and chemical properties and the contents of the available forms of selected macro- and microelements were determined. The activities of dehydrogenases (DEH), catalase (CAT), peroxidases (PER), alkaline (AlP) and acid (AcP) phosphatase, β-glucosidase (BG) and proteases (PR) were also determined. The relationship between enzymatic soil fertility indices (AlP/AcP, BIF, GMea, TEI, BA12 and BA13) and selected soil parameters was also determined. The research used principal component analysis (PCA) to distinguish significantly correlated parameters of a Phaeozem used for agricultural purposes. The study area showed low TOC and K contents and average P and Mg contents. Significant positive correlations were found between the TOC content and activity of the tested enzymes, evidencing that soil enzymes are an important parameter in carbon sequestration and soil nutrient dynamics.

Long-Term Changes in Organic Matter Content and Soil Moisture Determine the Degree of Root and Soil Respiration.

Carbon in soil is one of the most important indicators of soil fertility. Part of the carbon stored in them is returned to the atmosphere during soil respiration. Climate change and inappropriate land use can accelerate these processes. Our work aimed to determine how soil CO2 emissions change over ten years as a result of litter manipulation treatments. Plots at the Síkfőkút DIRT (Detritus Input and Removal Treatments) experimental site include doubling either leaf litter or wood, and removing all aboveground litter, all root inputs, or removing all litter inputs. With the help of this, we were able to examine not only the effects of the different organic matter intake but also the effects of the different microclimates that occur as a result of the treatments. Total soil respiration (root and microbial respiration) is a result of a persistent lack or excess of soil organic matter relative to soil moisture. Based on our studies, the increase in the intensity of root respiration on wetter soils was only half of the increase in respiration associated with decomposition activity. The sustained growth of leaf litter significantly increases soil respiration, which can be partly explained by the more favorable supply of nutrients to the decomposing organisms, and partly by the more favorable microclimatic conditions, however, these effects were only valid in the case of wetter soils. In the dry summer environment, we experienced higher CO2 emissions during litter removal treatments. In the first period between 2002 and 2004, even wetter root removal treatments showed a significantly higher CO2 emission, while in the period 2010-2012, surface litter removal treatments. The permanent removal of surface litter in the drier summer period resulted in the formation of a dense crack network, which increased the CO2 emission of these soils, which increases the soil organic carbon loss of the soil. Our study proves the advantages of mulching in terms of a more favorable microclimate of the soil surface and a balanced carbon balance of the soil-plant system.

Altered Organic Matter Chemical Functional Groups and Bacterial Community Composition Promote Crop Yield under Integrated Soil–Crop Management System

Sustainable agricultural production is essential to ensure an adequate food supply, and optimal farm management is critical to improve soil quality and the sustainability of agroecosystems. Integrated soil–crop management based on crop models and nutrient management designs has proven useful in increasing yields. However, studies on its effects on the chemical composition of soil organic carbon (SOC) and microbial community composition, as well as their linkage with crop yield, are lacking. Here, we investigated the changes in SOC content, its chemical functional groups, and bacterial communities, as well as their association with crop yield under different farmland management based on four farmland management field trials over 12 years (i.e., FP: farmer practice; IP: improved farmer practice; HY: high-yield system; and ISSM: integrated soil–crop system management). The crop yield increased by 4.1–9.4% and SOC content increased by 15–87% in ISSM compared to other farmland management systems. The increased proportion of Methoxy C and O-alkyl C functional groups with a low ratio of Alkyl C/O-alkyl C, but high Aliphatic C/Aromatic C in ISSM hints toward slow SOC decomposition and high soil C quality. The relative abundances of r-strategists (e.g., Firmicutes, Myxobacteria, and Bacteroidetes) was highest under the ISSM. Co-occurrence network analysis revealed highly complex bacterial communities under ISSM, with greater positive links with labile SOC functional groups. The soil fertility index was the main factor fueling crop yields, as it increased with the relative abundance of r-strategists and SOC content. Our results indicated that crop yield advantages in ISSM were linked to the high C quality and shifts in bacterial composition toward r-strategists by mediating nutrient cycling and soil fertility, thereby contributing to sustainability in cropping systems.

Assessment of soil fertility for wheat using combined Fuzzy and AHP techniques in Udham Singh Nagar of Uttarakhand, India

Assessing soil fertility is crucial for developing effective soil management strategies that can enhance soil health, increase crop productivity, and promote sustainable agricultural practices. The current study was conducted to assess the soil fertility index and, to prepare a soil fertility zonation map using combine fuzzy and analytical hierarchy process (AHP) approaches in Udham Singh Nagar of Uttarakhand. Sixty GPSbased surface soil samples were collected (0-30 cm depth) from different locations, and analyzed chemical properties using a stratified multistage random sampling method and maps were prepared to identify their spatial distribution. The results show that the values of soil fertility index on the fuzzy scale (0-1) was varied from 0.04-0.62 and, therefore, the study area was classified as very low, low, and moderate soil fertility classes comprising 55.61%, 44.24% and 0.14%, respectively. AHP analysis revealed that the most important limiting factor for wheat production was available nitrogen, followed by phosphorous, potassium, organic carbon, pH and electrical conductivity. A correlation coefficient between wheat yield and soil fertility index was found to be as high as 0.86, and its validating the zonation of soil fertility classes. This study infers that combined fuzzy-AHP techniques may be used to compute soil fertility index and limiting factors of wheat production.

Mikrobiološke i osnovne agrohemijske osobine fluvisola duž sliva Zapadne Morave

The most common type of soil in the valleys of large lowland rivers is Fluvisol or Alluvial soil. In order to determine the biogenity of this type of soil along the Western Morava basin, the representation of the total microflora, fungi, actinomycetes, ammonifiers, Azotobacter sp. and oligonitrophiles was examined. The samples were taken from soils used in the most common two different ways (plough fields and meadows). For that were used standard microbiological methods of inoculation a certain decimal dilution on appropriate nutrient media. No correlation was established between the number of examined groups of microorganisms and the way of land use, nor was there a correlation with chemical properties, primarily with pH and organic matter content. A good representation of Azotobacter sp., as an indicator of soil fertility, was found. Agrochemical analyses showed an acidic to neutral reaction, a low to medium percentage of organic matter, a very low to very high content of easily available phosphorus and easily available potassium.

Миграция 137Cs в экосистеме поймы р. Унеча

Purpose: to study the ¹³⁷Cs migration and concentration in the alluvial soils profile and the radionuclide transfer to plants in the river Unecha floodplain ecosystem. Materials and methods. Field studies were carried out in 2019–2021 in Bryansk region (Klintsovsky district, the village of Lopatni, the right bank of the river Unecha, the current reclamation system). The density of ¹³⁷Cs contamination of the territory after the Chernobyl accident was 185–555 kBq/m². Conjugated soil and plant samples were taken in various sub-systems of the floodplain (near-channel, central, near-terrace). Agrochemical indicators of fer-tility and ¹³⁷Cs specific activity in soil and plants were determined using generally accepted laboratory methods. Results. A strong variability of the agrochemical parameters of alluvial soils in layers every 5 cm within 0–20 cm was determined. A high content of mobile phos-phorus and a low content of potassium, a strongly acid reaction of the environment, and a ten-dency to the growth in the organic carbon content from the near-channel to near-terraсе floodplain subsystem was found. The ¹³⁷Cs horizontal distribution in the river Unecha flood-plain soils was determined by soil genesis of the floodplain subsystems; the maximum specific activity of ¹³⁷Cs 3953 Bq/kg was found in the near-terrace part of the floodplain. The ¹³⁷Cs maximum concentration was found in the near-channel and central subsystem in the soil layer of 0–5 cm, and in the near-terrace subsystem in the layer of 5–10 cm. In the floodplain of the river Unecha, the ¹³⁷Cs coefficient transfer from soil to plants decreases from the central to the near-channel and near-terrace. Conclusions. The formation of agrochemical indicators of al-luvial soil fertility and the ¹³⁷Cs vertical distribution is determined by soil genesis in floodplain subsystems; it can be uniformly decreasing or concentrated in separate layers at biochemical barriers. In the floodplain ecosystem, the ¹³⁷Cs concentration in the 0–20 cm layer increases from the near-channel to near-terrace subsystem. Forage production under the conditions of radioactive contamination of the near-river and central parts of the floodplain is possible without the use of protective measures.

Alternative technology of safflower cultivation by sewage sludge use as a fertilizer-ameliorant

The effect of sewage sludge as a fertilizer-ameliorant in the safflower cultivation was studied. Sewage sludge from Volzhskij wastewater treatment plants prepurified by enzyme-cavitation method was used as a fertilizer-ameliorant in the safflower cultivation. It was found that prepurified sewage sludge is environmentally friendly and has a high fertilizing value. The amino acid composition of safflower seeds was studied. The obtained data indicate that sewage sludge introduction made it possible to significantly increase the safflower nutritional value and the soil microbiological activity. It was found that the greatest increase in the safflower crop yields was observed in the case of sewage sludge introduction at a dose of 10 t/ha with chisel tillage. It can be stated that the technology of safflower cultivation proposed by us, including the application of sewage sludge as a fertilizer-ameliorant in combination with the chisel tillage, significantly affects its productivity. The increase in safflower crop yields over the years of the studies was 8.4-15.3%. In general, it can be concluded that sewage sludge has a complex effect on the soil: improves its water-physical, agrochemical and physico-chemical properties, increases the activity of soil biota and the content of organic matter – one of the main indicators of soil fertility.

亚热带退化森林不同恢复方式对土壤团聚体胶结物质及稳定性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 亚热带退化森林不同恢复方式对土壤团聚体胶结物质及稳定性的影响 DOI: 10.5846/stxb202204211092 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(32001298); 湖北省教育厅重点项目(D20201001); 大学生创新训练项目(S202110512085) Effects of different restoration approaches of subtropical degraded forests on bonding materials and stability of soil aggregate Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:退化森林的恢复一直是林业和生态学研究的热点。良好的森林土壤结构有助于林木生长发育,作为土壤最基本的结构单元,土壤团聚体组成和稳定性是衡量土壤肥力和质量的重要指标,其团聚结构的形成依靠土壤胶结物质。然而,土壤胶结物质与团聚体稳定性之间的关系尚不确定。为探明亚热带退化森林的不同恢复方式对团聚体稳定性的影响及其潜在机制,以自然恢复的次生林为对照(CK),选取了亚热带三种常见的人工林:一代杉木林(P1)、二代杉木林(P2)和黄山松林(P3),测定土壤团聚体稳定性及其胶结物质的含量,并分析了各胶结物质对团聚体稳定性的影响。研究发现:不同森林恢复方式显著影响了土壤pH值、碳氮比、速效磷含量、团聚体的组成和稳定性。所有森林类型中,三种人工林的团聚体稳定性显著高于CK,P2的大团聚体所占比例最大,团聚体稳定性最高。恢复方式显著影响了土壤游离氧化铁含量、菌根密度和易提取球囊霉素相关土壤蛋白(EEG)含量。团聚体稳定性与游离氧化铁含量、菌根密度呈正相关,但与EEG含量呈负相关。研究结果表明,亚热带退化森林的人工恢复比自然恢复更有助于增强土壤团聚体稳定性,土壤游离氧化铁、菌根密度和EEG是显著影响团聚体稳定性的胶结物质。 Abstract:The restoration of degraded forest has been a hot topic in forestry and ecology. As a basic structural unit of soil, soil aggregate composition and stability are important indicators of soil fertility and quality, and the formation of soil aggregate relies on aggregate bonding materials. However, the relationship between aggregate bonding materials and aggregate stability is uncertain. To explore the effects of different restoration approaches of degraded subtropical forests on aggregate stability and its underlying mechanisms, we compared the secondary forest (natural restoration) as a control (CK), with three different common subtropical plantations which were: (1) first-generation Cunninghamia lanceolata (P1), (2) second-generation C. lanceolata (P2), and a Pinus. taiwanensis plantation (P3). We measured the aggregate stability and the contents of different aggregate bonding materials, and then analyzed the influence of these materials on soil aggregate stability. Results showed that forest restoration approach significantly affected soil pH, C/N, available phosphorus, as well as the composition and stability of aggregate. Among all the forests, the aggregate stability was significantly lower in CK than in the other three plantations, and P2 had the greatest proportion of large aggregates and the highest aggregate stability. The forest restoration approach also significantly affected soil free Fe oxide content, mycorrhizal density, and easily extractable glomalin-related soil protein (EEG). Aggregate stability was positively correlated with free Fe oxide content and mycorrhizal density, but negatively correlated with EEG. For subtropical degraded forests, the results indicated that artificial restoration was better than natural restoration to enhance soil aggregate stability, with soil free Fe oxide, mycorrhizal density and EEG being the main bonding materials that significantly affected the aggregate stability. 参考文献 相似文献 引证文献

Drivers of the Chemical Quality of Market Gardening Soils in the Urban and Peri-Urban Environment of Bobo-Dioulasso (Burkina Faso): Impact of Fertilizers Sources and Sites Location

Urban and peri-urban agriculture plays a key role by providing many goods and services. In particular, it provides diversified food and employment for vulnerable groups (youth and women). However, it often involves negative externalities due to non-conventional soils fertility management practices. This study aimed to investigate the chemical quality of soils over six (06) sites of the market gardening area of Bobo-Dioulasso (Burkina Faso) as affected by fertilizers uses and sites location. Thirty (30) representative market gardening farms, located in urban, semi-urban and rural areas, were randomly selected from a baseline survey database. Within each farm, composite soil samples made up of 3 individual cores were taken over the 0 - 15 cm soil depth for determining soils carbon, total nitrogen, available phosphorus contents and pH-water. These data were normalized and summarized to compute a synthetic Soil Fertility Index (SFI). The data processing was focused on a Principal Component Analysis and an Ascendant Hierarchical Classification in order to make a typology of the vegetable farms. Fertilizers management effects on soils quality were compared through Variance Analysis (ANOVA) following a GLM procedure in Rstudio software. As main results, soils chemical parameters, except for available K, were affected by the location of the sites. Soils in urban farms are less acidic (on average pH = 6.9), while semi-urban and rural sites (Samadeni, Nakaguana) have more acidic soils. However, the latter site had the highest values of C and N. Moreover, the long-term application of organic matter sources results in improving of the chemical quality of the market garden soil. The SFI is positively correlated with the rate of applied organic fertilizers, and the cultivation duration. On the other hand, soil quality tends to decrease with the expansion of the area, due to a dilution effect of the organic fertilizer doses. All these results suggest that there is a real scope to reinforce the position of the market garden as an opportunity for recycling organic wastes and sequestration of carbon by promoting relevant fertilization packages that strongly rely on organic matters sources (Compost, Biochar, etc.).