Agricultural Soil Fertility Research Articles

International Scientific and Practical Conference “Problems of Soil Fertility in Current Agriculture” dedicated to the 70th anniversary of virgin and abandoned lands development (Krasnoyarsk, June 24–28, 2024)

International Scientific and Practical Conference “Soil fertility problems in current agriculture” (hereinafter referred to as Conference) took place on June 24–28, 2024, in Krasnoyarsk (Russia) to mark 70 years since virgin and long-abandoned lands were put into the agricultural use. The Conference attracted more than hundred participants, including three full and two corresponding members of the Russian Academy of Sciences, 26 doctors and 46 candidates of sciences, as well as postgraduate and doctoral students, researchers from the scientific centers and institutes of Krasnoyarsk and other regions of Russia, and also from Kazakhstan and Belarus. Sectional topics were as following: changes in soil and agrochemical properties during agricultural land use; urgent issues in soil degradation and soil-protection agriculture; assessment and regulation of soil fertility and agricultural productivity; the role of species and cultivar composition of agrocenoses in soil production capacity; digital technologies in agriculture, remote and ground monitoring of agroecosystems; history of virgin and abandoned lands development. The plenary lectures and other Conference materials are published in a book “Soil fertility problems in current agriculture” (2024). Besides the plenary and sectional events, the Conference participants attended a field trip to see experimental fields and soil profiles in Krasnoyarsk Region and Khakassia and enjoyed excursions around Krasnoyarsk and the National Park “Krasnoyarskiye Stolby”. The Conference provided a forum for discussing diverse and the most urgent issues of current agriculture and for getting acquainted with new approaches, concepts and technologies, applied in various spheres of agronomy for solving land use and soil preservation problems. The Conference participants, emphasizing its importance, expressed their confidence that Conference results and resolution will promote the progress of the agricultural industry in Russia.

An Investigation into Ensemble Learning Techniques for Evaluating Soil Fertility through Analytical Approaches

At the heart of India’s livelihood lies agriculture, a foundational and ever-evolving sector. The realm of agriculture faces modern challenges, encompassing unpredictable climate fluctuations, insufficient irrigation infrastructure, and erratic weather conditions. Amidst these challenges, machine learning has emerged as a valuable tool for evaluating soil fertility and Crop assessment in agriculture. Ensemble machine learning methodologies have garnered attention for their potential to enhance predictive capabilities. These techniques involve constructing meta-classifiers that collectively contribute to improved predictive accuracy. This paper centers on the analysis of soil data acquired from testing laboratories, to predict fertility based on a comprehensive dataset. The study employs prominent ensemble machine learning algorithms, specifically focusing on boosting techniques, to elevate predictive accuracy and ensure heightened consistency.The assessment of soil fertility categories involved the examination of 12 carefully chosen attributes. Diverse soil parameters were measured to facilitate the prediction of soil fertility levels. The outcomes of the experimentation revealed that the application of the boosting technique using the Xgboost algorithm yielded superior accuracy compared to alternative ensemble classifiers, achieving a remarkable 96% accuracy rate.

Pesticides in Agricultural Soils: Major Findings from Various Monitoring Campaigns in Switzerland.

Synthetic pesticides are widely applied in modern agriculture, where they are used against diseases, pests, and weeds to secure crop yield and quality. However, their intensive application has led to widespread contamination of the environment, including soils. Due to their inherent toxicity, they might pose a risk to soil health by causing harm to non-target organisms and disrupting ecosystem services in both agricultural and other exposed soils. Following the Swiss National Action Plan on the reduction of pesticide risks, Agroscope has conducted several soil monitoring studies that are briefly presented here. All of them resort to different multi-residue trace analytical approaches to simultaneously quantify up to about 150 modern pesticides by either accelerated solvent, or Quick, Easy, Cheap, Efficient, Rugged, Safe (QuEChERS) extraction, followed by separation and detection with liquid chromatography-triple quadrupole mass spectrometry. While partly still in progress, our investigations led to the following major findings this far: Multiple pesticides are commonly present in soils, with individual concentrations in agricultural soils often reaching up to a few tens of µg/kg. Pesticide occurrence and concentrations in agricultural soils primarily depend on land use, land use history and cultivated crops. Pesticides can prevail much longer than predicted by their half-lives, and were found in soils even decades after conversion from conventional to organic farming. Corresponding residual fractions can be in the order of a few percent of the originally applied amounts. We further found negative associations of pesticide residues with the abundance of beneficial soil life, underpinning their potential risk to the fertility of agricultural soils. Traces of pesticides are also detected in soils to which they were never applied, indicating contamination, e.g., via spray drift or atmospheric deposition. These results confirm the general notion of both scientists and legislators that prospective risk assessments (RA; as executed during registration and use authorization) should be confirmed and adjusted by retrospective RA (e.g., by environmental monitoring studies of currently used compounds) to jointly lead to an overall reduced environmental risk of pesticides.

Identification of Land Fertility and Farmers' Income After Earthquake Natural Disasters

Central Sulawesi's 2018 earthquake, liquefaction, and tsunami caused liquefaction in Palu City's Balaroa and Petobo neighbourhoods. Land surface changes affected agricultural land area and soil fertility, which can affect farmers' income. Soil fertility indicates its nutrient-providing capacity. This study aims to assess agricultural land fertility, farmer income, and the best ways to recover from natural disasters. This descriptive study included all Petobo farmers affected by the earthquake and liquefaction. Purposive sampling tested 25 respondents. The field survey collected soil samples at coordinate points. Twelve soil samples were taken from six points at 20 cm and 40 cm depths. The samples were analysed at Tadulako University's Environmental and Natural Resources Analysis Laboratory. The results showed that Petobo Village's liquefaction-affected and unaffected areas had low fertility due to low C-organic and Potassium content, which prevented plants from using soil nutrients. Low soil fertility reduces crop production. Farmers earn an average of Rp. 1,422,857 per hectare, up to Rp. 4,633,929 per season per hectare. To increase soil fertility, farmers can use compost, manure, crop residues like legume plant stover, rice straw, and chemical fertilisers according to dosage.

Mechanisms of soil respiration and its temperature sensitivity in black soil farmland

Soil respiration is the process of decomposition of organic matter in soil and microbial metabolism to produce carbon dioxide. In the context of climate warming and degradation of agricultural soil fertility, it becomes crucial to explore the mechanisms of soil respiration to increase carbon sequestration. In this paper, five biochar applications (0, 3.79, 7.58, 11.36, 15.15 t/ha) and two tillage methods (shallow ploughing, deep ploughing) were set up to explore the mechanism of soil respiration and its temperature sensitivity by studying the effects of tillage methods and different amounts of biochar application on soil properties, soil enzyme activities, soil respiration and its temperature sensitivity during the growing season of soybeans in the black soil area. The results showed that soil respiration rate increased with biochar application in the low biochar application range; the opposite trend was observed for high biochar application beyond the threshold (11.36 t/ha). The application of 11.36 t/ha of biochar amount had the strongest promotion effect on soil respiration, reaching 2.42 μmol m−2·s−1 in the shallow ploughing treatment and increasing 0.32 μmol m−2·s−1 in the deep ploughing compared to the shallow ploughing. The application of biochar significantly increased the activity of nitrogen and phosphorus enzymes and had an inhibitory effect on carbon cycle enzymes; the increased activity of nitrogen and phosphorus cycle enzymes provided sufficient substrate for microbial respiration and thus increased soil respiration, and the decrease in the enzymatic reaction of carbon cycle enzymes led to a decrease in temperature sensitivity. The temperature sensitivity of deep ploughing (2.18–2.59) got a more substantial reduction than that of shallow ploughing (2.34–3.53), which indicates that deep ploughing treatments can better reduce the mineralization of organic carbon than shallow tillage. Meanwhile, the temperature sensitivity of soil respiration reached a minimum with the application of 7.58 t/ha of biochar, which was reduced by 16% under deep ploughing treatment compared to the control, 33% under shallow ploughing treatment compared to the control, and also reduced by 27.27% under deep ploughing compared to shallow ploughing, which suggests that the addition of biochar reduces the loss of carbon to a certain extent. This study is important for assessing the effects of tillage practices and biochar combinations on carbon sequestration in agricultural soils in black soil areas.

Restoration Techniques Applied in Open Mining Area to Improve Agricultural Soil Fertility

Open pit mining causes damage in natural and rural regions; that is why soil restoration is necessary in order to recovery soil–plant systems. The application of waste can be a good solution for rehabilitation, and it clearly complies with the circular economy and the zero-waste strategy. This study was carried out in a quarry restoration area in the southeast of Spain, where experimental plots were designed and fertilized with different amendments (commonly used inorganic fertilizer N-K-P, pig slurry, pruning waste and urban solid wastes) with the objective of studying ways to improve the restoration of the soil by using these residues and increase the soil fertility before planting. The treatments applied were evaluated in the short term (two and four months from their addition to topsoil) and medium term (nine months) in order to determine if the restored soils will be adequate for agriculture based on nutrients’ availability. The results showed that in all the treatments, the pH exceeded 8.5 due to the nature of the soil matrix, but after 9 months of the application, in the plots treated with NPK and pig slurry, the pH decreased. In general, with the application of the treatments, soil macro- (N, P, K, Na, Ca and Mg) and micro-nutrients (Fe and Cu) were increased. However, pig slurry and urban solid waste favored N and P, respectively.

Monitoring the impacts of crop residue cover on agricultural productivity and soil chemical and physical characteristics

To the best of our knowledge, the impacts of crop residue cover (CRC) on agricultural productivity and soil fertility have not been studied by previous researchers. In this regard, this study aims to apply an integrated approach of remote sensing and geospatial analysis to detect CRC and monitor the effects of CRC on agricultural productivity, as well as soil chemical and physical characteristics. To achieve this, a series of Landsat images and 275 ground control points (GCPs) collected from the study areas for the years 2013, 2015, and 2021 were used. A convolutional neural network (CNN), a class of artificial neural network has commonly applied to analyze visual imagery, was employed in this study for CRC detection in two classes (Not-CRC and CRC) for the years 2013, 2015, and 2021. To assess the effects of CRC, the Normalized Difference Vegetation Index (NDVI) was applied to Landsat image series for the years 2015 (22 images), 2019 (20 images), and 2022 (23 images). Furthermore, this study evaluates the impacts of CRC on soil fertility based on collected field observation data. The results show a high performance (Accuracy of > 0.95) of the CNN for CRC detection and mapping. The findings also reveal positive effects of CRC on agricultural productivity, indicating an increase in vegetation density by about 0.1909 and 0.1377 for study areas 1 and 2, respectively, from 2015 to 2022. The results also indicate an increase in soil chemical and physical characteristics, including EC, PH, Na, Mg, HCO3, K, silt, sand, and clay from 2015 to 2022, based on physical examination. In general, the findings underscore that the value of an integrated approach of remote sensing and geospatial analysis for detecting CRC and monitoring its impacts on agricultural productivity and soil fertility. This research can offer valuable insight to researchers and decision-makers in the field of soil science, land management and agriculture.

Changes in the mycobiome structure in response to reduced nitrogen fertilization in two cropping systems of maize

Nitrogen (N) is an essential element for plant productivity; hence, it is abundantly applied to the soil in the form of organic or chemical fertilizers, which consequently have a negative impact on the environment. Therefore, the main objective of our study was to investigate the structure and richness of the soil mycobiome in response to reduced nitrogen fertilization under two cropping systems: plowing (P) and no-till (NT). Moreover, the scope of the study perfectly falls into the EU “From Field to Table” strategy, which recommends a 20 % reduction of nitrogen fertilization of agricultural soils by 2030.In our study, the samples were collected twice during a single growing season: before maize sowing (without fertilization) and after harvesting the crop (four different fertilization rates). The mycobiome structure was identified based on the next generation sequencing (NGS) technique.Overall, our research has proved that the cropping system is important in terms of the formation of the fungal mycobiome structure and relative abundance. In addition, we confirmed that soil properties have a significant impact on fungal communities. We determined that a 20 % lower nitrogen fertilization rate (92.0 kg N ha−1) had a positive effect on the abundance of fungal communities. Moreover, the highest biodiversity at each of the taxonomic levels tested (phylum, class, genus) in the NT system and at the class and genus levels in the P system was also evidenced at the 20 % lower N fertilization rate. We also recommended potential indicators confirming the positive impact of reduced fertilization in two cropping systems: plowing – Epicoccum, Metarhizium, Mycosphaerella, and Paraconiothyrium and no-till – Peziza, Podospora, Metarhizium, Trechispora, and Umbelopsis.

The use of visible and near‐infrared spectroscopy for in‐situ characterization of agricultural soil fertility: A proposition of best practice by comparing scanning positions and spectrometers

AbstractThe application of visible and near‐infrared (vis–NIR) spectroscopy to characterize soil samples has gained growing interest as a fast and cost‐effective methodology for soil fertility assessment. In order to profit from the full potential of vis–NIR spectroscopy, the acquisition of soil spectra directly in‐situ would increase the possibility to obtain data rapidly and at a high spatial and temporal resolution. In the present study, we test and propose the best practice to characterize a set of fertility‐related parameters (i.e. texture, organic carbon, pH, cation exchange capacity and major nutrients) of agricultural soils by measuring vis–NIR spectra in the field. To reach this goal, we compare the spectra obtained from different scanning positions with two portable spectrometers, that is, a micro‐electro‐mechanical systems (MEMS)‐based spectrometer and a research‐grade vis–NIR spectrometer. On the basis of 134 soil sampling points, vis–NIR spectra were recorded from: (1) the cutaway side of a soil sample collected with an Edelman auger to a depth of 20 cm, (2) the raw soil surface, as well as (3) the cleaned and smoothed soil surface. Partial least squares regression (PLSR) calibration models were built for the selected soil parameters, scanning positions and different spectral pretreatments for both spectrometers. The model performance was evaluated based on the ratio of performance to interquartile range (RPIQ), the R2, the root mean squared error (RMSE) and Lin's concordance correlation coefficient (CCC). Overall, the following soil parameters were successfully predicted: clay, sand, pH, organic carbon, cation exchange capacity, total nitrogen and exchangeable magnesium. In contrast, total and exchangeable Ca, K and P, as well as total Mg could not be predicted at a satisfactory level for both the spectrometers. The best scanning position for the successfully calibrated models was along the cutaway sides of the Edelman auger. Although the research‐grade spectrometer gave better performance indicators for most of the parameters, the calibrations with the MEMS‐based spectrometer still resulted in satisfactory predictions. Based on these findings, the proposed best practice for obtaining in‐situ soil vis–NIR scans is to scan along the cutaway sides of a soil core using at least five replicate scans.

The potential contribution of microplastic pollution by organic fertilizers in agricultural soils of Bangladesh: quantification, characterization, and risk appraisals

Although plastics are being recycled worldwide, a significant amount of plastic is still directly exposed to the environment and, in the end, forms microplastic (MP) particles (<5 mm). Soil is a significant sink for plastic waste. Thus, MP is considered an emerging threat to terrestrial ecosystems. Among several sources, organic fertilizer can be a potential source of MP to contaminate agricultural soils. Therefore, it is hypothesized that commercial organic fertilizer acts as a carrier of MP to agricultural soils in Bangladesh. Hence, 18 organic fertilizers were collected from different local markets in Bangladesh and subjected to the following available MP separation/extraction techniques. Then, a series of experimental steps were conducted, such as microscopic inspection, identification through Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and energy-dispersive X-ray analysis (EDAX), to identify and characterize MP. The data were analyzed statistically using both qualitative and quantitative approaches. On average, 1,529.62 ± 420.2 MP items/kg of organic fertilizer were detected in the study, ranging from 433.33 ± 152.75 items/kg to 3,466.67 ± 1,357.69 items/kg in different organic fertilizers. The size range of 0.5 mm–1.00 mm (30%) was predominant among five different size ranges. The fiber was dominant over various shapes, and seven colors were observed, with black being the most prevalent. Overall, in a year, 971.31–1,387.37 items/m3 area was introduced through organic fertilizer to land. These MPs further contaminate soil biota and groundwater by their distribution pattern. According to the polymer hazard index (PHI), pollution load index (PLI), and potential ecological risk index (PERI), this organic fertilizer belongs to hazard categories III, V, and extreme danger, respectively. This study clearly explains the presence of MP in commercially available organic fertilizers and their probable effects. This could be applicable in further policy planning to reduce contaminants in formulating organic fertilizers.

Importance of Dalbergia sissoo for restoration of degraded land: A case study of Indian dry tropical vindhyan regions

To achieve the UN Sustainable Development Goals and preserve biodiversity and ecosystem services, degraded land must be restored. The focus of the current study was to evaluate the impact of Dalbergia sissoo Roxb (D. sissoo), a multipurpose native Indian tree in restoring degraded land. The significance of this species in restoring the fertility of agricultural soil in the dry tropical region of India was also examined in this study. This study showed an improvement in the soil quality (physical, chemical, biological, and enzymatic properties) of rhizosphere zone of D. sissoo (DL) throughout three seasons (rainy, winter and summer) in comparison to D. sissoo based agricultural soil (AL) and degraded (barren) land soil (BL). Soil moisture and water holding capacity (WHC) was significantly higher in DL in all three seasons compared to AL and BL, whereas, lower soil temperature and bulk density were noted in the rhizospheric soil of DL. The amount of soil organic carbon (SOC) was 75–94% higher in DL rhizospheric soil and 12–20% in the AL compared to BL soil in all three seasons. Total nitrogen (TN) and total phosphorus (TP) in the rhizospheric soil of DL were significantly higher (TN, 0.15–0.17% and TP, 16.1–21%) than those in AL (TN, 0.05–0.06%; TP, 11.4–14.2%) and BL ((TN, 0.03–0.04%; TP, 11.6–10.5%) soils, while C: N ratio was higher in BL (13.2–14.8) than AL (10.8–12.1) and lower in DL (6.5–8.2) soil in all three seasons. The rhizosphere soil of DL had considerably greater levels of microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and soil dehydrogenase activity (SDA) than the AL and BL. Pearson's correlation showed a significant strong positive correlation of SOC with WHC, TN, TP, MBC, MBN and soil dehydrogenase activity (SDA) (p < 0.01). Additionally, the principal component analysis (PCA) showed large and positive loading of PC1 for TN, WHC, MBN, MBC, SOC and SDA, suggesting that the restoration efforts should focus on increasing the TN, MBC, MBN, SOC and SDA. Increased SOC, TN, TP, microbial biomass and SDA in the rhizosphere soil of D. sissoo indicate healthy soil conditions in the Vindhyan dry tropical region of India. Therefore, this study advises to use D. sissoo tree extensively in land restoration initiatives for the benefit of both nat ure and people and also to achieve the goal of the United Nations Decade on Ecosystem Restoration (2021−2030).

PENDAMPINGAN PENGOLAHAN KOTORAN SAPI MENJADI PUPUK ORGANIK

Behind its disgusting shape, cow dung has many ingredients that are very beneficial for soil fertility. This service was carried out in Slaharwotan Village, Ngimbang District, Lamongan Regency. In this village, the majority of people raise cattle, but the manure is wasted and not utilized. For this reason, this service aims to provide assistance to the cattle farming community to process wasted cow manure waste into organic fertilizer that can be used for agricultural soil fertility. This service method uses Participatory Action Research (PAR) with planning, implementation, and evaluation steps. Retrieval of community needs data by means of interviews and Focus Group Discussion (FGD). Assistance in making organic fertilizer is carried out in a simple way with additional ingredients in the form of EM4 and calcium. This activity is also an additional knowledge for farmers who do not understand how to make organic fertilizer properly. With this mentoring activity, the community knows that cow dung has beneficial value and can immediately practice independently in processing cow dung into organic fertilizer.

Metal oxide modified biochars for fertile soil management: Effects on soil phosphorus transformation, enzyme activity, microbe community, and plant growth

Metal oxide modified biochars are increasingly being used for intensive agricultural soil remediation, but there has been limited research on their effects on soil phosphorus transformation, soil enzyme activity, microbe community and plant growth. Two highly-performance metal oxides biochars (FeAl-biochar and MgAl-biochar) were investigated for their effects on soil phosphorus availability, fractions, enzyme activity, microbe community and plant growth in two typical intensive fertile agricultural soils. Adding raw biochar to acidic soil increased NH4Cl–P content, while metal oxide biochar reduced NH4Cl–P content by binding to phosphorus. Original biochar slightly reduced Al–P content in lateritic red soil, while metal oxide biochar increased it. LBC and FBC significantly reduced Ca2–P and Ca8–P properties while improving Al–P and Fe–P, respectively. Inorganic phosphorus-solubilizing bacteria increased in abundance with biochar amendment in both soil types, and biochar addition affected soil pH and phosphorus fractions, leading to changes in bacterial growth and community structure. Biochar's microporous structure allowed it to adsorb phosphorus and aluminum ions, making them more available for plants and reducing leaching. In calcareous soils, biochar additions may dominantly increase the Ca (hydro)oxides bounded P or soluble P instead of Fe–P or Al–P through biotic pathways, favoring plant growth. The recommendations for using metal oxides biochar for fertile soil management include using LBC biochar for optimal performance in both P leaching reduction and plant growth promotion, with the mechanisms differing depending on soil type. This research highlights the potential of metal oxide modified biochars for improving soil fertility and reducing phosphorus leaching, with specific recommendations for their use in different soil types.

Potato growth, yield and quality affected by calcium and nitrogen (CaN) compound fertilizers on andisol soil type in Lembang

The use of artificial chemical fertilizers that are very intensive and not in accordance with the availability of soil nutrients, has a negative impact on decreasing agricultural soil fertility and vegetable productivity. The aim of this experiment was to obtain an effective and efficient dose of compound fertilizer (Ca and N) for potato plants in Andisol soil type, Lembang. The experiment was carried out at Margahayu Experimental Field of Indonesian Vegetable Research Institute (IVEGRI) (1250 m asl), from June to November 2021. A randomized block design was used with 8 treatments and 4 replications. The treatments consisted of without N fertilizer, standard N single fertilizer, and 6 doses of compound fertilizer (33% Ca and 17% N). The results showed that, in general, CaN compound fertilizers increase the growth of potato plants. The application of compound fertilizer at 75% of N standard (300 kg/ha of CaN fertilizer) was the most effective dose for fertilizing potato plants on Andisol soil type in Lembang. This dose can save the use of N by 25% with a Relative Agronomic Effectiveness (RAE) value of 140%. This study showed that the use of CaN compound fertilizers at a dose of 300 kg/ha can not only reduce fertilizer input into the soil, but also increase potato yields.

Evaluation of the Use of a Material with Struvite from a Wastewater Treatment Plant as N Fertilizer in Acid and Basic Agricultural Soils

Struvite (MgNH4PO4 ∙ 6H2O) has been widely studied as an emerging recycled phosphorous fertilizer despite its low solubility. However, there are few studies on the use of this mineral as an N fertilizer. This article evaluates the use of two powder struvite-containing materials from wastewater treatment as an N fertilizer in agricultural soils. A 9-week soil incubation experiment was conducted to compare the effectiveness of this mineral as an N fertilizer in two soils with different pH values (8.2 and 6.7), using two different doses and a control soil. The use of these materials has a positive effect on soil fertility, especially in acidic soils where struvite seems to be more soluble. Thus, struvite can be a potential N fertilizer for agricultural soils and can promote circular economy opportunities for the wastewater industry, especially in acid soils (concentrations of mineral N between 453–339 mg/kg were obtained in the mixtures with acid soil, and values between 408–212 mg/kg in the mixtures with the basic soil after 6 weeks of soil incubation). However, associated with this process, an increase in soil salt content was observed (EC values reaching 3.9 dS/cm in mixtures with the acid soil and 2.8 dS/cm in the mixtures with the basic soil after nine weeks of soil incubation). Therefore, this parameter should be controlled in the case of continuous applications of the amendments, especially in conditions of poor drainage and/or non-percolating water regime, since it can be a limiting factor in crop development. These processes should be studied in detail in the future considering that the N soil cycle has a significant impact on soil chemistry and fertility and on the soil microbiological community.

Functional redundant soil fauna and microbial groups and processes were fairly resistant to drought in an agroecosystem

Climate change scenarios predict more frequent and intense drought periods for 2071 to 2100 for many regions of the world including Austria. Current and predicted lower precipitation scenarios were simulated at a lysimeter station containing a fertile and less fertile agricultural soil for 9 years. 13C and 15N-labeled green manure was added in year 8 with the aim to analyze how the predicted precipitation regime affects soil fauna and microbial groups and consequently nitrogen (N) and carbon (C) cycling. Among the investigated mesofauna (collembola and oribatida), the abundance and biodiversity of oribatida was significantly reduced by drought, possibly because they mainly represent K-strategist species with low mobility and consequently the need to adapt to long-term adverse environmental conditions. Microbial community composition and microbial biomass, investigated by phospholipid fatty acid (PLFA) analysis, was indistinguishable between the current and the predicted precipitation scenarios. Nonetheless, soil 13C-CO2 emissions and soil water 15N-NO3 data revealed decelerated mineralization of green manure under reduced precipitation in the first 2 weeks, but no effects were observed on soil C sequestration or on 13C incorporation into microbial PLFAs in the following 1.2 years. We found that over a 1-year time period, decomposition was rather driven by plant residue availability than water limitation of microorganisms in the investigated agroecosystem. In contrast, N2O emissions were significantly reduced under drought, and green manure derived 15N accumulated in the soil under drought, which might necessitate the adjustment of future fertilization regimes. The impacts of reduced precipitation and drought were less pronounced in the more fertile agricultural soil, due to its greater buffering capacity in terms of water storage and organic matter and nutrient availability.

Statement of Retraction: Monitoring of Fertilization and Increase of Fertility of Agricultural Soils

Statement of Retraction: Monitoring of Fertilization and Increase of Fertility of Agricultural Soils

Domestic Herbivores, the Crucial Trophic Level for Sustainable Agriculture: Avenues for Reconnecting Livestock to Cropping Systems

Domestic herbivores have been closely associated with the historical evolution and development of agriculture systems worldwide as a complementary system for providing milk, meat, wool, leather, and animal power. However, their major role was to enhance and maintain agricultural soil fertility through the recycling of nutrients. In turn, cereal production increased, enabling to feed a progressively increasing human population living in expanding urban areas. Further, digestion of organic matter through the rumen microbiome can also be viewed as enhancing the soil microbiome activity. In particular, when animal droppings are deposited directly in grazing areas or applied to fields as manure, the mineralization–immobilization turnover determines the availability of nitrogen, phosphorus, potassium, and other nutrients in the plant rhizosphere. Recently, this close coupling between livestock production and cereal cropping systems has been disrupted as a consequence of the tremendous use of industrial mineral fertilizers. The intensification of production within these separate and disconnected systems has resulted in huge emissions of nitrogen (N) to the environment and a dramatic deterioration in the quality of soil, air, and ground- and surface water. Consequently, to reduce drastically the dependency of modern and intensified agriculture on the massive use of N and phosphorus (P) fertilizers, we argue that a close reconnection at the local scale, of herbivore livestock production systems with cereal-based cropping systems, would help farmers to maintain and recover the fertility of their soils. This would result in more diverse agricultural landscapes including, besides cereals, grasslands as well as forage and grain crops with a higher proportion of legume species. We developed two examples showing such a beneficial reconnection through (i) an agro-ecological scenario with profound agricultural structural changes on a European scale, and (ii) typical Brazilian integrated crop–livestock systems (ICLS). On the whole, despite domestic herbivores emit methane (CH4), an important greenhouse gas, they participate to nutrient recycling, which can be viewed as a solution to maintaining long-term soil fertility in agro-ecosystems; at a moderate stocking density, ecosystem services provided by ruminants would be greater than the adverse effect of greenhouse gas (GHG).

ONION (ALLIUM CEPA L.) AS A TEST PLANT

Phytotesting has long been used to determine the quality of seeds, agricultural soil fertility, in biomedical research, and recently in the field of environmental protection to assess the ecological quality of natural environment (water, soil) in phytotesting of toxicants. Various plant representatives are used as model test organisms, in particular, onion (Allium cepa L.) is considered as a standard test plant for the determination of toxicants. The purpose of the work is to generalize methodological approaches of using onion (Allium cepa L.) in phytotesting of toxicants. Methodology. During the research, the following methods were used: 1) general scientific methods (methods of theoretical research of available information); 2) analytical and generalized methods (for the analysis of scientific and literature sources on the given problem); 3) empirical (for accumulating facts); 4) methods of argumentation (to prove one’s own judgments). Scientific novelty - methodical approaches of using onion in phytotesting of toxicants are summarized, formulas for calculating phytotoxic indices (root length index, phytotoxic effect of solutions, toxicity index of solutions for each test function, average toxicity index of the tested solutions) are presented. Conclusions - phytotesting is a commonly used method of assessing the quality of natural environment (water, soil) which is based on the sensitivity of plants to external chemical influences and is reflected in growth and morphological characteristics. The standard test plant for the determination of toxicant influence is the onion (Allium cepa), which can be used both in the growth test and in the Allium-test. The most sensitive characteristics of onion are the mitotic activity of the apical meristem cells and the frequency of cells with chromosomal aberrations.

More extreme and frequent drought periods reduced crop production and altered stable isotope ratios of C and N in plants

Summary Climate change scenarios predict more frequent and intense drought periods for 2071–2100 in the most important and intensively used agricultural region of Austria, the Marchfeld. Current and predicted lower precipitation scenarios were simulated at a lysimeter station for 9 years. Plant biomass, nitrogen (N) and carbon (C) content, and δ13C and δ15N values of plant compartments were monitored in years 7–9. Aboveground biomass of cereals and grain yield decreased under the predicted scenario, while the quality of grain (% N) was unaffected. Weed and catch crops grown in winter were not affected or were even positively affected, possibly due to the accumulation of nutrients in the soil following the lower plant uptake in summer. Accordingly, low plant δ15N values were mainly attributed to the presence of higher proportion of mineral fertilizer in the predicted precipitation scenario. As expected, water stress significantly increased δ13C values in plants grown over summer, while this was not seen for plants growing over winter. Fertile agricultural soil might ameliorate but cannot outbalance the negative impact of more frequent and intense drought periods.