Long-term Field Experiment Research Articles

THE EFFECT OF AMENDMENT AND FERTILIZATION ON SOME CHEMICAL CHARACTERISTICS OF THE SOIL

The paper presents the results obtained from the long-term experimental field within Agricultural Research Station Livada. The experience included 6 variants in which manure, amendments (CaCO3) and mineral fertilization with NPK were applied. The soil samples were collected at a depth of 0-20 cm after 5 years from the application of manure. By applying CaCO3 0.5t/ha/year the pH was maintained at the value of 6.0 and with 0.7 t/ha/year the pH value was maintained at 7.0. The amendment potential of the manure that was applied in a dose of 20 t/ha determined an increase in pH from 4.56 to 5.28 after 55 years of application. Long-term fertilization with 20 manure + N100P70K60 increased the level of soil total nitrogen supply from low to medium. Fertilization with manure + N100P70K60 led to high accumulations (highly significant compared to fertilization with manure alone) of phosphorus, accumulations stimulated in the amended varieties.Amending acidic soils with limestone (calcium carbonate) and proper fertilization are essential for maintaining and improving soil quality.

Evaluation and Selection of Bromegrass Genotypes under Phosphorus and Water Scarcity towards the Development of Resilient Agriculture Focusing on Efficient Resource Use

The relationship between phosphorus (P) availability and water restriction was explored in this study, focusing on its impact on phosphorus use efficiency (PUE) and water use efficiency (WUE) in various bromegrass (Bromus spp.) genotypes. Under controlled conditions, five bromegrass genotypes, as well as one ryegrass (Lolium perenne) cultivar, were compared by subjecting them to two P levels and two watering regimes. It was determined that combining water and phosphorus limitations led to reduced plant productivity. Initially, the ryegrass outperformed the bromegrass, but this result declined over time, while bromegrass exhibited consistent stability. Notably, under P and water stress, enhanced root development was observed in bromegrass compared to that in ryegrass. Distinct patterns of PUE and WUE allowed for the categorization of bromegrass genotypes into three groups. Genotype 3457 emerged as the most efficient, scoring 20 out of 24, while Pro 94-49 A achieved a score of only 10 out of 24. This study suggests that the drought resilience of bromegrass may be linked to increased root growth during the early vegetative stages, which potentially facilitates improved P acquisition. However, further validation through long-term field experiments is needed. The insights from this study are potentially valuable for use in shaping plant breeding programs by revealing the plant adaptation mechanisms for both P and water absorption.

Long term co-application of biochar and fertilizer could increase soybean yield under continuous cropping: insights from photosynthetic physiology.

Photosynthesis is the key to crop yield. The effect of biochar on photosynthetic physiology and soybean yield under continuous cropping is unclear. We conducted a long-term field experiment to investigate the effects of co-application of biochar and fertilizer (BCAF) on these parameters. Five treatments were established: F2 (fertilizer), B1F1 (3 t hm-2 biochar plus fertilizer), B1F2 (3 t hm-2 biochar plus reduced fertilizer), B2F1 (6 t hm-2 biochar plus fertilizer), and B2F2 (6 t hm-2 biochar plus reduced fertilizer). BCAF increased chlorophyll and leaf area, enhancing soybean photosynthesis. The net photosynthetic rate (Pn ), transpiration rate (Tr ), stomatal conductance (Gs ), water use efficiency (WUE) and intercellular carbon dioxide (CO2 ) concentration (Ci ) were enhanced by BCAF. In addition, BCAF improved soybean photosystem II (PSII) photosynthetic performance, driving force, potential photochemical efficiency (Fv /F0 ), and quantum yield of electron transfer (φE0 ). Furthermore, BCAF enhanced the accumulation of photosynthetic products, such as soluble proteins, soluble sugars and sucrose content, resulting in higher leaf dry weight. Consequently, BCAF increased the soybean yield, with the highest increase of 41.54% in B2F1. The correlation analysis revealed positive relationships between soybean yield and chlorophyll, leaf area, maximal quantum yield of PSII (Fv /Fm ), electron transport flux per cross-section at t = 0 (ET0 /CS0 ), trapped energy flux per cross-section at t = 0 (TR0 /CS0 ), composite blade driving force (DFTotal ), and leaf dry weight. We demonstrated that long-term BCAF enhances soybean photosynthesis under continuous planting, reduces fertilizer use and increases yield. This study reveals a novel way and theory to sustainably increase soybean productivity. © 2023 Society of Chemical Industry.

Application of machine learning methods for crop rotation selection in organic farming system

This study demonstrates the possibility of crop rotation selection based on the assessment of productivity and sustainability of crop production under different atmospheric moisture conditions. The study considers 8 crop rotations oriented to grain production. The data obtained in long-term field experiments in the forest-steppe of the Novosibirsk region were used. As a result of the implementation of the decision tree (CART) and the use of ensemble algorithm (Random Forest) the construction of a model characterized by a fairly high predictive ability was performed. Standardized Precipitation Index was chosen as the main predictor characterizing atmospheric moistening in different periods of vegetation. The most stable from the point of view of stability of crop yield – grain-fallow with winter rye, grain-fallow with legumes (vetch-oats), in conditions of manifestation of atmospheric drought of different severity were selected. The possibility of using machine learning methods (CART, Random Forest) as effective tools in the selection of crop rotation for sustainable grain production without the use of chemicalization in soil and climatic conditions of Siberia, as well as the assessment of possible risks in the transition of crop production to organic technologies were scientifically substantiated.

Plantas herbáceas com coloração foliar variegada, promissoras para paisagismo urbano

Abstract The article presents the results of a comparative analysis of the quantitative and qualitative composition of a sample of variegate herbaceous species and cultivars (36 names) from the collection fund of the Laboratory of Ornamental Plants, Tsitsin Main Botanical Garden, Russian Academy of Sciences. In the Poaceae Barnhart, Asteraceae Giseke, Lamiaceae Martinov and Saxifragaceae Juss. families have been found the largest number of genera containing species, which include forms with this leaf color. The analysis of data from long-term field experiments allowed us to assume the presence of a multidirectional influence of adaptive characteristics on the stability in the culture of different groups of introduced plants with variegate leaf color. Variegate plants are the most widely represented in the modern collection fund of the Laboratory of Ornamental Plants. For them, differences in stability in culture were revealed depending on the ratio of the differently colored parts of the leaf blade. Variegate plants have been studied according to their belonging to ecological groups, donor regions, life forms and the systematic status of natural ancestral species.

The impact of drying on the structure and photosynthesis of boreal peatland vegetation

Boreal peatlands harbour large stores of carbon as peat below their surfaces. Climate change is expected to cause drying in northern peatlands, which will in turn impact the carbon balance of these ecosystems that is maintained by high water tables and the hydrologically sensitive plants growing there. This study aims to quantify how vegetation will be structured (I) and photosynthesize (II, III) in a future climate as emulated by long-term water level drawdown (WLD). To do this, changes in the vegetation and its photosynthesis after WLD are linked, and the response of Sphagnum mosses to periodic drought is investigated. Field measurements were done at a long-term WLD field experiment that contained a rich (mesotrophic) fen, a poor (oligotrophic) fen and a bog (ombrotrophic) site. Measurements included vegetation surveys from existing permanent sample plots and leaf-level carbon dioxide exchange measurements. For an experiment in controlled conditions peatland surface cores from this field experiment were transported to a greenhouse where the photosynthesis of lawn Sphagna during and after an experimental periodic drought was measured. The field study revealed that the response of peatland vegetation to WLD depend on peatland type. The species composition in the rich fen was the most impacted by WLD, while the bog vegetation demonstrated stability. Similarly, large increases in photosynthesis occurred following WLD on the vascular plant-covered rich fen, while changes were negligible on the Sphagnum-carpeted bog. The vegetation on the two fens shifted from an open sedge-, or sedge and Sphagnum-dominated ecosystem, to a tree-dominated ecosystem. Canopy development following WLD further accelerated vegetation changes by shading and sheltering the understorey vegetation. Vascular plants were the most likely to increase productivity from WLD as they are best suited to utilize the nutrients made available by peat mineralization, while Sphagnum moss photosynthesis was impacted little. The greenhouse study revealed that lawn Sphagnum mosses exposed to long-term WLD were more vulnerable to drought compared to those from wet sites. Large capitula typical to fen Sphagnum species appeared to be beneficial for surviving periodic drought. This work demonstrated that climate change as emulated by long-term WLD will have a large impact on the vegetation composition of northern peatlands and increase photosynthetic function of these ecosystems, fens in particular. To better predict climate feedbacks from these changes, carbon dynamics including peatland vegetation dynamics should be updated in global process models. Future research to better understand the tipping point of different peatland types after WLD in different climatic regions will help us to predict changes in these diverse and globally important systems.

Positive experience in the application of soil- and carbon-saving agricultural technologies with the introduction of biochar in the conditions of the Russian Far East

Based on the positive results of a long-term field experiment on the introduction of bio-coal for vegetable crops in the Primorsky Territory on soils of heavy chemical composition, its sequestration effect and positive effect on the water-physical properties of soils were proved. After the first year of application of biochar, a significant decrease in CO2 flux in the field without a drainage system was shown by 4.5% at a dose of 1 kg/m2 of biochar and by 36.6% at a dose of 3 kg/m2 of biochar compared with a site without biochar. The decrease in CO2 flux indicates the reclamation effect of biochar due to its high sorption properties affecting the sequestration capacity of the soil. After the second year of application of biochar, the greatest decrease in CO2 flux was observed when 1 kg/m2 was applied. The greatest difference between the values of the CO2 flux at the control site and the sites with the introduction of biochar was noted in September after the abnormal amount of precipitation recorded in August (521 mm). So, at the control site in September, the CO2 flux was 2,276 mg CO2 m-2 h-1, at the site with the addition of 1 kg/m2 of biochar, the CO2 flux was 560 mg CO2 m-2 h-1, at the site with the addition of 3 kg/m2 – 975 mg CO2 m-2 h-1.

Long-Term Experiences with Fertilizers on Wheat and Maize Crops in the Pedoclimatic Conditions of the Bârlad Plateau

A large number of long-term field experiments demonstrate that optimal application of nitrogen fertilizers to crops did not result in loss of organic matter, nor did it adversely affect soil microbial activity. Optimal use of fertilizers on agricultural crops reduces soil erosion, but repeated application of high doses of nitrogen fertilizer can lead to soil acidification, a negative trait of soil health. The main objective of this paper is to study the particular effect, interaction and complementarity of NP, NPK and organo-mineral fertilizers on the production of agricultural crops. This paper presents production data as well as references that can be used to define the scientific bases of the multi-year application of fertilizers. The experimental technique is specific to the polyfactorial character and the analytical methods used are specific and current in the field. In this scientific paper, we present the results obtained for the cultivation of wheat and corn, during the period 2018-2023, at the “Mircea Moțoc” Perieni Research-Development Station for Combating Soil Erosion, by fertilizing with several types of organo-mineral fertilizers. The results obtained come from the long-term experiences with fertilizers with 25 variants in the NP experience, respectively 16 variants in the NPK experience and the organo-mineral experience, all being placed according to the block method with parcels subdivided into 6 repetitions. The obtained results were interpreted by analysis of variance. From the results of this long-term experience, it is concluded that the effect of long-term fertilization with NP, NPK and organo-minerals responds to the maximization of profit and the optimization of the soil-plant system and environmental protection.

Alone and Combined Application of Press Mud Compost and Fuller Earth for Abating Pb and Cd and Enhance Sorghum Growth in Polluted Soils

The aim present work was to examined the alone and combined impact of press mud compost and fuller earth at 0.5 and 1 % dosage on immobilization of Pb and Cd in Sharafi Goth and Malir polluted soils and reduce their uptake by sorghum plant. The results revealed that sorghum dry biomass yield was observed by 41.47 and 58.8 % with press mud compost (PMC) 1 % + fuller earth (FE) 1 % in Sharafi Goth soil and in Malir polluted soils than control. The immobilization of Pb was observed by 88.0 and 93.52 % with PMC 1 % + FE 1 %, and Cd was immobilized by 90.36 with PMC 1 % + FE 1 % and 78.0 % with PMC 0.5 % + FE 0.5 % in Sharafi Goth and Malir polluted soils than control. The uptake of Pb and Cd in shoot and root by sorghum was reduced both soils with application additives. The studied amendments increased the soil chemical properties such as electrical conductivity (EC), pH, cation exchange capacity (CEC), organic matter (O.M) and CaCO3 than control soil. The results of redundancy analysis showed that soil O.M had positive correlation with plant dry biomass, whereas EC, pH, CEC, O.M and CaCO3 showed negative correlation with Pb and Cd in soil and Pb and Cd in plant soot and root biomass. The results of present study indicated that press mud compost alone and in combined form shown positive impact on plant growth, immobilize Pb and Cd in both soils and reduced their uptake by sorghum plant. Future long-term field experiments must be carried out in multi-metals polluted soils and cultivate different genotypes.

Long-term effects of oil contamination on soil quality and metabolic function.

Widespread soil contamination with oil and the toxicity of petroleum hydrocarbons to soil biota make it extremely important to study microbial responses to oil stress. Soil metabolites reflect the main metabolic pathways in the soil microbial community. The examination of changes in the soil metabolic profile and metabolic function is essential for a better understanding of the nature of the pollution and restoration of the disturbed soils. The present study aimed to assess the long-term effect of oil on the ecological state of the soil, evaluate quantitative and qualitative differences in metabolite composition between soil contaminated with oil and non-contaminated soil, and reveal biologically active metabolites that are related to oil contamination and can be used for contamination assessment. A long-term field experiment was conducted to examine the effects of various oil concentrations on the biochemical properties and metabolic profile of the soil. Podzolic soil contaminated with oil demonstrated the long-term inhibition of soil biological activity and vegetation. Oil affected the metabolic activity of soil fungi increasing the production of toxic metabolites. A metabolomic approach was employed to determine soil metabolites. The metabolite profile was found to vary greatly between oil-contaminated and non-contaminated soils. Carbohydrates had the largest number of metabolites negatively affected by oil, while the content of organic acids, phenolic compounds, and terpenoids was mainly increased in oil-contaminated soil. The evaluation of the long-term impact of oil on microbial metabolism can make a valuable contribution to the assessment of soil quality and the activity of soil microorganisms being under stress from oil pollution. The results contribute to a further understanding of the role of microorganisms in the ecological functions of contaminated soil, which can be useful in the development of rehabilitation strategies for disturbed sites.

Effects of planting year of alfalfa on rhizosphere bacterial structure and function

In many areas across the world, alfalfa is still cultivated in the same place over many years, leading to gradually deplete the soil nutrients and increase plant disease and consequent decreases in the yield and quality. Agricultural management practices have been proved to affect largely soil microbial community structure and functions in many reports, but it remains unclear how planting year effects extend to the rhizosphere under a long-term cultivation practices of alfalfa. Exploring such impacts is of great importance to understand and develop plant-microorganism interactions for agricultural sustainability. A long-term field experiment was set up at Linze research station of Lanzhou University in Gansu province, where alfalfa was continuously planted for four years (Y4) and six years (Y6). Rhizosphere soils from two different planting years were collected to examine differences in the bacterial diversity, composition and co-occurrence patterns using 16S rRNA gene sequencing technologies as well as in functional profiles involved in nitrogen cycling predicted by FAPROTAX. We found that soil nutrients including soil organic carbon (SOC), AP (available phosphorus) and nitrate nitrogen (NO3−-N) differed significantly between planting years. Bacterial taxonomic diversity, composition and the relative abundance of functional groups involved in nitrogen cycling were significantly affected by planting years, sampling time and their interactions. Co-occurrence network analysis showed that keystone taxa in both planting years were affiliated to Proteobacteria and bacteria taxa had less complexity and more negative correlations in Y6 than in Y4. NO3−-N was a major factor affecting bacterial community diversity and composition across planting years. Together, our findings suggest that planting years of alfalfa can lead to large variations in soil nutrients and rhizosphere microbial community patterns. These results implies that in agricultural management practices, planting year effects can even extend to microorganisms in association with plant roots, which may affect crop growth given close linkages between rhizosphere processes and plant nutrition availability.

CO2 Emissions from Soils under Different Tillage Practices and Weather Conditions

CO2 emissions are one of the greenhouse gases that significantly contribute to climate change. The use of reduced soil tillage practices could contribute to the mitigation of CO2 emissions from soils under ongoing climate change conditions. The use of reduced and no-tillage practices in the summer period, the most critical period for CO2 and for water loss from soils, would contribute to the mitigation of CO2 emissions that is required by the European Union. The aim of this research was to contribute to the specification of CO2 emission factors, following different soil tillage practices in the summer period under variations in weather. Gentler tillage practices were defined in terms of reducing CO2 emissions from the soil. This research was carried out as a long-term field experiment. The effects of soil tillage practices on CO2 emissions were studied over a six-year period as a long-term field experiment and concerned the use of different soil tillage practices for over 20 years (established in 1995), with these including conventional tillage (CT; plowing to 20–22 cm), reduced tillage (RT; chiseling to 10 cm), and no-tillage (NT; without tillage). The crop rotation was winter wheat–winter oilseed rape–winter wheat–pea. CO2 emissions were measured at least 7–10 times during the summer–autumn period in the years 2017–2022 after agrotechnical operations following the winter wheat harvest. Soil moisture was determined in all the treatments. Weather conditions were measured by means of the meteorological station of the Crop Research Institute. The CO2 emissions were the highest in the summer period under CT in comparison with RT and NT. Reduced tillage and no-tillage practices, with mulch on the surface of the soil, decreased CO2 emissions by a 6-year average of 45% and 51%, respectively. The mean CO2 emissions were 6.1, 3.1, and 2.9 μmol CO2 m−2 s−1 for CT, RT, and NT. The highest CO2 emissions and the largest differences among different tillage practices were measured in 2019, with high temperatures and repeated rainfall. CO2 emissions under CT reached 22 μmol CO2 m−2 s−1, which was 7.5 and 5.8 times higher than under RT and NT, respectively. Current weather conditions, mainly temperature and precipitation, played an important role in CO2 emissions. The hot and dry weather in 2018 decreased overall CO2 emissions, with CO2 emissions, even under conventional tillage, reaching only 2.5 μmol CO2 m−2 s−1 on average. As a result of climate change, the temperatures also gradually increased in the later stages of the year, with more summer days being expected during autumn and higher CO2 emissions from soils being expected as a result.

Plant Nutrition-New Methods Based on the Lessons of History: A Review.

As with new technologies, plant nutrition has taken a big step forward in the last two decades. The main objective of this review is to briefly summarise the main pathways in modern plant nutrition and attract potential researchers and publishers to this area. First, this review highlights the importance of long-term field experiments, which provide us with valuable information about the effects of different applied strategies. The second part is dedicated to the new analytical technologies (tomography, spectrometry, and chromatography), intensively studied environments (rhizosphere, soil microbial communities, and enzymatic activity), nutrient relationship indexes, and the general importance of proper data evaluation. The third section is dedicated to the strategies of plant nutrition, i.e., (i) plant breeding, (ii) precision farming, (iii) fertiliser placement, (iv) biostimulants, (v) waste materials as a source of nutrients, and (vi) nanotechnologies. Finally, the increasing environmental risks related to plant nutrition, including biotic and abiotic stress, mainly the threat of soil salinity, are mentioned. In the 21st century, fertiliser application trends should be shifted to local application, precise farming, and nanotechnology; amended with ecofriendly organic fertilisers to ensure sustainable agricultural practices; and supported by new, highly effective crop varieties. To optimise agriculture, only the combination of the mentioned modern strategies supported by a proper analysis based on long-term observations seems to be a suitable pathway.

Can the Blended Application of Controlled-Release and Common Urea Effectively Replace the Common Urea in a Wheat-Maize Rotation System? A Case Study Based on a Long-Term Experiment.

The one-time application of blended urea (BU), combining controlled-release urea (CRU) and uncoated urea, has proven to be a promising nitrogen (N) management strategy. However, the long-term sustainability of blending urea remains largely unexplored. To assess whether a single application of blended urea could effectively replace split uncoated urea applications, a long-term field experiment was conducted in the North China Plain (NCP). The results indicated that, when compared to common urea (CU) at the optimal N rate (180 kg N ha-1), BU achieved comparable grain yields, N uptake and NUE (61% vs. 62). BU exhibited a 12% higher 0-20 cm soil organic nitrogen stock and a 9% higher soil organic carbon (C) stock. Additionally, BU reduced life-cycle reactive N (Nr) losses and the N footprint by 10%, and lowered greenhouse gas (GHG) emissions and the C footprint by 7%. From an economic analysis perspective, BU demonstrated comparable private profitability and a 3% greater ecosystem economic benefit. Therefore, BU under the optimal N rate has the potential to substitute split applications of common urea in the long-term and can be regarded as a sustainable N management strategy for wheat and maize production in the NCP.

Changing soil available substrate primarily caused by fertilization management contributed more to soil respiration temperature sensitivity than microbial community thermal adaptation

Substrate depletion and microbial community thermal adaptation are major mechanisms that regulate the temperature sensitivity (Q10) of soil microbial respiration. Traditionally, the Q10 of soil microbial respiration is measured using laboratory incubation, which has limits in the continuous input of available substrates and the time scale for microbial community thermal adaptation. How the available substrate and the soil microbial community regulate the Q10 of soil microbial respiration under natural warming conditions remains unclear. To fill this gap in knowledge, a long-term field experiment was conducted consisting of two years of soil respiration observations combined with a soil available substrate and microbial community thermal adaptation analysis under seasonal warming conditions. The Q10 of soil respiration was calculated using the square root method, and it was more affected by the available substrate than by microbial community thermal adaptation. Fertilization management has a stronger effect on soil available substrate than temperature. As the temperature increased, NH4-N proved itself to be important for the bacterial community in the process of Q10 regulation, while dissolved organic carbon and nitrogen were key factors for the fungal community. Based on the niche breadth of microbial community composition, the changing Q10 of the soil respiration was not only closely associated with the specialist community, but also the generalist and neutralist communities. Furthermore, bacterial community thermal adaptation primarily occurred through shifts in the abundances of specialists and neutralists, while changes in species richness and species replacement occurred for the fungal generalists and neutralists. This work indicates that changing available nitrogen and DOC primarily caused by fertilization management contributed more in regulating the Q10 of soil microbial respiration than microbial community thermal adaptation, and there are different mechanisms for bacterial and fungal community thermal adaptation under warming.

Enhancing nitrogen use efficiency and plant productivity in long-term precrop/crop rotation and fertilization management

ContextLong-term experiments are an important tool to investigate the effects of crop rotation and fertilization measures under climate change conditions. However, there are few studies on nitrogen use efficiency (NUE) of crops in long-term cropping systems in Europe, but no consolidate studies in Germany. ObjectiveWe analyzed a long-term experiment established in 1982 to observe the role of legumes on total nitrogen uptake, NUE, agronomic efficiency, nitrogen response index and N recovery efficiency compared to fallow land and cereals in a crop rotation over the long-term. MethodsThe experiment included five different precrops (fallow land, maize, oat, field bean and clover mulch) in combination with four levels of fertilization (control, PK, PK+N with reduced dosage, and PK+N with full dosage followed by three years of cereal cultivation (winter wheat, winter rye, summer barley) in all treatments. The field trial was conducted as a fully factorial split plot design, with spatially randomized field repetitions in four blocks. ResultsLong-term mineral NPK fertilization improved the N uptake of winter wheat (185.7 kg N ha−1), winter rye (152.2 kg N ha−1) and summer barley (92.2 kg N ha−1) when the higher level of fertilization (NPK 100%) was implemented. A year-round application of clover mulch as green manure in the rotational system resulted in higher NUE (up to 37%) compared to fallow land after 40 years. Crop rotation with oat and maize (100% cereals) led to lower NUE (up to 30%) compared to fallow land. Clover mulch (198%), field bean (155%), fallow land (148%) and maize (119%) significantly increased the N uptake of wheat compared to oat in 2015. Over time, the agronomic efficiency was increased. This increase was 4 or 5 times higher in the 9th and 10th crop rotation compared to the beginning of the experiment (in 1983). Nitrogen response index of clover mulch was approximately 33–37% lower than fallow land at the beginning of the experiment in 1983 and 45–50% lower over the 40 years. N recovery efficiency values of winter wheat (94%), winter rye (66%) and summer barley (46%) increased within the 10th crop rotation compared to the beginning of the long-term experiment. ConclusionsCombining clover mulch as a green manure with mineral fertilizer has greater potential to improve NUE and crop productivity by increasing soil N availability. ImplicationsOur study highlights the importance of evaluating agronomic management practices in long-term field experiments to understand their sustainable effects.

Soil organic mater management – a decisive measure in climate change mitigation and adaptation

Global warming requires the implementation of both immediate and long-term mitigation and adaptation measures in agriculture, which is affected by greenhouse gas emissions through the use of practices from the industrial model arsenal of agricultural intensification (oversaturation of planting areas with arable crops and lack of crop rotations with a greater diversity of arable and successive crops; excessive tillage; irrigation; application of mineral fertilizers, especially nitrogen etc.). Data from the long-term field experiments at Research Institute of Field Crops ”Selecția” (Bălți, Republic of Moldova) are proving the dominance of mineralization over humification of soil organic matter with the emissions of CO2 and oxides of nitrogen in the atmosphere. Chernozem soils have a high potential for carbon sequestration and consequently for mitigation and adaptation to climate change. Sustainable and resilient management of soil organic matter is one of the key issues for the transition to a more sustainable agriculture, capable to supply ecosystem and social services.

Impact of tillage systems on maize emergence

In Europe, there has been a significant change in the way tillage is approached in recent years. This change is due to a growing awareness among farmers, politicians and society as a whole that soil is not a renewable resource in itself. From an agricultural point of view, the greatest impact on soil condition can be achieved through the use of the applied tillage systems. My research takes this approach as a basis when examining the different tillage systems and their impact on the environment. In this context, conventional and a variety of no-tillage systems are examined in this paper. As a next step, it is examined how the environmental conditions created by the different tillage systems influence the emergence of maize hybrids. The analyses are carried out in a multi-factorial, long-term tillage field experiment. The same batch of the same hybrid seed was sown in several crop years, and the effects of environmental conditions on the emergence process were examined. Environmental effects and emergence-related uptake were measured in the examined plots. Measurements of environmental effects included air temperature, precipitation, soil temperature measured at seeding depth, as well as % cover of stem residue on the surface in the treated plots. The first emergence time measurements of the sown crop in the plots of each treatment were compared and relationships between these factors were investigated.

Changes in Soil Organic Matter and Biological Parameters as a Result of Long-Term Strip-Till Cultivation

The aim of the study was to determine the impact that three cultivation systems—conventional till (CT), reduced till (RT), and strip-till one-pass (ST-OP)—had on the biological parameters of the soil and their relationships with organic matter properties in the row zone (R) and inter-row zone (IR). For this purpose, a long-term static field experiment was carried out, from which soil samples were taken from a depth of 0–20 cm and the following were determined: TOC; TN content and fractional composition of organic matter; activity of dehydrogenases (DEHs), catalase (CAT), alkaline (AlP), and acid phosphatase (AcP); and the abundances of heterotophic bacteria (B), filamentous fungi (F), actinobacteria (Ac), and cellulolytic microorganisms (Ce). Soil samples for biological parameter tests were collected in summer (July) and autumn (October). RT and ST-OP increase the content of TOC, TN, carbon, and nitrogen in the humic and fulvic acid fractions. For the studied groups of microorganisms, the conditions for development were least favourable under CT cultivation. The results show that in July, the activities of DEH and CAT were the highest in ST-OP, whereas in October, they were the highest under CT. AlP and AcP activity were markedly the highest under ST-OP in both months. Enzyme activity was significantly the highest in the IR zone. The results indicate that, of the calculated multiparametric indicators, (AlP/AcP, GMea, BIF, BA12, and TEI), BA12 is a sensitive biological indicator of soil quality.

Effect of mineral fertilizers on sorghum crop yields in the southern forest-steppe of Western Siberia

The results of studying the productivity of sorghum crops under different conditions of mineral nutrition on meadow-chernozem soil of the southern forest-steppe of Western Siberia are presented. The study was conducted in 2019–2022 in the Omsk region as part of a long-term stationary field experiment. The soil of the experimental plot is meadow-chernozem moderately deep heavy loamy soil. The arable horizon is characterized by neutral reaction of the soil solution (pH 7.0–7.2). The scheme of the experiment is two-factor, includes application of nitrogen (N0, 30, 60) and phosphorus (P0, 60) mineral fertilizers before sowing sorghum crops. The dynamics of moisture content in the meter soil profile is closely related to the hydrothermal conditions of vegetation periods. In the most wetted year of 2019, the soil profile had a more stable and uniform moisture content, especially in the second half meter. In subsequent years, the atmospheric moisture deficit was clearly manifested in the content of total moisture both along the soil profile and in time. Drying out of the meter profile even in the initial growing season was observed in 2022, which can be considered as a result of low residual moisture in the preceding, also dry, season. In the control, mineral nutrition was limited by the low content of mobile phosphorus. The studies have shown that in conditions of insufficient and unstable moisture, typical for the south of Western Siberia, it is advisable to cultivate sorghum crops with high responsiveness to the use of mineral fertilizers in field fodder production. In the average of two years, the maximum yield of green mass of sugar sorghum on intensive background was 21.07 t/ha, sorghum-sudangrass hybrid – 16.62 t/ha, which is higher than the control by 47.2 and 62.7%, respectively. The most effective was the complex application of mineral fertilizers, which provided an increase in dry matter content of sugar sorghum from 3.97 to 6.08 t/ha (53.0%), sorghum-sudangrasas hybrid – from 2.81 to 4.73 t/ha (68.3%).