Herbicides In Soil Research Articles

Microbial rhizosphere communities in response to chlorimuron-ethyl herbicide in soils under alfafa crop

Biolog Eco technology was used to investigate the effects of different chemical herbicide application methods, such as pre-emergence after sowing and post-emergence (stem and leaf spraying), on the characteristics of carbon source utilization by microbial communities in alfalfa rhizosphere soil. The averages of well color development (AWCD) and microbial metabolism diversity indices of post-emergence herbicide spraying on stems and leaves were significantly lower than those of pre-emergence herbicide and without herbicide treatments. Furthermore, pre-emergence after sowing herbicide treatment did [...]

Soil residues of sulfosulfuron herbicide in wheat field determined by bioassay and laboratory methods

Although herbicides are used for weed control in the field, their residues can have unfavourable environmental impacts. The objective was to determine the sulfosulfuron herbicide residues in wheat field soil using bioassay and laboratory (HPLC) methods. The two-year experiment was a randomised complete-block design (RCBD) with three replicates using herbicide at control, recommended (26.6 g/ha, D1) and doubled (53.2 g/ha, D2) rates. Soil samples (0–10 cm) were collected randomly at intervals ranging from 0 to 125 days after spraying. Greenhouse experiments (bioassay method) with eight plant species indicated garden cress (Lepidium sativum L.) and corn (Zea mays L.) as the most and the least sensitive ones, respectively. The herbicide residues were stable at D1 up to 90 days after herbicide use, at 1.41 and 0.52 μg/kg in 2019 and 2020, respectively. However, 125 days after herbicide use no residues were observed. With time and for both treatments, soil herbicide residues decreased or the percentage of herbicide loss increased. The sensitivity of HPLC method to detect the herbicide residues was less than the bioassay method. The three-parameter sigmoid equation indicated the mean of DT<sub>50</sub> for D1, averaged for the two years it was 19 days.

Can soil type interfere in sorption-desorption, mobility, leaching, degradation, and microbial activity of the 14C-tebuthiuron herbicide?

Understanding the behavior in soil of herbicides applied PRE-emergence, such as tebuthiuron, is essential for more accurate weed management and less environmental impact. Thus, the objective of this research was to evaluate the effect of the physicochemical attributes of soils in 14C-tebuthiuron behavior. All studies were carried out by radiometric technique. The Kf and Kd values of 14C-tebuthiuron sorption were 30% and 35% higher in clay soil (1.15 mg(1–1/n) L1/n Kg−1 and 1.32 L Kg−1) compared to loamy sand soil (0.80 mg(1-1/n) L1/n Kg−1 and 0.85 L Kg−1, respectively). The desorbed amount was ∼19% higher in loamy sand soil compared to loamy sand soil, and this process was influenced by OC and clay content. The 14C-tebuthiuron leaching in clay soil was up to 10 cm depth, while in loamy sand soil was higher, up to 25 cm, and this difference can be explained by high mobility and low sorption of herbicide in loamy sand soil. 14C-tebuthiuron had a long persistence in both soils (DT90 of ∼385 and 334 d in loamy sand and clay soil, respectively). Although, the microbiological activity in soils differed little in the presence and absence of herbicide. Soil type interfered in 14C-tebuthiuron behavior, and then the application recommendation of this herbicide as a function of the physicochemical attributes of the soil is an alternative to increase efficiency in weed control and reduce the risk of environmental contamination.

Simazine degradation in agroecosystems: Will it be affected by the type and amount of microplastic pollution?

AbstractPlastics and herbicides represent two of the most extensive and persistent anthropogenic contaminants entering agroecosystems. The synergistic interaction of these pollutants on soil health, however, remains poorly understood. For the first time, we investigated the behavior of a common selective triazine herbicide (simazine) in soil containing 0%, 1%, 5%, 10%, and 20% (w/w) of two commonly found microplastics, namely polyethylene (PE) and polyvinyl chloride (PVC). The mineralization of 14C‐labeled simazine in soil decreased with the presence of both PE and PVC as indicated by the lower total 14CO2 loss. Consequently, the half‐life of simazine increased in the presence of microplastics, although there was little difference between microplastic types. The ratio of fungi‐to‐bacteria in the soil increased by 9%–18% after 1% of microplastics addition, while enzyme activities involved in C‐cycling decreased by 20%–46% in soil amended with PVC relative to the control. Further, enzyme activities were negatively correlated with the half‐life of simazine when added with PVC. Therefore, we ascribe the repression in simazine degradation to changes in microbial community structure (increased fungi‐to‐bacteria ratio) and reduced enzyme activities. Overall, microplastics accumulation in soil decreases herbicide breakdown resulting in herbicide residuals remaining, which in turn, may increase their risk of reaching ground or surface waters.

Weeding of safflower crops under the influence of agricultural treatments on non-herbicide and herbicide background

Weeds are a big problem with safflower crops. To control weeds, it is necessary to develop an effective system of herbicide use and mechanical methods of weed control for arid conditions of the Southern steppe of Ukraine. In weed–infested fields, the protein content of cereals decreases and that of oilseeds in oil fields. Weed reduction reduces the productivity of agricultural machinery and implements, increases production costs. Weeds reduce the effectiveness of fertilizers, irrigation and other measures aimed at increasing crop yields. The article presents the main results of research for 2017–2019 to study the impact of agricultural practices for the care of safflower crops on herbicide and herbicide–free backgrounds on the weediness of safflower crops. The research was conducted in the fields of the Institute of Oilseeds of NAAS. The system of the main tillage: classical. Variants of the crop care system: 1 – without care (control); 2 – harrowing before and after germination; 3 – 2 row spacing; 4 – harrowing and inter–row cultivation. Application of soil herbicide led to a decrease in the total number of weeds before harvesting in crops of safflower variety Zhyvchyk by 9,3–16,0 and in crops of variety Dobrynya by 8,3–17,7 pieces/m2. The number of weeds before harvesting was the lowest in the variants with two inter–row treatments and was equal to: 16,0 pieces/m2 – on a background with out herbicide and 6,7 pieces/m2–on a herbicide background in crops of Zhyvchyk variety; 14,3 and 6,0 pieces/m2, respectively, in crops of Dobrynya variety. The lowest values of air–dry mass of weeds before harvesting: 81,5 and 39,6 g/m2 in crops of Zhyvchyk variety and 84,3 and 36,9 g/m2 were obtained in the variant with two inter–row treatments. The highest yields were provided by growing safflower varieties using post–emergence harrowing + inter–row cultivation: on a herbicide–free background – 1,35 t/ha in the variety Zhyvchykand 1,40 t/ha in the variety Dobrynya, on a herbicide background 1,54 and 1,64 t/ha, respectively. Key words: safflower, variety, agricultural production, herbicide, weed, yield.

Amino functionalized magnetic covalent organic framework for magnetic solid-phase extraction of sulfonylurea herbicides in environmental samples from tobacco land.

An amino-functionalized magnetic covalent organic framework composite TpBD-(NH2 )2 @Fe3 O4 (Tp=Tp1,3,5-triformylphloroglucinol, BD-(NH2 )2 is 3,3',4,4'-biphenyltetramine) was prepared by post-synthesis modification. Due to its abundant benzene rings and amino groups, large specific surface area and porous structure, the prepared TpBD-(NH2 )2 @Fe3 O4 exhibits high extraction efficiency toward sulfonylurea herbicides. Based on this, a new method of magnetic solid-phase extraction with TpBD-(NH2 )2 @Fe3 O4 as the sorbent combined with high-performance liquid chromatography and ultraviolet detection was developed for trace analysis of sulfonylurea herbicides in environmental water, soil and tobacco leaves samples from tobacco land. Under the optimized conditions, the limits of detection within 0.05-0.14 μg/L were achieved with a high enrichment factor of 217-260-fold, and the relative standard deviations were 4.9-7.5% (n=7, c=0.5 μg/L). The linear range was around three orders of magnitude with the square of correlation coefficient higher than 0.9936. The method was applied to analyze five sulfonylurea herbicides in the environmental water, soil, and tobacco leave samples collected from tobacco land. No sulfonylurea herbicides were detected in these samples. The recoveries of target sulfonylurea herbicides in spiked environmental water, soil, and tobacco leaf samples were found in the range of 90.7-104, 70.7-99.0, and 59.3-97.8%, respectively. The results illustrate that the established TpBD-(NH2 )2 @Fe3 O4 -magnetic solid-phase extraction- high-performance liquid chromatography-ultraviolet detection method is efficient for the analysis of trace sulfonylurea herbicides in environmental samples.

Effectiveness of soil herbicides in sunflower crops grown by direct seeding technology

Relevance and methods. Sowing of agricultural crops using direct seeding technology is becoming more widespread in the fields of the Stavropol Territory and other regions of our country. In the first years of the development of this technology, changes in the species composition of weed vegetation and increase the infestation of cropsare possible, in this regard, effective protection of crops from weed vegetation plays an important role in increasing the yield and economic efficiency of crop cultivation. In 2018–2020, at the experimental field of the North Caucasus Federal Scientific Agricultural Center, located in the zone of unstable moisture of the Stavropol Territory on ordinary chernozem, studies were conducted to identify the effectiveness of the use of soil herbicides in sunflower crops sown at various times (April 5–10, April 25–30 and May 15–20) using direct seeding technology. In the experiment, the sunflower was sown in the studied time with the use of only a continuous herbicide 5–7 days before sowing and with the use of the same continuous herbicide in combination with the introduction of soil herbicides after sowing. Results. On average, over the years of research, it was found that the use of a continuous herbicide is most effective 5–7 days before sowing, followed by the use of a tank mixture of soil herbicides in the post-sowing period when sowing the crop in the second decade of May. This scheme of herbicide application, combined with the postponement of the sowing period to May 15–20, reduces the number of growing weeds in crops during the growing season to 8–19 pcs./m2 and increases the yield to 2.32 t/ha.

Front Cover: Switchable hydrophilic solvent‐based dispersive liquid‐liquid microextraction coupled with high‐performance liquid chromatography for the determination of four types of sulfonylurea herbicides in soils

DOI: 10.1002/jssc.202100703 The cover picture shows a novel method for the determination of four types of sulfonylurea herbicides in soils by switchable hydrophilic solvent-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography. Switchable hydrophilic solvent became an excellent extractant in sulfonylurea herbicide analysis due to the unique connection between the switchable hydrophilic solvent and the sulfonylurea herbicides. Therefore, the proposed method was proved to be green, more benign to the environment and easy to operate and had a potential to be applied to other complex samples.

Persistence and transformation of flucetosulfuron herbicide in soil as affected by biotic and abiotic factors

Effect of biotic and abiotic factors of soil on persistence and transformation of flucetosulfuron was studied in three soils from paddy growing zones of India. Herbicide residues in three soils dissipated with half-life ranging from 1.41 to 8.38 and 0.58 to 1.14 days under sterile and non-sterile conditions, respectively. Acidic pH and soil microbial activity contributed more toward the degradation of flucetosulfuron in soil. Under flooded soils, dissipation was bit slower than under field capacity moisture level. Five transformation products were identified with LC-MS/MS analysis. Ester hydrolysis and sulfonyl urea bridge cleavage seems to be the major transformation pathways for flucetosulfuron in soil.

Changed degradation behavior of pesticides when present in mixtures

Soil microorganisms are indispensable for a healthy soil environment, where the fate of pesticides is contingent on microbial activity. Conversely, soil ecosystems can be distorted by all kinds of variables, such as agrochemicals. These crop protection products have been universally in use for decades in agriculture. In modern crop cultivation, fungicides are increasingly applied because of their high and broad effectivity on plant pathogens. While their use can enhance harvest yields, fungicides, particularly broad-spectrum ones, are responsible for the alteration of the soil microflora. Furthermore, successive and combined application of pesticides is an agronomic routine, which aggravates the concurrent existence of synthetic chemicals in the soil and marine environments. Mutual interactions of such different molecules, or their effects on soil life, can negatively impact the dissipation of biodegradable pesticides from the ecosystems. The direct effects of individual agrochemicals on microbial soil parameters, as well as agronomic efficiency and interactions of mixtures have been thoroughly studied over the past 80 years. The indirect impacts of mixtures on soil and aquatic ecosystems, however, may be overlooked. Moreover, the current regulatory risk assessment of agrochemicals is based on fate investigations of individual substances to derive predicted environmental concentrations, which does not reflect real agricultural scenarios and needs to be updated. In this article, we summarized the results from our own experiments and previous studies, demonstrating that the degradation of pesticides is impacted by the co-existence of fungicides by their effects on microbial and enzymatic activities in soil. • Pesticide mixtures are typical for the agricultural practice and residues may accumulate in soil. • Fungicides can enhance crop yields, but they affect the soil microflora. • Fungicides can adversely impact the biodegradation of herbicides in soil. • Regulatory environmental risk assessment should consider pesticide mixtures.

Atrazine, mesosulfuron‐methyl, and topramezone persistence in North Carolina soils

AbstractInvestigating the effects of soil properties on herbicide persistence can aid in evaluating the carryover potential of herbicides in soil and the consequent injury risk to rotational crops. Laboratory incubation experiments were conducted to quantify the persistence of atrazine, mesosulfuron‐methyl, and topramezone in five regional soils under aerobic conditions at 23 °C. Additionally, mesosulfuron‐methyl persistence was tested at 7 °C, which is representative of regional average winter soil temperature. Herbicide half‐life was calculated with the logarithmic form of first‐order rate of degradation using linear regression and was correlated with soil properties. Half‐lives of atrazine (37–73 d) and topramezone (15–19 d) varied among soil types at 23 °C. Mesosulfuron‐methyl half‐life varied among soils at 7 °C (8.8–9.8 d) and 23 °C (5.4–5.8 d) and between temperatures. Atrazine and topramezone half‐lives were shortest in Candor sand (4% clay, 1.8% organic matter [OM], pH 5.1) and longest in Portsmouth sandy loam (13% clay, 5.3% OM, pH 4.3). Mesosulfuron‐methyl half‐life was longer at lower soil temperature. Half‐lives of atrazine, mesosulfuron‐methyl, and topramezone were correlated with soil OM content (r = .83, −.53, and .63, respectively) and pH (r = −.86, .55, and −.57). Additionally, atrazine and topramezone half‐lives were positively correlated with soil clay content (r = .83 and .71), and mesosulfuron‐methyl half‐life was negatively correlated with temperature (r = −.97). Correlations between soil OM content, clay content, and pH among soil types may have influenced herbicide persistence.

Optimization of ultrasound-assisted extraction of herbicides from soil and rice using Response surface modelling

ABSTRACT A simple, efficient and cost-effective ultrasound-assisted extraction method for the quantification of penoxsulam, anilofos, bispyribac sodium, butachlor and pretilachlor from soil and rice was developed and validated. Three independent variables, including ultrasonication temperature, ultrasonication time, type and volume of solvent, were studied by single-factor experiments. Box–Behnken design (BBD) was also used to determine the optimal parameters for efficient extraction of penoxsulam, anilofos, bispyribac sodium, butachlor and pretilachlor herbicides from soil and rice. Under optimum conditions, the mean percent recoveries ranged from 82.1 ± 3.32 to 93.8 ± 2.56 from soil and rice grain with relative standard deviation <10% and limit of quantification less than the maximum residue limits imposed by principal regulatory agencies. Results depicted that the experimental values were consistent with the predicted values, indicating that RSM is accurate and reliable method to find the optimal UAE extraction conditions for studied herbicides from soil and rice. Furthermore, the greenness was evaluated using AGREE metrics, and UAE was found to be a greener and efficient method for the determination of herbicides from soil and rice. The developed method was extended to the analysis of real samples and concentration of herbicides at 0 day in soil samples varied from 0.483 ± 1.65 to 1.420 ± 1.41 µg g−1. At harvest, the concentrations of herbicides in soil and rice were below the permissible limit (<0.01 µg g−1).

Improvement of agrotechnology of production of high-quality sunflower seeds

The largest share among the total production costs in the cultivation of sunflower falls on tillage. Its purpose is to increase the reserves of productive moisture in the soil, reduce the rate of its evaporation from the soil surface, improve plant nutrition and accumulation of precipitation, and prevent the accumulation of pathogens of various diseases, pests and weeds. Some of these tasks of soil treatment can be replaced, for example, by the introduction of organomineral fertilizers, the use of various pesticides, mulching of the soil surface with crushed straw, the introduction, in accordance with the specialization of the farm, scientifically based crop rotations with highly productive field crops. In this regard, the studies conducted on leached merged chernozems are devoted to the optimization of some elements of agricultural machinery for the production of sunflower seeds. The effect of dump plowing, shallow and deep non-fallow soil treatments on phytocenotic conditions for the formation of productivity of the sunflower hybrid Gorstar has been established. There was a strong (by 0,06–0,08 g/cm 3 ) compaction of the soil layer of 15–30 cm against the background of shallow non-fall soil treatment than with the other two methods. The reserves of available soil moisture in the 0–150 cm layer with deep tillage and dump plowing were 214,0 and 210,8 mm, respectively, and for shallow tillage – 196,0 mm. At the background of dump plowing, the minimum contamination of sunflower crops was obtained, which is 36,5% less for deep tillage and 63,5% less for shallow. The introduction of a tank mixture of pre-emergence herbicides Acetal Pro, CE and Brig, CS provides an increase in the yield of sunflower seeds by all methods of basic tillage by 0,14–0,27 t/ha, and the introduction of soil herbicide Gardo Gold, CE – by 0,13–0,14 t/ha.

Development and greenness evaluation of solid-phase extraction and salting-out liquid–liquid extraction method for determination of herbicides in water, soil and rice

Development and greenness evaluation of solid-phase extraction and salting-out liquid–liquid extraction method for determination of herbicides in water, soil and rice

A Glyphosate-Based Herbicide in Soil Differentially Affects Hormonal Homeostasis and Performance of Non-target Crop Plants.

Glyphosate is the most widely used herbicide with a yearly increase in global application. Recent studies report glyphosate residues from diverse habitats globally where the effect on non-target plants are still to be explored. Glyphosate disrupts the shikimate pathway which is the basis for several plant metabolites. The central role of phytohormones in regulating plant growth and responses to abiotic and biotic environment has been ignored in studies examining the effects of glyphosate residues on plant performance and trophic interactions. We studied interactive effects of glyphosate-based herbicide (GBH) residues and phosphate fertilizer in soil on the content of main phytohormones, their precursors and metabolites, as well as on plant performance and herbivore damage, in three plant species, oat (Avena sativa), potato (Solanum tuberosum), and strawberry (Fragaria x ananassa). Plant hormonal responses to GBH residues were highly species-specific. Potato responded to GBH soil treatment with an increase in stress-related phytohormones abscisic acid (ABA), indole-3-acetic acid (IAA), and jasmonic acid (JA) but a decrease in cytokinin (CK) ribosides and cytokinin-O-glycosides. GBH residues in combination with phosphate in soil increased aboveground biomass of potato plants and the concentration of the auxin phenylacetic acid (PAA) but decreased phaseic acid and cytokinin ribosides (CKR) and O-glycosides. Chorismate-derived compounds [IAA, PAA and benzoic acid (BzA)] as well as herbivore damage decreased in oat, when growing in GBH-treated soil but concentrations of the cytokinin dihydrozeatin (DZ) and CKR increased. In strawberry plants, phosphate treatment was associated with an elevation of auxin (IAA) and the CK trans-zeatin (tZ), while decreasing concentrations of the auxin PAA and CK DZ was observed in the case of GBH treatment. Our results demonstrate that ubiquitous herbicide residues have multifaceted consequences by modulating the hormonal equilibrium of plants, which can have cascading effects on trophic interactions.

Switchable hydrophilic solvent-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the determination of four types of sulfonylurea herbicides in soils.

In this study, switchable hydrophilic solvent-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography was developed for the determination of four sulfonylurea herbicides in soils. For the first time, the sample pretreatment was achieved due to the similar acid-base status of sulfonylurea herbicides and switchable hydrophilic solvent. In the extraction step, sulfonylurea herbicides were extracted as anions and transferred to an alkaline solution with switchable hydrophilic solvent anions. In the concentration step, two types of anions were transformed to their molecular state after the aqueous solution was acidified. In addition, the dispersion and microextraction processes were completed efficiently with the simultaneous formation of analytes and extractants. The factors affecting the extraction performance were optimized. Under the optimized conditions, good linearity was observed for each herbicide with correlation coefficients ranging from 0.9952 to 0.9978. The limits of detection were in the range of 0.1-0.2 μg/g. Moreover, the relative recoveries of the sulfonylurea herbicides at spiking levels of 0.5, 1, and 1.5 μg/g in soil samples were between 75 and 111% (relative standard deviations: 0.4-11.4%). Therefore, the proposed method in this study could be successfully applied to the analysis of four types of sulfonylurea herbicides in soil samples.

Agricultural Greenhouse Gas Fluxes Under Different Cover Crop Systems

Cultivated lands that support high productivity have the potential to produce a large amount of GHG emissions, including carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). Intensive land management practices can stimulate CO2, N2O, and CH4 emissions from the soil. Cover crop establishment is considered as one of the sustainable land management strategies under warm and humid environmental conditions. To better understand how the incorporation of cover crops affect three major GHGs, we compared trace gas fluxes in a no-till maize field over the whole growing season in 2018 in a no cover crop (Tr) system and three cover crop systems: crimson clover (CC), cereal rye (CR), and living mulch (LM) using white clover. In 2019, we further explored potential differences in the three GHGs between in-row (IR) and between-row (BWR) of maize for LM and Tr systems during the early growing season. Measurements were taken using a cavity ring-down spectroscopy gas analyzer in Watkinsville, GA. In 2018, the highest CO2 flux (7.00 μmol m−2 s−1) was observed from BWR of maize for LM. The maximum N2O flux observed in LM on June 20th in 2018 was when soil N increase rate was the largest. Soils served as sinks for CH4 and Tr system served as the smallest CH4 sink compared to the other three cover crop systems. For N2O, the highest fluxes were observed from the TrIR plot (4.13 μmol m−2 hr−1) in 2019 with the greatest N inputs. In 2019, we observed a smaller CH4 sink in TrIR (−0.13 μmol m−2 hr−1) compared to TrBWR (−0.67 μmol m−2 hr−1) due potentially to greater NH4+ inhibition effects on CH4 consumption from greater N fertilizer inputs. The net carbon equivalent (CE) from May 23rd to Aug 16th in 2018, taking into account the three GHG fluxes, soil carbon content, and fertilizer, irrigation, and herbicide application, were 32–97, 35–101, 63–139, and 40–106 kg ha−1 yr−1 for CC, CR, LM, and Tr, respectively. LM had the lowest net CE after removing white clover respiration (−16–60 kg ha−1 yr−1). Our results show that implementing different types of cover crop systems and especially the LM system have some potential to mitigate climate change.

Biodisponibilidade de oxyfluorfen em solos de Cerrado

ABSTRACT Oxyfluorfen is a pre-emergent herbicide applied via soil; however, the soil attributes have not been considered to predict the herbicide doses. This study aimed to evaluate the bioavailability of the oxyfluorfen herbicide in Brazilian Savanna soils with contrasting attributes. The experiment was carried out in a 6 x 8 factorial scheme, with 6 replications. The evaluated factors were soil types [Gleissolo Melânico distrófico - GMd (Typic Humaquept); Latossolo Vermelho ácrico - LVw (Rhodic Acrustox); Latossolo Vermelho distrófico - LVd (Rhodic Haplustox); Neossolo Quartzarênico órtico - RQo (Typic Quartzpsamment); Neossolo Flúvico Tb distrófico - RYbd (Fluventic Dystrustept); and washed sand] and oxyfluorfen doses (0; 360; 480; 720; 1,440; 2,880; 4,320; and 5,760 g a.i. ha-1). The herbicide bioavailability was determined according to the bioassay methodology. The dose that provided 80 % of Cucumis sativum control (C80%) ranged from 9.9 (LVw) to 1,884.4 g a.i. ha-1 (GMd), what can be attributed to the high sorption of the herbicide in the GMd, as observed by the adsorptive rate. The soil texture did not show correlation with the oxyfluorfen bioavailability. In the LVd, which is from the same order and with texture similar to that of the LVw, the C80% was 76 times higher (754.28 g a.i. ha-1). Furthermore, for the RYbd, which is a sandy soil, the C80% was even high (1,256.9 g a.i. ha-1). The cation exchange capacity (CEC) (-0.83**) was the only soil attribute able to predict the herbicide bioavailability. The oxyfluorfen bioavailability is highly dependent on the soil attributes, and, in Brazilian Savanna soils, it can be predicted using the CEC.

Cover crops and no-tillage reduce crop production costs and soil loss, compensating for lack of short-term soil quality improvement in a maize and soybean production system

Conservation agriculture has been marketed to producers as a sustainable way to increase soil productivity and buffer the effects of anticipated fluctuations in both climate and the price of fuel and fertilizer. Despite US Farm Bill financial incentives promoting the use of conservation practices such as no-tillage and cover crops among producers, widescale adoption of cover crops in the US remains low. Implementing no-tillage and cover crop use may take years of consistent management to show measurable soil quality improvement. Conversely, costs associated with cover crop planting and management must be incurred immediately and before the accrual of any benefits. Current research has largely focused on the soil quality benefits of cover crops without considering the short-term implementation costs for producers comparing their current production systems to conservation systems they may adopt. To help fill this knowledge gap, soil properties, cash crop yield, and annual production costs were evaluated in a three-year maize /soybean study comparing a conservation system to a conventional production system in Mississippi from 2016 to 2018. The conventional system included frequent tillage and control of winter weeds with a residual soil herbicide (conv. till + bare). We compared five different levels of conservation systems, including a conservation system with no-tillage and cover crops (no-till + cover). We found a lack of consistent improvement in soil properties such as soil organic matter increase or crop yield in the conservation system over the three-year period. The economic benefits of substituting no-tillage and cover crops for expensive conventional inputs were much greater than the modest soil property improvements observed from 2016 to 2018 crops. Though crop yields varied, the cost of cash crop production in the conservation system (no-till + cover) was 43% less than the cost of the conventional system ($29.67 per Mg of crop yield in the conv. till + bare to $17.04 per Mg of crop yield in the no-till + cover system), highlighting a short-term economic incentive for producers to switch to conservation agriculture. The greatest resource benefit from the conservation system was a reduction in estimated soil loss, as mean soil loss in no-till and cover crop decreased by 86% compared to the conventional system (3.5–25.1 t ha-1). These results demonstrate that conservation agriculture has the potential to decrease overall production cost while decreasing the risk of accelerated soil erosion during expected weather extremes associated with climate change, potentially making both farming operations and agroecosystems more resilient.

ELEMENTS OF YIELD STRUCTURE OF MAIZE HYBRIDS DEPENDING ON THE APPLICATION OF BIOLOGICAL PREPARATIONS IN FOREST-STEPPE CONDITIONS

The article presents the results of research on the effect of various biological preparations on productivity and formation of elements of grain yield structure of mid-season hybrid maize DKS 4014. A promising direction to increase plant productivity of maize and realization of its biological potential is the ecologization of cultivation technology of crops, creation of effective, environmentally safe biological preparations and development of technologies of their application is one of the priority directions in the scientific support of the agroindustrial complex of Ukraine. The use of such preparations is possible, both independently and in combination with other components of cultivation technology, such as mineral fertilizers and plant protection products. The use of biological preparations restores soil structure, restores fertility and accelerates the mineralisation processes in the soil. The effect of soil application of biofertilizer based on active strains of phosphorus-mobilizing and nitrogen-fixing bacteria and physiologically active substances, both alone and in combination with mycorrhizobearing bio-preparation treatment of maize seeds for active settling of root and root zone of maize hybrids was studied. The results of the obtained results of the study of biometric indicators, grain yield of maize depending on the application of soil biofertilizer, mycorrhizoforming biological preparation, and the combination of these preparations, as well as the application of soil herbicide together with a carrier-adhesive showed the improvement and increase in biometric indicators and productivity of maize, so we recommend the use of these preparations in the conditions of production. The best indicators of improving the structural elements of maize yield and yield in general were provided by the complex of preparations Graundfiks 4 l/ha + Micofrend 6 kg/ha, where the yield of mid-season hybrid DKS 4014 was 13.65 t/ha, which is 29.9% more than the control.