Crop Rotation Sequences Research Articles

Influence of Cropping Sequence and Tillage System on Plant-Parasitic Nematodes and Peanut (Arachis hypogaea) Response to Fluopyram Applied at Planting

Crop sequence and tillage can affect the yield of peanut (Arachis hypogaea L.) and other crops. Research was conducted from 2006 through 2022 to determine the response of peanut to previous crop sequences including corn (Zea mays L.) and cotton (Gossypium hirsutum L.) planted in continuous conventional tillage (e.g., disking, field cultivating, and bedding with in-row sub-soiling) or strip tillage (e.g., tilling a 45 cm section on rows spaced 91 cm apart using fluted coulters, rolling baskets, and in-row sub-soiling). In 2013, 2019, and 2022, the entire test area was planted with peanut. In 2019 and 2022, peanut was planted without or with fluopyram applied in the seed furrow at planting. Decreasing the number of years between peanut planting resulted in lower peanut yields compared with fewer years of peanut planting in the rotation sequence. Continuous conventional tillage and strip tillage resulted in similar peanut yields at one location, while the yield was lower at a second location when peanut was planted in continuous strip tillage. Fluopyram did not affect peanut yield regardless of previous crop rotation sequence, the number of years separating peanut plantings, or the tillage system. However, minor differences in the populations of plant-parasitic nematodes in soil were noted when comparing fluopyram treatment. The results from these experiments indicate that while fluopyram can reduce the populations of some plant-parasitic nematodes in soil, the magnitude of reduction does not translate into increases in peanut yield.

Effects of Four-Year Oilseed Flax Rotations on the Soil Bacterial Community in a Semi-Arid Agroecosystem

Crop rotation aims to improve the sustainability and production efficiency of agricultural ecosystems, especially as demands for food and energy continue to increase. However, the regulation of soil microbial communities using crop rotation with oilseed flax and its relationship with key soil physicochemical driving factors are still not clear. In order to investigate this matter, we carried out a field study lasting four years involving various crop rotation sequences including FWPF, FPFW, PFWF, FWFP, ContF, and ContF1. In addition to evaluating soil physicochemical parameters, we employed Illumina high-throughput sequencing technology to explore the structure and variety of soil microbial communities. The findings indicated a notable rise in pH value with the FPFW treatment in contrast to other treatments, along with significant increases in AP, MBC, MBN, and qSMBC compared to ContF. The number of OTUs in the FPFW, WFPF, FPFW, and PFWF treatments was significantly increased by 4.10–11.11% compared to ContF (p < 0.05). The presence of Actinobacteria and Acidobacteria was greatly impacted by the FPFW treatment, whereas the presence of Actinobacteria and Chloroflexi was notably influenced by the ContF treatment. The soil bacterial community was primarily influenced by TC, pH, and NO3−-N according to correlation analysis. Specifically, the FPFW therapy notably raised the soil pH level while lowering the TC level. Furthermore, the FPFW therapy led to a notable rise in the proportion of Acidobacteria and a significant decline in the proportion of Actinobacteria. These findings provide important theoretical support for using FPFW rotation to regulate soil microbial communities and solve the problems of continuous cropping.

Cover Crop and Crop Rotation Effects on Tissue and Soil Population Dynamics of Macrophomina phaseolina and Yield Under No-Till System.

The effects of crop rotation and winter cover crops on soybean yield and colony-forming (CFU) units of Macrophomina phaseolina, the causal agent of charcoal rot (CR), are poorly understood. A field trial was conducted from 2011 to 2015 to evaluate (i) the impact of crop rotation consisting of soybean (Glycine max [L.] Merr.) following cotton (Gossypium hirsutum L.), soybean following corn (Zea mays L.), and soybean following soybean over a 2-year rotation and its interaction with cover crop and (ii) the impact of different cover crops on a continuous soybean crop over a 5-year period. This trial was conducted in a field with 10 subsequent years of cover crop and rotation treatments. Cover crops consisted of winter wheat (Triticum aestivum L.) and Austrian winter pea (Pisum sativum L. subsp. sativum var. arvense), hairy vetch (Vicia villosa Roth), and a fallow treatment was evaluated with and without poultry litter application (bio-cover). Tissue CFU of M. phaseolina varied significantly between crop rotation treatments: plots where soybean was grown following cotton had significantly greater tissue CFU than plots following soybean. Poultry litter and hairy vetch cover cropping caused increased tissue CFU, though this effect differed by year and crop rotation treatment. Soil CFU in 2015 was substantially lower compared with 2011. However, under some crop rotation sequences, plots in the fallow treatment had significantly greater soil CFU than plots where hairy vetch and wheat was grown as a cover crop. Yield was greater in 2015 compared with 2011. There was a significant interaction of the previous crop in the rotation with year, and greater yield was observed in plots planted following cotton in the rotation in 2015 but not in 2011. The result from the continuous soybean planted over 5 years showed that there were no significant overall effects of any of the cover crop treatments nor was there interaction between cover crop treatment and year on yield. The lack of significant interaction between crop rotation and cover crop and the absence of significant differences between cover crop treatments in continuous soybean planting suggest that cover crop recommendations for midsouthern soybean growers may need to be independent of crop rotation and be based on long-term crop needs.

Soil Chemical Properties as Affected by Six Crop Rotation Sequences and Four Residue Levels

ABSTRACT Crop rotations with residue incorporation can be beneficial to the sustainability of agriculture, however as long-term studies are required to determine effects on soil properties, farmers usually don’t practice crop rotations. The objective of this study was to evaluate the effects of crop rotations with residue incorporation (0%, 50%, 100%, and 200%) on soil chemical properties of a volcanic soil after 4 years of cultivation. The evaluated rotations were canola (Brassica napus L.)-bread wheat (Triticum aestivum L.), canola-durum wheat (Triticum turgidum L.), canola-corn (Zea mays L.), bean (Phaseolus vulgaris L.)-bread wheat, bean-durum wheat, and bean-corn. The experiment consisted of six crop rotations, four levels of residue incorporation, and four replicates, analyzed as split-plot design. Samples were taken from the topsoil, and the following soil chemical properties were evaluated: pH, organic matter, electrical conductivity, nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), aluminum (Al), and sulfur (S). The results showed that crop rotations affected all the chemical properties evaluated, whereas the level of residue incorporation only affected the concentrations of exchangeable Mg and K. Most of the evaluated crops rotations had beneficial effects on the soil properties. The canola-durum wheat crop rotation recorded the lowest values in OM, available N and the exchangeable Ca, Mg, and Na. Exchangeable Mg and K had a directly proportional relationship with the level of residue incorporation. In conclusion, the incorporation of residues in different doses during 4 years of crop rotation in this volcanic soil had little effect on its chemical properties.

Managing Risk: a Decision Tool to Enhance Yield and Quality of Peanut (Arachis hypogaea) in Ghana

Peanut cultivation in Ghana is influenced by abiotic (e.g., drought, fertilization, etc.) and biotic (e.g., pests, diseases, etc.) factors that must be managed effectively to maximize yields. These factors differ across agro-ecologies and pose significant risks to yields and aflatoxin contamination and can limit financial returns to farmers. Knowledge of interactions among key production practices such as pest management, crop rotation sequence, varietal selection, tillage systems, and chemical inputs is required to mitigate these risks and to provide quality advice to peanut farmers by Agricultural Extension Agents (AEAs) and/or similar advisory groups. This paper describes the development of a comprehensive, Microsoft (MS) Excel based risk management tool to help farmers and their advisors implement practices that minimize the risk of yield loss and aflatoxin contamination while providing production cost estimates. This tool is based on a similar one developed for peanut production in North Carolina (USA). Three risk tools were developed; one for the interior savannah zone of northern Ghana which has a unimodal rainfall pattern, and two for the forest and transition zones of southern Ghana which are characterized by a bimodal rainfall pattern. These tools will aid AEAs and farmers to make informed decisions on the best combinations of production practices that will minimize risk and increase yields in Ghana. The development process considered the differences in selection of varieties, plant density, fertilization, and pest management between savannah and the forest-transition regions as well as the impact of their interactions on peanut yield and aflatoxin contamination. Overall, this risk management tool benefits extension service providers (government and private), breeding, agronomy, and plant protection programs as well as teaching in higher education institutions.

AI- and data-driven crop rotation planning

Crop rotation planning is the process of deciding the types and the temporal succession of plants on agricultural areas to increase soil quality, crop yield, and pest/weed resistance. The data sources and modalities available for crop rotation planning are very diverse and the domain lacks solely data-driven approaches. In this paper we used literature- and NDVI-measurement-based successor crop suitability matrices and crop-specific attributes such as contribution margin and nitrogen demand as input for training an DQN-based reinforcement learning agent to generate crop rotation sequences. Practitioners and crop rotation experts validated the generated crop rotation sequences and concluded that most of the sequences are realistic, comply with existing crop rotation rule sets, and can be applied in practice.

Nutritive value and net return of forage crop rotations in the central Great Plains

AbstractSustainable forage‐based rotations with greater forage nutritive values and efficient resource utilization are needed to increase forage availability in the central Great Plains. The objectives of the study were to quantify nutritive value and net return from individual crops and overall crop rotation sequence of winter triticale, forage sorghum, and spring oat. The study was conducted near Garden City, KS, from 2013–2020. There were six treatments in the study, that is, continuous sorghum [Sorghum bicolor (L.) Moench] (S‐S) no‐till (NT), triticale (×Triticosecale Wittm. ex A. Camus [Secale × Triticum])/sorghum‐sorghum‐oat (Avena sativa L.) (T/S‐S‐O) reduced till (RT) and NT, triticale/sorghum‐sorghum‐sorghum‐oat (T/S‐S‐S‐O) RT and NT, and triticale‐sorghum‐oat (T‐S‐O) NT. Crude protein concentration was 23%–31% greater for T‐S‐O and T/S‐S‐O compared with S‐S. The S‐S treatment had greater fiber content and least digestibility, calcium, and phosphorus concentrations compared with the remaining forage rotations. Annualized cost of production was 11%–32% greater for forage sorghum dominated NT systems (T/S‐S‐O, T/S‐S‐S‐O, S‐S [NT]) compared with T‐S‐O or T/S‐S‐S‐O (RT) rotation. T/S‐S‐S‐O (RT) was among the top in net return due to a combination of greater forage biomass production and forage nutrient value. The cost of production for forage sorghum and triticale were more economical compared to purchasing commercial feedstuffs. We concluded forage producers should consider productivity and market value, in addition to nutritive value and cost of production in selecting crops for a profitable forage‐based rotation system.

Intensifying dryland wheat systems by integrating guar increased production and profitability

Guar [Cyamopsis tetragonoloba (L.) Taub.], is a summer legume with heat- and drought-tolerance properties that is produced in the U.S. Southern Great Plains, but is often restricted to a catch crop or substitute crop following cotton failures. This is despite the large domestic market for guar gum and the opportunity to diversify regional cropping systems with guar, potentially adding ecosystem benefits like biological N fixation (BNF). To address this, a systems research study was conducted near Chillicothe, TX from 2018 to 2021 to evaluate the integration of guar into no-till dryland winter wheat (Triticum aestivum L.) systems. Treatments included integrated wheat-guar systems differing in cropping intensity, 1.33 crops yr−1 (WG1.3) and 2 crops yr−1 (WG2), plus guar (G1) and wheat (W1) monocrop systems with 1.0 crop yr−1. Results showed that crop rotation sequence influenced seasonal guar yields, with negative yield impacts when guar immediately followed wheat. Consequently, the average seasonal guar yield was greatest in G1 and WG1.3 (1.01 and 0.96 Mg ha−1, respectively), followed by WG2 (0.64 Mg ha−1). Seasonal wheat yield averaged 2.31 Mg ha−1 across years, with no differences among systems. Across years, cumulative system yield was greatest for WG2, followed by W1 and WG1.3, then G1. Similarly, average annual net income followed the trend of G1 < W1 < WG1.3 < WG2, with values ranging from US$ 62.7–213.0 ha−1 year−1. Although overall production and net income were somewhat greater for WG2 than WG1.3, seasonal risks of crop failure and economic loss were lower for the WG1.3 system under the regional climate. There was no direct evidence of guar BNF benefits on subsequent wheat yield and quality, though inclusion of guar enhanced soil NO3-N at varying levels among systems, particularly following wet growing seasons and in less intensive systems.

The shift of soil microbial community induced by cropping sequence affect soil properties and crop yield.

Rational cropping maintains high soil fertility and a healthy ecosystem. Soil microorganism is the controller of soil fertility. Meanwhile, soil microbial communities also respond to different cropping patterns. The mechanisms by which biotic and abiotic factors were affected by different cropping sequences remain unclear in the major grain-producing regions of northeastern China. To evaluate the effects of different cropping sequences under conventional fertilization practices on soil properties, microbial communities, and crop yield, six types of plant cropping systems were performed, including soybean monoculture, wheat-soybean rotation, wheat-maize-soybean rotation, soybean-maize-maize rotation, maize-soybean-soybean rotation and maize monoculture. Our results showed that compared with the single cropping system, soybean and maize crop rotation in different combinations or sequences can increase soil total organic carbon and nutrients, and promote soybean and maize yield, especially using soybean-maize-maize and maize-soybean-soybean planting system. The 16S rRNA and internal transcribed spacer (ITS) amplicon sequencing showed that different cropping systems had different effects on bacterial and fungal communities. The bacterial and fungal communities of soybean monoculture were less diverse when compared to the other crop rotation planting system. Among the different cropping sequences, the number of observed bacterial species was greater in soybean-maize-maize planting setup and fungal species in maize-soybean-soybean planting setup. Some dominant and functional bacterial and fungal taxa in the rotation soils were observed. Network-based analysis suggests that bacterial phyla Acidobacteria and Actinobacteria while fungal phylum Ascomycota showed a positive correlation with other microbial communities. The phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) result showed the presence of various metabolic pathways. Besides, the soybean-maize-maize significantly increased the proportion of some beneficial microorganisms in the soil and reduced the soil-borne animal and plant pathogens. These results warrant further investigation into the mechanisms driving responses of beneficial microbial communities and their capacity on improving soil fertility during legume cropping. The present study extends our understanding of how different crop rotations effect soil parameters, microbial diversity, and metabolic functions, and reveals the importance of crop rotation sequences. These findings could be used to guide decision-making from the microbial perspective for annual crop planting and soil management approaches.

Winter wheat productivity depending on the systems of primary tillage against the background of short-term crop rotations in the South of Ukraine

Topicality. In the current agricultural environment, there is a trend towards simplification of tillage, wrong crop rotation sequences, narrowing of specialisation of most agricultural enterprises, and therefore the role of the predecessor and tillage systems as one of the least costly ways to optimise winter crop cultivation will only increase. For this reason, the development and research of various schemes of primary tillage on the background of short-term crop rotation will continue to be a topical issue and will always be subject to scientific and practical interest. Purpose. Our research aimed to development of environmental friendly technologies for competitive production of high-quality crop production in the Black Sea Steppe of Ukraine. Methods. The field method was the main method, which was supplemented by analytical studies, measurements, calculations and observations in accordance with generally accepted methods and guidelines in agriculture and crop production. In the experiment, the systems of crop rotations and primary tillage were studied. Results. The influence of different systems of primary tillage on the winter wheat yield in short-term crop rotation was studied. It was found that in the conditions of the Southern Steppe of Ukraine, the moldboardless tillage created the best conditions for the formation of winter wheat yield in the 1st, 2nd and 4th crops. The highest yields were in all experimental variants after such predecessors as black fallow and green manure fallow with winter vetch. Conclusions. For all experimental variants, the best results in terms of yield were observed after black fallow and green manure fallow with winter vetch in the 1st and 4th crops. In the 2nd crop, green manure fallow with winter vetch had an advantage of 4.9 % compared to black fallow. In winter wheat, a positive effect on the formation of yields was manifested by moldboardless tillage. Key words: crop rotation, predecessors, primary tillage system, yield, winter wheat

Crop yield and water use efficiency in response to long-term diversified crop rotations.

Crop production and water productivity may be impacted by diverse crop rotation and management practices. A field study was conducted from 2017-2020 in the Loess Plateau to evaluate the effects of crop rotation sequences on pre-planting and post-harvest soil water storage (SWS), annualized crop yield, water use, and water productivity. Crops in rotation included oil flax (Linum usitatissimum L.) (F), wheat (Triticum aestivum L.) (W), potato ( Solanum tuberosum L.) (P). Twelve 4-year-cycle crop rotation treatments, along with a continuous oil flax treatment as a baseline, were included. The results showed that the average soil water content under the 0-150 cm soil layer in all treatments was increased after one rotation cycle, and the PWFW treatment achieved the highest SWC (17.1%). The average soil water storage (winter fallow season) and evapotranspiration (ETa) (growing season) under different crop rotation sequences were lower than those under continuous oil flax cropping. The ETa of FFFF increased by 28.9, 2.7, 15.3, and 28.4%, compared to average crop rotations in 2017, 2018, 2019, and 2020, respectively. Crop rotation had a significant effect on average annual yield and water use efficiency (WUE), which varied by year and rotation sequence. The crop rotations with the highest grain yield of oil flax were FFWP (2017), WFWP (2018),WPFF (2019) and FWPF (2020); the grain yield of wheat was highest when the two pre-crops (previously cultivated crops) were F-F, and potato yield was highest when the two pre-crops were W-F (except 2018). On average, the WUE of oil flax was 8.6, 38.7, 22.7, and 42.1% lower with FFFF than other diversity crop rotations in 2017, 2018, 2019, and 2020. We found that the WUE was not the largest when the grain yield of oil flax and wheat was highest. The treatments with maximum grain yield and WUE were not consistent. Our findings also revealed that wheat-potato-oil flax or potato-wheat-oil flax rotation could increase oil flax grain yields while wheat-oil flax-potato-oil flax markedly improved oil flax WUE.

Effect of Tillage Systems on Durum Wheat Production with Different Rotations in Semi Arid Area of Algeria

Background: Durum wheat is the most important cereal in Algeria. The yield of durum wheat is low and depends on climatic conditions and technical operations. Methods: The objective of this study is to compare the effect of the no-till system (NT) and conventional tillage system (CT) with three crop rotation sequences on wheat yield, yield components and some physiological traits under rain-fed conditions. The study was conducted at the technical institute of field crops-Sétif-in east of Algeria, over three crop seasons: 2016/17, 2017/18 and 2018/19. Result: The number of plants/m2, tillers/m2, spikes/m2​ and grain yield were affected by the tillage system and the environmental conditions. Seed weight, straw yield, biological yield, leaf relative water content and leaf chlorophyll content were significantly affected by the environment but not by the tillage system. While the spike density, the harvest index and the grain yield were significantly higher under NT system than in the CT system. Furthermore, wheat grain yield was also higher following legumes than in wheat monoculture. These results indicate that no-tillage and crop diversification by adding leguminous in rotation improves grain legumes yield of durum wheat under semi-arid conditions of Algeria.

Population dynamics of naturally occurring weed flora in response to crop rotation and HPPD-inhibiting herbicide-based treatments

AbstractA 3-yr field study was conducted in Keiser, AR, to investigate the response of the naturally occurring weed flora, dominated by Palmer amaranth, under various combinations of 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide-based programs and crop rotation sequences. In the first year, corn plots were established with three corn HPPD-based herbicide programs designed to represent a range of efficacies and selection pressures for resistance. In the following two years, corn as monoculture or with soybean and/or cotton crops was included in the rotation sequence for selected herbicide programs. Weed emergence, weed biomass, and soil seedbank were assessed through the entire experimental period. The results show that crop rotation, especially a rotation sequence with corn followed by (fb) soybean fb cotton, and the lowest-risk herbicide program involving seven sites of action over the course of the entire crop rotation was effective in reducing the emergence of naturally occurring weeds, including Palmer amaranth, prickly sida, morningglory species, and grass weeds (broadleaf signalgrass, large crabgrass, barnyardgrass, and johnsongrass) by 88.3%, 57.5%, 28.7%, and 76.3%, respectively. Treatments without crop rotation (corn as monoculture for 3 consecutive years) and poor herbicide programs, with one site of action, increased weed emergence, notably of Palmer amaranth and prickly sida, by 73.5% and 74.1%, respectively. The soil seedbank showed a similar trend to weed emergence. This study highlights the fact that reducing the weed seedbank cannot rely on one management practice but requires a multitactic approach with various control methods. HPPD-inhibiting herbicide programs seem to be effective on Palmer amaranth when coupled with crop rotation and should be used with other best management practices.

Residual Effects of 50-Year-Term Different Rotations and Continued Bare Fallow on Soil CO2 Emission, Earthworms, and Fertility for Wheat Crops.

In this study, our investigated hypothesis was that different pre-crops would have different effects on earthworm activity and soil CO2 emissions. We also hypothesized that a pre-crop clover–timothy mixture would perform best in terms of increasing the share of organic carbon in soil and, in this way, contribute to improving the sustainability of agroecosystems. The aim of this study was to explore the residual effects of using a 50-year-term of three different crop rotations and a continuous bare fallow period on soil CO2 emissions by investigating the soil earthworm populations, soil agrochemical properties, and winter wheat yields. A field experiment was carried out from 2016 to 2017 at Vytautas Magnus University in Lithuania (54°53′ N, 23°50′ E). The experiment was conducted in crop stands of winter wheat cv. ‘Skagen’, which were sown in three crop rotations with different pre-crops and a continuous bare fallow period. The pre-crop used for winter wheat in the cereal crop rotation (CE) was a vetch and oat mixture for green forage, LEG-CER; the pre-crop used for winter wheat in the field with row crops (FWR) crop rotation was black fallow, FAL-CER; the pre-crop used for winter wheat in the Norfolk (NOR) crop rotation was a clover–timothy mixture, GRS-CER; and finally, continuous bare fallow, FAL-CONTROL, was used as well. The highest soil CO2 emission intensity was determined after the pre-crops that left a large amount of plant residues (clover and timothy mixture) in the soil. Plant residues remaining after the pre-crop had the greatest effect on the number of earthworms in the soil after the harvesting of winter wheat. Winter wheat had the best yield when grown in grass and legume sequences. Crop rotation sequences that included perennial grasses accumulated higher contents of total nitrogen and organic carbon. The best values for the productivity indicators of wheat were obtained when it was grown after a fallow crop fertilized with cattle manure. An appropriate crop rotation that promotes the steady long-term contribution of organic matter and increases the content of organic carbon in the soil will have a positive effect on the agrochemical, biological, and physical properties of soil and agroecosystem sustainability; moreover, these effects cannot be achieved by technological means alone.

Short-term effects of conservation agriculture strategies on the soil quality of a Haplic Plinthosol in Eastern Cape, South Africa

The improvement of soil quality in agro-ecosystems is one of the major objectives of conservation agriculture (CA) strategies. The objective of this study was to evaluate, quantify and compare the effects of two tillage practices, four crop rotation sequences, two residue management systems and their interactions on the soil quality of a Haplic Plinthosol in South Africa using the Soil Management Assessment Framework (SMAF). The evaluation was done on a CA field trial established in 2012 in the Eastern Cape Province of South Africa. The trial was laid out in a split-split-plot design with tillage: conventional tillage (CT) and no-till (NT) as main plot treatments. Sub-treatments were crop rotations: maize-fallow-maize (MFM); maize-fallow-soybean (MFS); maize-wheat-maize (MWM); maize-wheat-soybean (MWS). Residue management treatments: removal (R-) and retention (R+) were in the sub-sub plots. Soils from the CA trial were sampled at 0 – 5 and 5 – 10 cm depths after five cropping seasons (2012–2015). Thirteen soil quality indicators were determined to assess soil quality. The SMAF soil quality index (SMAF-SQI) was used as an indicator of overall soil quality. The study results demonstrated the dominance of tillage practices in significantly affecting soil biological, chemical and physical properties in the short term than crop rotation sequences and residue management systems. The soil biological indicators viz. SOC, MBC and BG activity were more sensitive to CA strategies, which confirmed their effectiveness as tools for soil quality assessments in the short-term. The study also revealed the short-term significant effects of tillage on the overall SMAF-SQI while crop rotation and residue management had no significant effects. Overall soil quality assessment using the SMAF technique provided a sound basis for distinguishing the short-term impacts of CA strategies on the function of the Haplic Plinthosol in Eastern Cape, South Africa.

Biophysical Impact of Sunflower Crop Rotation on Agricultural Fields

Crop rotation is an important determining factor of crop productivity. Sustainable agriculture requires correct rules of crop rotation. Failure to comply with these rules can lead to deterioration of soil biochemical characteristics and land degradation. In Ukraine as well as in many other countries, sunflower monocropping is common practice and the impact of this fact should be studied to find the most precise rules to save the economic potential of land and minimize land degradation factors. This research provides an evaluation of the sunflower monocropping effect on the vegetation indices obtained from MODIS vegetation indices datasets for Ukraine as one of the countries with the biggest sunflower export in Europe. The crop rotation schemes are represented by their area proportions at the village level calculated based on the crop classification maps for 2016 to 2020. This representation gives the possibility to use regression models and f-test feature importance analysis to measure the impact of 3-year and 5-year crop rotation sequences. For these purposes, we use several models: a four-year binary representation model (model A1) and a model with all possible three-year crop rotation scheme representations (model B). These models gave the possibility to evaluate crop rotation schemes based on their biophysical impact on the next sunflower plantings and found that sunflower planting with an interval of three or more years is optimal in terms of the sustainability of soil fertility.

Western United States and Canada perspective: are herbicide-resistant crops the solution to herbicide-resistant weeds?

AbstractHerbicide-resistant (HR) crops are widely grown throughout the United States and Canada. These crop-trait technologies can enhance weed management and therefore can be an important component of integrated weed management (IWM) programs. Concomitantly, evolution of HR weed populations has become ubiquitous in agricultural areas where HR crops are grown. Nevertheless, crop cultivars with new or combined (stacked) HR traits continue to be developed and commercialized. This review, based on a symposium held at the Western Society of Weed Science annual meeting in 2021, examines the impact of HR crops on HR weed management in the U.S. Great Plains, U.S. Pacific Northwest, and the Canadian Prairies over the past 25 yr and their past and future contributions to IWM. We also provide an industry perspective on the future of HR crop development and the role of HR crops in resistance management. Expanded options for HR traits in both major and minor crops are expected. With proper stewardship, HR crops can reduce herbicide-use intensity and help reduce selection pressure on weed populations. However, their proper deployment in cropping systems must be carefully planned by considering a diverse crop rotation sequence with multiple HR and non-HR crops and maximizing crop competition to effectively manage HR weed populations. Based on past experiences in the cultivation of HR crops and associated herbicide use in the western United States and Canada, HR crops have been important determinants of both the selection and management of HR weeds.

Application of plant-soil feedbacks in the selection of crop rotation sequences.

Plant–soil feedback (PSF) can be a major driver of plant performance in communities, and this concept can be used in selecting crop rotation sequences to maximize agricultural yields. Potential benefits of using PSF in this context include nutrient use optimization, pathogen reduction, and enhancement of mutualisms between crops and microbes. Yet the contributions of these combined mechanisms are poorly understood. Here we investigated the relative contributions of these mechanisms using five major crops commonly cultivated in rotation (alfalfa, canola, maize, soybean, and wheat) under controlled conditions. We trained soil by growing each of the five crops in a “training phase,” and then reciprocally planted the five crops in the trained soils in a “feedback phase.” To tease out soil biota from nutrient effects, we established three treatments: “control” (trained unsterilized soil used in the feedback phases), “biota” (sterilized soil in the feedback phase inoculated with soil biota from the control treatment after the training phase), and “nutrient” (sterilized soils in both phases). Plant–soil feedback for each crop was calculated by comparing the total biomass of each crop grown in soils trained by each of the four other crops (i.e., in rotation) against total biomass in self‐trained soil (i.e., monocropping). We found that PSF values varied among crop combinations in all the treatments, but such variation was the greatest in the nutrient treatment. Overall, soil biota feedback tended to be lower, whereas nutrient feedback tended to be greater compared to the unsterilized control soil, suggesting that effects of antagonistic biota outweighed those of beneficial microbes in the biota treatment, and that plants optimized nutrient uptake when the soil microbiome was absent in the nutrient treatment. Furthermore, soils in the nutrient treatment trained by the legume crops (alfalfa and soybean) tended to provide the greatest positive feedback, emphasizing the important legacy of N2 fixers in crop rotation. Taken together, our data demonstrate how nutrients and soil biota can be integral to PSFs among crops, and that assessing PSFs under controlled conditions can serve as a basis to determine the most productive crop rotation sequences prior to field testing.

Cover crop and nitrogen fertilizer influence on inbred maize performance and soil nitrogen

The response of inbred maize (Zea mays L.) lines to nitrogen (N) fertilizer and cowpea (Vigna unguiculata cv. Iron Clay) cover cropping was evaluated in three consecutive croppings from 2014 to 2016 in a Guamaní (Torrifluventic Haplustepts) soil. The crop rotation sequence was maize (spring 2014), cowpea (summer 2014), maize (winter 2014-2015), cowpea (summer 2015), maize (winter 2015-2016) and cowpea (summer 2016). The N fertilizer levels were 0, 90, 135, 180 and 225 kg N/ha for 2014 and 2014-2015 seasons, and 0, 50, 100, 150, and 200 kg N/ha for the 2015-2016 season. Soils were sampled to a depth of 90 cm before and after each successive cropping. Cover crop did not affect maize yields. The effect of N fertilizer on seed yield was observed in two out of the three years with optimum seed yields of 7,034 and 4,708 kg/ha with fertilizer N of 135 and 90 kg N/ha, respectively. Residual soil N tended to increase due to N fertilizer and cover crop. A partial aboveground N budget showed that the net N balance was more positive and increased with each successive fertilizer N level, reaching values of +516 kg N/ha in fallow and +621 kg N/ha with cover crop after three consecutive croppings over a 30-month period. Part of the excess N (not taken up by the crop) was accounted for in the soil profile. A slightly greater positive N balance at higher N fertilizer rates was due to the cover crop rotation. Cover-cropping with cowpea continues to be an important practice that in the long term will result in improved N recycling due to scavenging of residual soil N after maize cropping or by N fixation. Nitrogen fertilizer rates in the range of 90 to 135 kg N/ha can result in good inbred maize yields and can be adjusted with knowledge of soil inorganic N to a depth of 30 cm, that will result in higher yields, improved N use efficiency and reduced losses to the environment.

Effect of crop sequences in combination with other ecofriendly practices for management of plant parasitic nematodes infecting jute (Corchorus olitorius L.)

Among the different biotic stress, plant parasitic nematodes are considered to be real menace to successful and profitable cultivation of crops. This tiny microscopic organism can effectively manage by application of chemical pesticides, but frequent use of chemical pesticides may induce residual effect, phytotoxicity, health hazards to human and live stocks including ground water contamination. To overcome these hazards, effort is being made to reduce the nematode infestation by some non chemical methods. Use of proper crop sequences seems to be one of the best methods to counter nematode problem. Incorporation of non host or poor host crop between two susceptible host crops can successfully reduce nematode infestation. In the present study four crop rotation sequences were tested for their efficacy to reduce the incidence of plant parasitic nematodes on jute in a naturally infested field of Biswanth College of Agriculture, Biswanath Chariali, Assam during 2019–20. Other ecofriendly nematode management practices like application of compost and crop residue, soil incorporation of dhaincha as green manure, application of bioagents were also combined with different crop sequence. Among the different crop sequences, Jute-Toria-Dhaincha-Jute was found to be most effective in reducing the final nematode population in soil and increasing the seed yield of jute followed in order of efficacy by the crop sequence Jute-Toria- Fallow- Jute. These crop sequences may be recommended for future record.