Secale Cereale Research Articles

Effect of cereal rye cover crop termination timings on weed control and corn yield under a two-pass herbicide program

Cover crops, including cereal rye, are generally known to suppress weeds in various cropping systems; however, research on their effective use is lacking. This study investigated the effects of different cereal rye termination timings on weed control and corn performance in a two-pass herbicide program across 5 site-years (2021–2023) in Arkansas, USA. The herbicide program consisted of one application at cereal rye (Secale cereale) termination (cereal rye environment) or at corn (Zea mays) planting (conventional system) and another at the V4 corn stage. Palmer amaranth (Amaranthus palmeri) at V4 corn was better controlled in cereal rye environments regardless of its termination timing (>75%) than in the conventional corn system (<50%), and the control was generally excellent in both systems 4 weeks later, with subtly greater control in the cereal rye environments. In contrast, yellow nutsedge (Cyperus esculentus) control, in general, was slightly less in the cereal rye environments than in the conventional system. Barnyardgrass (Echinochloa crus–galli) and broadleaf signalgrass (Urochloa platyphylla) control was similar to that of Palmer amaranth, especially at the V4 corn stage, with clear benefits in its control with the later termination timings. Corn height was greater (by 8% to 10%) in cereal rye environments terminated at 1 or 2 weeks after corn planting compared to the conventional system or other cereal rye environments. Corn yield was similar between the conventional system and the cereal rye environments terminated before corn planting; however, the yield was 16% to 22% less with those terminated at or after corn planting. These findings indicate the constrained use of cereal rye in corn, with its termination time optimized for 2 weeks before corn planting. Further research could identify factors that mitigate the yield loss from delayed cereal rye termination and improve its use as a cover crop in corn.

The effect of mini-till and no-till technologies on productivity and quality of malting barley grain

The purpose of the current work was to study the effect of mini-till, no-till and traditional agricultural technologies on productivity and quality of malting barley grain. Field trials were carried out in three crop rotation sequences ‘winter rye – spring wheat – barley’ on medium loamy gray forest soil of Chuvashia with 2.42 % of humus; 188 mg/kg of mobile phosphorus; 160 mg/kg of exchangeable potassium and 6.2 of exchangeable acidity. During the vegetation period of 2020, the hydrothermal coefficient was 1.04; in 2021 it was 0.60; and in 2022 it was 1.05. The object of the study was an early-maturing variety ‘Elf’. Traditional agricultural technology was based on autumn disk plowing and autumn plowing, early spring harrowing, seedbed cultivation and sowing with subsequent rolling. Mini-till cultivation included autumn disk plowing, spring cultivation and sowing with the multifunctional complex “Cultibar 9000”. No-till cultivation consisted of autumn treatment with the non-selective herbicide “Sprut Extra" and “direct” spring sowing “Cultibar 9000”. The seeding rate was 200 kg/ha. The dose of mineral fertilizers was N30P20К20. The crops were protected from weeds, diseases, and pests. On average, the largest (2.49 t/ha) productivity of malting barley grain was obtained using mini-till technology, and the smallest (2.34 t/ha) when using no-till. The mean productivity with traditional agricultural technology was lower than the maximum by 0.03 t/ha, but larger than the minimum by 0.12 t/ha. The analysis of the qualitative characteristics has shown a reliable effect of agricultural technologies on the brewing properties of barley grain. Thus, traditional technology contributed to obtaining grain of the 1st class, mini-till technology contributed to obtaining grain of the 2nd class, and no-till technology contributed to obtaining grain of the 3rd class of the interstate standard.

Development and characterization of a novel wheat-rye T2DS·2DL-2RL translocation line with high stripe rust resistance

Rye (Secale cereale L.), a close relative of common wheat, represents a valuable genetic resource for enhancing the disease resistance of common wheat. Introducing novel rye-derived genes into wheat can potentially improve disease resistance. In this study, we successfully developed a novel wheat-rye derivative line LCR4 through hybridization between hexaploid triticale line Currency and common wheat cultivar Jimai 22 (JM22). We confirmed that LCR4 was a T2DS·2DL-2RL translocation line via comprehensive molecular cytogenetic analyses, including genomic in situ hybridization, multi-color fluorescence in situ hybridization, molecular marker analysis, and wheat SNP-arrays genotyping. Notably, upon inoculation with Puccinia striiformis f. sp. tritici (Pst) race V26 at the seedling stage and mixed Pst races at the adult stage, LCR4 exhibited robust resistance against stripe rust infection at both stages. Subsequent genetic analysis further elucidated that the translocated 2RL chromosome segment is responsible for this resistance. Consequently, LCR4 harboring elite agronomic traits can be effectively employed in breeding programs against stripe rust.

Assessment of cover crop adoption and impact on weed management in Wisconsin corn‐soybean cropping systems

AbstractThe evolution and widespread occurrence of herbicide‐resistant weeds pose a major challenge for farmers and crop consultants across North America, warranting integrated management strategies. The adoption of cover crops offer weed suppression and soil health benefits but adds management complexity. A survey, targeting farmers and crop consultants, was conducted during the spring of 2023 to evaluate current cover crop management practices and perceptions in Wisconsin cropping systems. The survey included 26 questions across five sections: respondent profile, cover crop adoption and experience, cover crop management ahead of soybean [Glycine max (L.) Merr.], cover crop management ahead of corn (Zea mays L.), and general benefits and challenges of cover crop adoption. Farmers and crop consultants represented most respondents, influencing a total of 29,500 and 557,000 ha, respectively. Waterhemp (Amaranthus tuberculatus [Moq.] J.D. Sauer) and giant ragweed (Ambrosia trifida L.) were identified as the most troublesome weeds. Over 90% of respondents use herbicides to terminate their cover crops, and 68% of respondents agree that cover crops improved overall weed control in their farms/clients’ farms to some extent [cereal rye (Secale cereale L.) as main cover crop species]. Additionally, results demonstrate a strong consensus (85%) on cover crops positively influencing water retention, with 98% agreement on their efficacy in reducing soil erosion. Results from this survey can help guide farmers, agronomists, researchers, and policymakers with cover crop adoption, management, policies, incentives, and future research and education needs in Wisconsin and beyond to support the development of more sustainable and efficient weed and crop management strategies.

A triplicated wheat-rye chromosome segment including several 12-OXOPHYTODIENOATE REDUCTASE III genes influences magnesium partitioning and impacts wheat performance at low magnesium supply

We previously reported a structural rearrangement between wheat (Triticum aestivum) and rye (Secale cereale) chromosomes 1BS/1RS that increased the dosage of 12-OXOPHYTODIENOATE REDUCTASE III (OPRIII) genes involved in jasmonate biosynthesis (henceforth, 1RW line), and that drastically reduced primary root growth relative to a control line with the intact 1RS chromosome (henceforth, 1RS). In this study, we show that the increased gene-dosage of this region is associated with increases in the shoot-root partitioning of magnesium (Mg). Moreover, both a CRISPR-edited 1RW line with reduced OPRIII dosage and the 1RW line treated with the jasmonate biosynthesis inhibitor ibuprofen showed reduced differences in shoot-root Mg partitioning than 1RW. The observed differences in Mg partitioning between 1RS and 1RW plants occur over a wide range of external Mg supplies and imply opposite trends of Mg accumulation in roots and shoots. Furthermore, we show an association between the increase of shoot-root Mg partitioning and increased tolerance of the 1RW line to low levels of Mg supply. In summary, our results provide evidence of the role of the jasmonate pathway on the dynamics of Mg accumulation in roots and shoots, which correlates with the performance of wheat plants under conditions of Mg scarcity.

Effects of Cover Crop on Selected Abiotic and Biotic Soil Health Indicators

Current cropping systems, like cover cropping, aim to improve soil health and crop productivity, with the former a more sustainable route to the latter. This can be done by evaluating the influence of cover crops (CCs) on soil health indicators, both abiotic and biotic, as is the objective of this study. Several CCs (crimson clover [Trifolium incarnatum L.], oats [Avena sativa], hairy vetch [Vicia villosa Roth.], winter wheat [Triticum aestivum L.], winter peas [Lathyrus hirsutus L.], flax [Linum usitassimum L.], triticale [Triticale hexaploide Lart.], cereal rye [Secale cereale], and barley [Hordeum vulgare L.]) were used across two research sites, set up using a completely randomized design with two levels of CCs (CC vs no cover crop [NC]) and three replicates during 2023. Soil samples were collected at 0-10, 10-20, and 20-30 cm depths and analyzed for soil physico-chemical properties and microbial biomass and composition. Results showed significantly lower bulk density values, greater water content (at 0 kPa soil water matric potential), greater volume-specific heat capacity (at 0 and -33 kPa soil water matric potential), greater total nitrogen, and numerically greater soil organic carbon under CC compared with NC management. This led to numerically greater microbial biomass and community composition (e.g., arbuscular mycorrhizal fungi, gram-negative and gram-positive bacteria, eukaryotes, and fungi), and slightly lower microbial stress indicators (genotypic and chemical structure categorizations) under CC compared with NC management. However, the lack of significant differences between treatments suggests that three years is insufficient to detect improvements in measured soil health indicators. Further, the significant differences in measured soil health indicators between study sites suggests an influence of soil texture and order, and this warrants further investigations.

Development and Characterization of Two Wheat-Rye Introgression Lines with Resistance to Stripe Rust and Powdery Mildew.

Rye (Secale cereale L.) genes, which contribute to the tertiary gene pool of wheat, include multiple disease resistance genes useful for the genetic improvement of wheat. Introgression lines are the most valuable materials for wheat breeding because of their small alien segments and limited or lack of linkage drag. In the present study, wheat-rye derivative lines SN21627-2 and SN21627-6 were produced via distant hybridization. A genomic in situ hybridization analysis revealed that SN21627-2 and SN21627-6 lack alien segments, while a multi-color fluorescence in situ hybridization analysis detected structural changes in both introgression lines. At the seedling and adult plant stages, SN21627-2 and SN21627-6 were highly resistant to stripe rust and powdery mildew. Primers for 86 PCR-based landmark unique gene markers and 345 rye-specific SLAF markers were used to amplify SN21627-2 and SN21627-6 genomic DNA. Eight markers specific to rye chromosome 2R were detected in both introgression lines, implying these lines carry chromosome 2R segments with genes conferring stripe rust and powdery mildew resistance. Therefore, SN21627-2 and SN21627-6 are resistant to more than one major wheat disease, making them promising bridging parents for breeding disease-resistant wheat lines.

Влияние на две системи на земеделие върху продуктивността и биохимичните качества на лимец и ръж

The experiment was conducted in the period 2019 - 2022 in the experimental field of the Institute of Agriculture in Karnobat. The aim of the research was to determine the influence of two farming systems - organic and conventional on the productivity and biochemical characteristics of rye (Secale cereale L.) and triticale (Triticum monococcum L.). The crop structure and grain yield of rye and einkorn grown in different farming systems depend not only on the studied factor, but also on weather conditions during the growing season of the crops. Organic farming of both crops promotes the formation of higher number of spike-bearing stems compared to conventional farming. We believe that this is a compensatory mechanism, especially under unfavorable climatic conditions. In the case of organically grown rye and einkorn, the plant height, spike length, number of grains in the spike, mass of the grain in the spike were lower than the conventional ones. For organically grown einkorn, despite differences in agro-meteorological conditions, spike length remained stable over the years, but was 18% shorter than that of conventional. The biochemical parameters of the crops differ according to the cultivation method, with conventional rye having a higher percentage of crude protein and lower ash values compared to organic. The lysine content is almost the same in both cultivation methods, but the percentage of crude fiber is higher in conventional farming. Despite lower crude protein levels, organically grown einkorn showed greater stability in ash and fiber content over the years, as well as higher lysine content.

Cover crop characteristics modulate amount and timing of nitrogen supply of fertilized sugar beet (Beta vulgaris L.) in temperate climate

For temperate climate, there is little information on the effects cover crops grown in fall (CCs) on the nitrogen (N) supply for next year’s sugar beet (SB). Four field trials were conducted on silty soils to establish the CC N effect (Neff) compared to bare fallow separately for the periods sowing-summer and summer-autumn harvest. Biomass characteristics of radish (Raphanus sativus L.), spring vetch (Vicia sativa L.), saia oat (Avena strigosa Schreb.), and winter rye (Secale cereale L.) CCs before winter, soil mineral nitrogen in spring (SMN), and SB N accumulation and sugar yield (SY) were measured. In the period sowing-summer, characterized by a high SB N demand, Neff of overwintering, high biomass yielding rye CC was negative up to -50 kg N ha-1 at three site/years and varied around zero for the other CCs except vetch, for which Neff was positive. At SB autumn-harvest, Neff was negative up to -100 kg N ha-1 except for vetch in one trial. SY was lowest after rye CC. Regression analyses indicated a negative impact of CC biomass, C:N ratio and the difference in SMN between fallow (high SMN) and CCs (low SMN) on Neff. To conclude, if CCs yield a high amount of biomass surviving until spring and thus remove SMN from the soil which otherwise remains available for SB, early season mineralization of CC biomass N can be too low to ensure a N supply sufficient for maximum SB yield. Choosing leguminous CCs or early termination of CCs might alleviate this constraint.

Assessment of morphophysiological parameters of resistance of various varieties of winter rye to chloride salinity in laboratory conditions

Determining the tolerance of cultivated plants to salts is considered important and necessary in breeding practice in areas with primary and secondary soil salinization. This article examines the effect of salinity (NaCl) in laboratory conditions on the growth and development of plants of three varieties of winter rye (Chusovaya, Yantarnaya, Alisa) and the effectiveness of early diagnosis on resistance to the stress factor. The purpose of the study was to determine the resistance of winter rye varieties to chloride salinity based on the variability of morphophysiological characteristics under simulated conditions. Based on the identified differences in indicators characterizing the growth processes of plants in vegetation vessels in the control and on the substrate with NaCl, the varieties according to resistance to salt stress are distributed in the following order: Chusovaya, Yantarnaya, Alisa. The data obtained indicate the specificity of the response of varieties to a stress factor. It is shown that for a more objective characterization of genotypes for salt tolerance, a comprehensive study of traits (seed germination, morphometric parameters of shoots and roots, chlorophyll content in leaves, plant biomass) is necessary. The results of the study can be used in the selection of initial forms for the selection of winter rye, as well as in the cultivation of the studied varieties in different agro-ecological conditions.

Mapping predicted biomass in cereal rye using 3D imaging and geostatistics

Abstract Cover crops are becoming an increasingly important tool for weed suppression. Biomass production in cover crops is one of the most important predictors of weed suppressive ability. A significant challenge for growers is that cover crop growth can be patchy within fields, making biomass estimation difficult. This study tested ground-based structure-from-motion (SfM) for estimating and mapping cereal rye (Secale cereale L.) biomass. SfM generated 3D point clouds from red, green, and blue (RGB) videos collected by a handheld GoPro camera over five fields in North Carolina during the 2022 to 2023 winter season. A model for predicting biomass was generated by relating measured biomass at termination using a density–height index (DH) from point cloud pixel density multiplied by crop height. Overall biomass ranged from 320 to 9,200 kg ha−1, and crop height ranged from 10 to 120 cm. Measured biomass at termination was linearly related to DH (r2 = 0.813) through levels of 9,000 kg ha−1. Based on independent data validation, predicted biomass and measured biomass were linearly related (r2 = 0.713). In the field maps generated by kriging, measured biomass data were autocorrelated at a range of 5.4 to 42.2 m, and predicted biomass data were autocorrelated at a range of 3.4 to 12.0 m. However, the spatial arrangement of high- and low-performing areas was similar for predicted and measured biomass, particularly in fields with greatest patchiness and spatial correlation in biomass values. This study provides proof-of-concept that ground-based SfM can potentially be used to nondestructively estimate and map cover crop biomass production and identify low-performing areas at higher risk for weed pressure and escapes.

Does a native and introduced cover crop species differ in their ability to suppress weeds? A study in a table grape vineyard

This study compared the weed suppression ability of a native cover crop species phacelia (Phacelia tanacetifolia), an introduced cover crop species rye (Secale cereale L.), and a no cover crop (herbicide‑managed) system in a vineyard. Cover crops were sown in the interrow spaces of the grapevine rows. Percent weed cover after the cover crop termination was lower in the interrow of the phacelia than the no cover crop plots. During the cover crop growing season, phacelia suppressed weeds more than rye. However, the weed seedbank of the cover crop plots was greater than that of the no cover crop plots.

The Impact of Winter Cover Crops on Soil Nematode Communities and Food Web Stability in Corn and Soybean Cultivation.

There is increasing adoption of winter cover crops (WCCs) in corn and soybean production in Canada, primarily to reduce erosion and increase soil organic matter content. WCCs have the potential to influence nematode communities by increasing free-living nematodes and decreasing plant-parasitic nematodes or vice versa. However, the mechanism by which WCCs change nematode community assemblages still remains a key question in soil food web ecology. We tested the hypothesis that the long-term use of rye (Secale cereale), barley (Hordeum vulgare) and oat (Avena sativa) as monocultures or mixtures promotes nematode communities and improves overall soil health conditions compared to winter fallow. The results from this study revealed that the use of WCCs generally promoted a higher abundance and diversity of nematode communities, whereas plant parasitic nematodes were the most abundant in winter fallow. Moreover, the mixtures of WCCs had more similar nematode communities compared to rye alone and winter fallow. The structure and enrichment indices were higher with WCCs, indicating higher nutrient cycling and soil suppressiveness, which are signs of healthy soil conditions. Furthermore, WCCs significantly reduced the populations of root lesion nematode Pratylenchus, although their numbers recovered and increased during the main crop stages. Additionally, mixtures of WCCs promoted the highest abundance of the stunt nematode Tylenchorhynchus, whereas winter fallow had a higher abundance of the spiral nematode Helicotylenchus during the fallow period and the main crop stages. The results show that the long-term use of cover crops can have a positive impact on nematode communities and the soil food web, but these changes depend on the type of WCCs and how they are used.

Exogenous γ-aminobutyric acid (GABA) enhances rye (Secale cereale) seedling resistance to combined freeze-thaw and cadmium stress.

Freeze-thaw is a common stress at high altitudes in northern China. There is a risk of cadmium (Cd) contamination in the region. γ-aminobutyric acid (GABA) is a natural product that regulates plant growth. Rye (Secale cereale ) was used as research material to investigate the physiological effects of exogenous GABA on rye seedlings under the single and combined stresses of freeze-thaw and cadmium. The results showed that the combined stress severely inhibited shoot length, root length, fresh weight, and dry weight, increased malondialdehyde and hydrogen peroxide contents, and significantly decreased superoxide dismutase (SOD) activity. Foliar application of 5mM GABA alleviated the negative effects of stress on seedling growth, increased soluble protein content, and reduced malondialdehyde and hydrogen peroxide contents. Exogenous GABA application also enhanced the activities of SOD and peroxidase (POD). Additionally, the presence of exogenous GABA activated the GABA metabolic process and encouraged the accumulation of phytochelatins, glutathione, and non-protein thiol. These results indicate that exogenous GABA can effectively improve the resistance of rye seedlings to freeze-thaw and Cd by regulating the antioxidant enzyme system and enhancing its own detoxification mechanism, and they provide a basis for future applications of exogenous GABA, which is beneficial for ecological protection.

Comprehensive assessment of adaptability, stability and stress resistance of diploid winter rye varieties under conditions of Western Siberia

Currently, the adaptability and stability of the trait under study, i.e., the ability of a variety to maintain the optimal level of the trait in different soil and climatic conditions, is of particular importance in the breeding process. A research was conducted to comprehensively study the parameters of adaptability, stability and stress resistance in terms of yield of diploid winter rye varieties of different ecological and geographical origins in the conditions of Western Siberia. The experimental part of the study was carried out during 2019–2021, at the experimental site of SibNIIRS - a branch of the ICG SB RAS, located in the West Siberian region. The material for the research was: 6 varieties of winter rye from of the FRC «N.I. Vavilov All-Russian Research Institute of Plant Genetic Resources» (Korotkostebelnaya 69, Sibirskaya 87, Chulpan, Pamyati Kunakbaeva, Sinilga, Alisa) and 8 varieties from the Republican unitary enterprise «Research and Practical Center of National Academy of Sciences of the Republic of Belarus for Arable Farming» (Lota, Kalinka, Golubka, Vostok, Verdun, Talisman, Zubrovka, Yubileinaya). According to the results of two-factor analysis of variance, the yield was influenced by genotypic differences between varieties - 77.34% (P < 0.05) and the prevailing growing conditions in different years of research - 11.98% (P < 0.05). The varieties Sibirskaya 87 (689.0 g/m2) and Yubileinaya (706.0 g/m2) were characterized by productivity at the level or higher than the standard Korotkostebelnaya 69 (650 g/m2). As a result of a comprehensive assessment using ranking for adaptability, stability and stress resistance, the following winter rye varieties were identified: Yubileynaya (102), Korotkostelnaya 69 (97), Sibirskaya 87 (87), Zubrovka (79), Alisa (77), Talisman (74). The selected varieties are capable of producing relatively high yields in the contrasting conditions of Western Siberia.

Variation in rye (Secale cereale L.) inbred lines with different type of glaucousness

Variation in rye (Secale cereale L.) inbred lines with different type of glaucousness

Machine learning reveals dynamic controls of soil nitrous oxide emissions from diverse long-term cropping systems.

Soil nitrous oxide (N2O) emissions exhibit high variability in intensively managed cropping systems, which challenges our ability to understand their complex interactions with controlling factors. We leveraged 17 years (2003-2019) of measurements at the Kellogg Biological Station Long-Term Ecological Research (LTER)/Long-Term Agroecosystem Research (LTAR) site to better understand the controls of N2O emissions in four corn-soybean-winter wheat rotations employing conventional, no-till, reduced input, and biologically based/organic inputs. We used a random forest machine learning model to predict daily N2O fluxes, trained separately for each system with 70% of observations, using variables such as crop species, daily air temperature, cumulative 2-day precipitation, water-filled pore space, and soil nitrate and ammonium concentrations. The model explained 29%-42% of daily N2O flux variability in the test data, with greater predictability for the corn phase in each system. The long-term rotations showed different controlling factors and threshold conditions influencing N2O emissions. In the conventional system, the model identified ammonium (>15 kg N ha-1) and daily air temperature (>23°C) as the most influential variables; in the no-till system, climate variables such as precipitation and air temperature were important variables. In low-input and organic systems, where red clover (Trifolium repens L.; before corn) and cereal rye (Secale cereale L.; before soybean) cover crops were integrated, nitrate was the predominant predictor of N2O emissions, followed by precipitation and air temperature. In low-input and biologically based systems, red clover residues increased soil nitrogen availability to influence N2O emissions. Long-term data facilitated machine learning for predicting N2O emissions in response to differential controls and threshold responses to management, environmental, and biogeochemical drivers.

Planting soybean green: how cereal rye biomass and preemergence herbicides impact Amaranthus spp. management and soybean yield

Abstract Cereal rye (Secale cereale L.) cover crop and preemergence herbicides are important components of an integrated weed management program for waterhemp [Amaranthus tuberculatus (Moq.) Sauer] and Palmer amaranth (Amaranthus palmeri S. Watson) management in soybean [Glycine max (L.) Merr.]. Accumulating adequate cereal rye biomass for effective suppression of Amaranthus spp. can be challenging in the upper Midwest due to the short window for cereal rye growth in a corn–soybean rotation. Farmers are adopting the planting green system to optimize cereal rye biomass production and weed suppression. This study aimed to evaluate the feasibility of planting soybean green when integrated with preemergence herbicides for the control of Amaranthus spp. under two soybean planting time frames. The study was conducted across 19 site-years in the United States over the 2021 and 2022 growing seasons. Factors included cover crop management practices (“no-till,” “cereal rye early-term,” and “cereal rye plant-green”), soybean planting times (“early” and “late”), and use of preemergence herbicides (“NO PRE” and “YES PRE”). Planting soybean green increased cereal rye biomass production by 33% compared with early termination. Greater cereal rye biomass production when planting green provided a 44% reduction in Amaranthus spp. density compared with no-till. The use of preemergence herbicides also resulted in a 68% reduction in Amaranthus spp. density compared with NO PRE. Greater cereal rye biomass produced when planting green reduced soybean stand, which directly reduced soybean yield in some site-years. Planting soybean green is a feasible management practice to optimize cereal rye biomass production, which, combined with preemergence herbicides, provided effective Amaranthus spp. management. Soybean stand was a key factor in maintaining soybean yields compared with no-till when planting green. Farmers should follow best management recommendations for proper planter and equipment setup to ensure effective soybean establishment under high levels of cereal rye biomass when planting green.

Tillage and cover cropping influence phosphorus dynamics in soil and water pools

AbstractWinter cover crops (CCs) have the potential to reduce phosphorus (P) loss by temporarily fixing P into CC biomass. A field experiment with no‐tillage (NT) and conventional tillage (CT) was used to study the ability of different CC species planted after corn (Zea mays L.) and soybean (Glycine max L.) harvests to reduce the P availability in soil solution. The effect of three crop rotations (corn–no CC–soybean–no CC [C–S], corn–cereal rye (Secale cereale)–soybean–hairy vetch (Vicia villosa) [C–R–S–HV], corn–cereal rye–soybean–oats (Avena sativa)+ radish (Raphanus sativus L.) [C–R–S–OR]) and two tillage (NT and CT) treatments was determined on soil available P and soil solution P content through pan (A horizon) and tension (100‐cm depth) cup lysimeters. The experiment was set up as a randomized complete block design with tillage as a split factor with three replicates. Over the study period, incorporating hairy vetch in C–R–S–HV rotation reduced the Mehlich‐3 P content in soil by 26%–29% compared to the C–S and C–R–S–OR rotation. Both CC rotations (C–R–S–HV and C–R–S–OR) were effective in reducing dissolved reactive P (DRP) concentration in pan and tension cup lysimeters compared to the C–S in both CT and NT systems. However, these results varied with CC species grown and seasonal variability in precipitation. A significantly lower DRP load with crop rotation and tillage treatments was observed mainly during the CC growing season. During the study period, crop rotations with reduced labile soil P content and DRP loss were ranked in an order of C–R–S–HV > C–R–S–OR > C–S. Overall, this study showed that CCs have the potential in both CT and NT systems to significantly reduce P in soil and soil solution, and these effects are resilient to a wide range of precipitation conditions.

Competitiveness of chia against brassica weeds improves through a narrow spatial arrangement

Chia (Salvia hispanica L.) is a promising crop valued as a sustainable source of omega-3. However, chia yield and quality are reduced because of weed competition and the lack of registered herbicides. This study evaluated how chia spatial arrangement suppresses weed growth and provided management options for this crop. The performance of chia plants was assessed over three growing seasons in field experiments using a factorial design that considered spatial arrangement (narrow and wide), weed management (control without weeds, soil bank brassica (Brassica rapa L.), and sown brassica), and cover crop (with or without a rye (Secale cereale L.) cover crop during chia fallow). Chia and brassica are not complementary, leading to resource competition (relative yield total around 1) and negative effects on each other. A significant decrease in chia grain yield of 0.9% per unit increase in the percentage of weeds in total biomass was observed. As chia had a competitive advantage over brassica, the grain yield reduction was ameliorated with a narrow spatial arrangement. Narrow spatial arrangement promotes faster canopy closure during the early growth stages, decreasing light penetration and suppressing weed growth. The high extinction coefficient of chia (0.91) and the low critical LAI (3.3) contributed to this light interception behavior. Accordingly, to maximize chia productivity and profitability, a narrow spatial arrangement is an effective management strategy to suppress weeds. This study contributes valuable insights into chia-weed interactions and emphasizes the importance of sustainable crop management practices.