Citrus is the world's largest fruit category, yet it is frequently damaged by weeds during cultivation and management. As a green cultivation measure, covering crops in orchards effectively controls weeds and enhances soil quality. At present, the research on covering crops is mostly focused on soil, but there is still a lack of research on how crops affect citrus trees. This study aims to provide theoretical support for the widespread adoption of the green management practices. The previous research of us found that rattail fescue and vicia villosa had notably enhanced the organic matter and alkali-hydrolyzable nitrogen levels in orchard soils. Consequently, this study treated citrus orchards with sowing rattail fescue and vicia villosa between rows, with manual tillage serving as the control, to investigate the impact of two-year grass cultivation on N metabolism in citrus roots. Results indicated that both types of grass significantly enhanced amino acid metabolism in citrus roots at depths of 0-20 cm, significantly increasing activities of nitrate reductase, nitrite reductase, glutamine synthetase, NADH-glutamate synthetase, and NADPH-glutamate dehydrogenase, as well as expression levels of NR and NiR. Rattail fescue demonstrated superior effects. There was no discernible pattern in amino acid levels at depths of 20-40 cm, with both grass types significantly increasing NR, NADH-GOGAT enzyme activity, and also increasing gene expression levels for NiR, GDH1, and GDH2. Both types of grass significantly promoted N metabolism in citrus roots at depths of 0-20 cm, with rattail fescue outperforming vicia villosa.

Cold climate viticulture is challenged by climatic variability, including increased frost risk, shorter growing seasons, and unpredictable weather events that impact vine productivity and grape quality. Global warming is altering traditional viticulture zones, prompting the exploration of new regions for grape cultivation, the selection of climate-resilient cultivars, and the implementation of adaptive practices. This review synthesizes recent advances in adaptive viticulture practices and plant growth regulator applications, highlighting novel molecular and physiological insights on cold stress resilience and berry quality. Key strategies include delayed winter pruning to mitigate frost damage, osmoprotectant application to improve freeze tolerance, and canopy management techniques (cluster thinning and defoliation) to enhance berry ripening and wine composition. Their effectiveness depends on vineyard microclimate, soil properties and variety-specific physiological response. Cover cropping is examined for its role in vine vigor regulation, improving soil microbial diversity, and water retention, though its effectiveness depends on soil type, participation patterns, and vineyard management practices. Recent transcriptomic and metabolomic studies have provided new regulatory mechanisms in cold stress adaptation, highlighting the regulatory roles of abscisic acid, brassinosteroids, ethylene, and salicylic acid in dormancy induction, oxidative stress response, and osmotic regulation. Reflective mulch technologies are currently examined for their ability to enhance light interception, modulating secondary metabolite accumulation, improving technological maturity (soluble solids, pH, and titratable acidity) and enhancing phenolic compounds content. The effectiveness of these strategies remains highly site-specific, influenced by variety selection and pruning methods particularly due to their differences on sugar accumulation and berry weight. Future research should prioritize long-term vineyard trials to refine these adaptive strategies, integrate genetic and transcriptomic insights into breeding programs to improve cold hardiness, and develop precision viticulture tools tailored to cold climate vineyard management.

Cover crops are increasingly recognized for their role in enhancing the multifunctionality and health of soil. Previous studies have focused largely on the effects of cover crop residues and have overlooked the impacts of living cover crops on the soil biochemical processes and nutrient cycling. The aim of this study is to bridge this gap by examining the effects of different types of living cover crops, such as legumes, grass, and their mixtures, on the soil nutrients and microbial communities. We conducted a field experiment in northeastern China using an Alfisol and intercropped cover crops with maize. During the growing season, we characterized microbial biomass and community structure using phospholipid fatty acid (PLFA) analysis and assessed microbial activity through enzyme activities related to carbon (C), nitrogen (N) and phosphorus (P). Additionally, we employed the enzyme vector model to evaluate potential microbial metabolic limitations. Compared with the control plots without cover crops, the legume treatment significantly increased dissolved organic carbon (DOC) and available nitrogen, particularly altering the microbial community structure during the maize growth stages. This change shifted the microbial functional group ratios towards enhanced C acquisition by soil microbes, indicating alleviated microbial C limitation in legume treatment. In contrast, the grass treatment maintained the soil organic carbon (SOC) and total nitrogen (TN) levels, and increased the total microbial biomass at the later growth stage. Compared with those in the other treatments, the biomass of bacterial groups in the grass treatment was more responsive, and the activities of the C, N and P enzymes were higher. Furthermore, the mixture treatment merged the benefits of both the legume and grass cover crops, enhancing both DOC and available N contents and maintaining SOC and TN levels. The mixture treatment significantly affected the microbial community structure without altering microbial nutrient limitations. Thus, the mixture treatment is recommended for application in cover crop-maize intercropping systems. In conclusion, our study captured the temporal dynamic shifts in the microbial functional groups associated with different microbial life strategies from intercropping different types of living cover crops with maize. This research refines our understanding of the role of cover crops in supporting belowground ecosystems and highlights the importance of living mulch in sustainable agricultural management.

The response of soils to extreme weather events will become increasingly important in the future as more frequent and severe floods and droughts are expected to subject soils to drying and rewetting cycles as a result of climate change. These extreme events will be experienced against a backdrop of overall warming. Farmers are adopting cover cropping as a sustainable management practice to increase soil organic matter and benefit soil health. Cover crops may also increase the resilience of soils to help mitigate the impacts of climate change. We examined the legacy of warming and cover crops on the response of soil microbial function to repeated drying and rewetting cycles. We introduced open-top chambers to warm the soil surface of a field plot experiment in which cover crops (single-species monocultures and 4-species polycultures) were grown over the summer after harvest and before planting autumn sown cash crops in a cereal rotation. Soil samples were collected from warmed and ambient areas of the experimental plots in spring, before harvesting the cereal crop. Warming significantly increased, and cover crops significantly decreased, the abundance of genes encoding fungal beta-glucosidase. We quantified respiration (a measure of soil microbial function) with high-frequency CO2 flux measurements after 0, 1, 2, 4 or 8 wet/dry cycles imposed in the laboratory and the addition of barley grass powder substrate at a rate of 10 mg g-1 soil. We observed lower cumulative substrate-induced respiration in soils previously planted with cover crop mixtures than expected from the average of the same species grown in monoculture. Repeated drying and rewetting cycles increased the cumulative substrate-induced respiration rate observed, suggesting that repeated perturbations selected for a community adapted to processing the barley shoot powder more quickly. When we calculated the cumulative respiration after 8 wet/dry cycles, relative to cumulative respiration after 0 wet/dry cycles (which we infer represents the extent to which microbial communities adapted to repeated drying and rewetting cycles), our data revealed that the legacy of warming significantly reduced soil microbial community adaptation, but the legacy of cover crops significantly increased, soil microbial community adaptation. This adaptation of the soil microbial community was positively correlated with the concentration of water-extractable organic carbon in the soils before imposing the drying and rewetting cycles and/or adding the substrate. We conclude that cover crops may enhance the ability of the soil microbial community to adapt to drought events and mitigate the impact of warming, possibly due to the provision of labile organic carbon for the synthesis of osmolytes which then prime the decomposition of labile plant material upon rewetting.

Anthropogenic activities have resulted in land desertification in various regions of the world, leading to the degradation of critical soil characteristics such as organic matter (OM) content, nutrient stock, and prevailing biodiversity. Restoring such degraded soils through organic matter amendments and diversified crop rotations is thus an intrinsic part of organic farming. This review discusses a wide range of organic farming impacts on soil health and crop productivity by focusing on organic fertilizers and crop diversification. Conventional fertilizers were considered vital for agricultural production to harvest high crop yields. Nevertheless, they are now deemed as environmentally hazardous and an obstacle to sustainable agroecosystems due to intensive chemical inputs that damage the soil over time and have long-lasting impacts. Conventional fertilization results in nutrient depletion, loss of microbial diversity, organic matter reduction, and deterioration of physical characteristics of the soil. Conversely, organic fertilization makes use of naturally existing resources to improve soil health. Organic amendments such as biochar, manure, and fermented grass improve soil's physical, chemical, and biological properties and promote the growth and diversity of beneficial soil microorganisms-important in nutrient cycling and soil stability. They facilitate the uptake of nutrients, hinder crop pathogen growth, mitigate heavy metals, and decompose xenobiotic organic substances. Moreover, growing cover crops is also a major strategy to improve soil health. Diversified crop rotation with combinatorial use of organic fertilizers may improve soil health and agricultural yields without any detrimental impacts on the environment and soil, ensuring sustainable food production, safety, and security. This integrated approach contributes to minimizing the use of chemical fertilizers and their effects on environmental health. It also contributes to reducing agricultural inputs along with enhancing OM, soil microbial diversity and biomass, nitrogen fixation, and carbon sequestration. Therefore, cover crops and organic fertilization may offer sustainable agroecosystems and climate change mitigation.

By improving soil properties, cover crops can reduce wind erosion and sand damage to emerging cotton (Gossypium hirsutum L.) plants. However, on the Texas High Plains, questions regarding cover crop water use and management factors that affect cotton lint yield are common and limit conservation adoption by regional producers. Studies were conducted near Lamesa, TX, USA, in 2017-2020 to evaluate cover crop species selection, seeding rate, and termination timing on cover crop biomass production and cotton yield in conventional and no-tillage systems. The no-till systems included two cover crop species, rye (Secale cereale L.) and wheat (Triticum aestivum L.) and were compared to a conventional tillage system. The cover crops were planted at two seeding rates, 34 and 68 kg ha(-1), and each plot was split into two termination timings: optimum, six to eight weeks prior to the planting of cotton, and late, which was two weeks after the optimum termination. Herbage mass was greater in the rye than the wheat cover crop in three of the four years tested, while the 68 kg ha(-1) seeding rate was greater than the low seeding rate in only one of four years for both rye and wheat. The later termination timing produced more herbage mass than the optimum in all four years. Treatments did not affect cotton plant populations and had a variable effect on yield. In general, cover crop biomass production did not reduce lint production compared to the conventional system.

Context or problem: Lone-term application of chemical fertilizers in farmland ensure adequate or profitable crop yields but may damage soil structure. Cover crops (CCs) have great potentials to improve soil quality and promote sustainable crop production. However, the combined impacts of CCs with nitrogen fertilization on soil quality and crop yields are not clear. Objective or research question: We aimed to examine the effects of CCs combined with N fertilization rates on soil physical properties, C and N fractions in both bulk soils and aggregates, and crop yields, and to find the best management practice that improve both soil quality and crop yields synthetically. Methods: A 4-year summer CCs - winter wheat field experiment was conducted in the Loess Plateau of China. CCs with different species and combinations (CC) were soybean (SB), sudan grass (SG), a mixture of both (SS), and no cover crop (CK) and N fertilizer (NR) were applied to winter wheat at rates of 0 (N0), 60 (N60), and 120 (N120) kg N ha(-1). Soil physical properties and C and N fractions in both bulk soils and aggregates were evaluated at 0-10, 10-20, and 20-40 cm soil depths. Results: Soil total porosity (TP), saturated water content (SWC), capillary water capacity (CWC), and C and N fractions decreased while bulk density (BD) increased with the increase of soil depth. The CC, NR, and their interaction (CCxNR) had significant effects on soil BD, aggregate size distribution and stability (MWD), and C and N fractions and only CC and CCxNR had significant effects on other physical properties. The incorporation of CCs significantly increased the proportions of > 5 mm aggregates and C and N fractions in both bulk soils and aggregates, especially in 0-10 and 10-20 cm. And SB and SS improved soil other physical properties more than SG, especially in 0-10 cm, which decreased BD by 13.2% and 12.6% while increased TP by 6.5% and 8.3%, SWC by 14.3% and 15.3%, CWC by 13.9% and 14.2%, MWD by 16.6% and 14.4%, respectively, compared to CK. Additionally, soil physical properties improved more with N60 while the C and N fractions in both bulk soils and aggregates increased more with N120. However, BD increased by 2.6% and 3.3% in N60 and N120 than N0, respectively. The correlations between the proportion of macro-aggregates and soil C and N fractions at 0-10 and 10-20 cm indicated the positive effects of CCs on improving soil structure and fertility simultaneously. Aggregated-associated C and N fractions decreased firstly and then increased with the reduced aggregate sizes, and were higher in micro-aggregates than in other size classes. N60-SB increased wheat yields by 98.7% compared with N0-CK. Conclusions: Overall, the incorporation of soybean residue was the best management practice for winter wheat yield and soil fertility under the reduced N fertilization.

There is a need to explore management practices that reduce nitrate (NO3-) leaching and aid in meeting current greenhouse gas reduction goals. Tile drainage involves using perforated pipes to remove excess subsurface water from agricultural fields, also removing nutrients. The inclusion of cover crops in tile -drained systems in the Midwest has been shown to reduce NO3 - losses and is potentially a strategy to mitigate soil nitrous oxide (N2O) emissions. The objectives of this research were to 1) evaluate cumulative soil NO3 - and soil N2O losses with and without the inclusion of cover crops in a corn -soybean rotation on a tile -drained landscape and; 2) assess the environmental damage cost (EDC) of N losses with and without the inclusion of cover crops in a corn -soybean rotation on a tile -drained landscape. Corn (Zea mays L.) was grown in 2017, and soybean (Glycine max L.) in 2018. The cover crop used in this experiment was a 92% cereal rye (Secale cereal L.) and 8% daikon radish (Raphanus sativus L.) blend. Treatments included cover crop inclusion, no cover crop inclusion, and a zero control, which did not include cover crops or receive N fertilization. Each treatment was replicated three times in individually tile -drained plots established in Lexington, IL during the 2017 and 2018 growing seasons. In 2017, cover crop inclusion led to a reduction in NO3- losses of over 50% when compared to the no cover and zero control. In 2018, total N losses were identical; however, there was an increase in soil N2O emissions across all treatments compared to 2017. Despite the apparent tradeoff between N loss pathways in 2018, the overall EDC was reduced primarily because of the reduction in NO3 - loss in the presence of cover crops. The results of this study indicated that the inclusion of a cover crop resulted in a sizeable reduction in N loss during the corn year that equated to a 64% reduction in EDC across a two-year crop rotation.

Some soils in Brazil are contaminated with zinc (Zn). Even though it is an essential micronutrient, Zn, when in excess, harms plant growth. The Pampa biome has a great diversity of grasses. However, few studies have evaluated the growth potential and physiological and biochemical responses of these plants to excess Zn. The study aimed to evaluate, physiological point of view, the native grass species of the Pampa biome most tolerant species to excess Zn. The grass species of the Pampa biome used in the experiment were Andropogon lateralis, Axonopus affinis, Paspalum plicatulum, and Paspalum notatum. Three Zn doses were added to the solution, corresponding to 2 mu M (original concentration of the nutrient solution), 150, and 300 mu M of Zn in the form of ZnCl2 for the cultivation of the four grasses. The increase in Zn availability increased the photosynthetic rate in the four species. Andropogon lateralis increased shoot and root dry matter production with increasing Zn concentration in solution. Andropogon lateralis increased phosphorus (P) retention in the root system, contributing to the increase of Zn in the roots. Axonopus affinis does not reduce its shoot growth when faced with increased Zn levels. Zn translocation when exposed to intermediate Zn levels. In Paspalum Notatum, antioxidant enzymatic activity is induced in response to excess Zn. Paspalum plicatulum absorbs a high concentration of Zn in the shoot. Andropogon laterallis was the only plant that showed an increase in biomass when grown in a higher dose of Zn.

The use of cover crops has proved to be a promising strategy in soil decompaction. Thus, the objective was to evaluate the morphophysiological characteristics of maize plants ( Zea mays L.), Urochloa ruziziensis and Panicum maximum growing in soil with or without subsurface compaction. The experiment was conducted in a greenhouse, adopting the factorial scheme 4 x 2, being three cover crops (single corn, U. ruziziensis, P. maximum - BRS Zuri) and a corn-U. ruziziensis intercrop grown in soil with and without compaction in the layer of 10-15 cm of depth, with four replications. Physiological and morphological variables and dry matter accumulation of roots and shoots were evaluated. Subsurface compaction reduced the shoot dry mass of U. ruziziensis, corn-U. ruziziensis and single corn. The U. ruziziensis and single corn plants had a reduction in the dry mass of roots in different layers of depth and in conditions of subsurface compaction. The U. ruziziensis and P. maximum grasses showed higher photosynthetic rate when growing in compacted soil. Corn was the species most sensitive to subsurface compaction, showing the greatest reduction in physiological parameters and biomass accumulation. The corn-U. ruziziensis intercrop minimizes the damage of soil compaction to maize plants. P. maximum grass is a promising species to be cultivated in compacted soils, as it demonstrates good adaptability and resistance to this condition; the U. ruziziensis is an efficient species in soils without subsurface compaction.