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Soil organic carbon is critical to reducing anthropogenic CO2 emissions, highlighting the importance of carbon sequestration on agricultural lands. No-till agricultural practices have been shown to be effective in improving soil quality and sequestering carbon, thereby supporting global efforts to mitigate climate change. Based on the edaphoclimatic conditions of the region, five reference areas were selected, with different characteristics in terms of conditions (A1, A2, A3, A4, and A5) in 5 different farms in the municipality of Rio Verde, GO, Brazil. Soil and biomass samples left by the crop after harvest were collected. These areas represent 3 priority management systems in the Cerrado region of central Brazil, namely: no-till with soybean and maize in sequence in a rainfed system; no-till with soybean and maize in sequence in a central pivot irrigation system; first cut sugar cane; second cut sugar cane.In October 2022, 15 points per area were sampled for soil carbon stock estimation and for chemical and physical characterization purposes along linear transects. Transect sampling approach is widely used in soil attributes studies for comparison and data collection. Biomass samples were used to estimate soil biomass accumulation and carbon stock indices. The physic-chemical parameters of the soil in each area were determined through a complete analysis of the 0–20 cm profile. By presenting a new dataset of soil organic carbon stocks and carbon credits from several long-term no-till areas in central Brazil, this article contributes to the knowledge of the potential of conservation management systems for carbon trading, providing insights into their current contributions and future modelling.

Raphanus sativus L. is a potential source of raw material for biodiesel fuel due to the high oil content in its grains. In Brazil, this species is cultivated in the low rainfall off-season, which limits the productivity of the crop. The present study investigated the effects of water restriction on the physiological and biochemical responses, production components, and oil quality of R. sativus at different development stages. The treatments consisted of 100% water replacement (control), 66%, and 33% of field capacity during the phenological stages of vegetative growth, flowering, and grain filling. We evaluated characteristics of water relations, gas exchange, chlorophyll a fluorescence, chloroplast pigment, proline, and sugar content. The production components and chemical properties of the oil were also determined at the end of the harvest cycle. Drought tolerance of R. sativus was found to be mediated primarily during the vegetative growth stage by changes in photosynthetic metabolism, stability of photochemical efficiency, increased proline concentrations, and maintenance of tissue hydration. Grain filling was most sensitive to water limitation and showed a reduction in yield and oil content. However, the chemical composition of the oil was not altered by the water deficit. Our data suggest that R. sativus is a drought-tolerant species.

Climate change has emerged as a challenge for soybean cultivation around the world, stimulating the development of technological alternatives that aim to mitigate the damage caused by water deficit. From this perspective, algae extract-based biostimulants have been tested to reduce water stress in several crops, but little is known about their effects on soybean. Thus, we hypothesize that a commercial biostimulant based on Ascophyllum nodosum can improve the physiological performance and water relations of Glycine max plants subjected to water deficit. To test this hypothesis, we set up an experiment in controlled conditions in a greenhouse, considering five treatments (control; application of biostimulant; water deficit (WD); WD + application of biostimulant; and WD + split application of biostimulant). The experiment was designed in completely randomized blocks with four replications per treatment and conducted in polyethylene pots containing 10 L of soil and three plants per pot. The irrigation was carried out daily; the water deficit was 50% soil moisture at field capacity, starting at the R1 stage (beginning of flowering, where there is at least one flower open at any node on the plant) and maintained for ten days. The biostimulant was applied concurrently with the onset of water deficit. We confirmed the hypothesis that foliar application of 1.0 L ha−1 of the biostimulant reduces the deleterious effects of the common water deficit at the beginning of the reproductive stage of soybean through the reduction of damage from oxidative stress (reduction of malondialdehyde synthesis by 31.2% in relation to the WD plants), maintenance of water potential and cellular homeostasis (10.2% increase in relative water content when compared with WD plants), and conservation of the contents of chlorophyll in leaves and stimulation of photosynthesis and carboxylation (68% increase in net photosynthetic rate and 49.3% increase in carboxylation efficiency in relation to WD plants). However, when applied in installments, the biostimulant was not efficient in reducing soybean water stress. Therefore, we conclude that the application of a biostimulant based on A. nodosum can help reduce the harmful effects of water deficit on soybean plants, opening up perspectives for the mass use of this extract in agricultural crops produced on a large scale.

Hymenaea courbaril L. is a fruit species widely distributed throughout the Neotropics and possibly tolerant to a range of environmental variations, including adaptation to dry soils. Therefore, we hypothesized that growth-promoting microorganisms isolated from the roots and rhizosphere of this plant affect its resistance to water suppression. We aimed at testing our hypothesis by biopriming the seeds of this species using microorganisms previously tested for the expression of functional traits associated with growth promotion, followed by cultivating this plant under a water deficit regime for three months. The inoculation effect was evaluated in terms of growth parameters, photosynthetic pigments, photochemical performance, and gas exchange. Bacteria, particularly isolates of Bacillus cereus, B. thuringiensis, and Paenibacillus alvei, were more effective than fungi in promoting growth in H. courbaril L. under water suppression. However, the inoculation treatments with B. thuringiensis and Curvularia intermedia minimized the water deficit-induced photochemical damage, with the observed values being similar to or higher than those observed in irrigated plants. In general, microbial inoculation increased the photosynthetic rate and stomatal conductance in leaves, and the C. intermedia and B. thuringiensis inoculation induced the rates of net assimilation and carboxylation efficiency that also exceeded the average observed in irrigated plants. These microorganisms potentially assist H. courbaril L. in its dispersal through water-poor soils and, based on the plant growth-promoting rhizobacterial effect observed in B. thuringiensis, could be applied in agriculture as stress reducers and growth promoters. Aiming the future production of inoculants, we indicate the use of B. thuringiensis and C. intermedia, however, we suggest that phytopathogenicity studies are previously carried out with this endophytic strain of C. intermedia. Alternatively, this work showed the expression of phytopathogenic traits by the rhizospheric fungus Penicillium shearii, possibly stimulated by drought stress conditions.

Background Previous studies have shown that Crambe abyssinica and Raphanus sativus are physiologically tolerant to water deficits; however, there is a lack of information on the mechanisms responsible for their tolerance regarding root morphological characteristics. This study aimed to characterize morphological changes in the root system of C. abyssinica and R. sativus subjected water deficit, as well as to identify the responses that improve tolerance and post-stress recovery capacity of these plants. Methods Independent experiments for each specieswere performed in a controlled greenhouse, where plants were randomly set in a randomized block design with five replicates. Plants of C. abyssinica and R. sativus were cultivated in pots and exposed to well-watered treatment (WW; 90% water holding capacity–WHC of the substrate) or water deficit (WD; 40% WHC) conditions, at 28 days after planting. The plants were kept under WD for 7, 14, or 21 days with rehydration soon after each episode of water deficit. Assessment of water relations, biomass allocation, leaf and root system morphological characteristics and gas exchange were performed after each period of water deficit and 48 h after rehydration. Results The water deficit reduced the water status of both species, and morphological and biomass allocation were not recovered after rehydration. Photosynthesis of C. abyssinica decreased with prolonged water deficit, which was also not recovered after rehydration. In R. sativus, photosynthesis was not altered by WD for 21 days, and a higher WUE was recorded. Root morphology of R. sativus was mainly affected at 14 days of WD, while the traits related to very fine roots increased at 21 days of WD, when compared to WW plants. Thus, R. sativus has shown greater tolerance to water deficits mainly due to the presence of very fine roots throughout the period of stress, when compared to C. abyssinica in which the fine roots predominated.

Changes in plant metabolism due to water deficit combined with other stresses, such as high irradiance and high temperatures, cause damage to the physiology and development of crops, which can lead to significant yield losses. The aim of this study was to determine the potential of potassium phosphite (PP) to induce tolerance to water deficit combined with high irradiance in soybean plants. The experiment was carried out in an acclimatized growth chamber. Soybean plants, upon reaching the R1 developmental stage, received the following treatments: PP application (0 L ha−1–control; 0.6 L ha−1 PP; and 1.2 L ha−1 PP), two levels of PAR irradiance (650 µmol m−2 s−1–control; and 1500 µmol m−2 s−1–high irradiance (HI)), and three water availability levels (90% of field capacity (FC), and water deficit at 40% FC and 50% FC). The treatments were maintained for 12 days. The PP increased the photosynthetic rate of plants submitted to a dosage of 1.2 L ha−1 and stresses of 50% FC + HI. PP also decreased the intensity of lipid peroxidation, and rate of electrolyte leakage, which suggests stability of cell membranes. These responses may have occurred due to the activation of the antioxidant enzymes superoxide dismutase and peroxidase. Furthermore, the application of PP increased the proline concentrations, suggesting osmotic adjustment in response to stress. These results provide the first record of PP-induced tolerance in plants under combined water and HI stresses. PP proves to be a potential alternative method to reduce the harmful effects caused by the combined stresses of water deficit and high irradiance in soybean.