A Semi-Systematic Review of Capillary Irrigation: The Benefits, Limitations, and Opportunities

Poly-γ-glutamic acid enhanced the yield and photosynthesis of soybeans by adjusting soil aggregates and water distribution

BACKGROUND

Poly-γ-glutamic acid (γ-PGA) is employed extensively in agriculture to enhance soil water retention; however, the underlying mechanism by which γ-PGA improves soil structure and soybean productivity in arid regions remains poorly understood. A micro-scale field experiment was conducted in the arid region of northwest China, employing five concentrations of γ-PGA to investigate its impacts on soybean yield, photosynthesis, and water-use efficiency, as well as soil aggregates and water distribution. The five levels of γ-PGA were 0 (CK), 10 (P1), 20 (P2), 40 (P3), and 80 kg ha-1 (P4).

RESULTS

The results demonstrated that the application of γ-PGA significantly improved soybean yield, photosynthesis, and chlorophyll content. It resulted in a decrease in soil aggregate content with a maximum diameter of less than 0.053 mm and an increase in the stability of soil aggregates in the uppermost layer of the soil (0-30 cm). The application of γ-PGA significantly increased soil water content, particularly in the uppermost layer of the soil, and effectively reduced water consumption and improving water use efficiency in soybeans. Overall, the P3 treatment exhibited the most pronounced improvement of soybean yield, photosynthesis, water-use efficiency, as well as distribution of soil aggregates and water. The correlation matrix heatmap also revealed a strong correlation between improvement of soybean yield or photosynthesis at various γ-PGA application levels and the enhancement of soil stability or soil water content.

CONCLUSION

The multivariate regression analysis revealed that an optimal application level of 46 kg ha-1 γ-PGA could enhance effectively both yield and water use efficiency of soybean in the arid region of northwest China. © 2024 Society of Chemical Industry.

Nitrogen deficiency tolerance conferred by introgression of a QTL derived from wild emmer into bread wheat

KEY MESSAGE

Genetic dissection of a QTL from wild emmer wheat, QGpc.huj.uh-5B.2, introgressed into bread wheat, identified candidate genes associated with tolerance to nitrogen deficiency, and potentially useful for improving nitrogen-use efficiency. Nitrogen (N) is an important macronutrient critical to wheat growth and development; its deficiency is one of the main factors causing reductions in grain yield and quality. N availability is significantly affected by drought or flooding, that are dependent on additional factors including soil type or duration and severity of stress. In a previous study, we identified a high grain protein content QTL (QGpc.huj.uh-5B.2) derived from the 5B chromosome of wild emmer wheat, that showed a higher proportion of explained variation under water-stress conditions. We hypothesized that this QTL is associated with tolerance to N deficiency as a possible mechanism underlying the higher effect under stress. To validate this hypothesis, we introgressed the QTL into the elite bread wheat var. Ruta, and showed that under N-deficient field conditions the introgression IL99 had a 33% increase in GPC (p < 0.05) compared to the recipient parent. Furthermore, evaluation of IL99 response to severe N deficiency (10% N) for 14 days, applied using a semi-hydroponic system under controlled conditions, confirmed its tolerance to N deficiency. Fine-mapping of the QTL resulted in 26 homozygous near-isogenic lines (BC4F5) segregating to N-deficiency tolerance. The QTL was delimited from - 28.28 to - 1.29 Mb and included 13 candidate genes, most associated with N-stress response, N transport, and abiotic stress responses. These genes may improve N-use efficiency under severely N-deficient environments. Our study demonstrates the importance of WEW as a source of novel candidate genes for sustainable improvement in tolerance to N deficiency in wheat.

A novel method for irrigating plants, tracking water use, and imposing water deficits in controlled environments

The study of genomic control of drought tolerance in crops requires techniques to impose well defined and consistent levels of drought stress and efficiently measure single-plant water use for hundreds of experimental units over timescales of several months. Traditional gravimetric methods are extremely labor intensive or require expensive technology, and are subject to other errors. This study demonstrates a low-cost, passive, bottom-watered system that is easily scaled for high-throughput phenotyping. The soil water content in the pots is controlled by altering the water table height in an underlying wicking bed via a float valve. The resulting soil moisture profile is then maintained passively as water withdrawn by the plant is replaced by upward movement of water from the wicking bed, which is fed from a reservoir via the float valve. The single-plant water use can be directly measured over time intervals from one to several days by observing the water level in the reservoir. Using this method, four different drought stress levels were induced in pots containing soybean (Glycine max (L.) Merr.), producing four statistically distinct groups for shoot dry weight and seed yield, as well as clear treatment effects for other relevant parameters, including root:shoot dry weight ratio, pod number, cumulative water use, and water use efficiency. This system has a broad range of applications, and should increase feasibility of high-throughput phenotyping efforts for plant drought tolerance traits.

Improving Boron and Molybdenum Use Efficiencies in Contrasting Cultivars of Subirrigated Greenhouse-Grown Pot Chrysanthemums

Fertilizer boron (B) and molybdenum (Mo) were provided to contrasting cultivars of subirrigated pot chrysanthemums at approximately 6-100% of current industry standards in an otherwise balanced nutrient solution during vegetative growth, and then all nutrients were removed during reproductive growth. Two experiments were conducted for each nutrient in a naturally lit greenhouse using a randomized complete block split-plot design. Boron (0.313-5.00 µmol L^-1) or Mo (0.031-0.500 µmol L^-1) was the main plot, and cultivar was the sub-plot. Petal quilling was observed with leaf-B of 11.3-19.4 mg kg^-1 dry mass (DM), whereas Mo deficiency was not observed with leaf-Mo of 1.0-3.7 mg kg^-1 DM. Optimized supplies resulted in leaf tissue levels of 48.8-72.5 mg B kg^-1 DM and 1.9-4.8 mg Mo kg^-1 DM. Boron uptake efficiency was more important than B utilization efficiency in sustaining plant/inflorescence growth with decreasing B supply, whereas Mo uptake and utilization efficiencies appeared to have similar importance in sustaining plant/inflorescence growth with decreasing Mo supply. This research contributes to the development of a sustainable low-input nutrient delivery strategy for floricultural operations, wherein nutrient supply is interrupted during reproductive growth and optimized during vegetative growth.

Soil and Water Management Factors That Affect Plant Uptake of Pharmaceuticals: A Case Study

Water and food security are of global concern. Improving knowledge on crops’ potential uptake of pharmaceutical compounds (PhCs) is necessary to guarantee consumer health and improve the public’s perception of reclaimed water reuse. This study aimed to determine how water management (bottom-up applied for being supplied by Subsurface Drip Irrigation) and the plant rhizosphere effect on the uptake of PhCs. Five PhCs were mixed: atenolol, carbamazepine, dicoflenac, ibuprofen and valsartan. A total of 5 treatments were considered: 3 concentrations of PhCs in agricultural volcanic soil: 0.1, 10 and 100 µg·L−1; 0.1 µg·L−1 in sterilized soil; and a blank with three plant replications at 30, 45, and 60 days after emerging. The maximum quantity of the added PhCs was 100 µg·kg soil−1. A variant of the QuEChERS method was followed to extract PhCs from samples. The limits of quantification were between 10 ng·L−1 and 100 ng·L−1 in extracts. No PhCs over the limits of detection were detected (0.06–0.6 µg·kg−1 of dry plant sample). Hence, the described water reuse methodology poses a negligible consumer risk, which contrasts with hydroponic systems in which this risk has been shown. The results are discussed in terms of the effects of irrigation system, water management and the soil-plant barrier.

How to Measure Organic Fruit Consumer Behavior: A Systematic Review

This review article seeks to systematically identify appropriate ways to measure the consumption behavior of organic fruits. The systematic review of the literature was performed according to the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the eligibility criteria were declared through the PICOS (population, interventions, comparators, outcomes, and study) tool based on 277 article records scientiometrically identified in both the Journal Citation Report databases from Web of Science. The literature review stages determined a reduced set of articles that presented valid and reliable measurement scales that covered determinant constructs in organic fruit consumer behavior (OFCB). The measurement scale with the best results reported within the screened articles covered the constructs related to health, fear, environment, effort, and economy, allowing it to serve as a reference instrument in further studies on food consumer behavior.

From plant biology research to technology transfer and knowledge extension: improving food quality and mitigating environmental impacts

Academic scientists face an unpredictable path from plant biology research to real-life application. Fundamental studies of γ-aminobutyrate and carotenoid metabolism, control of Botrytis infection, and the uptake and distribution of mineral nutrients illustrate that most academic research in plant biology could lead to innovative solutions for food, agriculture, and the environment. The time to application depends on various factors such as the fundamental nature of the scientific questions, the development of enabling technologies, the research priorities of funding agencies, the existence of competitive research, the willingness of researchers to become engaged in commercial activities, and ultimately the insight and creativity of the researchers. Applied research is likely to be adopted more rapidly by industry than basic research, so academic scientists engaged in basic research are less likely to participate in science commercialization. It is argued that the merit of Discovery Grant applications to the Natural Sciences and Engineering Research Council (NSERC) of Canada should not be evaluated for their potential impact on policy and (or) technology. Matching industry funds in Canada rarely support the search for knowledge. Therefore, NSERC Discovery Grants should fund basic research in its entirety.

Allotments in the Future: Building Resilience to Climate Change through Improved Site Design and Efficient Water Practices

In recent years, there has been a resurgence in the popularity of allotments and home- grown food in the UK. This interest is likely to increase as people become more aware of the health benefits of spending time outdoors. Climate projections for the UK indicate that over the next 20 years, winters will become warmer and wetter, and the summers hotter and drier. Most UK allotments and community gardens are a collection of individual plots whose holders are free to manage them as they wish, within site rules. The efficacy of individual efforts to collect and store rainwater is often limited as most allotment sites were laid out when water practices were a secondary consideration. Our research, which included visiting allotment sites and reviewing growing practices, suggests that grouping plots and sharing water facilities could enable plot holders to store sufficient water to meet anticipated demand for thirty rain-free days in midsummer. This combined with growing practices that improve soil moisture capacity and water use efficiency will provide effective mitigation against climate change.

Pozzolan Based 3D Printing Composites: From the Formulation Till the Final Application in the Precision Irrigation Field

A new eco-composite polymer for material extrusion fabrication based on fine fraction pozzolan waste was developed. In addition, the composite materials obtained were used to produce a self-watering pot with complex geometry and a permeable porous part to regulate the passage of water from the storage area to the roots of the plant. Moreover, the system was devised with a cover characterized by a UV-B barrier film. The results have shown the possibility of the 3D printing of complex geometric parts as microporous structures or thin films using a composite based on poly lactic acid (PLA) and pozzolan. The pozzolan has an effect of reinforcement for the composite and at the same time improves the cohesion between the layers of the part during printing.