Journal of Agronomy and Crop Science最新文献

Silicon (Si) has emerged as a pivotal element influencing various aspects of plant growth and development. This review explores the multifaceted effects of Si on plants, encompassing both biotic and abiotic dimensions. Si, primarily absorbed by plants in the form of orthosilicic acid, demonstrates a diverse range of roles in enhancing plant resistance to environmental stresses. Biotic stresses, including pathogen attacks and insect infestations, are notably mitigated by the deposition of Si in plant tissues, fortifying cell walls and triggering defence mechanisms. Furthermore, Si plays a crucial role in alleviating abiotic stresses such as drought, salinity and metal toxicity, imparting resilience to plants in challenging environments. The interaction between Si and plant physiology involves intricate mechanisms, impacting nutrient uptake, photosynthesis and hormonal regulation. As research in this field advances, a comprehensive understanding of the nuanced effects of Si on plants emerges, paving the way for innovative agricultural practices and the development of stress-resistant crop varieties. This review delves into the contemporary knowledge surrounding the effects of Si on plants, underscoring its significance in promoting plant resilience and sustainable agriculture.

In regions of South Asia where rainfed maize is grown, effective crop management during drought is essential for maximising yield. A variety of water-conserving planting practices are used, and more recently, techniques such as foliar supplementation to maintain nutrients during drought have also shown promise. However, specific combinations of these approaches are often untested for optimality. Here, we explore the effects of two maize planting practices (ridge sowing and mulching) to conserve water, in combination with foliar thiourea. Drought stress response of crop was assessed at two experimental sites (L-I and L-II), through split-plot design (main plots: flat sowing + mulch, flat sowing, ridge sowing + mulch [RS + M] and ridge sowing; sub-plots: unsprayed, water spray, 500 ppm thiourea and 1000 ppm thiourea). Plant performance was assessed via dry matter accumulation, grain growth rate, stomatal parameters, grain yield, stover yield and nitrogen uptake. Rainfall breaks induced three dry spells during the pre-anthesis and grain-filling period. RS + M showed maximum drought tolerance by enhancing rainwater and nutrient use (N uptake [88.1 and 115.1 kg ha⁻¹]) and recorded significantly higher periodic dry matter accumulation (149.2 and 156.8 g) along with higher 1000-grain weight (181.0 and 196.6 g), grain-filling duration (36.3 and 34.9 days) and leaf health parameters over the flat-sown treatments. Furthermore, foliar supplementation of thiourea at 1000 ppm caused improved leaf health, likely through activation of a source to sink response (transfer of energy and materials from leaves to other plant organs) that alleviated moisture stress. Ultimately, the combination of RS + M and 1000 ppm thiourea led to the highest grain yields (32.1 and 39.5 qha⁻¹).

Nitrogen (N) is crucial for crop production. Crop sequences with different legume participation affect N availability and therefore N fertiliser management. The study aimed to assess the inclusion of winter crops (WC) with different amounts of residues and different C:N ratios on the following: (i) the response to N fertilisation in the following late-maize (Zea mays L.), and to carry that comparison into a subsequent wheat crop (Triticum aestivum L.), and (ii) identify soil N indicators associated with these responses. Two field experiments (E1 and E2) were conducted in the Argentinean Pampas during two growing seasons to evaluate a WC/late-maize-wheat sequence under no-tillage. In each experiment, late-maize was sown after a bare-fallow and three WC: wheat, vetch (Vicia villosa L.) and field pea (Pisum sativum L.), where five rates of N fertilisation were evaluated. An area of late-maize that was not fertilised with N within each previous WC was used to evaluate the response to N fertilisation in the subsequent wheat crop. Indigenous N was estimated by using N uptake in the non-N-fertilised treatments. Soil N indicators and C:N ratio of WC residues were evaluated as indicators of response to N fertilisation in both crops. Significant responses to N fertilisation in grain yield and N uptake were observed in late-maize when bare-fallow and wheat were the previous treatments in both experiments. In contrast, vetch and field pea supplied 32 and 40 kg N ha⁻¹ in E1 and E2, respectively, and showed no response to N fertilisation, satisfying the N required by late-maize. However, this supply was not enough to sustain the N demand of the subsequent wheat, where the response to N addition ranged from 36% to 74% when vetch and wheat were the previous WC, respectively. Only soil inorganic N indicators were associated with indigenous N supply. Moreover, the apparent net WC effect was linked to late-maize (r² = 0.91) and subsequent wheat (r² = 0.67) grain yield response, which was also related to the C:N ratio of the WC residues in late-maize and the subsequent wheat (r² = 0.78), suggesting that mineralisation occurs when C:N ratio is below 18. Consequently, in future studies the C:N ratio of the WC residues can be included in N fertilisation recommendation schemes when late-maize is sown as a double crop in more intensified crop sequences.

Waterlogging is a critical abiotic stress increasing in importance due to more intense, erratic rainfall associated with climate change. Waterlogging leads to significant yield losses in sensitive crops, such as soybean (Glycine max [L.] Merr.). Identifying soybean genotypes and traits associated with better waterlogging tolerance is of high interest. We assessed the response of six soybean genotypes, selected from a field screening of over 190 genotypes, to 10 days of waterlogging at the R1 (onset of flowering) and R4 (grain filling) stages. We evaluated yield and its components, as well as shoot and root dry weights (DW) at the end of the waterlogging treatments and at maturity, along with morphological traits such as plant branch number, stem diameter and plant height. By integrating all these traits, a waterlogging tolerance index (WTI) was calculated for each genotype to rank their sensitivity. The WTI showed variations among genotypes from 0.61 to 0.77, indicating genotypic variation in response to waterlogging. Greater reductions in root DW compared to shoot DW were observed immediately after waterlogging. By maturity, shoot DW of waterlogged plants was more severely reduced than root DW in all genotypes. Despite similar DW losses at R1 and R4 at physiological maturity, seed number per plant and 100-seed weight responses differed between the treatments. Genotypes that performed well under control conditions suffered significant yield reductions of 70%–85% after waterlogging, mainly due to fewer fertile nodes and seeds per pod, with some also experiencing a notable decrease in 100-seed weight. In contrast, other genotypes had milder responses, with less severe reductions in seed and pod traits. Identifying breeding soybean genotypes tolerant to waterlogging during reproductive stages that maintain the number of fertile nodes and pods per node without changes in seeds per pod could significantly mitigate yield losses from waterlogging.

Waterlogging affects a high proportion of cultivated land worldwide. Sunflower, soybean and sorghum growth and yield can be affected differently depending on the moment and duration of waterlogging stress. If stress conditions occur during the critical period for yield potential definition (flowering in, sunflower and sorghum and end of pod formation in soybean) they directly reduce grain number, but if the stress occurs during the grain-filling period, grain weight would be affected. The aim of this study focuses on determining the effects of the moment and duration of waterlogging stress on the yield and its components in sunflower, soybean and sorghum. This information will be useful to understand the effects of waterlogging on yield and to choose a suitable crop or sowing date based on predicted weather conditions for a certain place. To achieve this objective, four experiments were conducted at the Experimental Station of INTA (Reconquista, Santa Fe, Argentina). The effect of the waterlogging in terms of moment (vegetative, critical and grain-filling periods) and duration (3, 7 and 10 days) on the three crops was evaluated. Sunflower expressed the most negative impact of waterlogging during the vegetative stages (26, 78 and 98% of yield losses with 3, 7 and 10 days, respectively) while soybean suffered major reductions when the stress occurred during the critical period (5%–17% of yield loses). Sorghum did not express any negative responses for the moments and durations tested. This study suggests that the critical period for a waterlogging event differs, according to crops, from the critical period cited for other stresses. Moreover, the magnitude of the damage will mainly depend on the duration of the event. Further studies are needed to elucidate different physiological responses of the species during waterlogging stress.

Heat and drought are two important constraints to global wheat productivity; understanding the genotypic responses for quality parameters under harsh production conditions (drought and heat) is very important for developing nutrient-dense wheat varieties. A set of 15 modern bread wheat (Triticum aestivum L. subsp. aestivum) and durum wheat (Triticum turgidum subsp. durum) cultivars were tested in nine environments, including three different production conditions (normal, heat and drought) during 2020–21. Genotype stability performance for yield, nutrition and quality parameters is assessed using multienvironment trials through AMMI and GGE Biplot analysis. We discovered intriguing stress dynamics in grain zinc content (Zn) and grain iron content (Fe). Under heat stress, zinc concentration increases but decreases under drought stress, while iron does the opposite. Selecting zinc, starch and kernel weight under terminal heat stress can boost yield. Protein content and yield are inversely related, making it difficult for breeders to optimise both traits. G × E interactions and stability indices across all environments have found genotypes with high-yielding stable genotypes, G12 (MP1358) (42.09 ppm) and G5 (HI1544) (42.41 ppm) have high Fe content. G12 (MP1358) (14.98%) ranked highest in protein concentration. Meanwhile, for Zn content, G11 (MACS 4058) (45.23 ppm) and G15 (WH730) (42.44 ppm) were top performers across environments. G7 (HI 1636) and G12 (MP1358) stand out as a win-win genotype for their high potential and stability in yield, protein, Zn and Fe content. Our study shows the complex relationships and possible suggestions for targeted breeding programmes under heat and drought stress conditions to improve wheat grain quality and micronutrient profiles without yield loss.

A significant basis for winter wheat production in China is the North China Plain (NCP). However, winter wheat production is severely hampered by water shortages in this area. Transpiration co-occurs with photosynthesis, affecting crop water productivity (CWP). The purpose of this experiment is to use Root Zone Water Quality Model (RZWQM2) to study actual transpiration (AT) and evaporation (AE) under different irrigation schedules and then determine its impact on grain yield and CWP. In the 2019–2022 winter wheat growing seasons, four experimental treatments were set up: no irrigation during growth period (I0), irrigation at jointing stage (I1), irrigation at jointing and anthesis stage (I2) and irrigation at jointing, anthesis and filling stage (I3), and the RZWQM2 model was calibrated and verified in this experiment. A higher yield (7840.90 kg/ha for an average of 3 years) and the highest CWP can be obtained in I2 treatment (increased by 12.72%, 5.98% and 4.28% for an average of 3 years, respectively, compared to the other three treatments). The model has a good simulation effect on soil water dynamic change and plant physiological performance of the four treatments; the model showed that irrigation increased the simulated AE and AT; however, reduced AE/actual evapotranspiration. For the whole growth period, AT in I3, I2, I1 and I0 was 351.70, 317.30, 271.50 and 223.70 mm, respectively. Especially in the late growth stage of winter wheat, the AT in I3 was 65.20 mm for an average of 3 years, which was significantly higher than I2, I1 and I0 by 31.60, 13.50 and 10.00 mm, respectively. Thus, I3 increased AT at the late growth stage of winter wheat and resulted in an increase in grain yield; however, it did not significantly increase CWP. This study demonstrated that irrigation at winter wheat jointing and anthesis stages can improve the CWP to achieve the goal of stable grain yield and water saving.

The reduction of photosynthetically active radiation impacts the growth and productivity of soybean in agroforestry and intercropping systems. Thus, this report explored the responses of 16 soybean cultivars submitted to shade levels in field conditions. Multi-faceted and relative importance analyses revealed that the steam diameter and plant height are fundamental morphological markers for selecting shade-resilient cultivars, both were high and positively correlated to yield components. Moreover, the responses to shade varied among soybean cultivars, with certain genotypes demonstrating distinct tolerance levels, which allowed also the estimative of genetic variance that revealed strong participation of genetic components in responses to shade. Multivariate and clustering analysis using steam diameter and plant height in combination with two yield components resulted in the identification of four soybean cultivars more tolerant to shade environments and two sensible. Therefore, this report provides insights into soybean cultivation under varying light conditions, provides a robust foundation for the integration of morphological and yield markers in breeding programmes focused on shade tolerance and guides future endeavours in crop improvement for optimal and sustainable yield and resilience in the climate change context.

Agriculture plays an important part in the overall growth and development of a nation. Concerns about agriculture continue to be a recalcitrant obstacle in the path of upward movement. Although agricultural yields are increased, however, low- and middle-income countries still have difficulty in producing all of the required foods with the current state of agricultural technology. Smart agriculture is becoming increasingly important to the farmers as a means of ensuring optimal field growth and higher crop yield. This systematic study analysed and briefly explained the effects of using smart agriculture techniques (SATs) from a variety of countries, including China, the United States of America, Australia, India, the Philippine Islands, South Africa, Pakistan and Iran, among others. Increased climatic change resulting in abiotic stress and other harmful effects on plants have resulted in decreased productivity under traditional agricultural practices. Stats from the literature have shown that the launching of SATs has resulted in a significant increase in cotton–wheat and rice–wheat crop yields, resultantly increased incomes of the farmers. Application of SATs, including satellite remote sensing, drones, machine learning and image processing, monitoring, wireless sensor networks, IoT–based robotics, precision agriculture and agroforestry could be extremely useful in developing intelligent agricultural systems in underdeveloped and developing countries, with improved plant growth, high crop yield and ensuring food security. These technologies could help farmers by storing additional water, spraying pesticides with drones, practicing precision agriculture and employing sensors for assessing different environmental parameters. By making efficient use of these technologies, countries could be able to increase the yield of their crops, which, in turn, will contribute to the reduction of poverty and the elimination of food insecurity.