Journal of Agronomy and Crop Science最新文献

Grain-filling rate and duration largely affect the grain-filling capacity, which determines the grain yield of maize (Zea mays L.). Nevertheless, there is little about the mechanism of how various soil mulching practices affect the leaf photosynthetic potential and subsequent grain-filling capacity of maize. Field experiments were undertaken on rainfed summer maize in northwest China under flat cultivation without mulch (FNM), flat cultivation with straw mulch (FSM), flat cultivation with transparent film mulch (FTF), flat cultivation with black film mulch (FBF), ridge-furrow cultivation with transparent film mulch (RTF) and ridge-furrow cultivation with black film mulch (RBF) in 2021 and 2022. This study explored the impact of various soil mulching patterns on soil hydrothermal condition, leaf growth, photosynthetic potential, aboveground dry matter growth and grain-filling process of rainfed maize. The dynamics of leaf area index (LAI) and grain-filling were fitted with growth equations, and the relationships of grain-filling rate, leaf area duration and LAI withering rate were quantified. The results showed that, compared with FNM, other five soil mulching practices improved soil hydrothermal condition, the maximum LAI and leaf expansion rate but reduced leaf withering rate, thereby increasing radiation interception rate (RI) at the grain-filling stage. The soil mulching practices also increased leaf SPAD value, net photosynthetic rate, photosynthetic nitrogen use efficiency and the aboveground dry matter. Compared with FNM, other five practices extended the effective grain-filling period and the active period of grain-filling, increased the maximum and mean grain-filling rates, improved the 100-kernel weight and the average kernel per ear (KPE), thereby increasing grain yields by 9.2%, 33.7%, 38.0%, 46.3% and 58.6%, respectively. The functional relationships of grain-filling rate and accumulated leaf area duration (y = a/(1 + b*exp(−kx))), and the functional relationships of grain-filling rate and LAI withering rate (y = (a + cx + ex²)/(1 + bx + dx²)) were first proposed. In conclusion, various soil mulching practices improved the soil hydrothermal condition, green leaves growth process and RI, which improved the leaf photosynthetic potential and the grain-filling capacity, thereby increasing the 100-kernel weight, KPE and grain yield. This study can help us quantitatively describe and better understand the maize grain-filling process under various mulching practices.

Maize, a cereal crop of global significance, encounters cultivation challenges in the subtropical regions of Guangxi, mainly due to variable rainfall and low soil fertility, exacerbating the effects of drought. This study evaluated the effects of irrigation and nitrogen fertilisation on overcoming these challenges and improving maize growth and yield. Between 2020 and 2021, a split-plot experiment was conducted. The main plots were assigned to two irrigation treatments: irrigated and rainfed. Within each main plot, subplots were treated with different nitrogen levels (0, 150, 200, 250 and 300 kg ha⁻¹). The results showed that nitrogen levels and water regime significantly impacted several key factors, including the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), intercellular carbon dioxide concentration (Ci), photosynthetically active radiation (PAR), carbon-metabolising enzymes and total carbon (TC) content accumulation. Under drought-like rainfed conditions, the application of nitrogen, RN300 (rainfed application nitrogen 300 kg ha⁻¹), IN250 (irrigated application nitrogen 250 kg ha⁻¹) significantly enhanced the Pn (10.0%), Tr (3.17%), Ci (3.41%) and Gs (2.6%). Additionally, PAR was significantly influenced by the water regime and nitrogen levels. Under IN250, the capture ratio (Ca) increased (2.36%), while the penetration ratio (Pe) and reflectance ratio (Re) decreased by 13.12% and 46.36%, respectively, compared to RN300. The levels of carbon metabolism enzymes (sucrose phosphate synthase and phosphoenolpyruvate carboxylase) and the TC content were higher under RN300 compared to IN250; however, these differences were not statistically significant. Path analysis revealed that thousand kernel weight had the most significant impact on yield under both water regimes. The effect was stronger under irrigated conditions, with a path coefficient of 0.647, compared to 0.459 under rainfed conditions. Correlation analysis indicated that plant height (0.938), stem diameter (0.906), ear diameter (0.928) and ear length (0.803) were positively correlated with nitrogen levels. In conclusion, maize under IN250 exhibited superior photosynthetic performance and carbon accumulation. This suggests that balanced irrigation and nitrogen management can effectively mitigate the adverse impacts of drought on maize, optimising growth and yield sustainably.

The Crop Water Stress Index (CWSI) is a widely used method for quantifying crop water status and predicting yield. However, its evaluation across different irrigation methods and its stage-specific response to crop yield is rarely evaluated. In this study, controlled field experiments were conducted on winter wheat using drip irrigation (DI) and flood irrigation (FI) during the 2021–2022 and 2022–2023 seasons in western Uttar Pradesh, India. The irrigation treatments included 50% MAD (maximum allowable depletion) (DI), 55% MAD (DI), 60% MAD (DI), 50% MAD (FI), local farmer's field replication (FI), rain-fed, and well-watered treatment (DI). The derived mean CWSI values for the irrigation treatments ranged from 0.03 to 0.66 in season 1 and 0.06 to 0.57 in season 2 across treatments. The seasonal mean CWSI for 50% MAD (DI) was 0.12 (season 1) and 0.11 (season 2), while 50% MAD (FI) yielded higher mean CWSI values of 0.29 (season 1) and 0.22 (season 2). The 50% MAD (DI) treatment produced the highest grain yield and water use efficiency in both seasons. A comprehensive analysis of stage-specific CWSI values and grain yields revealed that grain yield was more sensitive to post-heading CWSI as compared to pre-heading CWSI values. Among the growth stages, CWSI values during the flowering stage were the most critical for predicting wheat yield. The study recommends that the CWSI values in the flowering and post-heading stages are more relevant in predicting wheat yield accurately as compared to the pre-heading and seasonal mean CWSI.

Elevated CO₂ concentration (eCO₂) can modulate the response of crop plants to drought stress (DS). This study aimed to investigate the response of leaf gas exchange, chlorophyll fluorescence, antioxidant activities, osmotic adjustment substance, phytohormone and signal transduction regulatory enzymes, as well as related genes in foxtail millet to DS (water stress for 10 days), ambient condition (aCO₂, 400 μmol mol⁻¹) and eCO₂ (600 μmol mol⁻¹). eCO₂ significantly increased the net photosynthetic rate, maximum net photosynthetic rate, chlorophyll a content, transpiration rate and stomatal conductance, but did not affect leaf instantaneous water-use efficiency under DS. eCO₂ also significantly enhanced the quantum yield of Photosystem II (PSII), photosynthetic electron transport, and proportion of open PSII reaction centers under DS. Moreover, eCO₂ significantly increased abscisic acid (ABA) content, proline content, and the activities of peroxidase, superoxide dismutase, and calcium-dependent protein kinase under DS, leading to a significant reduction in malondialdehyde content. eCO₂ significantly increased the expressions of gene encoding ABA-, stress- and ripening-induced proteins and ABA-responsive element binding factor under DS. Our results clearly demonstrated the vital role of eCO₂ in mitigating the drought-induced damage over ambient CO₂ grown foxtail millet.

Rice, a staple food crop for over half of the global population, is facing a serious threat of rising temperature due to climate change, especially in the areas producing Basmati rice. The main objectives of the study were to compare the promising cultivars of Basmati rice for heat stress tolerance and to assess how elevated temperature affects leaf physiological and morphological parameters of fine rice at seedling stage. A 2-year-controlled pot experiment was carried out to evaluate how different Basmati rice varieties respond to heat stress. The experiment was carried out at the Agronomic research area, University of Agriculture Faisalabad, Pakistan, during 2022 and 2023. The design of experiment was completely randomised design (CRD) with split treatment structure and four replications. Plant morphology, leaf temperature, chlorophyll contents, relative cell injury and relative water contents were evaluated for both experimental years. Heat stress significantly affected all morphological and physiological attributes such as chlorophyll contents, relative water contents and relative cell injury across different varieties. There was variation in the behaviour of different varieties under stress conditions as compared to no heat, but from the results it was very clear that Kisan Basmati and PK-1121 Aromatic constantly showed poor performance under both conditions for all the recorded parameters. However, in almost each parameter evaluated, Basmati-515, Super Basmati and NIAB-16 exhibited Superior thermo tolerance and better performance. On the basis of observed morphological and physiological attributes, Kisan and PK-1121 Aromatic Basmati were graded as sensitive varieties, while Basmati-515, Super Basmati and NIAB-16 showed tolerance to heat stress as compared to other varieties. However, further research is needed to explore the underlying mechanisms and genetic factors contributing to the sensitivity or tolerance observed in these varieties.

Cereal crops are cultivated across diverse regions globally, facing numerous environmental challenges, with salinity posing a significant threat to their growth and productivity. Plants respond to salinity stress (SS) through various morphological and physiological mechanisms. Notably, root system architecture (RSA) has emerged as a crucial factor in aiding nutrient uptake and ensuring efficient water supply, reshaping plant responses, particularly under SS. However, assessing and visualizing RSA and growth patterns in different crops is more challenging than aboveground parts, often leading to neglect in research. Roots serve a dual role in SS: preventing Na⁺ (sodium) uptake from soil and its accumulation into shoots. This review highlights the impact of SS on remodeling RSA, encompassing phenology, cytology, and genetic regulation. It offers comprehensive insights into root architecture, functionalities, hormonal crosstalk, and agronomic strategies tailored for cereals crops. These insights aim to optimize resource capture, mitigate Na⁺ uptake—known to reduce yield in saline conditions—and explore potential avenues for engineering roots to circumvent SS.

Waterlogging during the anthesis, exacerbated by continuous rainy weather and heavy soil, has become a primary limiting factor affecting wheat yield in southern China's rice-wheat rotation regions. Previous research indicates that utilizing exogenous 6-benzylaminopurine (6-BA) can effectively alleviate the adverse effects of continuous rain on wheat yield, while the fundamental process is yet to be fully understood. In this research, two wheat varieties with contrasting waterlogging sensitivities were selected, which were exposed to waterlogging and shading for 7, 11, and 15 days after anthesis. Subsequently, three different concentrations of 6-BA solution (15, 25, and 35 mg L⁻¹) were applied through spraying. The application of 6-BA significantly increased the total soluble sugar and starch content in grains during the filling process, as well as enhanced the activities of starch synthesis-related enzymes: sucrose synthase (SuS, EC 2.4.1.13), ADP-glucose pyrophosphorylase (AGPase, EC 2.7.7.21), and starch phosphorylase (Pho, EC 2.4.1.1). Moreover, the application of 6-BA notably enhanced the transfer and transport rate for non-structural carbohydrates (NSC) in the stem and sheath. It resulted in a notable increase in the distribution ratio of dry matter in the grain, ultimately leading to higher grain weight and yield. Applying 6-BA through spraying mitigated the adverse effects of waterlogging and shading on starch accumulation and dry matter transport in grains, thereby improving grain weight. The most effective concentration in this experiment was 25 mg L⁻¹.

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.