Context. Intercropping of cereal–legume forages with integrated nutrient management could be an effective agronomic strategy to increase forage biomass production and economic returns. However, the energy-carbon footprints of the management strategies are of utmost importance in the present era of climate-conscious agriculture.

Aim. To identify the best possible combinations of fodder-based cropping patterns and nutrient management with higher yield and profitability with lower energy-carbon footprints.

Methods. This field study was carried out with four fodder-based cropping patterns under different nutrient management options in a split-plot design.

Key results. The maize (Zea mays) + cowpea (Vigna unguiculata) (1:1)–oats (Avena sativa) under 75% recommended fertiliser dose with zinc, plant growth promoting rhizobacteria and farmyard manure significantly increased system productivity and profitability and saved fertiliser by 25% compared to the same with 100% recommended dose only. In comparison to maize–oats, this combination showed lower energy and carbon footprints, but higher system productivity and profitability. The system yield and net returns of this combination were significantly higher than those of cowpea–oats cropping pattern, despite having a higher energy-carbon footprint.

Conclusions. The 1:1 cereal–legume intercropping-based cropping pattern maize + cowpea (1:1)–oats under 75% recommended dose of N, P₂O₅, K₂O with zinc, plant growth promoting rhizobacteria and FYM could be the most productive, profitable fodder-based cropping pattern with lower energy-carbon footprints in north-west India.

Implications. The study identified the most profitable combination of fodder-based cropping patterns and nutrient management with low energy and carbon footprints in north-west India, which could be a component of climate-smart agriculture in similar agro-climates of the globe.

Context. Rice (Oryza sativa) panicle provides important information to improve production efficiency, optimise resources, and aid in successful breeding of high-performing rice varieties.

Aims. In order to efficiently count rice panicles, a rice panicle recognition model based on YOLOv5s-Slim Neck-GhostNet was evaluated.

Methods. We used the developmental stages from heading to maturity as the time period to collect data for testing and validating the model. The GSConv convolution module from the YOLOv5 (You Only Look Once) model was compared with the original Conv convolution. We improved the original C3 module and replaced it with VoVGSCSP module, which further enhanced the detection ability of the model for small targets, such as rice panicles. To further optimise the performance of the model and reduce the computational complexity, we replaced the original backbone network of the model with a lightweight and efficient GhostNet structure.

Key results. Our results showed that the precision of the test set was 96.5%, the recall was 94.6%, the F1-score was 95.5%, and the mAP@0.5 was 97.2%. Compared with the original YOLOv5s model, mAP@0.5 increased by 1.8%, and the model size is reduced by 5.7M.

Conclusions. The improved YOLOv5 model had increased capability to detect and count rice panicles in real time. Our method reduced the size of the model while maintaining an acceptable level of accuracy.

Implications. The technology provides an intelligent and automated solution to better monitor rice panicle development, and has the potential for practical application in agricultural settings.

Context. Salinity is one of the major abiotic stresses challenging alfalfa (Medicago sativa) production.

Aims. In this study, we evaluated the potential of nano-sized chitosan-proline (NsCP) seed priming and biochar application to enhance salt tolerance in alfalfa.

Methods. Seeds of two alfalfa genotypes (OMA-84, salt-sensitive; and OMA-285, salt-tolerant) were soaked for 18 h in aerated distilled water (hydropriming) or a solution of NsCP (100 mM) for seed priming. Seeds were then planted in plastic pots containing acid-washed pure sand supplemented with or without biochar (25 g kg⁻¹ sand) and with or without salt stress (120 mM).

Key results. Both genotypes showed significant reduction in root and shoot growth, biomass production, and carbon assimilation under salinity stress, with more pronounced effects on OMA-84. However, applying both NsCP seed priming and biochar significantly improved the biomass production and plant photosynthetic assessment traits. Notably, this combined approach proved more effective in enhancing salt tolerance than individual treatments. Biochar amendment increased the Na⁺ and Cl⁻ concentration but it also contributed to salt tolerance by elevating K⁺ level, promoting proline accumulation, and antioxidant activities.

Conclusions. NsCP seed priming enhanced the salinity stress tolerance in alfalfa genotypes by facilitating osmotic adjustment (proline accumulation), maintaining ionic homeostasis (higher K⁺ and lower Na⁺ concentration), and increasing the levels of α-tocopherol, flavonoids, and the activities of antioxidant enzymes.

Implications. Integrated application of NsCP and biochar significantly enhanced salt tolerance in alfalfa, demonstrating practical strategies for sustainable agriculture in saline environments by promoting ionic homeostasis, osmotic adjustment, and antioxidant defence mechanisms.

Context. Unmanned aerial seeding (UAS) of rice (Oryza sativa) has inherent advantages, but may not achieve a high and stable yield when extensive stubble is returned.

Aims. This study aimed to determine the optimal planting density for achieving high yield and lodging resistance in UAS rice.

Methods. The experiment evaluated yield and lodging of two rice varieties (conventional japonica and hybrid indica–japonica) at four planting densities 105 (D1), 150 (D2), 195 (D3), and 240 (D4) seedlings m⁻² for conventional japonica; 45 (D1), 82.5 (D2), 120 (D3), and 157.5 (D4) seedlings m⁻² for hybrid indica–japonica).

Key results. Our results showed that yield initially increased and then decreased with increasing density, and the highest yield was obtained under treatment D3. Increasing planting density increased the proportion of main stem panicles and the effective panicles, but decreased the number of grains per panicle, seed setting rate, and 1000-grain weight. The population growth rate was lower in seeding-jointing and heading-maturity stages for treatments D1 and D2, higher in seeding-jointing stage for treatment D4 but insufficient in subsequent stages, while treatment D3 had higher population growth rate throughout the whole growth stage, especially in heading-maturity stages, ultimately achieving high yield. Densification led to a reduction in plant height and ear length, as well as slender internodes and thinner base wall.

Conclusions. A planting density of 195 seedlings m⁻² was optimal for conventional japonica rice, and 120 seedlings m⁻² for indica–japonica.

Implications. Achieving high yield of UAS rice can be facilitated by increasing planting density, but may compromise lodging resistance.

Context. Yellow dwarf viruses (YDVs) form a complex of economically important pathogens that can significantly reduce grain yield in cereals. Mixed infections, or infection with two or more YDV species, can be particularly damaging.

Aims. We aimed to examine the proportion of single and multiple virus infections present in symptomatic cereal and grass plants in Victoria, south-eastern Australia.

Methods. Over 3 years (2020–2022), symptomatic cereal and grass plants from within and around cereal fields in Victoria, Australia were individually tested using tissue-blot immunoassay (TBIA) for barley yellow dwarf virus PAV, barley yellow dwarf virus MAV, cereal yellow dwarf virus RPV, wheat streak mosaic virus, and with a generic TBIA test that can detect multiple luteovirus and/or polerovirus species.

Key results. Across 2020–2021, 34% of virus-positive plants were infected with multiple YDV species. The proportion of mixed infections was similar in each individual year. However, higher proportions of wheat (Triticum aestivum, 47%) and wild oat (Avena fatua, 36%) plants were infected with multiple YDV species compared to barley (Hordeum vulgare, 8%) and brome grass (Bromus spp.,17%).

Conclusions. The proportion of virus-positive plants infected with multiple YDV species found was almost four times higher than previously reported in a similar study in Victoria, Australia in 1985. The proportion of plants infected with multiple YDV species varied more with host type than between individual years.

Implications. These findings demonstrate the complex epidemiology of these damaging viruses, and the challenges associated with developing virus-resistant cereal cultivars, while also highlighting the importance of regular surveillance over multiple years.

Context. The Gran Chaco is a livestock producing region of Argentina with several under-utilised legume forage genetic resources, including species from the genus Macroptilium.

Aims. We aimed to generate reliable characterisation and selection schemes in germplasm of Macroptilium for biological nitrogen fixation with native rhizobia, and evaluate the germplasm variability for initial growth and nodulation capacity with native soil of subtropical environment.

Methods. The trial evaluated 20 accessions of four Macroptilium species with or without added nitrogen. The variables were analysed through a nested ANOVA with the factor species, accessions nested within species, nitrogen level, and the corresponding interactions. Relationships between variables and accessions were examined using principal component analysis.

Key results. There was variability in the symbiotic response and initial growth, and most of the variance was explained by differences between species. Nodulation capacity was related with biological nitrogen fixation, since the accessions with higher nodule number and nodule weight showed higher initial growth and higher crude protein content in shoot.

Conclusions. We found variability for nodulation capacity associated with biological nitrogen fixation within the evaluated germplasm of Macroptilium. In relation to effectiveness, five of 20 accessions evaluated were classified as effective.

Implications. Our breeding approach could contribute to develop native legume forage cultivars with better symbiosis with native rhizobia, which would reduce implantation costs and reduce the use of chemical nitrogen fertilisers.

Context. Lithium (Li) is an essential trace element for human health. Although the biofortification of rice (Oryza sativa) with Li is a promising strategy to overcome its deficiency, little is known about its biological activity in plants.

Aims. We determined the effect of sources and doses of Li applied via the leaves on the biofortification, physiological components, and production of irrigated rice.

Methods. The experimental design consisted of randomised blocks in a 5 × 3 factorial arrangement, with four replicates. The factors consisted of five doses of Li (0, 50, 100 150, and 200 g ha⁻¹) and three sources (lithium sulfate, Li₂SO₄·H₂O; lithium hydroxide, LiOH·H₂O; and lithium chloride, LiCl).

Key results. Regardless of the source used, foliar application of Li allowed bioaccumulation in rice grains without influencing the development and grain yield of the crop. Supplying Li to rice plants in the form of Li₂SO₄·H₂O increased the photosynthetic rate and water use efficiency. Moreover, regardless of the source used, the consumption of rice grains biofortified with Li at a dose of 200 g ha⁻¹ can supply more than 50% of the minimum recommended daily intake of the element.

Conclusions. Foliar spraying of Li is effective for agronomic biofortification of rice.

Implications. Biofortification of rice with Li can contribute to reducing its deficiency in naturally poor regions.