Aydin Enez

Rice (Oryza sativa) is a high water-demand crop, with yield strongly dependent on irrigation water availability, particularly in the semi-arid Riverina region of Australia. Enhancing the drought resilience of rice production therefore requires improved water management strategies, such as Aerobic Rice (AR) as an alternative to the traditional Continuous Flooding (CF) strategy. To better characterize AR water-saving potential, the main components of the water balance were measured under these systems. Net irrigation was measured using the Agriflo XCi ultrasonic Doppler sensor, and evapotranspiration (ET) with the LI-710 Eddy Covariance sensor. Three commercial-scale rice farms during the 2024–2025 season in the Riverina region were monitored. The analysis focused on three aspects: (i) rice crop development, (ii) water management and water balance, and (iii) rice performance and water productivity indicators. Water savings associated with AR were estimated at 18.4% in a side-by-side comparison. In addition, final harvested yield increased by 5.5%, resulting in a 29.5% increase in water productivity. ET from the AR paddock was 6.5% higher than under CF. Nevertheless, AR reduced Deep Percolation (DP) by 59.0% compared with CF. Two other CF paddocks were also monitored across the region, and water use from 13.0 to 14.5 ML ha^-1 has been observed as the baseline irrigation water requirement for permanent ponded rice paddocks in this region. These findings provide evidence that AR can deliver meaningful water savings while improving water productivity in commercial-scale rice paddocks in this semi-arid region of Riverina.

Aims: Intensive agricultural practices have led to severe soil degradation in the Central Highlands of Vietnam. Integrating legumes as cover crops is a promising strategy to restore soil fertility via biological nitrogen fixation (BNF). Arachis pintoi has been increasingly promoted in Vietnam for adoption as a cover crop but the diversity and efficiency of its native rhizobial partners remain poorly documented. This study assessed the diversity of indigenous rhizobial strains nodulating A. pintoi in the Central Highlands of Vietnam and evaluated their symbiotic efficiency and ability to support plant growth under greenhouse conditions. Methods and results: Nodule occupancy was analyzed by Restriction Fragment Length Polymorphism and 16rDNA sequencing was performed for representative strains of each group. Seven distinct profiles were found, all identified as Bradyrhizobium spp. While the diversity of rhizobia was relatively similar across both provinces, nodule occupancy varied markedly between locations. Strains from IGS 04 group dominated in Dak Lak (66.3%), whereas IGS 01 was the most prevalent group in Gia Lai (78.3%). A greenhouse trial was conducted to assess the performance of the different rhizobial groups. Inoculation significantly improved plant growth and nitrogen levels compared to uninoculated treatment. Plants inoculated with IGS 03 and IGS 06 groups exhibited the highest performance, exceeding that of the positive control. Conversely, IGS 01 and IGS 07 strains demonstrated the poorest symbiotic efficiency. Conclusions: These results highlight the critical need to select high-efficiency native strains for bioinoculants to maximize BNF potential and support the long-term sustainability of perennial agroecosystems in Vietnam.

Glyphosate-based foliar spray herbicides are the most common method for urban weed control due to their broad-spectrum and efficacy for burndown applications. As interest in glyphosate alternatives has increased in recent years, this project assessed the efficacy of the following non-glyphosate-based alternative weed management strategies: glufosinate, imazapyr, MCPA + dicamba, prodiamine, pine oil, clove oil, nonanoic acid, acetic acid + hydrochloric acid and steam against untreated (negative) controls and glyphosate-treated sites. Across all four seasonal treatments (winter, spring, summer and autumn), glyphosate and glufosinate reduced weed coverage (>65% after 4 and 12 weeks); imazapyr reduced weed coverage by >80% after 12 weeks; and steam reduced weed coverage by >80% after 4 weeks, and after 12 weeks showed to reduce weed coverage by >20% after the second application. The MCPA + dicamba, prodiamine, pine oil, clove oil, nonanoic acid and acetic acid + hydrochloric acid treatments had mixed impacts on weed coverage. Minimal alterations to soil physicochemical properties were observed across the two sites for all treatments. Assessment of impacts the different weed management strategies had on arthropod and microbial relative abundance showed minimal alterations; with only steam observed to reduce relative microbial abundance. Glufosinate, imazapyr and steam may be considered alternatives to glyphosate for reducing weed coverage but may not be as effective or have undesirable off-target effects. Overall, glyphosate provided the most consistent weed reduction at both sites over 12 weeks, without any recorded negative off-target or soil biota impacts.