Alternate wetting and drying irrigation (AWD) has been shown to decrease water use and trace gas emissions from paddy fields. Whereas genotypic water use shows little variation, it has been shown that rice varieties differ in the magnitude of their methane emissions. Management and variety‐related emission factors have been proposed for modelling the impact of paddy production on climate change; however, the magnitude of a potential reduction in greenhouse gas emissions by changing varieties has not yet been fully assessed. AWD has been shown to affect genotypic yields and high‐yielding varieties suffer the greatest loss when grown under AWD. The highest yielding varieties may not have the highest methane emissions; thus, a potential yield loss could be compensated by a larger reduction in methane emissions. However, AWD can only be implemented under full control of irrigation water, leaving the rainy seasons with little scope to reduce methane emissions from paddy fields. Employing low‐emitting varieties during the rainy season may be an option to reduce methane emissions but may compromise farmers’ income if such varieties perform less well than the current standard. Methane emissions and rice yields were determined in field trials over two consecutive winter/spring seasons with continuously flooded and AWD irrigation treatments for 20 lowland rice varieties in the Mekong Delta of Vietnam. Based on the results, this paper investigates the magnitude of methane savings through varietal choice for both AWD and continuous flooding in relation to genotypic yields and explores potential options for compensating farmers’ mitigation efforts.

Soybean Glicine max. (L.) Merr. is one of the most major food crops. In some areas, its responses to different climates have not been well studied, particularly in tropical countries where other crops are more dominant. Accordingly, we adopted the SIMPLE crop model to investigate the responses of soybeans to the climate. We conducted two experiments on crop growth in the Summer–Autumn season of 2020, and Winter–Spring 2021 in the Hoa Binh Commune, in the Mekong Delta, Vietnam, which is an area that is vulnerable to climate change impacts, to obtain data for our model input and assessment. The assessment was concerned with the effects of climate variables (temperature and CO₂) on soybean biomass and yield. The results indicated that the SIMPLE model performed well in simulating soybean yields, with an RRMSE of 9–10% overall. The drought stress results showed a negative impact on the growth and development of soybeans, although drought stress due to less rainfall seemed more serious in Spring–Winter 2021 than in Summer–Autumn 2020. This study figured out the trend that higher temperatures can shorten biomass development and lead to yield reduction. In addition, soybeans grown under high CO₂ concentrations of 600 ppm gave a higher biomass and a greater yield than in the case with 350 ppm. In conclusion, climate variance can affect the soybean yield, which can be well investigated using the SIMPLE model.

Alternate wetting and drying irrigation (AWD) is a promising technique that has been tried across Southeast Asia to reduce water consumption and methane emissions in irrigated rice cultivation. The study conducted in the upper Vietnamese Mekong Delta compared the effectiveness of plant growth, yield components, and yield under three different water application regimes: the treatments of community AWD (AWD_C), household individually (AWD_H), and continuous flooding (CF) with the expectation to explore the ability to use water effectively in rice cultivation. The results showed no significant difference in water use between the three treatments. However, there was a considerable difference in coefficient of variation value (CV); the CV value of the water column in the AWD_C (1.32%) was a significant difference from that of AWD_H (0.87%) and CF (0.89%). The mean chlorophyll content, the yield, and the weight of 1,000 grains of the AWD_H treatment were significantly higher than that of the other two treatments. In another aspect, the water productivity of the AWD_H treatment was the highest (0.66 kg/m3), a statistically significant difference compared to the AWD_C and CF (0.37; 0.33 kg/m3). In conclusion, the AWD_H shows efficiency in leaf chlorophyll content, 1,000-grain weight, yield, and water productivity. The AWD_C is inferior to the AWD_H due to the large variation of field elevation. It is noted that field elevation is critical to the technique’s success in being applied on a large scale.

Light-emitting diodes (LEDs) show promise as a radiation source for intensive crop cultivation systems, especially for vegetables in the greenhouse. Regarding mustard greens, most studies have investigated the effects of LED lights at the seedling stage under chamber conditions for microgreens not addressed throughout their growing period up to harvest. Therefore, this study is focused to evaluate the effect of additional LED lighting time from 6 pm on the growth, yield and quality of mustard greens under a greenhouse in Kien Giang province as a typical tropical region. The experiment was arranged in a completely randomized design with 3 replications, from August 1st to September 18th, 2023. Four treatments: AL0, AL2, AL4 and AL6 correspond to lighting durations of 0, 2, 4 and 6 h of LED light, which includes a combination of 3 white lights: 1 pink light, 58 μmol·m−2·s−1 PPFD, and a Blue (18 %): Green (41 %): Red (41 %) ratio. Results showed that AL4 had the most significant positive impact on mustard plant growth, with higher dry and fresh weight, plant height, leaf width and length. However, AL6 inhibited most parameters except leaf number. Additionally, under AL4 conditions, mustard allocated more biomass to leaves, while those under AL6 conditions allocated more biomass to stems. In terms of quality, LED lighting duration negatively influenced protein content. For instance, AL0 showed the significantly greatest protein value (2.87 ± 0.08 g·kg−1) compared to others. Apart from AL0, AL6 had a considerably higher value of protein content (2.58 ± 0.2 g·kg−1) compared to AL2 (1.74 ± 0.04 g·kg−1) and AL4 (2.17 ± 0.07 g·kg−1). The additional durations of LED lighting influenced mature mustard greens’ morphology, physiology and quality, providing valuable scientific information for improving vegetable quality and quantity in tropical zones. HIGHLIGHTS 4 hours of additional LED light had the most significant positive impact on mustard plant growth, with higher dry and fresh weight, plant height, leaf width, and length. Additionally, leaf number increased under 6 hours of additional LED light. Under 4 hours of additional LED light, mustard allocated more biomass to leaves, while those under 6 hours of additional LED light allocated more biomass to stems. Lighting with LED resulted in a lower protein value, and different durations of LED lighting resulted in varying protein content values. GRAPHICAL ABSTRACT

Magnaporthe oryzae-induced rice blast remains a critical threat to sustainable rice farming, causing extensive losses in many rice-producing regions worldwide. Due to increasing concerns about pesticide overuse and its impact on the environment and human health, alternative control methods are being actively explored. Nanotechnology has recently gained attention as a potential tool for sustainable disease management. This review summarises current progress in the use of nanomaterials—including metal and biopolymer nanoparticles, nanoemulsions, targeted delivery systems, and biosensors—for the detection and control of rice blast. Studies have reported that nanomaterials can reduce disease severity by up to 70% and improve rice yield by 10–20% under field or greenhouse conditions. The mode of action, effectiveness under field conditions, and possible integration into integrated pest management (IPM) programs are discussed. The selection of literature followed the PRISMA-P framework to ensure a systematic and transparent review process. Challenges such as biosafety, environmental risks, and regulatory issues are also addressed, with emphasis on green synthesis methods and the need for field validation before practical application.