Bernard Dell

Quinoa (Chenopodium quinoa Willd.) has gained worldwide recognition for its nutritional values, adaptability to diverse environments, and genetic diversity. This review explores the current understanding of quinoa tolerance to environmental stress, focusing on drought, salinity, heat, heavy metals, and UV-B radiation. Although drought and salinity have been extensively studied, other stress factors remain underexplored. The ever-increasing incidence of abiotic stress, exacerbated by unpredictable weather patterns and climate change, underscores the importance of understanding quinoa’s responses to these challenges. Global gene banks safeguard quinoa’s genetic diversity, supporting breeding efforts to develop stress-tolerant varieties. Recent advances in genomics and molecular tools offer promising opportunities to improve stress tolerance and increase the yield potential of quinoa. Transcriptomic studies have shed light on the responses of quinoa to drought and salinity, yet further studies are needed to elucidate its resilience to other abiotic stresses. Quinoa’s ability to thrive on poor soils and limited water resources makes it a sustainable option for land restoration and food security enterprises. In conclusion, quinoa is a versatile and robust crop with the potential to address food security challenges under environmental constraints.

Climate warming impacts soil nitrogen cycling in forest ecosystems, thus influencing their productivity, but this has not yet been sufficiently studied. Experiments commenced in January 2012 in a subtropical Castanopsis hystrix Hook. f. and Thomson ex A. DC. plantation and in May 2011 in a temperate Quercus aliena Blume forest, China. Four treatments were established comprising trenching, artificial warming (up to 2 °C), artificial warming + trenching, and untreated control plots. The plots were 2 × 3 m in size. In 2021 and 2022, soil nitrogen mineralization, soil nutrient availability, fine root biomass and microbial biomass were measured at 0–20 cm soil depth in 6 replicate plots per treatment. Warming significantly increased soil temperature in both forests. In the C. hystrix plantation, warming significantly increased available phosphorus (AP) and fine root biomass (FRB), but it did not affect soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP) and their ratios. Warming depressed the net mineralization rate (NMR) and net ammonification rate (NAR) of the C. hystrix plantation, probably because the competition for nitrogen uptake by fine roots and microorganisms increased, thus decreasing substrates for nitrogen mineralization and ammonification processes. Trenching and warming + trenching increased the net nitrification rate (NNR), which might be related to decreased NH4+-N absorption of trees in the trenched plots and the increased microbial activity involved in soil nitrification. In the Q. aliena forest, warming significantly increased NH4+-N, MBC/MBN, Root C/N, Root N/P, and decreased pH, MBN, MBN/MBP and Root P; and there was no effect of trenching. Notably, the NAR, NNR and NMR were largely unaffected by long-term warming. We attributed this to the negative effect of increasing NH4+-N and decreasing MBN/MBP offsetting the positive effect of soil warming. This study highlights the vulnerability of subtropical forest stands to long-term warming due to decreased soil N mineralization and increased NO3−-N leaching. In contrast, the soil N cycle in the temperate forest was more resilient to a decade of continuous warming.

Cinnamon tree (Cinnamomum cassia), ironwood tree (Erythrophleum fordii), African mahogany (Khaya senegalensis) and kassod tree (Senna siamea) are grown in large numbers in urban areas in Vietnam. However, there is mounting concern for the viability of these tree species due to recent tree mortality. We described a new disease causing stem cankers, discolored wood, wilting and tree death in urban areas and forest plantation parks. From β-tubulin gene sequencing, we concluded that Ceratocystis fimbriata is causing disease in C. cassia, E. fordii, K. senegalensis and S. siamea in Hanoi, Vietnam. Fungal isolates were shown to be pathogenic on seedlings of these four host plants in a nursery trial. Cankers on trees were associated with wounding caused by humans, insects or animals. To minimize further damage, wounding should be limited and appropriate management solutions should be identified, especially for old trees.

In most agricultural fields, when soil pH is high, elemental sulfur or sulfuric acid are used to reduce soil pH and increase the availability of macro and micronutrients for optimum crop yield. However, how these inputs impact soil greenhouse gas emissions is unknown. This study aimed to measure the amount of greenhouse gas emissions and pH after the application of various doses of elemental sulfur (ES) and sulfuric acid (SA). Using static chambers, this study quantifies soil greenhouse gas emissions (CO2, N2O, and CH4) for 12 months after the application of ES (200, 400, 600, 800, and 1000 kg ha−1) and SA (20, 40, 60, 80 and 100 kg ha−1) to a calcareous soil (pH 8.1) in Zanjan, Iran. Also, in order to simulate rainfed and dryland farming which are common practices in this area, this study was conducted with and without sprinkler irrigation. Application of ES slowly decreased soil pH (more than half a unit) over the year whereas application of SA temporarily reduced the pH (less than a half unit) for a few weeks. CO2 and N2O emissions and CH4 uptake were maximum during summer and lowest in winter. Cumulative CO2 fluxes ranged from 1859.2 kg−1 CO2-C ha−1 year−1 in the control treatment to 2269.6 kg CO2-C ha−1 year−1 in the 1000 kg ha−1 ES treatment. Cumulative fluxes for N2O-N were 2.5 and 3.7 kg N2O-N ha−1 year−1 and cumulative CH4 uptakes were 0.2 and 2.3 kg CH4-C ha−1 year−1 in the same treatments. Irrigation significantly increased CO2 and N2O emissions and, depending on the amount of ES applied, decreased or increased CH4 uptake. SA application had a negligible effect on GHGs emissions in this experiment and only the highest amount of SA altered GHGs emissions.

In the context of climate change, the occurrence of water stress in forest ecosystems, which are solely dependent on precipitation, has exhibited a rising trend, even among species that are typically regarded as drought-tolerant. Remote sensing techniques offer an efficient, comprehensive, and timely approach for monitoring forests at local and regional scales. These techniques also enable the development of diverse indicators of plant water status, which can play a critical role in evaluating forest water stress. This review aims to provide an overview of remote sensing applications for monitoring water stress in forests and reveal the potential of remote sensing and geographic information system applications in monitoring water stress for effective forest resource management. It examines the principles and significance of utilizing remote sensing technologies to detect forest stress caused by water deficit. In addition, by a quantitative assessment of remote sensing applications of studies in refereed publications, the review highlights the overall trends and the value of the widely used approach of utilizing visible and near-infrared reflectance data from satellite imagery, in conjunction with classical vegetation indices. Promising areas for future research include the utilization of more adaptable platforms and higher-resolution spectral data, the development of novel remote sensing indices with enhanced sensitivity to forest water stress, and the implementation of modelling techniques for early detection and prediction of stress.

Payments for carbon services (C-PFES) is a mechanism used to meet national emission reduction targets via either forest protection or reforestation. However, while carbon is a unique environmental service traded in national and international markets, there are challenges in implementing C-PFES schemes at the local level. Simply put, the views of local participants who will undertake the abatement activities have not been considered. By analysing at the local level the views of potential sellers, potential buyers and intermediaries, this paper investigated the feasibility of applying C-PFES for mangroves in Ca Mau province, Vietnam. While local stakeholders had a strong understanding of the likely impacts of climate change on their production and were aware of the environmental roles of mangroves, the carbon sequestration capacity of mangroves was rarely mentioned, and this will be a challenge in implementing a C-PFES scheme. While potential sellers and intermediaries showed strong support for C-PFES, potential buyers were less likely to join the scheme. As the carbon sequestration capacity of mangroves can also be purchased by international entities, it is recommended that the scope of the current Vietnamese C-PFES scheme be broadened to allow participation of entities from outside Ca Mau province, including private companies, government agencies and international investors. We also identified the need for education training programs to enhance stakeholders’ perspectives prior to the implementation of C-PFES at the local level. This study provides insights for countries with mangrove ecosystems seeking to implement a C-PFES.

Zinc (Zn) biofortification can improve grain yield and nutritional quality in rice, but its effectiveness is subject to agronomic practices and other factors. In a previous study, the application of Zn to soil enhanced grain Zn in lowland rice in well-drained and waterlogged soil, whereas grain Zn in upland rice increased only in well-drained soil. This new study explores the hypothesis that the application of foliar Zn can enhance grain Zn in upland and lowland rice grown under waterlogged and well-drained conditions. Two rice varieties, CNT1 (wetland rice) and KH CMU (upland rice) were grown in containers in waterlogged or well-drained soil with three Zn treatments (no Zn, soil Zn and foliar Zn). For the soil Zn treatment, 50 kg ZnSO4 ha−1 was applied to the soil before transplanting. For the foliar treatment, 0.5% ZnSO4 (equivalent to 900 L ha−1) was applied at booting and repeated at flowering and milky growth stages. Grain yield in CNT1 was 15.9% higher in the waterlogged than in the well-drained plants, but the water regime had no effect on grain yield in KH CMU. Grain Zn concentration in CNT1 increased from 19.5% to 32.6% above the no Zn control when plants were applied with soil or foliar Zn. In KH CMU, there was an interaction between the water regime and Zn treatment. Application of foliar Zn increased grain Zn by 44.6% in well-drained and 14.7% in waterlogged soil. The results indicate strong interaction effects between variety, water regime and Zn fertilizer application on Zn biofortification in rice. Thus, the selection of rice varieties and growing conditions should be considered in order for producers to achieve desirable outcomes from high grain Zn concentrations.

Dalbergia tonkinensis is being promoted in Vietnam for the future supply of prized wood for furniture and chemical extraction. Expansion of the plantation area requires a reliable source of quality seed. This study evaluates the field performance of progeny from mature mother trees in natural forests and urban environments. Trials were established in Tan Son and Doan Hung districts of Phu Tho province and assessed 3 years later. There were significant differences in growth and survival between provenances. The best families reached heights of >3.5 m and came from mother trees in a natural forest. The number of leaflets per leaf on mother trees was positively correlated with height (Ht) and diameter at breast height (Dbh) of the trial trees. The individual heritabilities (h(2)) for Ht and Dbh were 0.39 and 0.49 for Tan Son, and 0.33 and 0.48 for Doan Hung, respectively. The coefficient of additive variation (CVA) of Ht and Dbh were 36% and 58% for Tan Son, and 23% and 30% for Doan Hung, respectively. Interactions between the growth traits in the two trials were strongly correlated (R-2 = 0.88 for Ht, 0.90 for Dbh). These results identify D. tonkinensis gene sources with advantages for early growth performance in plantations. These superior genetics can be used for seed orchards, clonal propagation and for implementing a breeding program.

Damage by the shoot-tip borer Hypsipyla robusta (Lepidoptera: Pyralidae) has limited the commercial cultivation of Chukrasia tabularis (Meliaceae) in many parts of the world. Recently, a number of C. tabularis families in Vietnam have shown field resistance to H. robusta. This study explores whether endophytic bacteria in C. tabularis can inhibit the development of H. robusta. Endophytic bacteria from resistant trees had strong repellent (73–97%) and antifeedant (74–84%) activity with H. robusta in laboratory trials. The most biologically active isolates were identified as Bacillus bombysepticus (4 isolates) and Bacillus velezensis (2 isolates) based on phylogenetic analysis of 16S rRNA, gyrB, pycA and rpoB. Fifteen days after releasing H. robusta larvae in a nursery trial, spray inoculation with bacterial solutions from resistant trees reduced shoot tip damage by over 60% compared with the control. Spray treatments with bacterial endophytes from susceptible trees were less effective. These findings have application to the future development of biological control of H. robusta, and the selection of resistant trees for breeding.

The planted forest area in Vietnam increased from 3.0 to 4.4 million hectares in the period 2010–2020, but the loss of productivity from pests and diseases continues to be a problem. During this period, frequent and systematic plantation forest health surveys were conducted on 12 native and 4 exotic genera of trees as well as bamboo across eight forest geographic regions of Vietnam. Damage caused by insects and pathogens was quantified in the field and laboratory in Hanoi. The threats of greatest concern were from folivores (Antheraea frithi, Arthroschista hilaralis, Atteva fabriciella, Hieroglyphus tonkinensis, Lycaria westermanni,Krananda semihyalina, and Moduza procris), wood borers (Batocera lineolata, Euwallacea fornicatus, Tapinolachnus lacordairei, Xyleborus perforans, and Xystrocera festiva), sap-sucking insects (Aulacaspis tubercularis and Helopeltis theivora) and pathogens (Ceratocystis manginecans, Fusarium solani, and Phytophthora acaciivora). The number of new and emerging pests and pathogens increased over time from 2 in 2011 to 17 in 2020, as the damage became more widespread. To manage these pests and diseases, it is necessary to further invest in the selection and breeding of resistant genotypes, improve nursery hygiene and silvicultural operations, and adopt integrated pest management schemes. Consideration should be given to developing forest health monitoring protocols for forest reserves and other special-purpose forests.