Vol. 6 No. 2 (2023): Vietnam Journal of Agricultural Sciences

The objective of this study was to evaluate the effects of land preparation methods and iron-coated (Fe-coated) rice seeds on the growth, yield, and Fe uptake of rice in alluvial soils in the Mekong Delta region. The experiment was conducted in the 2020 summer-autumn cropping season under the triple rice cultivation system in Chau Thanh district, An Giang province. The field experiment was designed as a randomized complete block design (RCBD) with six treatments and four replications. The treatments were: (T1) puddled + water seeding + Fe-coated seeds; (T2) non-puddled + dry seeding + Fe-coated seeds; (T3) zero-tillage + non-puddled + dry seeding + Fe-coated seeds; (T4) puddled + water seeding + sprouted + non-Fe-coated seeds; (T5) puddled + wet seeding + sprouted + non-Fe-coated seeds; and (T6) puddled + transplanting + sprouted + non-Fe-coated seeds. The results showed that changes in the land preparation, planting method, and Fe-coated seeds did not significantly affect the number of tillers, plant height, yield components, soil chemical properties, grain yield, or Fe uptake of the rice plants and grains. However, the T3 and T6 treatments tended to have higher grains yields (5.86-5.90 tons ha-1), and higher total Fe content in grains (93.0-94.3 mg kg-1) and rice plants (83.1-84.0 mg kg-1). The findings from this study confirmed that the new planting method using zero-tillage + non-puddled + dry seeding + Fe-coated seeds can maintain the germination rate, growth, and grain yield of rice.

Rice (Oryza sativa L.) grain attributes, such as grain length and shape, milling quality, and physicochemical quality, are crucial for varietal development and subsequent farm adoption. Thus, it is crucial to comprehend the phenotypic range of these grain attributes and how they relate to one another. Therefore, this study analyzed the main grain quality traits in medium-grain rice, namely the amylose content (AC), gelatinization temperature (GT), gel consistency (GC), ratio of head rice (HR), and percentage of chalkiness (PC). Correlations among the major quality characteristics were then calculated through Pearson correlation matrix analysis. The results showed that AC was highly connected with GC, and PC and HR (GC) showed a strong correlation. The correlation between GT and GC was average. The other quality traits did not correlate significantly. The phenotypes of the grain quality traits provide a basis for improving the quality of medium-grain rice populations.

Improving fertilizer and water use efficiencies is an important strategy in agricultural production. This study aimed to evaluate the effect of nitrogen fertilization on the daily whole-plant transpiration, growth, and physiological activities of sugarcane. The pot experiment was conducted under glass-house conditions. Five treatments of various nitrogen application rates (0, 4, 8, 12, and 16mM) were assigned in a randomized complete block design with three replications. The result showed that higher nitrogen applications led to higher growth, physiological, and biomass parameters. Nevertheless, biomass nitrogen use efficiency and photosynthetic water use efficiency declined because of applying nitrogen at higher rates. During the first weeks of plant growth, no significant differences in plant height, leaf number, SPAD, and whole-plant transpiration among nitrogen treatments indicated that higher nitrogen added was not necessary during this time. Nitrogen and water use efficiencies could be improved if the remaining soil nitrogen and crop growth stage nitrogen requirements are estimated in cultivation practice.   

The current experiment aimed to determine the effects of peptidoglycan, known as a prebiotic compound, on the growth, feed efficiency, and disease resistance in Nile tilapia. Fish at an initial body weight of 22.6 ± 0.3g were distributed into a 100 L-glass tank system. Peptidoglycans extracted from Lactobacillus sp. were added to commercial feed at ratios of 0, 5, and 10 g kg-1 diet corresponding to the PG0, PG5, and PG10 treatments, respectively. Fish were then fed at 4% their body weight for four weeks. After a 4-week trial, fish were infected with Streptococcus agalactiae at 50% the lethal dose (1.1×106 CFU mL-1), and monitored for 14 days. After 2 and 4 weeks of the feeding trial (T2 and T4) and on the second day of the bacterial challenge, fish blood samples were collected for hematological analysis. The results indicated that the dietary supplementation of peptidoglycan induced a positive effect on fish growth performance and the highest value was observed in the PG5 treatment. The lowest value of cumulative mortality was also observed in the PG5-fed fish indicating that the dietary supplementation at 5 g kg-1 diet supported the highest resistance to S. agalactiae. In conclusion, the beneficial effects of dietary supplementation of peptidoglycan extracted from Lactobacillus sp. were recorded on the growth performance and disease resistance in Nile tilapia.

This study aimed to assess the perception of H'mong farmers in the northwest mountainous region on climate change, its impacts on crop production, and their adaptation strategies. Reports on natural disaster events and their damages for the period ranging from 2012-2021, together with meteorological data including daily temperature and precipitation for 1991-2021, were collected. Fifty households among the H’mong farmers were randomly selected from four villages of Pa Lau commune for interviews based on structured questionnaires. The results showed that most H’mong farmers know that the climate is changing. However, their perceptions of the trends of these changes in terms of rainfall, temperature, and extreme weather events were not consistent with the analysis of meteorological data. The results also revealed that this is because the farmers evaluated the changes mainly based on their observations of short-term climate changes and the associated impacts that directly affect their livelihoods. The farmers perceived that soil erosion and hot and extreme cold weather have tended to increase their impacts on the production of some major local crops. Other types of natural disasters such as droughts, floods, landslides, pests, and strong winds have tended to have more or less impacts depending on the crop type. Adaptation measures taken by farmers to mitigate the effects of climate change are mainly simple, flexible, seasonal and low-cost measures. This study provides basic information for authorities at all levels to mitigate the negative impacts of climate change.

The study was conducted to analyze the factors affecting the use of pig wastewater for crop cultivation in Hanoi city. Through the application of the Theory of Planned Behavior to develop the theoretical framework and structural equation modeling, the study showed that the behavior intention influenced the recycling behavior. Attitude toward the behavior (AT), social norms (SN), and perceived behavioral control (PBC) were important influencing factors on the intention to perform this behavior with standardized regression coefficients of ß = 0.96 (P <0.001), ß = -0.826 (P  <0.001), and ß = -0.34 (P <0.001), respectively. These research results serve as the initial reference for policies and studies related to the use of pig wastewater.