Suitable Period Research Articles

Wild-Grown and Cultivated Glechoma hederacea L.: Chemical Composition and Potential for Cultivation in Organic Farming Conditions.

Glechoma hederacea L. is a medicinal plant that is known in traditional medicine for its anti-inflammatory, antibacterial, antiviral, and anticancer properties. This study evaluated the potential for commercial production of G. hederacea and compared the chemical composition and activity of 70% ethanol extracts and steam-distilled essential oils from wild-grown and cultivated G. hederacea collected in different harvesting periods. The main compounds identified in the 70% ethanol extracts were phenolic acids (chlorogenic and rosmarinic acids) and flavonoid O-glycosides. The essential oil varied in the three accessions in the range of 0.32–2.98 mL/kg−1 of dry weight. The extracts possessed potent antioxidant and anti-inflammatory properties in LPS-treated bone-marrow-derived macrophages. The results of flow cytometry show that extracts from different vegetation periods reduced the conversion of macrophages to the proinflammatory phenotype M1. The chemical composition varied the most with the different harvesting periods, and the most suitable periods were the flowering and vegetative phases for the polyphenolic compounds and essential oils, respectively. G. hederacea can be successfully grown under organic farming conditions, and cultivation does not significantly affect the chemical composition and biological activity compared to wild-grown plants.

Mass culture of the rotifer Brachionus plicatilis under laboratory condition

In the present study the rotifer Brachionus plicatilis was cultured under controlled laboratory conditions, in Marine Science Center, Dept. of Marine Biology, the temperature was 22 ºC. The rotifers feeding on two type of food, the first was baker's yeast and second the animal manure. General, used the animal manure was better than baker's yeast. The density of rotifers culture at 22 ºC which fed on animal manure was 145 ind /ml, while growth rate was 2.67 and doubling time was 0.25 day. While, the density, growth rate and doubling time of rotifers culture at 22 ºC which fed on beakers yeast were 75 ind./ml, 2.01 and 0.34 day respectively. The importance of this study to determined the ability to depending on animal manure as cheap resource and available to improve rotifer growth compared with baker's yeast. Additional, to suitable period determined to culture of rotifer for supply it to larvae of fish and crustacean.

Nitrogen and density treatment to improve resource utilization and yield in late sowing <italic>japonica</italic> rice

<p id="C3">Recently, the phenomenon of late sowing and late transplanting in rice is becoming more and more common in central Jiangsu, a rice and wheat double cropping system area, which is caused by climate change and the expanding of comprehensive rice-and-shrimp planting model. It will lead to the mismatch of rice growth period with light and temperature resources, restricting the stable high yield of rice. This study was conducted under the condition of late sowing and late transplanting (sowing date was June 12th, transplanting date was June 30th) and the seedling was transplanted by machine. Four nitrogen application rates (N₀: 0 kg hm^-2; N₂₄₀: 240 kg hm^-2; N₃₀₀: 300 kg hm^-2; N₃₆₀: 360 kg hm^-2) and three density treatments (D₃: 3 seedlings per hole; D₄: 4 seedlings per hole; D₅: 5 seedlings per hole) were arranged, and the suitable sowing period (May 29), conventional nitrogen application rate, and the seedling number per hole (N₃₀₀D₄) were taken as the controls. Our goal is to explore the effects of nitrogen fertilizer and seedling number per hole on the growth and yield formation in late-sown <italic>japonica</italic> rice, and to provide theoretical basis for improving yield potential and resource use efficiency in late sowing and late transplanting <italic>japonica</italic> rice in central Jiangsu province. The results showed that compared with CK, the yield of each treatment decreased, mainly because of the significantly reduced spikelet number under the late sowing and late transplanting condition. The highest spikelet numbers were 11.94% and 8.12% lower than those of CK in the two years. In addition, the utilization rate of temperature and light resources, nitrogen uptake, and nitrogen utilization rate decreased under late sowing and late transplanting treatment, leading to a decrease in dry matter accumulation and yield. The yield increased with the increase of nitrogen application rate and seedling number per hole under the late sowing and late transplanting condition, while there was no consistent with the trend under N₃₆₀D₅ treatment. We assumed that it was mainly due to the increased spikelet number, larger leaf area index at heading stage, the larger proportion of efficient leaf, and the extended growth period. In summary, the utilization of temperature and light resources and the dry matter accumulation at maturity stage was improved, and the decline in yield was alleviated. Nitrogen use efficiency increased first and then decreased with the increase of nitrogen rate, and N₃₀₀D₅ treatment reached the maximum. In general, under the late sowing and late transplanting condition, in order to alleviate the yield loss and reduce nitrogen fertilizer waste, we should increase the seedling number per hole and then increase the amount of nitrogen fertilizer.

VẬN DỤNG CHỈ SỐ KHÍ HẬU MÙA DU LỊCH HCI ĐỂ ĐÁNH GIÁ CHO PHÁT TRIỂN DU LỊCH Ở MỘT SỐ ĐỊA PHƯƠNG THUỘC ĐÔNG NAM BỘ

The climate conditions for tourism development by using the HCI - Holiday Climate Index developed by Mantao Tang (2013). HCI index assesses the impact of climate through 4 elements of climate: thermal comfort index; average rainfall; cloud cover and average wind speed. The result shows that Ba Ria - Vung Tau province has the most favorable level of climate for tourism development. Moreover, the monthly HCI index shows that the most suitable period for tourist activities every year usually appears from December to February of the following year with favorable levels from Good to Very Good.

THE IMPACT MECHANISM OF HUMAN ACTIVITIES OVER CLIMATE SUITABILITY BASED ON SOCIAL NETWORK DATA: EVIDENCE FROM CHINA

The impact mechanism of human activities on climate suitability is critical for understanding the human-environment nexus. In this study, social network data from Sina Weibo Platform was collected to quantitatively examined the relationship between the seven major types of human activities and climate suitability. The results indicated that the impacts of entertainment, tourism and daily life related human activities on climate suitability are significant (p-value &lt; 0.05). With one-unit (one check-in record/km2) increase of entertainment and tourism related human activities, the coverage rate of climate suitable zone and the length of climate suitable period increase by 0.003% and 0.026 months, respectively. In contrast, one-unit of increase of daily life activities made the Theil entropy index of climate inequity and the length of climate suitable period increase 0.00035 units and shorten 0.014 months, respectively. Moreover, the impact mechanism of human activities on climate suitability showed a significant spatial heterogeneity within regions at different economic level or topographical conditions, which could be explained by the discrepancy of environmental policies, urban form and urban ventilation channel design strategies in China. This work exhibited a further step to new possibilities in clarifying the climate effect of human activities using open-sourced social network data.

누룩 미생물 천이와 품질 특성 분석

Nuruk is a traditional Korean fermentation starter containing various microbes; it is utilized for the synthesis of alcoholic beverage. In this study, the changes in the quality characteristics and microbial community during the cultivation period of nuruk were analyzed. The results indicated that the fungal richness, expressed as Chao 1, from 70.0 to 19.3 on day 10 and subsequently increased to 35.0 on day 30 of cultivation. The content ratio of Aspergillus sp., Rhizopus sp. and Saccharomycopsis sp. increased with the progress of cultivation. Among the fungi, the content of the Aspergillus genus increased from 0.01% before cultivation to 70.4 %. Among the bacteria, the content of the Pantoea genus increased to 69.76% on day 7 and decreased to 44.80% on day 14. Considering the enzyme activity, saccharogenic power, α-amylase and carboxy peptidase exhibited the highest activity on day 7 while lipase exhibited the highest activity on day 14. Considering only the enzyme activity, the results indicated that it would be appropriate to terminate cultivation before day 14. The traditional cultivation period of nuruk is approximately 14 days; However, it is necessary to determine a suitable cultivation period for the application of nuruk as enzyme source.

Growth attributes and wood properties of lesser-grown agroforestry tree species in the semi-arid zone for quality pulp and paper production

Growth traits, wood properties, fibre dimensions and fibre derived indices of five lesser-grown agroforestry tree species viz., Ailanthus excelsa, Eucalyptus tereticornis, Leucaena leucocephala, Melia dubia and Neolamarckia cadamba were studied to evaluate the suitability of these species for pulp and paper production in the semi-arid zone of Bundelkhand, India. The result showed that there was a significant variation for all the studied traits. The range of all the studied growth and wood traits among five pulpwood trees were recorded for tree height (5.2-5.9 m), GBH (20-24 cm), volume (0.017-0.027 m3), biomass (8.50-15.28 kg), wood basic density (509.6-584.4 kg/m3), fibre length (819.8-1416.0 μm), fibre diameter (14.6-37.9 μm), fibre lumen diameter (7.5-29.8 μm), fibre double cell wall thickness (4.8-9.7 μm), Runkel ratio (0.23-0.94), Rigidity coefficient (0.19-0.49), Flexibility coefficient (51.54-81.44), Slenderness ratio (31.68-62.74) and Luce’s shape factor (0.20-0.58). Kadamb performed better, however all five species were found to be suitable for making good quality pulp and paper on the basis of wood properties and fibre derived indices grown in such hot and dry conditions. Tree height and GBH traits were positively influenced on the wood physical and anatomical properties, therefore these traits can be used as indirect selection for further improvement of the species which shown high potentiality for promising pulpwood tree species under agroforestry. Further, tree improvement research work required to test the suitable harvesting period for high pulp yield and better paper quality to fulfil the fastest growing demand of pulpwood for paper industries in India.

Evaluating Freshness Loss of Green Tea with Q10 Method and Weibull Hazard Analysis under Accelerated Shelf Life Testing

The important quality of green tea is freshness, but high temperature, light, oxygen, and humidity during storage may reduce the freshness of green tea. Thus, this study investigated the freshness loss of green tea (FLGT) under an accelerated shelf-life testing (ASLT) by sensory evaluation and acceptability test. The FLGTs of the samples stored at 20°C, 30°C, and 40°C, were determined as 67 days, 55 days, and 45 days, respectively by the Q10 method. In addition, they were further determined as 67 days, 57 days, and 42 days, respectively, by the Weibull Hazard Analysis (WHA). The sensory evaluation and acceptability test confirmed the correctness of the above results by 2-alternative choice analysis and chemical analysis. The Q10 method was applied to predict the FLGTs stored at 4°C and −20°C which were 93 days and 150 days, which was further verified by 2-alternative choice analysis and chemical analysis. The results show that it is possible to predict the suitable drinking period of green tea during storage by the Q10 method.

Incorporation of Magnetite in Toughened PLA Nanocomposite: Tensile and Thermal Stability

In this study, liquid natural rubber (LNR) toughened polylactic acid (PLA) incorporated with magnetite (Fe3O4) nanocomposites were fabricated via melt-compounding in an internal mixer and followed by hot/cold pressing. The effects of ultrasonic treatment time (1-3 hours) and Fe3O4 (0.5-4.0 wt%) nanoparticles loading on tensile, morphology and thermal stability were investigated. Based on tensile testing results, the ultrasonication time of 1 hour was served as the most suitable treatment period to achieve the optimum distribution of Fe3O4 within PLA/LNR matrix. Among the investigated nanoparticles loading, 1 wt% Fe3O4 nanocomposite presented the highest tensile strength of 23.7 MPa, Young’s modulus of 1293.5 MPa and strain at break of 2.8%. SEM micrographs showed that the over-treated nanocomposites with 2-3 hours and over-high nanoparticles loading had resulted in the formation of clusters in the matrix. With increasing Fe3O4 loading, the decomposition of PLA/LNR nanocomposites was initiated earlier.

Effect of various combinations of temperature during different phenological periods on indica rice yield and quality in the Yangtze River Basin in China

Rice grain yield and quality declines are due to unsuitable temperatures from wide regions and various sowing dates. This study aimed to evaluate the effects of temperature on rice yield and quality at different phenological periods and obtain suitable temperatures for phenological periods in the Yangtze River Basin, China. This study conducted experiments on different sowing dates under different areas in the Yangtze River Basin to observe and compare the differences in rice growth, yield, and quality, controlling for regional varieties. The results showed significant differences in rice growth, yield, and quality among sowing dates and areas, which were related to the average daily temperature during the vegetative period (VT) and the first 20 days of the grain-filling period (GT20). In addition, there was a smaller variation in the average daily temperature in the reproductive period (RT) than in the two phenological periods. Therefore, according to the VT and GT20 thresholds of different yields and qualities, the experimental results were divided into four scenarios (I, II, III, and IV) in this study. In Scenario I, high head rice production (rice grain yield multiplied by head rice rate) and rice quality could be obtained. The head rice production of Scenarios III and IV was lower than that of Scenario I, by 30.1 and 27.6%, respectively. In Scenario II, the head rice production increased insignificantly while the chalky grain rate and chalkiness were 50.6 and 56.3% higher than those of Scenario I. In conclusion, the Scenario I combination with VT ranges of 22.8–23.9°C and GT20 ranges of 24.2–27.0°C or the combination with VT ranges of 23.9–25.3°C and GT20 ranges of 24.2–24.9°C, which can be obtained by adjusting sowing date and selecting rice varieties with suitable growth periods, is recommended to achieve high levels of rice grain yield and quality in the Yangtze River Basin.

Antioxidative potential of propolis on Staphylococcus aureus infected BALB/c mice: A biochemical study

Drug resistance, according to World Health Organization, is one of the most serious threats to public health. This makes antibiotics ineffective and reduces their therapeutic potential. One of the most prevalent multidrug-resistant bacteria is Staphylococcus aureus which is considered to be the most common pathogen and mortality factor in both hospital and non-hospital environments worldwide. Due to an unprecedented increase in reports of drug resistance in pathogens, and also due to adverse and severe side effects of drugs, there is an urgent need to redirect scientific efforts towards search for anti-oxidative natural substances and other alternative sources having therapeutic potential against microbes. Natural products such as propolis seem to exhibit most promising therapeutic potential against microorganisms. Thus, present study is focused on antioxidative potential of propolis in combination with standard antibiotics ampicillin and amoxicillin against S. aureus infected BALB/c mice. For this, mice were divided into seven groups, they were decapitated after suitable experimental periods, then their liver, kidney and spleen were excised from control and experimental groups, which were homogenized and then used for different biochemical estimations following the standard protocols. Results showed that S. aureus caused severe biochemical alterations by 5th day of infection that is, lipid peroxidation increased significantly (P <0.05), reduced glutathione level and activity of antioxidant enzymes (SOD, CAT, GPx, GR, GST) decreased significantly (P <0.05) in liver, kidney and spleen of S. aureus infected mice. Ethanolic extract of propolis at a dose of 250 mg/kg body weight of mice when used alone to treat S. aureus infection gave significantly good results by 15th day of treatment. Better results were observed when propolis was used along with antibiotics. The levels of antioxidant molecules and enzymes along with liver and kidney function enzymes were restored to near normal after 15 days of treatment. So it can be concluded that propolis along with antibiotics acts as a potent free radical scavenger and can be used as a potential therapeutic agent against staphylococcal infection.

Selecting the best general circulation model and historical period to determine the effects of climate change on precipitation

Assessing the effects of climate change is a key component of the sustainable management of water resources and food security. In this paper, general circulation models (GCM) were evaluated using historical information for Birjand synoptic station, Iran. Modeling was performed using 35 models of the Fifth Climate Change Report for 27 historical periods. The results showed that longer annual periods are the most suitable periods for hydrological simulation when data are available. Therefore, the periods of 1960-1990 may be the most appropriate periods due to the adaptation to the observation data. To estimate rainfall, periods with more years showed a more accurate forecast of the future. Moreover, the results showed more changes in the RCP 8.5 scenario than in the RCP 4.5 scenario. According to the comparison of models, the NorESM1-M model with a root mean square error (RMSE) of 0.091 and the GISS-E2-R model with a low percent bias (PBIAS) can be an appropriate model for estimating rainfall.

Development of Test and Measurement of Knowledge Level of Sunflower Farmers

A test was constructed to measure the farmers’ knowledge level on sunflower cultivation during 2021-22. Relevant items were collected from review of literature and discussed with scientists. For relevancy test, 39 items were sent to 320 experts for their judgement. Based on 45 experts judgement, 18 items (overall mean score &gt; 2.57) were selected for item analysis and administrated to 60 farmers of Chinnakoduru village of Siddipet district. Item analysis was done by item difficulty index, item discrimination index and point biserial correlation and 15 items were finalized for knowledge test. Reliability (Cronbach alpha, Spearman brown coefficient and Guttman split-half) and validity (point biserial correlation) were estimated for standardization of the test and found to be highly significant. The test was administered to 140 respondents in Andhra Pradesh and Telangana states. In Andhra Pradesh, 78.8 per cent and in Telangana 85.0 per cent of respondents were in medium level of knowledge category. The item analysis indicated significant differences in knowledge level of farmers pertaining to most suitable period of sowing sunflower crop during Rabi, suitable sunflower hybrids, optimum seed rate, critical period of weed competition, application of fertilizers and bee keeping in sunflower in two states.

Operationalisation of Model for Dynamics of COVID-19 in Kenya: Trajectory of Omicron Wave in Kenya

Kenya has experienced five COVID-19 surges driven by Alpha, Beta, Delta (2x), and Omicron. These waves are accurately predicted by the OTOI-NARIMA model. Consequently, in Kenyan Lake Region Economic Bloc (LREB), private sector and NGO partnerships have been forged to strengthen regional health systems and prepare effectively for epidemic resurgence. The co-development and implementation of the so-called “LREB COVID-Dx” digital platform enable efficient epidemic monitoring in semi-real time, referral of patients, optimal use of limited resources, and community of practice among regional health practitioners. In this paper, we describe the practical implementation of the OTOI-NARIMA model and COVID-Dx digitized platform in Kenyan COVID-19 reality, with emphasis on the latest Omicron wave. In estimating the trajectory of Omicron wave, 612 data points of daily case infections are used. The order of moving average is calculated and corresponds to reproduction number, R0. The series are normalized, superimposed, and used to derive OTOI-NARIMA model. The model is estimated and interpreted. Test statistics including Ljung-Box test, ACF, and PACF are conducted. The COVID-Dx data digitization is used to inform epidemic preparedness. The OTOI-NARIMA model in general successfully established the periodicity and seasonality of COVID-19 resurgences in Kenya. The model is used to inform preparedness, including vaccines rollout. During alert stages of the wave, on December 4, 2021, the model was reused to nowcast the trajectory of the wave. Omicron wave was projected to peak in Kenya between November 23, 2021, and January 4, 2022. The wave showed strong likelihood of declining after January 29, 2022. In reality, Omicron wave was experienced from November 27, 2021, to January 29, 2022. The model predicted that Omicron variant will have run its full course by June 22, 2022, and possibly replaced by another variant, recombinant or sub-variant. According to OTOI-NARIMA model, dominant variants are replaced after every six months, which gives insights into suitable periods for administration of vaccine boosters. The total number of Kenyan patients (symptomatic or asymptomatic) during Omicron resurgence was estimated to be ~4.5 million. The total number of patients hospitalized during the wave is estimated to be ~2000. Effective, efficient, and economical response to Omicron resurgence in LREB benefitted from meticulous infusion of mathematical modelling and digitization of relevant data for epidemic preparedness and rapid decision making. The study has two limitations: Incomplete merging of stochastic processes and deterministic methods; calculating with accuracy the period it takes to fully replace a dominant COVID-19 variant. These two limitations may be considered for further research.

Comparative Analysis of Major Flavonoids among Parts of Lactuca indica during Different Growth Periods.

L. indica L. cv. Mengzao, a medicinal plant of the Ixeris genus, is rich in flavonoids. In order to thoroughly analyze the the distribution and dynamic change of major flavonoids in its various parts from different growth periods, the flavonoids extracted from L. indica L. cv. Mengzao were identified and quantitatively analyzed by ultra-high-performance liquid chromatography mass spectrometer (LC-MS/MS). Results indicated that 15 flavonoids were identified from L. indica L. cv. Mengzao, and rutin, luteolin, luteolin-7-O-glucoside, kaempferol, quercetin, and apigenin are the major flavonoids in L. indica L. cv. Mengzao. In general, the total flavonoids’ content in different parts of L. indica L. cv. Mengzao followed the order flowers > leaves > stems > roots. Flowers and leaves are the main harvesting parts of L. indica L. cv. Mengzao, and the flowering period is the most suitable harvesting period. This study provides valuable information for the development and utilization of L. indica L. cv. Mengzao and determined the best part to harvest and the optimal time for harvesting.

Experimental study on the compression characteristics of soft soil based on low temperature effect

Based on the characteristics of long annual freezing time and short suitable construction period of soft soil in cold region, this paper discusses the feasibility of foundation treatment of soft soil in freezing-thawing layer under freezing condition. The deformation characteristics of soft soil in freezing-thawing layer in Hulunbuir area in China are studied by using two compression test methods, namely, constant temperature and variable load (CTVL) test, variable temperature and variable load (VTVL) test. The compressibility indexes under different temperatures and consolidation pressures are obtained. The research shows that the freezing-thawing soft soil has large compressibility, the maximum strain of CTVL test is 19.89%, and the maximum compression of VTVL test can reach 18.16%. The results of CTVL compression tests show that when the soil temperature is in the range of severe phase change (-1.5℃-0℃), the temperature change has the greatest influence on the compression coefficient of soil. The result of VTVL compression test shows that some additional deformation occurs under the action of low temperature. The additional deformation is further increased when the soil is under high consolidation pressure and in the severe phase change (-1.5℃-0℃).

Monthly Variation and Ultraviolet Stability of Mycosporine-like Amino Acids from Red Alga Dulse Palmaria palmata in Japan

Mycosporine-like amino acids (MAAs) are the natural ultraviolet (UV)-absorbing compounds from micro- and macro-algae. The MAAs in algae change with the environmental conditions and seasons. We previously determined an efficient extraction method of MAAs from red alga dulse in Usujiri (Hokkaido, Japan) and revealed monthly variation of MAA in 2019. Dulse samples in 2019 for MAA preparation were suitable from late February to April. In this study, to confirm the suitable timings to extract MAAs from Usujiri dulse, we also investigated the monthly (from January to May) variation of MAA content in 2020. There were the most MAAs in the sample on 18 March (6.696 µmol g−1 dry weight) among the samples from January to May 2020. From two years of investigation, we deduce that samples of Usujiri dulse from late February to early April were suitable for MAA preparation. The UV stability of the two major purified MAAs in Usujiri dulse—palythine and porphyra-334—was tested. The two MAAs and 2-hydroxy-4-methoxybenzophenone were stable for up to 12 h under a 312 nm lamp at 200 µW cm−2, but 2-ethylhexyl-4-methoxycinnamate formed a cis/trans-mixture in a short time. The data in this study show the suitable sampling period for Usujiri dulse and the possible application for UV protection from food and cosmetics.

No Local Findings after Subclavian Catheter Removal. Is Everything Alright? Case Report

A 10-year-old male patient was admitted to the paediatric intensive care unit due to septic shock and oliguric acute renal failure. A haemodialysis catheter (11.5 Fr) was inserted into left subclavian vein for haemodialysis and cytokine-adsorption therapy. Haemodialysis and cytokine adsorption filter was applied to the patient for a total of two days, and then haemodialysis catheter was not used. The catheter was removed from the patient who was decided to transfer to the service on the fifth day of his admission. Tachycardia and hypotension developed and general condition deteriorated immediately after removal of the catheter. With rapid interventions, shock findings were corrected and the patient was reintubated and followed up in mechanical ventilation. On chest X-ray and thorax ultrasonography, the left hemithorax was completely filled, and a total of 1,500 mL of blood was drained by inserting a thorax tube. The patient was transferred to the paediatric pulmonology clinic after nine days of intensive care stay. Haemothorax development after subclavian catheter removal is a rare but a life-threatening condition. For these reasons, we believe that cases with removed subclavian or internal jugular vein catheters should be followed up for a suitable period of time.

Infrared thermography detection of delamination in bottom of concrete bridge decks

Infrared thermography (IRT) has been widely used in detecting the subsurface delamination of bridge deck. However, IRT inspection on delamination zones of the bridge deck which have limited exposure to direct solar radiation (e.g., the bottom surface of the bridge deck) is rather challenging due to the relatively low thermal contrast (∆T) development in these zones. Therefore, the purpose of this study is to conduct a series of experimental studies in conjunction with numerical modeling for investigating the effectiveness of IRT in delamination detection of bridge deck components which are normally not exposed to direct solar radiation. Specially, the effects of different environmental conditions, thickness of bridge deck, and defect characteristics on the absolute thermal contrast (∆T) development were systematically investigated. The results show that IRT can effectively detect the subsurface delamination of concrete bridge deck located in regions that are not exposed to the direct solar radiation. In addition, the development of detectable thermal contrast (>0.5°C) is much dependent on the rate of change in ambient temperature with a suitable detection period between 8 am and 4 pm. Furthermore, it shows that the value of ∆T increases with the increase of bridge deck thickness and delamination size.

Potential benefits of altering the cassava farming practices in the water shortage regions of Vietnam

The work was proceeded to define the suitable period for planting cassava crops in Han Thuan Bac district of Binh Thuan province, Vietnam to reduce the negative impacts of weather factors. The work was deployed applying the FAO-Aqua Crop model to calculate the tuber yield of cassava plants under the cassava farming practices (CFP) to seek the suitable planting period (SPP). The applied model was appraised through the calibration and validation procedures with the index of agreement (IA), correlation coefficient (CC) and the Root Mean Square Error (RMSE) varying from 0.82 to 0.88, 0.81 to 0.89 and 0.21 to 0.29, respectively. Based on the calibrated and validated procedures it can state that the proposed model is suitable for simulating the tuber yield of cassava across the study area. The simulated results indicated that the application of the CFP on Julian days from 110 to 150 for Vu Xuan crop and from 100 to 140for Vu He crop the tuber yield of cassava can improve up to 8.9 per cent and 6.0 per cent, respectively compared to the current farming practices.