Screening cotton genotypes for their drought tolerance ability based on the expression level of dehydration-responsive element-binding protein and proline biosynthesis-related genes and morpho-physio-biochemical responses.

Drought stress adversely affects growth, development, productivity, and fiber quality of cotton (Gossypium hirsutum L). Breeding strategies to enhance drought tolerance require an improved knowledge of plant drought responses necessitating proper identification of drought-tolerant genotypes of crops, including cotton. The objective of this study was to classify the selected cotton genotypes for their drought tolerance ability based on morpho-physio-biochemical traits using Hierarchical Ward's cluster analysis. Five genotypes of cotton (Takfa 3, Takfa 6, Takfa 7, Takfa 84-4, and Takfa 86-5) were selected as plant materials, and were grown under well-watered (WW; 98 ± 2% field capacity) and water-deficit (WD; 50 ± 2% field capacity) conditions for 16 days during the flower initiation stage. Data on morpho-physio-biochemical parameters and gene expression levels for these parameters were collected, and subsequently genotypes were classified either as a drought tolerant or drought susceptible one. Upregulation of GhPRP (proline-rich protein), GhP5CS (Δ1-pyrroline-5-carboxylate synthetase), and GhP5CR (Δ1-pyrroline-5-carboxylate reductase) in relation to free proline enrichment was observed in Takfa 3 genotype under WD condition. An accumulation of free proline, total soluble sugar, and potassium in plants under WD conditions was detected, which played a key role as major osmolytes controlling cellular osmotic potential. Magnesium and calcium concentrations were also enriched in leaves under WD conditions, functioning as essential elements and regulating photosynthetic abilities. Leaf greenness, net photosynthetic rate, stomatal conductance, and transpiration rate were also declined under WD conditions, leading to growth retardation, especially aboveground traits of Takfa 6, Takfa 7, Takfa 84-4, and Takfa 86-5 genotypes. An increase in leaf temperature (1.1 - 4.0 °C) and crop water stress index (CWSI > 0.75) in relation to stomatal closure and reduced transpiration rate was recorded in cotton genotypes under WD conditions compared with WW conditions. Based on the increase of free proline, soluble sugar, leaf temperature, and CWSI, as well as the decrease of aboveground growth traits and physiological attributes, five genotypes were categorized into two cluster groups: drought tolerant (Takfa 3) and drought susceptible (Takfa 6, Takfa 7, Takfa 84-4, and Takfa 86-5). The identified drought-tolerant cotton genotype, namely, Takfa 3, may be grown in areas experiencing drought conditions. It is recommended to further validate the yield traits of Takfa 3 under rainfed field conditions in drought-prone environments.

Alleviation of water-deficit stress in turmeric plant (Curcuma longa L.) using phosphate solubilizing rhizo-microbes inoculation.

The objective of this study was to assess the effects of phosphate solubilizing rhizo-microbes inoculants on nutrient balance, physiological adaptation, growth characteristics, and rhizome yield traits as well as curcuminoids yield at the secondary-rhizome initiation stage of turmeric plants, subsequently subjected to water-deficit (WD) stress. Phosphorus contents in the leaf tissues of Talaromyces aff. macrosporus and Burkholderia sp. (Bruk) inoculated plants peaked at 0.33 and 0.29 mg g-1 DW, respectively, under well-watered (WW) conditions; however, phosphorus contents declined when subjected to WD conditions (p ≤ 0.05). Similarly, potassium and calcium contents reached their maximum values at 5.33 and 3.47 mg g-1 DW, respectively, in Burk inoculated plants under WW conditions, which contributed to sustained rhizome fresh weight even when exposed to WD conditions (p ≤ 0.05). There was an increase in free proline content in T. aff. macrosporus and Burk inoculated plants under WD conditions, which played a crucial role in controlling leaf osmotic potential, thereby stabilizing leaf greenness and maximum quantum yield of PSII. As indicators of drought stress, there were noticeable restrictions in stomatal gas exchange parameters, including net photosynthetic rate, stomatal conductance, and transpiration rate, accompanied by an increase in leaf temperature. These changes resulted in reduced total soluble sugar levels. Interestingly, total curcuminoids and curcuminoids yield in Burk inoculated plants under WD conditions were retained, especially in relation to rhizome biomass. Burk inoculation in turmeric plants is recommended as a promising technique as it alleviates water-deficit stress, sustains rhizome biomass, and stabilizes curcuminoids yield. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-024-03922-x.

Understanding vegetable farmers' adoption, dis-adoption, and non-adoption decisions of pest management by pheromone trapping.

The use of pheromone traps can minimize the excess application of synthetic insecticides, while can also benefit the environment. The use of pheromone traps has been promoted and suggested to vegetable farmers of Bangladesh for widespread adoption. However, the majority of farmers have continued to spray insecticides instead of using pheromone traps. The present study investigated the factors influencing farmers' adoption, dis-adoption, and non-adoption behavior of pheromone traps for managing insect pests. Primary data were collected from 438 vegetable growers. Data were analyzed using descriptive statistics and multinomial logistic regression. About 27% of the farmers abandoned the technique shortly after it was adopted as it was time-consuming to manage insect pests. Marginal effect analysis revealed that the likelihood of continued adoption was 34.6% higher for farmers who perceived that pheromone traps were useful in controlling insect pests. In contrast, the likelihood of dis-adoption was 16.5% and 10.4% higher for farmers who maintained communication with private pesticide company agents and neighbor farmers, respectively. Extension services by government extension personnel might be encouraged and maintained as a key component in increasing farmer awareness regarding the use of pheromone trap. Strategies to promote pheromone traps in vegetable production should highlight the positive impacts to farmers and the environment, as this would most likely lead to their continued and widespread use after initial adoption.

Ecology, Biology, Environmental Impacts, and Management of an Agro-Environmental Weed Ageratum conyzoides.

Ageratum conyzoides L. (Billy goat weed; Asteraceae) is an annual herbaceous plant of American origin with a pantropical distribution. The plant has unique biological attributes and a raft of miscellaneous chemical compounds that render it a pharmacologically important herb. Despite its high medicinal value, the constant spread of the weed is noticeable and alarming. In many countries, the weed has severely invaded the natural, urban, and agroecosystems, thus presenting management challenges to natural resource professionals and farmers. Its interference with agricultural crops, grassland forbs, forest ground flora, and its ability to replace native plant species are of serious concern. Therefore, it is pertinent to monitor its continuous spread, its entry into new geographic regions, the extent of its impact, and the associated evolutionary changes. While management strategies should be improvised to control its spread and reduce its adverse impacts, the possible utilization of this noxious weed for pharmacological and agronomic purposes should also be explored. The objective of this review is to provide a detailed account of the global distribution, biological activities, ecological and environmental impacts, and strategies for the management of the agro-environmental weed A. conyzoides.

Factors influencing participation in collective marketing through organic rice farmer groups in northeast Thailand.

Despite the significant roles of farmer groups in collective action for production and marketing of organic paddy, limited literature has studied the farmer-level determinants of participation in collective action in northeast Thailand. This study examined factors associated with participation in collective marketing for three organic rice farmer groups (Nam Om Community Enterprise Network, Na So Farmer Group, and Moral Rice Farmer Group) in Yasothon Province of Thailand, producing organic jasmine rice for export and domestic markets through contract farming. Primary data were collected from 335 farmers and analyzed by descriptive statistics and the two-limit tobit regression method. The descriptive results showed relatively high levels of social, economic, institutional, and environmental benefits arising from the participation in those groups. In particular, environmental benefits were higher than the other types of benefits. The regression analysis found that age and agricultural loan negatively influenced the extent of participation in collective marketing through farmer groups, whereas education, paddy cultivation area size, non-agricultural income, experience in rice farming, experience in organic rice farming, group membership duration, perceived economic benefits, and membership with Na So farmer group were positively associated with the extent of participation. The effect of experience with organic rice farming was relatively small in Na So Farmer Group. The findings suggest that economic benefits from participation in organic farmer groups should be enhanced in order to increase the collective marketing of organic rice produce. Moreover, the government should provide alternative employment opportunities, knowledge-based training, and low-interest credit to support production and collective marketing of organic rice.

Arbuscular mycorrhizal fungi inoculation and phosphorus application improve growth, physiological traits, and grain yield of rice under alternate wetting and drying irrigation.

Climate change and agricultural malpractices are exacerbating drought in many parts of the world causing a substantial agricultural production loss. The improvement of drought tolerance in rice is crucial for maintaining productivity and ensuring global food security. Alternate wetting and drying (AWD) irrigation along with plant-microbe interaction through arbuscular mycorrhizal fungi (AMF) is a potential approach for enhancing rice production through AMF-induced up-regulation of tolerance and resilience against drought stress. Therefore, the ameliorative role of AMF inoculation and phosphorus (P) application on growth, physiological traits, and grain yield of rice was evaluated under water stress imposed through AWD irrigation. A factorial experiment consisting of four fertilizer treatments where the P percentage varied along with the recommended dose of nitrogen (N) with or without AMF inoculation (P100 as the control, P100 + AMF, P75 + AMF, and P50 + AMF), three soil water potential levels (0, -15, and -30 kPa), and two cultivation methods (wet direct seeding and transplanting) was conducted in a polyhouse. The subscript values of 100, 75, and 50 under P represent 100%, 75%, and 50% of the recommended field application dose. Data were collected on selected growth parameters, physiological traits, levels of mycorrhizal colonization, yield and its components, and water productivity of rice. The results revealed that P100 + AMF inoculated plants had 11%, 14%, 74%, and 54% higher leaf greenness, leaf relative water content, net photosynthetic rate, and grain yield, respectively, for wet direct-seeded plants at reduced soil water potential (-30 kPa) compared with non-inoculated plants (P100). Free proline accumulation gradually enhanced with decreasing soil water potential, and it was maximized by 77% at -30 kPa compared with 0 kPa for P50 + AMF (for transplanted plants). Free proline accumulation was also higher with decreasing soil water potential in AMF-inoculated plants than non-inoculated plants regardless of cultivation methods. Leaf osmotic potential was reduced by -0.5 to -1.2 MPa at -30 kPa compared with 0 kPa under different fertilizer doses. However, AMF inoculation (P100 + AMF and P75 + AMF) improved leaf osmotic potential of plants under severe water stress (-30 kPa) maintained through AWD irrigation resulting in better osmotic adjustment than non-inoculated plants. AMF inoculation improved the response of most of the evaluated physiological traits of rice and enhanced grain yield with higher P availability (even with a 25% reduction in its recommended dose) in the rhizosphere under drought stress. Thus, it can be concluded that AMF inoculation coupled with judicious P management is a promising approach for improving physiological and biochemical traits, grain yield, and water productivity of rice under AWD irrigation regardless of cultivation methods.

Household food insecurity and dietary diversity of women of reproductive age among smallholder farming households in northwest Bangladesh.

Despite Bangladesh's remarkable progress in agricultural production over the past few decades, household food and nutrition insecurity persist, especially in rural areas. The nutrition security and dietary diversity are even more critical for women of reproductive age among smallholders. This study examined household food insecurity and dietary diversity of women of reproductive age in the rural areas of northwest Bangladesh. Using cross-sectional data collected from 252 smallholder households, we measured household food insecurity and dietary diversity of women of reproductive age by the Household Food Insecurity Access Scale and the Minimum Dietary Diversity for Women, respectively. Determinants of household food insecurity were examined, and associations between household food insecurity and low dietary diversity were determined. The majority of the households were mildly insecure (51.2%) followed by moderately insecure (27.4%). The households felt anxiety of food insecurity for more than six months a year (Food Security Index = 2.10 out of 4.00). The mean food group consumed by women was 4.63 indicating low dietary diversity and dominance of diets by grains and dark green leafy vegetables. The findings also indicate a significant and positive association between household food insecurity and low dietary diversity of women. Education of household heads, household size, access to information sources, access to credit support, and perceived impacts of climate change on crop production were identified as determinants of household food insecurity. The study recommends that appropriate interventions be formulated to improve the food and nutrition security in the study areas.

Physio-morphological traits and osmoregulation strategies of hybrid maize (Zea mays) at the seedling stage in response to water-deficit stress.

Drought has been identified as a major factor restricting maize productivity worldwide, especially in the rainfed areas. The objective of the present study was to investigate the physiological adaptation strategies and sugar-related gene expression levels in three maize (Zea mays L.) genotypes with different drought tolerance abilities (Suwan4452, drought tolerant as a positive check; S7328, drought susceptible as a negative check; Pac339, drought susceptible) at the seedling stage. Ten-day old seedlings of maize genotypes were subjected to (i) well-watered (WW) or control and (ii) water-deficit (WD) conditions. Leaf osmotic potential of cv. S7328 under WD was significantly decreased by 1.35-1.45 folds compared with cv. Pac339 under WW, whereas it was retained in cv. Suwan4452, which utilized total soluble sugars as the major osmolytes for maintaining leaf greenness, Fv/Fm, ΦPSII, and stomatal function (Pn, net photosynthetic rate; gs, stomatal conductance; and E, transpiration rate). Interestingly, sucrose degradation (65% over the control) in cv. Pac339 under WD was evident in relation to the downregulation of the ZmSPS1 level, whereas glucose enrichment (1.65 folds over the control) was observed in relation to the upregulation of ZmSPS1 and ZmSUS1. Moreover, CWSI (crop water stress index), calculated from leaf temperature of stressed plants, was negatively correlated with E, gs, and Pn. Overall, growth characteristics, aboveground and belowground parts, in the drought-susceptible cv. Pac339 and cv. S7328, were significantly decreased (> 25% over the control), whereas these parameters in the drought-tolerant cv. Suwan4452 were unaffected. The study validates the use of leaf temperature, CWSI, Pn, gs, and E as sensitive parameters and overall growth characters as effective indices for drought tolerance screening in maize genotypes at the seedling stage. However, further experiments are required to validate the results observed in this study under field conditions.

Expression levels of genes involved in metal homeostasis, physiological adaptation, and growth characteristics of rice (Oryza sativa L.) genotypes under Fe and/or Al toxicity.

Acid sulphate soil contains high amounts of iron (Fe) and aluminum (Al), and their contamination has been reported as major problems, especially in rainfed and irrigated lowland paddy fields. Rice is sensitive to Fe and Al grown in acid soil (pH < 5.5), leading to growth inhibition and grain yield loss. The objective of this study was to evaluate Fe and/or Al uptake, translocation, physiological adaptation, metal toxicity, and growth inhibition in rice genotypes grown in acid soil. Fe and Al in the root tissues of all rice genotypes were enriched depending on the exogenous application of either Fe or Al in the soil solution, leading to root growth inhibition, especially in the KDML105 genotype. Expression level of OsYSL1 in KDML105 was increased in relation to metal uptake into root tissues, whereas OsVIT2 was downregulated, leading to Fe (50.3 mg g-1 DW or 13.1 folds over the control) and Al (4.8 mg g-1 DW or 2.2 folds over the control) translocation to leaf tissues. Consequently, leaf greenness (SPAD), net photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (E) in the leaf tissues of genotype KDML105 under Fe + Al toxicity significantly declined by 28.4%, 35.3%, 55.6%, and 51.6% over the control, respectively. In Azucena (AZU; Fe/Al tolerant), there was a rapid uptake of Fe and Al by OsYSL1 expression in the root tissues, but a limited secretion into vacuole organelles by OsVIT2, leading to a maintenance of low level of toxicity driven by an enhanced accumulation of glutathione together with downregulation of OsGR expression level. In addition, Fe and Al restrictions in the root tissues of genotype RD35 were evident; therefore, crop stress index (CSI) of Fe + Al-treated plants was the maximum, leading to an inhibition of gs (53.6% over the control) and E (49.0% over the control). Consequently, free proline, total phenolic compounds, and ascorbic acid in the leaf tissues of rice under Fe + Al toxicity significantly increased by 3.2, 1.2, and 1.5 folds over the control, respectively, indicating their functions in non-enzymatic antioxidant defense. Moreover, physiological parameters including leaf temperature (Tleaf) increment, high level of CSI (>0.6), SPAD reduction, photon yield of PSII (ΦPSII) diminution, Pn, gs, and E inhibition in rice genotype IR64 (Fe/Al-sensitive) under Fe + Al treatment were clearly demonstrated as good indicators of metal-induced toxicity. Our results on Fe- and/or Al-tolerant screening to find out the candidate genotypes will contribute to present screening and breeding efforts, which in turn help increase rice production in the Fe/Al-contaminated acid soil under lowland conditions.

Factors Influencing the Intensity of Adoption of the Roundtable on Sustainable Palm Oil Practices by Smallholder Farmers in Thailand.

The Roundtable on Sustainable Palm Oil (RSPO) was formed in 2004 in response to adverse environmental impacts caused by the expansion of oil palm production. It created voluntary standards to accelerate adoption of improved practices along the supply chain to ensure environmental benefits. However, the rate of adoption among smallholders of the practices RSPO recommends remains low. This study assessed the factors influencing smallholder farmers' adoption decisions and the intensity of adoption using primary data obtained from 723 randomly selected oil palm producers in the southern region of Thailand, of which 333 RSPO were adopters and 390 were non-adopters. The results of the binary logit and two-limit Tobit regressions revealed that total farm labor, farm size, number of training sessions attended, access to information, extension services, support services, and perceived ease of adoption of the practices had positive effects on the intensity of adoption. However, the age of oil palm trees negatively influenced the intensity of adoption. The results suggest that strengthening capacity building activities and extension services would increase the adoption of the RSPO practices among small-scale farmers.

Assessment of climate change impacts on water balance and hydrological extremes in Bang Pakong-Prachin Buri river basin, Thailand.

Among many factors the hydrology of a watershed is mainly influenced by climate and land use change. This study examined the impacts of climate change on water resources and extreme events in the Bang Pakong-Prachin Buri River Basin, Thailand using three different Regional Climate Models (RCMs) ACCESS1-CSIRO-CCAM, CNRM-CM5-CSIRO-CCAM, and MPI-ESM-LR-CSIRO-CCAM under RCP4.5 and RCP8.5 emission scenarios. Soil and Water Assessment Tool (SWAT) was used to simulate the future streamflow and Extreme Value Type I distribution (EVI) was used to analyze the extreme events under projected climate conditions. The result of this study showed an increase in maximum (1.9 °C/3.6 °C) and minimum (1.6 °C/3.3 °C) temperatures under RCP4.5/8.5 at the end of the 21st century. In addition, projected rainfall is expected to decrease up to 6.8% (8.5%) in 2050s and then increase slowly such that the decrement remains 4.2% (11.0%) under RCP4.5 (RCP8.5) at the end of the century. The rainfall pattern is projected to considerably fluctuate, in particular, a shift in long term average annual peak event from September to August is predicted in 2080s under emission scenario RCP4.5 (RCP8.5). On the other hand, the average annual discharge is expected to increase up to 13.5% (2020s) and 7.6% (2050s) under RCP4.5 and RCP8.5 respectively with decreasing trend in low flows and increasing trend in high flows. Further analysis on extreme events; strengthened the results from hydrological modeling with an increase in flow volume for the same return period under changed climate conditions. This raises water resources management issues in the Bang Pakong-Prachin Buri River Basin regarding the frequency of flood and drought events in the future calling for proper policy formulation and implementation.

Evaluation of climate change impacts and adaptation strategies on rainfed rice production in Songkhram River Basin, Thailand.

This study investigates rice yield and evaluates potential adaptation measures on field management practices for rainfed rice production under climate change scenarios in the Songkhram River Basin, Thailand. The top-down and bottom-up approaches are combined to evaluate the future climate conditions in the Songkhram River Basin and identify adaptation strategies respectively. An ensemble of four Regional Climate Models (RCMs) bias-corrected using the Quantile Mapping technique was used to project the future climate under two climate change scenarios (RCP4.5 and RCP8.5). The DSSAT crop simulation model was used to simulate rice yield and evaluate the impacts of climate change on rice yield, as well as the feasibility of four adaptation options, which were solicited from four hundred farmers through questionnaire surveys in the basin. The strategies include (i) change in planting date, (ii) change in fertiliser application date, (iii) change in fertiliser application dose, and (iv) supplying irrigation water. Based on the model results, future maximum and minimum temperatures are expected to increase by 2.8 and 3.2 °C respectively under RCP8.5 scenario for 2080s. Although annual rainfall may be unchanged, rainfall patterns will shift earlier in future. Evaluation of adaptation strategies suggest that supplying irrigation water under RCP4.5 and RCP8.5 scenarios respectively are the best strategies to increase rice yield under climate change scenarios. Change in fertiliser application date and change in planting date can increase the future rice yield by 12 and 8%, respectively under RCP4.5 scenario for 2080s. Adjusting the fertiliser application dose may however reduce future rice yield. Although supplying irrigation water can aid the production of rainfed rice, other concerns such as the source of water are involved. The feasibility of adaptation actions would depend largely on available resources and mindset of farmers. Further work is warranted in exploring a combination of adaptation strategies and management plans to combat the adverse impacts of climate change.

Evaluating the impacts of climate and land-use change on the hydrology and nutrient yield in a transboundary river basin: A case study in the 3S River Basin (Sekong, Sesan, and Srepok).

Assessment of the climate and land-use change impacts on the hydrology and water quality of a river basin is important for the development and management of water resources in the future. The objective of this study was to examine the impact of climate and land-use change on the hydrological regime and nutrient yield from the 3S River Basin (Sekong, Srepok, and Sesan) into the 3S River system in Southeast Asia. The 3S Rivers are important tributaries of the Lower Mekong River, accounting for 16% of its annual flow. This transboundary basin supports the livelihoods of nearly 3.5 million people in the countries of Laos, Vietnam, and Cambodia. To reach a better understanding of the process and fate of pollution (nutrient yield) as well as the hydrological regime, the Soil and Water Assessment Tool (SWAT) was used to simulate water quality and discharge in the 3S River Basin. Future scenarios were developed for three future periods: 2030s (2015-2039), 2060s (2045-2069), and 2090s (2075-2099), using an ensemble of five GCMs (General Circulation Model) simulations: (HadGEM2-AO, CanESM2, IPSL-CM5A-LR, CNRM-CM5, and MPI-ESM-MR), driven by the climate projection for RCPs (Representative Concentration Pathways): RCP4.5 (medium emission) and RCP8.5 (high emission) scenarios, and two land-use change scenarios. The results indicated that the climate in the study area would generally become warmer and wetter under both emission scenarios. Discharge and nutrient yield is predicted to increase in the wet season and decrease in the dry. Overall, the annual discharge and nutrient yield is projected to increase throughout the twenty-first century, suggesting sensitivity in the 3S River Basin to climate and land-use change. The results of this study can assist water resources managers and planners in developing water management strategies for uncertain climate change scenarios in the 3S River Basin.

The Effects of Different Media, Sucrose Concentrations and Natural Additives on Plantlet Growth of Phalaenopsis Hybrid 'Pink'

ABSTRACT The effects of various sucrose concentrations as carbon source and natural additives in different media on plantlet growth of Phalaenopsis hybrid 'Pink' were studied. Plantlets were cultured on two media (Murashige and Skoog [MS] and Vacin and Went [VW]) supplemented with 0, 10, 20, 30 and 40 g L-1 sucrose either with 0, 10 and 20% (v/v) coconut water (CW) or carrot juice (CJ) as natural additives. After four months of culture, the combination of sucrose and CW supplemented with both media affected plantlet growth where most of the plantlets showed slow growth and survival frequency (0-80%) with increasing concentrations of CW in all sucrose concentrations. However, plantlet growth on both media containing only 20 g L-1 sucrose without CW was optimal in terms of root number, root length, leaf number, leaf length, leaf width, fresh weight, dry weight and plant height. The combination of sucrose and CJ supplemented with MS medium resulted in overall good plantlet growth with 100% survival frequency. The combination of sucrose (20 g L-1) and CJ (10%) supplemented with MS medium increased root length, leaf length, leaf width and plant height. Plantlet growth was also optimal in the combination of 20 g L-1 sucrose and 10% CJ supplemented with VW medium. The results of this study indicate that Phalaenopsis hybrid 'Pink' cultured on the combination of sucrose (20 g L-1) and CJ (10%) supplemented with either MS or VW media can be used for plantlet growth of this species.

Field measurements for evaluating the RZWQM and PESTFADE models for the tropical zone of Thailand.

Evaluation of the field scale agricultural non-point source (NPS) simulation model against field experimental data is an important step that must be considered before a model can be used as a management tool. Therefore, the present study focuses on the testing of two NPS models known as the RZWQM (Root Zone Water Quality Model) and the PESTFADE (PESTicide Fate And Dynamics in the Environment). These models are used to predict the soil water content, metribuzin fate, and transport in a sprinkler-irrigated soybean field located at the experimental farm of the Asian Institute of Technology (AIT) in the Pathumthani Province, Thailand. Field soil water content and metribuzin residue adsorbed at soil profile depths of 0-10, 10-20, and 30-40 cm at different time periods were intensively measured by the gravimetric method and Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS), respectively. When comparing the field measured data, it was observed that the RZWQM performed better in simulating the soil water fcontent, whereas the performance of the PESTFADE model was better at simulating the metribuzin residue in the soil. Specifically, a reasonable agreement existed between the measured soil water content and that predicted by the RZWQM for 0-10 and 30-40 cm soil depths. The model slightly overpredicted the metribuzin residue at 0-10 cm soil depth one day after herbicide application, whereas the prediction of metribuzin residue at 10-20 and 30-40 cm soil depths was in accordance with the measured values. The PESTFADE model performed relatively well in simulating the soil water content at 10-20 cm and metribuzin residue concentration at 0-10 and 10-20 cm soil profile depths. However, the model performed relatively poorly at 30-40 cm soil profile depth. These results indicate that when properly calibrated, both the RZWQM and PESTFADE models can be used to predict the movement of water and metribuzin residue in the soil of tropical zones.