Wet Zone Research Articles

A Systematic Review on Buffalo Breeds, Lactation Performance, and Buffalo Milk Production Characteristics in Sri Lanka

Purpose: The current study aimed to systematically review the publications originating from Sri Lanka on buffalo milk to identify potential dairy buffalo breeds and their lactation performances, milk composition, physicochemical properties, and products originating from buffalo milk.Research Method: Articles published over the last 6 decades were found through Scopus and Google Scholar databases using keywords. Original Research articles which are relevant and published in English were only selected. The six-step selection process in line with the Preferred Reporting Items for Systematic Reviews and Meta-analysis Approach (PRISMA) was adopted.Findings: The majority of the publications focused on product development aspects rather than buffalo milk production aspects. Pure breeds of the locals, Murrah, Surti, and Nili-Ravi, and their crossbreeds are frequently cited in the literature. The daily average milk yields of Murrah, Local, Surti, and Nili-Ravi pure breeds were 4.7±2.3, 3.1±1.3, 3.0±1.19, and 1.2 L, respectively. Daily milk yields of the crossbreeds ranged from 1.1 – 5.0 L. Average lactation lengths were largely dependent on the breed in which Murrah recorded the highest (341±100 days). The average lactation length of the local breed was exceptionally shorter (156±27 days) than that of the exotic breeds (>235 days). The calving interval of the Murrah and Local buffaloes was the same (636 d). Pure breeds of Surti and Nili-Ravi recorded calving intervals of 489 and 411 d, respectively. Whereas, it ranged from 417-477 d among crossbreeds. Studies focused on milk compositions and physicochemical properties were extremely rare. Curd and cheese were the most focused products originating from buffalo milk.Value: This study summarises the buffalo milk production aspects in Sri Lanka and identifies research gaps in the area. Current literature reflects a satisfactory level of information relevant to the buffaloes reared in the Dry-Zone. This study recommends more research in milk composition analysis and lactation performance of the breeds and buffalo production in the Low-Country Wet Zone and Up-Country regions.

Seasonal forecasting of Bactrocera dorsalis Hendel, 1912 (Diptera: Tephritidae) in bioclimatic zones of Sri Lanka using the SARIMA model

Bactrocera dorsalis Hendel is a severe fruit pest that causes significant economic losses globally. Despite B. dorsalis having been distributed mostly across Asia, studies on its current and future density variation in Sri Lanka are sparse to date. The present study was thus carried out to assess the contemporary density variation (2020–2022) and future density fluctuation (2023–2025) of B. dorsalis in bioclimatic zones of Sri Lanka. The density was assessed using the monthly-based fruit fly trap collection method from randomly selected 40 locations in all bioclimatic zones (wet, intermediate, dry, and arid). The SARIMA modelling technique was applied for delineating the best-fit model and for density forecasting in each bioclimatic zone. The density variations were depicted for the year and for the bioclimatic zone (2020–2025) by colour intensity maps using QGIS. According to the findings, B. dorsalis shows a seasonal component to its year-round density variation and an ascending trend in its density from 2020 to 2025. Density forecasting records a 20%, 30%, 26%, and 37% density increase in the wet, intermediate, dry, and arid zones, respectively, in 2025. In 2025, the highest predicted B. dorsalis density from the arid zone and the lowest predicted density from the wet zone were recorded. This study contains the first forecasting attempt for B. dorsalis density using the SARIMA approach as well as the application of colour-intensity depiction for its density variation in Sri Lanka, which leads decision makers and stakeholders in economic agriculture to plan the scientific management of B. dorsalis to avoid its current and potential future threat to the country’s fruit industry.

Consideration of Vadose Zone Moisture Dynamics in Remediation of PFAS‐Impacted Soils

AbstractOilfield brines are soluble, non‐volatile, and recalcitrant contaminants that are vulnerable to capillary effects and evapoconcentration and have been known to recontaminate clean fill soils emplaced after excavations. This problem may also occur for some poly‐ and perfluoroalkyl substances (PFAS) at PFAS sites. In this paper, we consider the soil moisture characteristic curve, wetting front dynamics, and the moisture redistribution cycle to understand the potential behavior of different PFAS in the vadose zone. Drawing on experience with remediation of soils impacted by brine spills, we provide recommendations on the design and implementation of soil excavation and cover remedies such as capillary barriers to prevent recontamination.

Long-term evaluation of pasture production, seasonality, and variability: An application of the DairyMod pasture model for three tropical species

Adoption of improved pastures coupled with intensified management provide quality pastures in adequate quantities and thus improve livestock productivity. While pasture modelling is imperative for exploring the performance of newer pastures, models are little used for long-term simulations of multiple tropical pastures (genotype), under varying soil, climate (environment) and pasture production systems (management). We applied the DairyMod, a biophysical model to simulate the long-term pasture production of Brachiaria ruziziensis x B. decumbens x B. brizantha ‘Brachiaria Mulato II’ (BM), Megathyrsus maximus ‘Gatton Panic’ (GP), and Chloris gayana ‘Rhodes grass cv. Reclaimer’ (RR) across major dairying regions of Sri Lanka under different management scenarios and characterize the long-term pasture growth, seasonality and spatial variability, and possible implications for dairying in Sri Lanka. Simulations of three pasture species were carried out for 16 locations (8 dry (DZ), 5 intermediate (IZ), and 3 wet zone (WZ)) over 30 years (1980–2010). Three pasture management scenarios simulated were; 1) potential pasture production system under non-limiting N and irrigation (Yp) 2) rainfed pasture production system under non-limiting N fertilizer (Yw), and 3) rainfed pasture production system under current nitrogen (N) fertilizer rate (Ya). Statistical techniques were used to identify the long-term growth rates, variability, and trends in pasture production. The long-term pasture production varied greatly among climate, species, and management scenarios. Overall, the Ya showed a seasonal cycle following the rainfall pattern, with a reduction in growth rates in dry seasons (May–September). Pasture growth rates were greater in GP at Ya, and BM at Yw and Yp while RR showed the lowest growth rate at all times. Variability of pasture growth was high in DZ (May–September) and RR has the lowest growth variability. The Yw increased the growth rate (doubled) while the Yp substantially increased (nearly tripled) the growth rate and growth pattern producing less variable pastures. Simulated growth rates suggest that GP in low-input and BM in high-input farming areas would be more suitable. Our study suggested that the BM, GP, and RR are edaphic-climatologically fit for major dairying regions in Sri Lanka and the appropriate fertilizer and irrigation management can greatly increase the herbage accumulation and availability of year-round pastures. While this study offers valuable insights, the species-specific growth pattern, growth variability, yield potential under different managements and the possible implications for herbage quality need to be sensibly considered when selecting the appropriate species.

The dominant pests (Coleoptera) of cereal crops, and population forecast for this

Goal. Create a forecast of the development of harmful organisms in cereal crops, to determine the economic feasibility of applying plant protection measures.
 Methods. Analysis of the phytosanitary state of cereal crops in Ukraine, where the main attention is paid to the dominant pest species. Analysis of the areas of distribution of these pests, population dynamics, their phenology and the state of populations in the context of natural and climatic zones (Steppe, Forest-steppe and Polissya). To assess the phytosanitary state of crops, and its dynamic changes, the following are used: — the results of phytosanitary monitoring of crops (according to generally accepted methods), which were carried out directly by the staff of the forecast laboratory of the Institute of Plant Protection of NAAS; — current reports of researchers from other laboratories of the Institute of Plant Protection of NAAS from the places of business trips; — materials of decadal reports of regional plant protection stations, as well as signaling and forecasting points; — information on the phytosanitary situation from regional state research stations and institutes of NAAS.
 Results. A study of the phytosanitary state of cereal crops on the territory of Ukraine was carried out, the dominant species of pests were identified, materials were prepared regarding the peculiarities of the phytosanitary state in the conditions of the year, and a long-term (annual) forecast of the development of pests for the next year was drawn up, based on the appropriate analysis of the data obtained.
 Conclusions. In recent years, climate change in Ukraine has manifested itself through an increase in the average annual temperature, and an increase in the sum of effective temperatures. A decrease in the zone of sufficient soil moisture was noted, its line shifted to the north. Under the influence of abiotic factors, pests constantly change the boundaries of their habitat and zones of damage, therefore reliable protection of crops is impossible without constant monitoring, constant clarification of the species composition of phytophages, and phytosanitary forecast. Improved methodological approaches for assessing the phytosanitary state of acrocyanoses and the promptness of obtaining relevant data will allow agricultural producers to make timely decisions on the economic feasibility of using certain plant protection products.

Niche partitioning association of fungal genera correlated with lower Fusarium and fumonisin-B1 levels in maize

Through partitioning of ecological niches, several fungi are able to coexist on the same host crop. In (partial) absence of niche partitioning, competitive exclusion among fungi can occur. Competitive exclusion is one of the bases for biocontrol. We investigated fungal correlations, in terms of relative abundance of the fungi, in pre-harvest maize, as a natural ecosystem model. Internal mycobiome fungal relative abundance of maize was used to establish correlations. The maize had been harvested from dry and wet agro-ecological zones of Zambia. The relative abundances of the fungal genera were determined using DNA amplicon sequencing. For this study, positive or absence of correlations between fungal genera signified good niche partitioning (co-existence), whereas negative correlations signified poor niche partitioning and potential for competitive exclusion. When species compete within one niche (competitive exclusion), we may expect to detect higher levels of mycotoxins—since mycotoxins are considered antagonistic agents aimed at defending or invading an ecological niche. To estimate the importance of mycotoxins in competitive exclusion, we measured the influence of the fungal correlations on levels of fumonisin-B1 (FB1) in the maize. FB1 data were derived from a previous study on the maize, determined by HPLC. Results showed that Sarocladium and Stenocarpella had the strongest significant negative correlation with Fusarium, suggesting poor niche partitioning and potential for antagonism of these genera with Fusarium. Furthermore, higher levels of Stenocarpella resonated with lower levels of FB1 and vice versa. It was also observed that, when Sarocladium was in low abundance (< 10%), the frequency of detection of higher levels of FB1 (> 100 µg kg−1) in the pre-harvest maize was highest.

Cultivar-Specific Growth and Yield of Mukunuwenna (&lt;em&gt;Alternanthera sessilis&lt;/em&gt;) in the Low Country Wet Zone, Sri Lanka

Joyweed/Mukunuwenna (Alternanthera sessile) is a globally significant leafy vegetable, yet its maximum yield potential remains largely unrealized due to the limited genetic diversity of existing varieties. Farmers frequently lack precise knowledge about the yield potential, growth characteristics, and quality of the produce. Few attempts of research attentions were given to assess its growth characteristics, susceptibility to diseases and pests, consumer acceptability, and yield potential. Therefore, this study aims to comprehensively evaluate growth and yield traits, sensory qualities and morphological features of eight carefully selected Mukunuwenna cultivars. Thus, identifying the most suitable Mukunuwenna cultivars for the Low Country Wet Zone, Sri Lanka. In this investigation, we assessed four Mukunuwenna selections, including one wild (red) variety, alongside three local Mukunuwenna cultivars, focusing on their growth, yield and morphological characteristics under upland field conditions at the Agriculture Research Station, Thelijjawila, Sri Lanka. The study followed a randomized complete block design (RCBD) with three replicates. Data were meticulously collected for eight growth parameters and two yield parameters including average internodal distance, average leaf length, average leaf width, average number of shoots per unit area, average number of leaves per stem, average number of flowers per stem, average shoot height, average chlorophyll content, average leaf to stem ratio, and average yield per plot. The results, analyzed through ANOVA and mean separation demonstrated significant differences (P&lt; 0.05) among Mukunuwenna cultivars across various attributes, To assess the diversity in growth and yield, a principle component analysis was conducted. A sensory evaluation was performed to assess the consumer preference. Notably, the Piliyandala selection exhibited the most promising growth and yield traits, particularly excelling leaf to stem ratio and gaining the highest consumer preference. Other notable performers were the Colombo selection, Weda Mukunuwenna and Cultivar M7 showing preferable growth and yield traits with strong consumer appeal. Considering these findings, we conclude that Piliyandala selection, Colombo selection, and Cultivar M7 exhibit preferable growth and yield traits for commercial cultivation, while Weda Mukunuwenna stands out as an ideal choice for home garden cultivation under upland conditions in the Low Country Wet Zone, following recommended agronomic practices. This study’s outcomes hold significant promise for further research endeavors, focusing on enhancing desirable growth and yield traits.

Impact of Organic and Chemical Fertilizer Combinations on Growth, Yield, and Soil Carbon in in Oil Palm Cultivation at Talgaswella Estate, Sri Lanka

The success of oil palm cultivation hinges on factors such as planting material quality, management practices, and the availability of essential macro and micro-nutrients. Insufficient nutrient supply adversely impacts both vegetative growth and the ultimate yield in terms of quantity and quality. To address this issue, an experiment was conducted at Talgaswella Estate, belonging to Elpitiya Plantations PLC., situated in the Low Country Wet Zone (LCWZ) of Sri Lanka. The objective was to enhance the productivity and profitability of marginal oil palm lands. A ten-year-old oil palm field was chosen as the experimental site, employing a Randomized Complete Block Design (RCBD) with eleven treatments and three replicates, including an absolute control. Each trial plot consisted of six palm trees, totaling 198 trees in the experiment. Treatments involved varying combinations of Empty Fruit Bunches (EFB), Palm Oil Mill Effluent (POME), and Poultry Litter (PL), with and without chemical fertilizer. Soil, plant, and yield parameters were measured, and the data were analyzed using the Minitab statistical tool. After three years, results indicated that 100% organic fertilizer-received plots (T11) and 100% chemical fertilizer-treated plots (T2) exhibited significant increases in average fresh fruit bunch weight (22.81 Kg and 21.82 Kg), soil organic carbon percentage (3.00 and 2.23), and leaf chlorophyll content (78.79 and 75.07) of the 17th frond compared to T11 and T2 treated plots. Intermediate results were observed in the remaining fertilizer combined plots (T3, T4, T5, T6, T7, T8, T9, T10). The findings suggest that the use of organic fertilizer in marginal oil palm lands not only improves crop and soil factors but also contributes to environmental sustainability through the recycling of oil palm waste products. It is recommended to periodically apply organic fertilizer, especially on marginal oil palm lands, to enhance overall crop productivity and land sustainability.

Distribution status and influence of climate change on patterns of distribution of hornbills in Sri Lanka

There is ample evidence for the impacts of recent climatic changes on ecology. Climate plays a major role in the population dynamic of birds. Hornbills are confined to Asia and Africa with only two species present in Sri Lanka. In this study, we utilized field observations and filtered e-bird records to generate current and future climatic models for the two hornbill species in Sri Lanka (Ocyceros gingalensis and Anthracoceros coronatus). Critical reduction of predicted ecological niches was observed in Anthracoceros coronatus throughout the period considered (2000–2100). Special conservation interventions are required for these two species. However, predicted suitable ecological niches for the Ocyceros gingalensis show little reduction towards the wet zone of Sri Lanka. This shift in species distribution boundaries coincides with periods of global warming suggesting a possible connection. This study provides supporting evidence for the possible influence of climate change on hornbill species distribution.

Are the stream macrobenthos impacted by the wastewater from rubber factories?

We assessed how the wastewater generated from raw rubber factories affected the water quality parameters and how such changes influenced the stream macrobenthic assemblages in some streams in the wet zone of Sri Lanka. For this assessment, water quality parameters viz. DO, COD, BOD5, conductivity, TDS, T, pH, and OMC in the sediment were measured, and the macrobenthic fauna were sampled during the dry season at six sampling sites established based on judgemental sampling technique viz. rubber factory wastewater effluent canal (site A), point of wastewater discharge in the stream (site B), 50 m upstream site from site B (site C), 50 m downstream site from site B (site D), 100 m downstream site from site B (site E), and 150 m downstream site from site B (site F) following standard field sampling techniques. Secondary research data (dry season) from two other streams subjected to rubber factory wastewater effluents, namely Rakwatte Ela (2001) and Gurugoda Oya (2011), were also used for this assessment. Results revealed that the COD, BOD5, OMC, conductivity, and TDS levels were elevated, and the DO level was reduced significantly in the highly polluted A and B sites in all three streams. Parallel to them, the macrobenthic diversity decreased significantly (p&lt;0.5; ANOVA) at these two sites. However, the complete opposite was observed at the furthermost downstream site F, where the water quality parameters and the microbenthic composition became almost the same as that in the upstream control site C. It is evident that the changes made to the stream water quality and the macrobenthic assemblages by the rubber factory wastewater are never permanent and disappear within a relatively short stretch of 150 m along the streams, most probably due to the dilution of wastewater along the stream. The pollution-tolerant tubificids and chironomids were bioindicator candidates to detect such changes where they became highly abundant at the highly polluted wastewater effluent canal (i.e., Site A) and point of wastewater discharge in the stream (i.e. Site B), but their abundance gradually decreased along the downstream sites probably due to wastewater dilution by the fresh water supply from the stream.

Human biomonitoring of trace metals from different altitudinal settings of Pakistan.

Human biomonitoring of toxic trace elements is of critical importance for public health protection. The current study aims to assess the levels of selected trace metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) into paired human nail and hair samples (n = 180 each) from different altitudinal setting along the Indus River, and which were measured by using inductively coupled plasma mass spectrometry (ICP-MS). The human samples (hair and nail) were collected from four different ecological zones of Pakistan which include frozen mountain zone (FMZ), wet mountain zone (WMZ), riverine delta zone (RDZ), and low-lying southern areas (LLZ). Our results showed the following occurrence trends into studied hair samples: higher values (ppm) of Zn (281), Co (0.136), and Mn (5.65) at FMZ; Cr (1.37), Mn (7.83), and Ni (1.22) at WMZ; Co (0.15), Mn (11.89), and Ni (0.99) at RDZ; and Mn (8.99) and Ni (0.90) at LLZ. While in the case of nails, the levels (ppm) of Mn (9.91) at FMZ and Mn (9.38, 24.1, and 12.5), Cr (1.84, 3.87, and 2.33), and Ni (10.69, 8.89, and 12.6) at WMZ, RDZ and LLZ, respectively, showed higher concentration. In general, among the studied trace elements, Mn and Ni in hair/nail samples were consistently higher and exceeded the WHO threshold/published reference values in most of the studied samples (> 50-60%) throughout the Indus basin. Similarly, hair/nail Pb values were also higher in few cases (2-10%) at all studied zones and exceeded the WHO threshold/published reference values. Our area-wise comparisons of studied metals exhibited altitudinal trends for Cd, Cr, Zn, and Mn (p < 0.05), and surprisingly, the values were increasing from south to north (at higher altitudes) and indicative of geogenic sources of the studied toxic elements, except Mn, which was higher at lower floodplain areas. Estimated daily intake (EDI) values showed that food and drinking water had the highest contribution towards Zn, Cu, Mn, and Ni and accumulation at all studied zones. Whereas, dust also acts as the main exposure route for Mn, Co, Cr, and Cd followed by the food, and water.

Drought susceptibility mapping in Iraq using GRACE/GRACE-FO, GLDAS, and machine learning algorithms

Drought susceptibility mapping is crucial for mitigating water scarcity and its cascading effects. This study utilizes machine learning (ML) and Gravity Recovery and Climate Experiment (GRACE) data to identify drought-prone areas in Iraq. Terrestrial water storage anomaly (TWSA) data derived from GRACE observations was utilized, in conjunction with various meteorological and topographical factors (temperature, precipitation, wind speed, potential evapotranspiration, aridity index, normalized difference vegetation index, groundwater storage, root zone moisture, elevation, and slope) sourced from diverse global datasets, primarily those comprising the Global Land Data Assimilation System (GLDAS). These combined datasets served as input for five machine learning models to identify the drought prone area of Iraq: linear discriminant analysis, classification and regression trees, support vector machine, random forest, and k-nearest neighbor. All models exhibited exceptional performance (>0.9 accuracy, >0.8 kappa values, >0.9 areas under the receiver operating characteristic curve) highlighting the effectiveness of the combined TWSA and multi-factor approach. The analysis identified five drought susceptibility zones across Iraq, ranging from very low to very high. An area of approximately 160,650 km2, primarily concentrated in the northeastern and Mesopotamian plains of central and southern Iraq, was identified as exhibiting high to very high drought susceptibility, highlighting the necessity for targeted mitigation strategies. This study pioneers the use of GRACE-derived TWSA and GLDAS data for drought susceptibility mapping in Iraq, paving the way for data-driven water management interventions.

An Analysis of Stream Flow and Flood Frequency: A Case Study from Downstream of Kelani River Basin, Sri Lanka

River floods in Sri Lanka are mainly associated with extreme rainfall events. The Kelani and Kalu rivers are recorded the highest flood frequencies and the accompanying flood damages among the river basins in wet zone (UNDP, 2011). Therefore, the specific objective of the study is to estimate the temporal probability of occurrence of flood events in downstream of Kelani river basin. Secondary data were used for the study. Daily discharges data were obtained from Hanwella gauging station for the period of 1990 to 2019 from the Department of Irrigation, Sri Lanka. Trend analysis, normal distribution and flood frequency analysis have been used. The results of the study revealed that there was a bi-modal pattern of discharges that occurred in June and October. The results also indicated that ten return periods were covered the total period of 30 years, and there was a 97 per cent probability of flood occurrence almost annually and 64 per cent probability of occurring once every two years. This study, therefore, was recommended to design flood control structures for mitigating flood risk; and to determine the economic value of flood control projects and the effect of encroachments on flood plain. Keywords: floods, frequency, downstream, return period, probability

Habitat Utilization and Behavioral Patterns of the Endemic Sri Lankan Green Pit Viper (Craspedocephalus trigonocephalus) in the Wet Zone of Sri Lanka

Behavioral patterns and habitat utilization of the endemic Green Pit Viper (GPV) Craspedocephalus trigonocephalus were studied in the wet zone of Sri Lanka. The region, which is covered by the wet zone, has no significant dry periods and a moderately high mean annual rainfall of over 2,500 mm. Data collection occurred between April 2021 and March 2022 with a total of 260 hours of standardized sampling effort distributed throughout the collection period. The method used was an active search which consists of a visual search of up to six meters from the central line along each side of the quadrate. Quadrats were placed in habitats, taking each GPV sighting as the center of a quadrate. At each GPV-occupied quadrat, ambient temperature, body surface temperature, prey availability, perch position and perch light level were recorded. The day was divided into six-time periods as; early morning, morning, mid-day, evening, late evening, and night. Activity level was determined considering the number of GPV that could be visually observed. A total of 49 GPV were examined during the study. Focal animal sampling was conducted, and an ethogram was developed. A strong positive relationship was observed between ambient temperature (Ta) and body surface temperature (Ts) of GPVs (Pearson correlation r=0.936). The highest number of individuals preferred filtered sun light (57.14%). C. trigonocephalus mostly preferred distal position on the branches followed by middle and apical. There was a significant difference in the percentage of individuals with different behaviors [ANOVA, F=3.64, p&lt;0.05]. Behavioral pattern of GPV varied in the temporal scale during the day. During the morning time slot, C. trigonocephalus spent most of the time ambushing (16.12%) and basking (6.42%) respectively. During the mid-day they spent most of their time basking (10.57%), followed by resting (7.15%). The evening, late evening, night, and early morning slots were spent mostly on ambushing. The highest average time of 239 min was spent on ambushing behavior. Feeding behavior (9.8 min) had relatively short time on average. Results of this study indicate that C. trigonocephalus is well adapted for the utilization of its preferred habitat in the wet zone, and that, it displayed behavioral patterns that vary within temporal scales, which results in more efficient and effective utilization of resources. Therefore, this study provides important insights for conservation and management of C. trigonocephalus by critically evaluating the requirements of this species. &#x0D; Keywords: Craspedocephalus trigonocephalus, Behavior, Endemic pit viper, Wet zone

Fungal Diversity in the Wounded Tissues of Gyrinops walla Trees and the Surrounding

Gyrinops walla (Gaertn) of family Thymelaeaceae, is believed to be endemic to Sri Lanka and is mainly found in the lowland wet zone where the elevation is lower than 1,000 m and the annual rainfall is between 2,000 to 3,000 mm. This species is known for producing a valuable resin called agarwood in its trunk after being infected by pathogens, mainly fungi. Over 20 capable fungal species have been identified to stimulate agarwood formation in the trees of the agarwood- producing genus, Aquilaria. However, since such information is lacking for G. walla, this study aimed to determine the fungal taxa that induce agarwood formation in G. walla and to compare the fungal diversity between G. walla tissues, surrounding trees, and the soil. Samples were taken from four locations in the wet zone, Olugala, Morapitiya, Weragala, and Elpitiya, and one location in the intermediate zone, Kirimetimulla. Collected naturally wounded tissues from G. walla trees of those locations were surface sterilized before culturing. In addition, the stem samples were taken from the surrounding trees at 5 m radius from the sampled G. walla trees. Soil samples were collected at each location at 2.5 m distance along the north south directions of sampled G. walla trees which is from the sub-surface. A standard dilution series up to 1:10,000 was prepared for soil culturing. All the fungal colonies emerging from initial soil, stem cultures were isolated as pure cultures in separate PDA plates. Based on the colony morphology and growth parameters, all the pure cultures were categorized into 13 fungal isolates. Morphological and microscopic characteristics were used to identify the fungal isolates. Out of the 13, six isolates were identified as Aspergillus sp. (1, 2, 3), Rhizopus sp., Trichoderma sp., and Mucor sp. The unidentified isolates, due to the lack of reproductive structures, were named as morphotypes 5, 7, 8, 9, 11, 12 and 13. After identification, their presence and frequency of occurrence in different sample types i.e. resinous tissues and nonresinous tissues of G. walla, surrounding tree tissues and soil were evaluated in all five locations. For the comparison, diagrams were built. Thereby, predominant fungal isolates in each of the sample types were identified. Based on the occurrence of fungal isolates in each location, Olugala had the greatest fungal diversity, while Morapitiya had the lowest. Morphotype 07 was identified as the dominant isolate in resinous tissues of G. walla due to the presence of 15 isolates. Rhizopus sp. was also found as a common fungal isolate in the wounded tissues of all five locations. Trichoderma sp. was more abundant in the surrounding, while Aspergillus sp (1) was dominant in soil. Fungal isolates in resinous tissues were also present either in the non-resinous tissues of G. walla, surrounding tree tissues, or soil. Therefore, inocula are believed to enter the wounded tissues from nearby trees or from the soil, and spores from water, wind or carriers like insects. &#x0D; Keywords: Gyrinops walla, Fungal isolates, Surrounding trees, Soil

Comparative Study of Soil Nutrients in Selected Paddy Lands in Wet Zone Treated with Organic and Chemical Fertilizers

In Sri Lanka, paddy consumes the most significant part of chemical fertilizers and accounts for approximately 50 percent of the widespread use of chemical fertilizers. With the immediate banning of inorganic fertilizers, there was a huge argument between the government and the farmers about organic farming. Since the soil fertility change takes a long time, the impact of long-term application of the same fertilizer should be assessed. Field experiments were conducted in six selected paddy fields in wet zone considering fertilizer type and rice variety. Total 30 samples from each site were collected and soil initial nitrogen (N), phosphorus (P) potassium (K), Organic C, and composition of used fertilizers were analyzed. Nutrient status compared using critical, optimum ranges, and general management practices are discussed. This study revealed that the total N level in all the sites varies near the critical level and is inadequate to produce expected yields. Soil organic C (3.8-6.7%) and N (0.06-0.2%) levels in organic sites were higher than the chemical sites (0.09-0.19N%, 1.4-2.1C%). Phosphorus level is below the critical level (0.9-8.4 mg/kg) in organic sites, and varies from medium to high (7.5-27.0 mg/kg) in chemical sites. The sites using chemical fertilizers showed excessive K (395-480 mg/kg), and organic sites were below the optimum range (82-92 mg/kg). According to the fertilizer analysis, organic fertilizers are rich in organic C (40-90 g/kg), while organic C is absent (0%) in chemical fertilizers. All the other nutrient amounts are very low (N:0.7-19.3 g/kg, P:0.06-0.8 g/kg, K:33.2-15.4 mg/kg) in organic fertilizers, and the composition is unstable. Chemical fertilizers have an exact composition of nutrients and can easily be applied at the particular growth stage of the plant which is beneficial. An external supply of essential soil nutrient through organic or chemical fertilizer sources is required to produce expected yields. Regular and continuous monitoring of soil quality, pre-nutrient assessment of organic fertilizers, site-specific fertilization, and proper agronomic practices are highly recommended. These results will be beneficial in selecting or manufacturing suitable fertilizer type/types for paddy cultivation, including bio-fertilizers. &#x0D; Keywords: Organic fertilizers, Status of soil nutrients, Soil fertility, Rice varieties

Estimation of Aboveground and Belowground Carbon Stocks in Homegardens of Low Country Wet Zone, Sri Lanka

&#x0D; &#x0D; &#x0D; Homegardens are one of the most significant and oldest types of land use systems in Sri Lanka which have been recognized as an essential component in providing a variety of ecosystem services. In these systems, trees and shrubs are grown together with food crops under family labor, creating a multitude of biological interactions. Due to rich tree diversity and density, homegarden agroforestry systems are known to have a great capacity to capture and store carbon in their biomass and soil, and thus greatly contribute to mitigation of climate change. Even though the importance of homegardens with regard to the above is highlighted significantly, large knowledge gaps remain on their total carbon storage potential, particularly in low country wet zone homegardens of Sri Lanka. Therefore, the current study aims to estimate the total aboveground and belowground carbon stocks of homegardens in Kalutara district. The study was conducted in ten homegardens ranging from 0.15 Ha to 0.43 Ha. The study focused on all perennial woody trees present in the homegardens. Heights and diameters at breast height (DBH) were measured in a total of 966 woody trees. Aboveground biomass of each tree was calculated nondestructively, using allometric equations which incorporated wood density, DBH and tree height. Belowground biomass was calculated using root: shoot ratios of trees. Total biomass of each tree was converted to total carbon stocks using a conversion factor of 0.5 extracted from literature, considering that total carbon stock of a tree is equivalent to half of its biomass. In order to get the total carbon stock, soil organic carbon (SOC) content of each home garden was analyzed in the laboratory from collected soil samples using the Loss-on-ignition method. Belowground biomass carbon stock and the SOC stock together were taken as the total belowground carbon stock of each homegarden. Estimated mean aboveground carbon stock was 91.4±11.4 Mg ha-1, while the mean belowground carbon stock was determined as 134.3±12.3 Mg ha-1 in low country wet zone home gardens. Aboveground carbon stock, together with the belowground carbon stock, was taken as the total carbon stock of the homegardens. Calculated total carbon stock per unit area for low country wet zone homegardens ranged between 179.873 Mg ha-1 and 286.606 Mg ha-1 with a mean value of 225.7±11.9 Mg ha-1. Above findings of the study present evidence for significant carbon storage capacity of low country wet zone homegardens.&#x0D; Keywords: Homegarden, Low country, Wet zone, Carbon stock, Climate change&#x0D; &#x0D; &#x0D;

Potential of a Charcoal Evaporative Cooling Chamber for Extending the Shelf Life of Vegetables

&#x0D; &#x0D; &#x0D; There are wide varieties of vegetables in Sri Lanka. The ambient temperature and relative humidity have an impact on rate of vegetables deteriorate. Evaporative cooling is a well-known, cost- effective way to reduce postharvest lost in order to lower the temperature and increase the relative humidity. This research was done to create a charcoal cooling chamber for increase the shelf life of vegetables combining polythene packaging and active packaging additives. The study was carried out in wet zone, Sri Lanka with a sizable chamber made of coconut shell charcoal. A rectangular box made of chicken wire with a 1 m3 capacity serves as the evaporative cooling chamber. It made of chicken wire mesh with a hardwood frame. The walls filled with 50 mm thick coconut shell charcoal and a water outflow 8.33 ml/min for wetting the walls. Vegetable samples without any treatment were placed in the charcoal chamber along with vegetables wrapped in sealed polyethylene (gauge 300) with and without active packing components. With a control sample held in ambient settings, the treatments were put to the test four times over the course of nine days. Both unloading and loading situations were used to evaluate the performance of chamber. Temperature drops of 4° C on average and 2.07° C on average, respectively, were seen in dry and wet climate conditions. 92.49% on average was the cooling efficiency. Sealed polyethylene bags without active packaging components were found to be the best treatment when taking into account physiological weight loss and sensory tests. When compared to the control group on days 3, 6 and 9 physiological weight loss was considerably (P&lt;0.05) less in the sealed polyethylene bags without active packing components. When compared to the control sample total soluble solid content less in sealed polythene bag. The sensory evaluation for the treatments inside the chamber was more acceptable than for the control. Vegetables can store fresh for up to three days in evaporative cooling chamber without packaging. These chambers can install vegetable stalls on the side of the roads in Sri Lanka for temporary purposes.&#x0D; Keywords: Charcoal, Evaporation, Shelf-life, Temperature, Vegetables&#x0D; &#x0D; &#x0D;

Impacts of Organic and Non-Organic Cultivation Practices on Soil Fertility Parameters of Selected Paddy Lands Based on the Duration of Cultivation in Wet and Intermediate Climate Zones of Sri Lanka

Sri Lanka has been practicing the cultivation of rice as its main staple food in two major agricultural techniques; organic and non-organic. The major aim of the present study was to analyze and compare the time duration-based impacts of the above two agricultural practices on paddy soil fertility indicators as the preliminary step of a long-term research project. Organic and non-organic paddy fields that have been cultivated for 2 seasons in Thorapitiya in the Matale district were selected as short-term cultivated lands. Land cultivated for 10 years organically in Homagama and land with a non-organic cultivation history of 20 years in Kottawa was selected as long-term cultivated lands. A total number of 35 samples were collected including the control samples from adjacent uncultivated land during the first phase of the Maha season 2021/2022. The samples were dried, sieved and then analyzed in their physical and chemical properties; color, texture, particle size distribution, pH, electrical conductivity (EC), organic carbon content (OCC), total nitrogen content (TNC), available phosphorus content (APC), exchangeable potassium content (EPC), and exchangeable magnesium content (EMC). The soil samples from Thorapitiya had a reddish-brown nature while most of the samples from Kottawa and Homagama had a grayish-brown color. Higher clay percentages were found in the soil samples from long-term organically cultivated lands in Homagama. The uniformity coefficient (Cu) values for soils from study areas except Homagama lie in the range for well-graded soil while the coefficient of gradation (Cc) values of all three areas were not in the above range. Short-term cultivation using organic and non-organic fertilizers did not show a significant difference in soil texture, pH, EC, APC, EPC, and EMC values. Most of their cultivated lands had a lower pH (~5.5–6.0) than the corresponding control plots (~5.8–6.4). The TNC levels in non-organically cultivated lands were significantly higher than in organic lands. Practicing agricultural activities for a prolonged period has resulted in significant differences in soil texture, pH, EC, OCC, TNC and APC between organic and non-organic lands. Higher OCC and lower pH, EC and APC values have been obtained for long-term organically cultivated lands than their non-organic counterparts. The TNC, APC and EPC levels were higher in most of the long- term organic and non-organic lands than in their control samples. Several amendments have to be made to bring the fertility parameters to an optimum level in long-term cultivated lands. &#x0D; Keywords: Soil fertility, Paddy soil, Cultivation history, Organic cultivation, Non-organic cultivation

Pollen Morphological Studies on Selected Species of Family Dilleniaceae in Sri Lanka

Dilleniaceae is an angiosperm family including 11 genera and about 500 known species with a pantropical distribution extending into Australia. In Sri Lanka, four genera and 16 species including one introduced species have been reported in the family Dilleniaceae. Most of these species are endemic or native, while Schumacheria is an endemic genus. Morphological characters of the pollen grains are a significant taxonomic identification tool in the systematics of higher plants. The aim of the study is to provide detailed palynological descriptions of selected pollen species and maintain pollen reference collection. Four plant species, Dillenia retusa, Dillenia suffruticosa, Dillenia triquetra, and Schumacheria castaneifolia of the family Dilleniaceae (Genus Dillenia and Schumacheria) were collected from different localities in the wet zone including Nugegoda and Baduraliya during the period from September 2022 to November 2022. The voucher specimens were authenticated using revised handbook to the flora of Ceylon and deposited in the Herbarium of the Department of Botany, University of Sri Jayewardenepura, Sri Lanka. Fresh flowers or dried flowers were taken to collect pollen. Pollen grains were acetolysed and observed under Optika microscope (BG-Italy) after mounting on a clean glass slide using glycerin jelly with Basic fuchsin. Thirty pollen grains were used to determine the pollen size for each selected species. All measurements were taken within seven days of pollen preparation using OptikalSview (3.9.0.604) software. The shape, size, and surface features of pollen grains, as well as the length and width of the pollen and apertures and Polar/Equatorial ratios, were observed. Descriptive statistical analysis was performed using Minitab 18 software for the quantitative variables related to measurements of pollen obtained with light microscope. The ranges of variation were 15-22 μm for polar axis, 16-26 μm for equatorial axis, 0.8-3.5 μm for colpus width and 5.0-12.5 μm for colpus length. The pollen grains of all the species are monad, isopolar, and radially symmetrical. Pollen grains were identified as suboblate to oblate spheroidal, small or medium-sized, tricolpate (Dillenia spp.) or tetra-colpate (Schumacheria castaneifolia), with the surface ornamentation punctate to reticulate. The longest and widest pollen grains were reported in Dillenia suffruticosa (22.0×26.4 μm), while the smallest were observed in Schumacheria castaneifolia (15.2×16.4 μm). Based on the length of the longest spore axis, except D. suffruticosa all other species are categorized into small-size pollen. According to the results, the distinction between species can be determined using palynological features such as shape, size, and aperture type. &#x0D; Keywords: Pollen morphology, Dilleniaceae, Palynology, Reference collection