Mid Country Intermediate Zone Research Articles

Appropriate conventional methods for estimating missing precipitation values in Sri Lanka

This study focused on finding the most appropriate conventional method for estimating missing precipitations values in different climate zones in Sri Lanka. The main location and surrounding locations were selected from each zone considering their data availability. Monthly precipitation data for each selected locations were collected from 1980 to 2020. Three temporal methods; Holt Winter’s Exponential Smoothing, Seasonal Auto Regressive Integrated Moving Average and, Multiple Aggregation Prediction Algorithm and four spatial methods; namely, Arithmetic Mean Method (AMM), Normal Ratio Method (NR), Inverse Distance Weightage Method (IDW) and Aerial Precipitation Ratio (APR) method were used for estimating missing values. Root Mean Square Error, Mean Absolute Error, and Mean Absolute Percentage Error values were used for selecting the most appropriate method for estimating missing values for each location. It was difficult to name one method as the most appropriate method for all climate zones. Spatial methods have performed better than temporal methods in all seven climate zones. The missing values in the Low Country Wet Zone and Up Country Wet Zone could be estimated using AMM and NRM methods. APR method is the most suitable for estimating missing values in the Mid Country Wet Zone and Low Country Intermediate Zone. IDM method performed well in Mid Country Intermediate Zone, Up Country Intermediate Zones and Low Country Dry Zone. However, further improvement of both temporal and spatial methods for estimating missing values is necessary as none of these methods are capable of giving estimates with high accuracy.

Deleterious Effects of Storage Environmental Conditions on The Seed Quality of Two Varieties of Tomato (Solanum lycopersicum L.) Stored in Triple Laminated Aluminum Packing in Sri Lanka

Tomato is one of the most commonly growing vegetable crops among the farmers in Sri Lanka. Standard laboratory germination of tomato seeds fulfills the regulatory requirements of seed marketing. However, poor field performance is an overwhelming problem to farmers. Present study was focused on the longevity of two varieties of tomato seeds as affected by their quality characters (percentage germination, moisture, field emergence and vigour index, seed protein and carbohydrate contents) including seed health (exposure of Clavibacter michiganensis subsp. Michiganensis (CMMV), Spotted wilt virus (TSWV) and Leaf curly top virus (LCTV)) under four different storage environmental conditions during a one-year long storage study. Seeds were packed in triple-laminated aluminum packets (TLA) and stored in low temperature storage conditions (17±1 °C and 65% RH) and in ambient conditions in Gannoruwa, Kundasale, and MahaIlluppallama that represent the three agro-ecologically zones; Mid Country Wet Zone (MCWZ), Mid Country Intermediate Zone (MCIZ) and Low Country Dry Zone (LCDZ) respectively. Seed quality parameters displayed varied responses depending on the variety. Physiological changes that occur in seeds due to temperature, RH, changes in proteins and carbohydrate content, CMMV and TSWV during storage were manifested as reduction in seed germination, field emergence and vigour index. However, none of the seedling carried LCTV and therefore its effect on seed quality parameters could not be assessed. The seeds could be stored for ca. 29 months at low and constant temperatures and RH conditions without compromising local seed germination standards compared to ambient storage in the three environments. CMMV and TSWV detected in all seed samples indicated potential threats to tomato farmers in Sri Lanka.

Multilocational Evaluation of Growth and Antioxidant Content of Curly Kale (Brassica oleracea L. var acephala) and Chinese Kale (Brassica oleracea var. alboglabra) in Sri Lanka

Curly kale (Brassica oleracea var. acephala) and Chinese kale (Brassica oleracea var. alboglabra) are cruciferous vegetables, which have recently gained great popularity in the world as a ‘superfood’. Generally, kale has the capacity to tolerate diverse climatic conditions while demanding fewer inputs, thus making it possible to cultivate them with a minimum cost for crop management. However, kale is still not widespread in Sri Lanka as a vegetable. Therefore, it has not been a commercialized crop to date. This study was conducted to explore the potential for cultivating kale in Sri Lanka. Two cultivars of curly kale (‘Dwarf green curled’ and ‘Winterbor F1’) and Chinese kale were cultivated in three agro-climatic zones representing three main climatic zones in the country, namely the Mid-Country Wet Zone, Mid country Intermediate Zone and Low-Country Dry Zone, using three different media (M1: Existing soil in each location; M2: Sand and coir dust mixture – ratio 1:1; M3: Sand, coir dust, and soil - ratio 1:1:1) at each location. The experiment was carried out as a three-factor factorial with three replicates as a pot experiment. Based on the present study results, even though all the varieties displayed a significantly (p < 0.05) higher growth in terms of dry matter accumulation in the Wet Zone, the growth in the other two locations was also found to be satisfactory. Dry matter accumulation was not significantly different among the varieties within each location. Different media did not have a significant influence on growth. Even though the antioxidant contents in all varieties varied among locations, the values were within the acceptable range. Therefore, both curly kale and Chinese kale can be successfully grown in the tested locations in Sri Lanka and can be easily introduced to local consumers as a ‘superfood’.

Evaluation of Energy Balance in Tropical and Temperate Crossbred Dairy Cows at Post-Partum Transition Stage: A Case Study

Objective of the present study was to assess the energy balance of tropical (Sahiwal x Jersey) and temperate (Friesian x Jersey) crossbred dairy cows in Sri Lanka using serum metabolic profile. The study consisted of tropical and temperate crossbred dairy cows which were at post-partum transition stage, and were from two medium-scale farms in low country dry zone, and mid country intermediate zone, respectively. Each cow was bled (0800 hours) on the day of data collection and serum metabolic profile was assessed. Milk production, body weight and body condition score (BCS) of cows were recorded whereas, dry matter, crude protein and metabolizable energy contents of the mixed rations fed to cows in both farms were analysed. Results revealed that, serum non-esterified fatty acids (NEFA), urea and calcium contents were significantly (P

Quality Deterioration of Commercial Bean (Phaseolus vulgaris) Seeds Stored under Contrasting Environmental Conditions in Sri Lanka

Bean is a popular vegetable grown in most parts of Sri Lanka. Farmers and home gardeners purchase seeds in packeted form retail outlets. However, quality problems are frequently reported, especially on low field germination. Quality parameters namely, percentage germination, field emergence, seedling length, vigour index and chlorophyll fluorescence analysis were used to determine the effect of different storage environmental conditions on seed longevity of two bean varieties during a two-year storage period, 2016 to 2018. Seeds in triple-laminated packets stored in four contrasting conditions; low temperature storage conditions (Tem. 5oC, 65% RH); three geo-environmental conditions namely, Gannoruwa (mid country wet zone), Kundasale (mid country intermediate zone), and Mahailuppallama (low country dry zone) showed varied behavior in seed quality parameters respective of the variety. It was apparent that germination test alone does not represent the full potential of field emergence. Results of the present study revealed that when field emergence and vigour are also taken in to account, both varieties of bean seeds can be stored under ambient conditions at Gannoruwa, Kundasale or MahaIlluppallama for a maximum period of 12 months, without compromising the seed quality. The seeds stored under low temperature conditions (i.e. 5 °C), maintained the seed germination over 75% for a period of 24 months.

Sustenance of Seed Germination Potential of Two Okra (<em>Abelmoschus esculentus</em> L. Moench) Varieties under Different Environmental Conditions in Sri Lanka

Okra (Abelmoschus esculentus L. Moench) is a popular vegetable grown in most parts of Sri Lanka. Farmers and home gardeners purchase seeds in packed-form from retail outlets. However, quality problems are frequently reported, especially claiming low field germination even with the laboratory-tested and certified seeds. Quality parameters namely, percentage germination, moisture, field emergence and vigour index analysis were used to determine the effect of different storage environmental conditions on seed longevity of two okra varieties during a two-year storage period, from March 2016 to March 2018. Seeds in triple-laminated packets stored in four contrasting environments, namely, low temperature storage conditions (17°C and 60-65% RH); three geoenvironmental conditions namely; Gannoruwa (Mid Country Wet Zone), Kundasale (Mid Country Intermediate Zone), and MahaIlluppallama (Low Country Dry Zone) displayed varied behavior in seed quality parameters respective of the variety. It was apparent that germination test alone does not represent the full potential of field emergence. Results of the present study revealed that when field emergence and vigour are also taken in to account, both varieties of okra seed (with initial germination and moisture of ca. 94% and ca. 10%) can be stored under ambient conditions at Gannoruwa, Kundasale or MahaIlluppallama for a maximum period of 12 months, without compromising the seed quality. The seeds stored under low temperature conditions (i.e. 17°C), maintained the seed germination over 75% for a period of 24 months.

Β-Carotene content of M. Longifolia seed oil in different agro-climatic zones in Sri Lanka, the effect of heat on its stability and the composition of seed cake

M. longifolia is a plant with a seed rich of edible oil (more than 50%), but is still under-utilized for edible purposes in Sri Lankan context. It shows a wide distribution throughout the country representing several agro-climatic zones. No studies have done yet to discover variations of M. longifolia seed oil with respect to its different geographical locations. In this study, the content of β-carotene in M. longifolia seed oil samples obtained from four different agro-climatic zones in Sri Lanka was evaluated. The effect of heat on the stability of β-carotene in M. longifolia seed oil was also studied. Dried, fallen seeds were collected from randomly selected trees in four agro-climatic zones in Sri Lanka named low country dry zone (LD), low country wet zone (LW), low country intermediate zone (LI) and mid country intermediate zone (MI). Oil was extracted with a small scale, mechanical oil expeller (cold pressed method). β-carotene content in four samples was assessed with MPOB test method using Ultraviolet-Visible (UV-VIS) spectrophotometer and with High Performance Liquid Chromatography (HPLC) using Chase et al., (1994) method. A series of heat treatment (50 °C - 300 °C) was given and the content of β-carotene was determined at each temperature with the above mentioned two methods. There were some differences in the content of β-carotene for two types of methods. β-carotene content varies from 17.69 to 13.51 ppm in four agro-climatic zones for HPLC method and 20.46 - 27.69 ppm for spectrophotometric method. The reduction of β-carotene content up to 150 °C from the room temperature (30 °C) was not prominent. But after 150 °C, a sudden, sharp decrease was reported. Nutritional composition of seed cake varied significantly (p <0.05) among the different agro-climatic zones. Protein content, similar to Palm kernel was reported which ranged from 15.44 - 17.76%.

Study on Variation in Seed Morphology, Oil Content and Fatty Acid Profile of Madhuca longifolia Grown in Different Agro-Climatic Zones in Sri Lanka

The aim of this study was to determine the variation in morphology of seeds, seed oil content and the fatty acid profile of M. longifolia and, to find the relationship between oil content and fatty acid composition with environmental conditions. Seeds were collected representing four agro-climatic zones in Sri Lanka. The length (2.7333-3.4333 cm), width (1.0633-1.2967 cm) and the weight (0.9262-1.4018 g) were determined in seeds. Significant differences were there within agro-climatic zones. Oil from seed kernel was extracted with Soxhlet method using n-Hexane (bp. 65-70° C) and the fatty acid profile was determined using GC-MS (Gas chromatography-Mass spectrophotometry). Results reveal significant differences in oil content (50.07-53.85%) among agro-climatic zones. As the major fatty acids, Oleic, Stearic, Palmitic and Linoleic were resulted in all four agro-climatic zones. The total saturated fatty acid content (C18:0, C16:0, C14:0, C17:0, C19:0, C22:0, C24:0, C26:0, C20:0 and C8:0) varied from 40.87-47.20%. However the total unsaturated fatty acid content (C16:1, C18:1, C18:2, C20:1) was within the range of 49.6-53.86% (TMUFA+TPUFA), here the highest content was recorded in low country intermediate zone and the lowest in mid country intermediate zone. Oil content and the fatty acid composition were not correlated with the studied geographical parameters.

TREE-CROP INTERACTIONS IN AGROFORESTRY SYSTEMS INVOLVING DIFFERENT TREE SPECIE

The present experiment was conducted to quantify the variation of soil water content and growth ofthe annual crop when grown in agroforestry systems involving different tree species as contourhedgerows.The final objective is to select a tree species which has a minimum of negativeinteractions (i.e. competition) and a maximum of positive interactions with the annual crop.The experiment was conducted at Pallekelle in the mid-country intermediate zone (1M] ) during theyala season in 1997. TIle experimental site contained five tree species established as hedgerowsalong contours at an inter-hedgerow distance of 4 m. The five tree species were Calliandracalothyrus, Desmodium ranson ii, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia.Bush bean (var, Top crop) was grown as the annual crop between hedgerows at a spacing of 30 em x8 cm. Soil water content was measured gravimetrically in two soil depths (0-10 em and 20-40 em) atthree distances (0-30 ern, 150-180 em and 300-360 em ) from the hedgerow. Measurements weremade at IO-day intervals. Annual crop growth was measured by taking the total dry weight of bushbean at flowering. Dry weight measurements were done at six distances (30, 90, 150, 210, 270 and330 em) from the hedgerows. Measurements were also made in a control treatment which was a solecrop of bush bean without.a hedgerow. Each treatment had three replicates.The soil water content at both depths varied significantly with varying distance from the hedgerowon all dates of measurement. Moreover, there were significant differences between soil watercontents under different hedgerow species at both depths of sampling. The effect of interactionbetween species and distance from the hedge was not significant. Plots with hedgerows had asignificantly greater soil water content in the surface soil layer (0-10 em depth) as compared to thesole crop control on all dates of measurement except at 30 days after sowing (30 DAS). This couldprobably be due to the shading effect of the hedgerows which would reduce evaporation from thesurface layers of the soil. Calliandra and Desmodium had consistently higher soil water contents inthe surface layers. On the other hand, Tithonia had consistently lower surface soil water contents.The soil water content of the 0-10 em depth layer decreased significantly as the distance from thehedgerow increased. TIle greater soil water availability in the surface soil layers closer to thehedgerows could probably be due to the greater shading effect near the hedges.Plots with hedgerows had significantly greater soil water contents at 20-40 em depth than the solecrop control on all dates of measurement. Consistently greater levels of soil water content wereobserved at this depth under Calliandra, Desmodium and Flemingia. Conversely, plots withGliricidia had consishtentiy lower soil water contents at 20-40 ern depth. In contrast to the 0-10 cmlayer, at 20-40 cm depth, the soil water content closer to the hedge (0-30 em) was significantly lowerthan at 150- 180 em and 300-330 cm distances.Total dry weight of bush bean plants showed decreases of varying magnitudes in crop rows closer(30 ern) to the hedgerows. This growth decline was observed under all hedgerow species whereas nosuch decline was observed in the sole cropped control. At a distance closer to the hedgerow (30 em),bean plants had a lower total dry weight than the control under all tree species except Desmodium.Conversely, at a distance of 150 em from the hedgerows, bean plants under all tree species exceptFlemingia had greater total dry weights than the control. The distance from the hedgerow at whichbean plant dry weight was maximum varied For different tree species. This indicated that differenttree species exerted varying levels of competition on the annual crop. The least competition wasexerted by Desmodium followed respectively by Gliricidia, Calliandra, Tithonia and Flemingia.There are significant differences between tree species in the degree of environmental interaction andcompetition exerted by them on the annual crop in agroforestry systems involving tree species ascontour hedgerows.

EVALUATION OF Gliricidia sepium PROVENANCES IN THE INTERMEDIATE ZONE OF SRI LANKA

Seven selected Gliricidia sepium provenances from the Oxford Forestry Institute were evaluated for growth, soil improvement, competition with Agricultural crops and woody biomass production, in two experiments, a pure plot and an alley cropping experiment, at Dodangolla Experiment Station, Kundasale in the intermediate zone of Sri Lanka.The height, basal diameter and number of branches of different provenances differed; but outstanding were local cutting, 17/84 and 14/84 at the first lopping, one year after planting. Height and diameter of local cutting were significantly better than the others due to stage of growth and availability of resource material. In the pure plot experiment the control Acacia showed its best performance in number of branches which was significantly different from G.sepium provenances. In the alley cropping experiment, local cutting and 14/84 showed better yields of agricultural crops compared to other provenances. The woody biomass production was very high in local cutting and 14/84, and significantly better than other provenances. All seven provenances contributed to improvement of soil Nitrogen (N) but only for Phosphorus (P) and Potassium (K), were significant differences observed among the provenances. In soil improvement, the outstanding were 14/86, 10/86, 14/84 and local cutting. These provenances could be recommended for planting for soil improvement.After evaluating for growth, soil improvement and woody biomass production, local cutting (the best performer), 17/84, and 14/84 could be recommended as more suitable for planting in the mid-country intermediate zone of Sri Lanka.

A comparison of methods used in estimating missing rainfall data

Precipitation or rainfall (in tropics) is an important climatic parameter and the studies on rainfall are commonly hampered due to lack of continuous data. To fill the gaps (missing observations) in data, several interpolation techniques are currently used. However, the lack of knowledge on the suitability of these methods for Sri Lanka is a practical problem. In view of this problem, this study is aimed at comparing a few selected methods used for the estimation of missing rainfall data with a new method introduced by the authors to determine their suitability in Sri Lankan context. The methods studied were Arithmetic Mean (Local Mean) method, Normal Ratio method and Inverse Distance method. The new method introduced by the authors is named as Aerial Precipitation Ratio method.In this approach, rain gauging stations where complete monthly rainfall data sets are available were selected in such a way that the selected stations represent each of the seven major Agro-ecological zones of Sri Lanka. This selection procedure of stations makes it possible to generalize the results to the entire country. The period of data ranged from 15 years in the case of mid country intermediate zone to 28 years Up country intermediate zone and Mid country wet zone. Subsequently, monthly rainfall data of each station were estimated using the data of surrounding stations based on the above selected methods so that actual data and the estimated data can be compared. Each estimated series was compared with the actual data series using different statistical comparison techniques. These comparisons include Descriptive Statistics of Error, Root Mean Square Error, Mean Absolute Percentage of Error and Correlation Coefficient. Results of the study show that the Inverse Distance method is the most suitable method for all three Low-country zones (wet, intermediate, and dry). However, for Mid-country and Upcountry Intermediate zones, Normal Ratio method is the most suitable method. Further, Arithmetic Mean method is more appropriate for Upcountry Wet zone while Aerial Precipitation Ratio method is more suitable for Mid-country Wet zone.

Competition between six hedgerow tree species and mung bean (Vigna radiata (L.)Wilczek) in the mid-country intermediate zone

The Journal of the National Science Foundation of Sri Lanka publishes the results of research in all aspects of Science and Technology. The journal also has a website at http://www.nsf.gov.lk/. 2021 Impact Factor: 0.682The JNSF provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge.