http://repository.rjt.ac.lk/handle/123456789/4977 2026-04-13T07:00:44Z 2026-04-13T07:00:44Z De Silva, A.G.S.D. Abeysingha, N.S. Duminda, D.M.S. http://repository.rjt.ac.lk/handle/123456789/4984 2025-10-10T04:21:44Z 2019-12-01T00:00:00Z

Trace elements in commercially available Triple Super Phosphate Fertilizers in Sri Lanka De Silva, A.G.S.D.; Abeysingha, N.S.; Duminda, D.M.S. This study tested the trace elements in commonly used Triple Super Phosphate (TSP) fertilizers in Sri Lanka. TSP samples collected from two Fertilizer Companies (A and B) were used. Six replicates of each company fertilizers were digested following the method of the Association of Official Agricultural Chemists. The concentration of eleven trace elements (Cr, Mn, Cu, Cd, Pb, Zn, Fe, Ni, Co, Mo and As) in each TSP fertilizers were determined by ICP-OES as an analytical technique. ICP-OES analysis revealed a group of non-lethal metal species, present as impurities. The highest average concentrations were, 4229.30 mg of Fe, 469.16 mg of Mn, 195.34 mg of Zn, 8.73 mg of Ni, 7.78 mg of Cu, 2.36 mg of Co and 1.39 mg of Mo per kg-1 of fertilizer. Considerable amount of hazardous elements such as Pb, Cr, As and Cd were detected with average concentrations of 53.93 mg of Pb, 25.56 mg of Cr, 3.19 mg of As, 1.05 mg of Cd per kg -1 of fertilizer, respectively. Trace metal concentrations of samples collected from two fertilizer companies were compared using two sample t–test (α = 0.05). It was observed that, Mn, Cu and Zn were significantly higher in company A fertilizer samples than those of the company B. Concentrations of Cr, Cd, Pb, Fe, Co and Mo were significantly lower in company A fertilizer samples compared to samples of company B. However, there was no significant difference in concentrations of Ni and As contents in fertilizer samples of company A and company B. This study suggests the future course of action for the quality of the TSP fertilizer imported and the protocol or an act to regulate the standard limits of metal impurities present in TSP fertilizers imported to Sri Lanka.

2019-12-01T00:00:00Z Wijayawardhana, D. Herath, V. Weerasinghe, P.A. http://repository.rjt.ac.lk/handle/123456789/4983 2025-10-10T04:31:34Z 2019-12-01T00:00:00Z

Cadmium Tolerance of Rice (Oryza Sativa L.): Effects on Plant Growth and Physiology Wijayawardhana, D.; Herath, V.; Weerasinghe, P.A. The effects of cadmium (Cd) toxicity on plant growth and physiology were investigated in rice (Oryza sativa L.) grown in sand medium. Suwandel and Bg300 rice varieties were evaluated against 0, 0.5 and 3 mg kg-1 Cd levels using thirteen plant growth and physiological parameters. The only parameter that influenced by the rice variety and Cd level interaction effect was the transpiration rate. All other parameters were not changed significantly by the said interaction effect. Cadmium level of 3 mg kg-1 significantly decreased the shoot dry weight and photosynthetic rate. It also increased the transpiration rate of Suwandel variety. Hence, 3 mg kg-1 level was the most critical one for shoot dry weight, photosynthetic rate and transpiration rate. However, Cd levels were not significantly changed plant height, leaf area, root dry weight, death leaf percentage, relative leaf chlorophyll content, stomatal conductance to H2O, intercellular CO2 concentration, computed leaf temperature, cell membrane permeability and relative water content. This concluded that Bg300 and Suwandel can compensate the toxic effects exerted by 0.5 and 3 mg kg-1 Cd levels without affecting the plant growth and physiology.

2019-12-01T00:00:00Z Pokharel, Sujan Poudel, Kabita Suraj, K.C. Adhikari, Sabuj Giri, Kushal Shriwastav, C.P. http://repository.rjt.ac.lk/handle/123456789/4982 2025-10-10T04:05:37Z 2019-12-01T00:00:00Z

An Economic Analysis on Production and Marketing of Rapeseed in Kailali, Nepal Pokharel, Sujan; Poudel, Kabita; Suraj, K.C.; Adhikari, Sabuj; Giri, Kushal; Shriwastav, C.P. A study was conducted in 2019 to analyze the economics of production and marketing of rapeseed in Kailali district of Nepal. This study used 127 rapeseed farmers which were selected by simple random sampling technique to study the production aspects and to study marketing aspects, 5 local traders, 5 wholesaler/commission agents and 3 processors were surveyed. Descriptive statistics and chi-square test were used for data analysis using SPSS and MS-Excel. Farmers were categorized into large farmer (n=45) and small farmer (n=82) based on rapeseed farm size category. The average area under rapeseed production was 0.53 ha. Rapeseed was found to be a profitable enterprise which has the benefit-cost ratio of 1.55. Benefit-cost ratio of large farms (1.74) was found to higher as compared to small farms (1.46). It was found that rapeseed sub sector contributes about 9.2 percent of household income in the study area. Human labor (40.08% of total variable cost) was an important and largely used input in the production of rapeseed. On an average, marketed surplus was found to be 55.2 percent of total produce. The marketed surplus was higher in case of large farms (58.4%) as compared to small farms (46.8%). It was found that Channel II (Producer-Local collector-Wholesaler/commission agent-Processor) was the most adopted marketing channel for rapeseed marketing. The marketing cost (NRs 340/quintal) and market margin (NRs 450/quintal) was found to be higher in case of Channel II. Unavailability of inputs, lack of irrigation facilities, low price of output and incidence of disease and pests were the major problems of rapeseed production and marketing.

2019-12-01T00:00:00Z Ranaweera, L.T. Jayarathne, H.S.M. Gayathree, T.H.I. Karunarathne, S.I. Kannangara, S.K. Ananda, G.K.S. Ranasinghe, R.D.G.A. Weebadde, C.K. Sooriyapathirana, S.D.S.S. http://repository.rjt.ac.lk/handle/123456789/4981 2025-10-10T03:53:19Z 2019-12-01T00:00:00Z

Discrimination of the Species and Toxic Heavy Metal Contents of Alternanthera Sessilis (Sessile Joyweed), A. Philoxeroides (Alligator Weed) and Other Related Alternanthera Species Ranaweera, L.T.; Jayarathne, H.S.M.; Gayathree, T.H.I.; Karunarathne, S.I.; Kannangara, S.K.; Ananda, G.K.S.; Ranasinghe, R.D.G.A.; Weebadde, C.K.; Sooriyapathirana, S.D.S.S. Alternanthera sessilis [sessile joyweed (SJ)] is a staple leafy vegetable in Sri Lanka. However, A. philoxeroides [alligator weed (AW)] often gets mixed up with SJ due to the similar appearance. Alligator weed is an invasive species and also bio-accumulate toxic heavy metals. Genus Alternanthera has some other species that are occasionally being consumed in rural areas as leafy vegetables or grown as ornamental plants. It is essential to delimit AW from SJ and the rest of the Alternanthera species and study the heavy metal profiles of the shoot-top samples. In the present study, the species delimits and the phylogenetic relationships of the commonly grown A. philoxeroides, A. sessilis, A. caracasana, A. paronychioides, A. ficoidea, and A. bettzickiana were assessed using rbcL, ITS and matK-trnT DNA barcoding markers. The composition of the heavy metals in the market samples of the AW and SJ and field-grown samples of the other species were assessed using X-ray fluorescence (XRF) and Atomic Emission Spectroscopy (AES) methods. A. philixeroides and A. sessilis are positioned as sister taxa showing the close evolutionary relationship. The results showed that AW contains the highest amounts of the heavy metals, Pb and Sn. Red-SJ, a type of A. sessilis, contains the highest amount of As. The market samples of LS-1 and LS-2 did not contain significant levels of toxic heavy metals. The haplotypes of the markers ITS, and matK-trnT provide a clear basis to discriminate AW from the other Alternanthera spp.

2019-12-01T00:00:00Z