Browsing by Author "Kumudika, W.A.H."

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    Investigation on Durable Plant Materials as Alternative Sources of Mulch in Tea New Clearings in the Upcountry Intermediate Zone
    (Uva Wellassa University of Sri Lanka, 2020) Kumudika, W.A.H.; Premathilake, K.G.; Leelarathne, C.
    Mulching as a cultural technique is an eco-friendly practice to manage weeds. Hence, a field experiment was conducted to investigate the potential use of different plant materials as mulches in a tea new clearing at Ury estate, Passara, from September to December 2019. Tertiary branches of Acacia mangium (Acacia), Cassia spectabilis (Kahakona), Grevillea robusta (Sabukku) with leaves, and Megathyrsus maximus (Guinea grass) were used as treatments and Cymbopogon confertiflorus (Mana grass) was used as the ‘Control’. Each mulch was spread on randomly selected tea plots each sized 14.4 m2 at a rate of 1 kg dry matter m-2 and replicated three times. The rate of decomposition of each material was assessed in terms of ground exposure percentage and weight reduction in litter bags filled with each mulch material at fortnight intervals. Weed density and weed dry weight were measured at 2 and 4 weeks intervals, respectively. Plant growth parameters were measured before and after 12 weeks mulching. Soil moisture and soil carbon content were measured. A bioassay was also conducted for any allelopathic effect of mulch materials. Half-life (time taken for 50% ground exposure) as 8.1, 9.2, 10.0, 10.3, 12.0 weeks was recorded for Kahakona, Acacia, Guinea grass, Mana grass, and Sabukku respectively. Whilst, the same was recorded as 100%, 98%, 88%, 68%, and 50% respectively 12 weeks after mulching. The weight of Sabukku mulch was significantly higher (p<0.05) than other materials. Weed density and weed dry weight were significantly lower with Sabukku. Tea growth was not significantly affected by any treatment. Guinea grass and Sabukku were found to be increased the soil carbon level while high moisture content was recorded underneath the mulch of Mana and Sabukku. Sabukku was found to be more durable and could effectively suppress weed growth. Guinea grass and Mana grass showed some comparable performances. Sabukku and Guinea grass can be used as alternatives mulches for Mana grass Keywords: Allelopathic effect, Decomposition of mulch materials, Suppression, Tea, Weed growth.
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    Investigation on Durable Plant Materials as Sources of Mulch in Tea New-Clearings in the Upcountry Intermediate Zone
    (Uva Wellassa University of Sri Lanka, 2015) Kumudika, W.A.H.
    With the restrictions imposed for the use of chemical herbicides in tea emphasis is to be given to cultural and ecological weed management strategies. Ground coverage with use of dead plant materials is an eco-friendly practice to manage weeds. Currently two grass species have been recommended for mulching tea field However, mulching is practiced at a minimum level due to scarcity of materials and high cost. Hence, a field experiment was conducted to investigate the potential of using plant materials as alternative mulches in a tea new clearing at Ury estate, Passara, of the Balangoda plantations PLC, during September to December 2019. Tertiary branches of Acacia mangium (Acacia), Cassia spectabilis (Kahakona), Megathyrsus maximus (Guinea grass) and Grevillea robusta (Sabukku) were used as treatments and Cymbopogon confertiflorus (Mana grass) was used as the 'Control'. Each mulch was spread on randomly selected plots each sized 14.4m2 at a rate of 1 kg dry matter rn-2 and replicated three times. The rate of ground exposure occurred in concurrence of mulch break down was visually assessed every other week. Weed density (counts ft-2) was measured at fortnight interval and weed dry weight was measured at four weeks interval. A bioassay was also carried out to study any allelopathic effect of same mulches on the suppression of weeds. Tea plant growth was also measured. Soil moisture, soil pH and soil P and Soil C content were measured. Half-life (time taken for the 50% ground exposure) as 8.1, 9.2, 10, 12, 10.3 weeks was reported for C. spectabilis, A. mangium, M maximus, G. robusta, and C. confertiflorus respectively. The weight of a bagged mulch material of C. spectabilis and A. mangium was significantly lower than the other treatments while the highest weight of bagged mulch was reported with G. robusta. Weed density and weed dry weight were also significantly lower with G. robusta. C. spectabilis and C. confertiflorus showed some allopathic potential to suppress weed growth. Megathyrsus maximus shows some improvement in soil C and P. Tea growth was not significantly affected by any treatment. The highest soil moisture content and soil pH was recorded for C. confertiflorus. G. robusta was found to be more durable hence, weeds were effectively controlled compared to other mulches. Grevillea robusta and Megathyrsus maximus can be used as alternative mulching materials. Keywords: Ground exposure, Mulching materials, Tea, Weed growth