Agriculture, Vol. 25 No. 2, 2019.
Original scientific paper
https://doi.org/10.18047/poljo.25.2.3
Use of a chlorophyll meter to evaluate the ripeness of flue-cured tobacco leaves for harvesting
Kristina Gršić
; Croatian Agency for Agriculture and Food, Plant Protection Center, Gorice 68b, 10000 Zagreb
Miroslav Čavlek
orcid.org/0000-0001-8242-4752
; Tobacco Institute Zagreb Ltd., Svetošimunska cesta 25, 10000 Zagreb
Abstract
In order to determine the possibility of using chlorophyll meter to estimate the optimal ripeness of flue-cured tobacco leaves for harvest, two-year field experiments were carried out. Treatments in the experiments were fertilization with nitrogen (25 and 35 kg ha-1) and harvesting time (early, middle and late harvest). The relative chlorophyll content of leaves 7, 11, 15 and 17 was measured at harvest time. After harvesting and drying these leaves, yield and price, as well as the content of nicotine and reducing sugars, were analysed. There was no significant influence of nitrogen fertilization on average yield, price and reducing sugars content. However, two interactions fertilization x harvesting time for yield were obtained. Higher nitrogen fertilization resulted in higher average nicotine content, but only in the 15th and 17th leaf in 2010. Given the time of harvest, the results of the research, with a few exceptions, showed that higher yields, prices, nicotine contents and reducing sugars contents were achieved in the middle and/or late harvest. To find the chlorophyll content index range within which the tobacco leaf harvests should be carried out, the mathematical parameters of the relationship between chlorophyll content index at harvest and investigated properties were used. In this study, the optimal time for tobacco leaf harvesting was in the chlorophyll content index range of 11 to 15 CCI.
Keywords
flue-cured tobacco; nitrogen fertilization; time of harvest; chlorophyll content index
Hrčak ID:
229475
URI
Publication date:
5.12.2019.
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