Tag Archives: leaf area index

21-30 V. Eremeev, A. Lõhmus and J. Jõudu
Effects of thermal shock and pre-sprouting on field performance of potato in Estonia
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Effects of thermal shock and pre-sprouting on field performance of potato in Estonia

V. Eremeev, A. Lõhmus and J. Jõudu

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences(EMU), Kreutzwaldi 64, EE51014 Tartu, Estonia;e-mail: Viacheslav.Eremeev@emu.ee

Abstract:

Pre-sprouting (PS), and to a lesser degree, pre-planting thermal shock (TS) had positive effects on tuber yield and other performance indicators. The experiment was carried out during the 2000, 2001 and 2002 growing seasons in the Department of Field Crop Husbandry of the Estonian University of Life Sciences. An untreated control (0) was comparedοοwith TS (2 days at 30 C, then 5 days at 12–15 C in a lighted room just prior to planting) and PSο(35–38 days before planting in a humid (85–90%) and lighted room at 12–15 C). All treatments were applied to three varieties: ‘Agrie Dzeltenie’ (early), ‘Piret’ (medium early) and ‘Ants’ (medium late). In the present study, the TS accelerated the emergence of plants by 2–5 days and PS by 7–12 days. Averaged over 3 years and 3 varieties, maximum leaf area index (LAI, 3.9 units) was reached 74 days after planting (DAP) and on the 50th day after emergence. Maximum LAI was 3.7 at 72 DAP for PS, 3.8 at 73 DAP for TS, and 4.1 at 76 DAP for the control. TS accelerated the beginning of tuber formation by about 5 days compared to the control, but the tuber yield of the control equalled TS from 65 days onward. Tuber formation began even slightly earlier in the PS treatment, and tuber yield exceeded PS throughout the season. All treatments reached maximum yield by 120 DAP.

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293-297 A. Marcinkevičienė, S. Raudonius and R. Velička
Weed suppression by increasing spring rape crop density
Abstract |
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Weed suppression by increasing spring rape crop density

A. Marcinkevičienė, S. Raudonius and R. Velička

Lithuanian University of Agriculture, Studentu 11, Akademija, Kaunas district, LT-53067,Lithuania, e-mail: lzuustotis@hotmail.com, steponas.raudonius@lzuu.lt

Abstract:

Field experiments were conducted in 2003 and 2004 at the Experimental Station of the Lithuanian University of Agriculture to study the influence of different spring rape (Brassica napus L.) densities (50.1–100, 100.1–150, 150.1–200, 200.1–250, 250.1–300, 300.1–350, 350.1–400, 400.1–450 plants m-2) on weed abundance. Increase of crop density and herewith increase of canopy should intensify the competition ability of spring rape plants and suppress weeds better. The results show that light intensity on the soil surface decreases when the assimilation area of spring rape leaves and total crop biomass increases. Weed density decreases when spring rape crop is densier. A significant negative relationship exists between weed biomass and spring rape leaf area index (LAI) (r = -0.62, P < 0.05), as well as between weed biomass and spring rape biomass (r = -0.67, P < 0.01). A significant positive correlation appears between weed abundance and light intensity on soil surface (r = 0.68, P < 0.01).

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