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Viacheslav Eremeev Juhan Jotildeudu Peeter Lääniste Erkki Mäeorg Arvo Makke Liina Talgre 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):236-244
Abstract In field trials conducted in 2000–2002, we examined the influence of pre-planting treatments of seed tubers on the formation of leaf area index. The potato varieties used were Agrie Dzeltenie (early), Piret (middle-maturing) and Ants (late). The following treatments were used: untreated control, thermal shock and pre-sprouting. Pre-sprouting treatments of all varieties and thermal shock treatment of the variety Agrie Dzeltenie had a significant effect on the leaf area index. The value and timing of maximum leaf area index were: variety specific, 4.0 units of the early variety Agrie Dzeltenie, 3.7 units of the middle-maturing variety Piret and 3.9 units of the late variety Ants. The weight of the haulms of the plants developed from physiologically older seed tubers formed faster and remained smaller. Pre-planting treatment of seed tubers provided quicker field emergence. The slower the potato plants developed the haulms, the greater the maximum weight achieved. Pre-planting treatments influence the leaf area index. The importance of this influence lies in potato varieties with different maturity times since increases in quality and yield depend on the size of the photosynthetic area. 相似文献
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Peeter Lääniste Juhan Jõudu viacheslav Eremeev Erkki mäeorg 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(4):342-348
Abstract In 2001–2005 an overwintering investigation of winter oilseed rape (Brassica napus L.) was carried out at the Institute of Agricultural and Environmental Sciences of the Estonian University of Life Sciences. In our trial we used two winter oilseed rape varieties: ‘Wotan’ and ‘Express’. The sowing was performed at four different times, with weekly intervals: 8, 15, 22 and 29 August. The soil type was Stagnic Luvisol by WRB classification; the texture was sandy loam with a humus layer of 20–30 cm. Our research indicated that successful wintering of winter oilseed rape depends directly on sowing date. From the data obtained it may be seen that differences between sowing dates and overwintering were statistically significant. Overwintering depends on numbers of growing-degree-days (GDD) in the autumn vegetative period. Three years’ data showed that in the autumn period plants need 416 GDD for developing a strong root system and to prepare for wintering. 相似文献
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Vasenev Viacheslav I. Morel Jean Louis Nehls Thomas Shaw Richard K. Kim Kye John Hajiaghayeva Ramilla A. 《Journal of Soils and Sediments》2019,19(8):3123-3126
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Viacheslav I. Kharuk Valeriy V. Kuzmichev Sergey T. Im Kenneth J. Ranson 《Scandinavian Journal of Forest Research》2014,29(5):421-426
Birch (Betula pendula Roth) growth within the Western Siberia forest-steppe was analyzed based on long-term (1897–2006) inventory data (height, diameter at breast height [dbh], and stand volume). Analysis of biometry parameters showed increased growth at the beginning of twenty-first century compared to similar stands (stands age = 40–60 years) at the end of nineteenth century. Mean height, dbh, and stem volume increased from 14 to 20 m, from 16 to 22 cm, and from ～63 to ～220 m3/ha, respectively. Significant correlations were found between the stands mean height, dbh, and volume on the one hand, and vegetation period length (rs = 0.71 to 0.74), atmospheric CO2 concentration (rs = 0.71 to 0.76), and drought index (Standardized Precipitation-Evapotranspiration Index, rs = ?0.33 to ?0.51) on the other hand. The results obtained have revealed apparent climate-induced impacts (e.g. increase of vegetation period length and birch habitat drying due to drought increase) on the stands growth. Along with this, a high correlation of birch biometric parameters and [CO2] in ambient air indicated an effect of CO2 fertilization. Meanwhile, further drought increase may switch birch stand growth into decline and greater mortality as has already been observed within the Trans-Baikal forest-steppe ecotone. 相似文献
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Viacheslav I. Adamchuk Eric D. Lund Todd M. Reed Richard B. Ferguson 《Precision Agriculture》2007,8(3):139-149
Since conventional sampling and laboratory soil analysis do not provide a cost effective capability for obtaining geo-referenced
measurements with adequate frequency, different on-the-go sensing techniques have been attempted. One such recently commercialized
sensing system combines mapping of soil electrical conductivity and pH. The concept of direct measurement of soil pH has allowed
for a substantial increase in measurement density. In this publication, soil pH maps, developed using on-the-go technology
and obtained for eight production fields in six US states, were compared with corresponding maps derived from grid sampling.
It was shown that with certain field conditions, on-the-go mapping can significantly increase the accuracy of soil pH maps
and therefore increase the potential profitability of variable rate liming. However, in many instances, these on-the-go measurements
need to be calibrated to account for a field-specific bias. After calibration, the overall error estimate for soil pH maps
produced using on-the-go measurements was less than 0.3 pH, while non-calibrated on-the-go and conventional field average
and grid-sampling maps produced errors greater than 0.4 pH. 相似文献
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An instrumented blade system for mapping soil mechanical resistance on-the-go was developed. The system consists of a cutting edge that transfers the load from cutting through soil media to a vertical shank equipped with an array of strain gage bridges. The resulting force is transferred between the cutting edge and the blade at three distinct locations and the soil mechanical resistance profile is modeled as a second-order polynomial. The geometry of the blade was determined using an optimization procedure minimizing the total error associated with potential strain gage noise. The instrument was built and calibrated using a set of known point loads. It was found that signal adjustment was needed in order to account for the mechanical transfer of force through the cutting edge. This adjustment was applied using a set of coefficients found through a multiple linear regression. Coefficients of determination, R2, for regressions between adjusted and theoretical second-order profiles were greater than 0.99. Results of field evaluation and discussion on the potential applicability of the system developed will be presented in a follow-up publication. 相似文献