Joint International Conference on Long-term Experiments ...

Table 2: Yield losses millet hay due to petroleum polution. (q/ha) 1993-1995
Variant
Years (Y) Average Semnification
(V) 1993 1994 1995 1993-1995
(%) (q/ha) (q/ha) (q/ha) q/ha Diference V VxY
0 - - - 34,2 - - -
1 -3,4 -10,2 -4,0 28,3 -5,9 ooo -
3 -5,5 -18,7 -10,0 22,2 -11,4 ooo oo
5 -7,4 -27,2 -14,3 17,9 -16,3 ooo oo
10 -11,2 -29,2 -18,7 14,5 -19,7 ooo ooo
1993 1994 1995 Variant (V) Variant x Years (VxY)
DL 5 % 2,46 5,25 5,56 2,49 7,83
DL 1 % 3,46 7,37 7,80 3,33 11,39
DL 0,1 % 4,88 10,41 11,02 4,39 17,09
3. Average annual yield in spring wheat from the unpolluted witness parcels, were
between 21,8 q/ha , in the 4 th year of observation (1996) and 4 q/ha in 2000 (which was
considered to be one of the years with most drought ever) (Figure 3.)
Yields (q/ha)
25
20
15
10
5
0
2002
2001
2000
1999
1998
1997
0 1 3 5 10 1996
Petroleum concentration (%)
Figure 3. Annual spring wheat yield (q/ha)
The yields from the variant`s repetition had a linearly evolution in each and every one
of the seven years with spring wheat crop (1996-2002), inverse proportional with the
petroleum concentration from the ploughed layer. The linearly correlations thus
established are significant statistically, in the first five years of the interval (R = 0,8096
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