Proceedings of the III. Alps-Adria Scientific Workshop, Dubrovnik, 1-6 March 2004. Croatia.
(Szilvia H and Gyuricza C. Editors) Hungarian Academy of Sciences Budapest. P. 295-299.
PRECIPITATION INFLUENCES ON MAIZE YIELDS IN EASTERN
CROATIA
Kovacevic Vlado
Faculty of Agriculture, Trg sv. Trojstva 3, HR-31000 Osijek, Croatia
Introduction
Maize is the most widespread crop on arable lands in Croatia. It occupies nearly
0.5 million hectares or nearly a third of arable land areas of the country. Maize
grain yields in eastern Croatia are about 30% higher in comparison with mean
yields of the country. Besides the degree of soil fertility, precipitation quantities
and their distribution during a growing season significantly influence maize
yields as well. In general, under environmental conditions of eastern Croatia,
there is usually a close connection between low maize yields and precipitation
shortage, especially during the two summer months, July and August
(Kovacevic and Josipovic 1998, 2001). These findings are consistent with
experiences from the USA Corn Belt (Shaw, 1988).
Material and methods
The data of State Bureau for Statistics were used as the source of grain yields
data. The eastern Croatia region covered 11,090 km2 until 1992. It was divided
in 14 municipalities. The following four former municipalities were chosen for
our study: Vukovar (VU) and Osijek (OS) = eastern part; Donji Miholjac (DM)
and Podravska Slatina (PS) = western part of the region.
Due to war escalation in Croatia in the period from 1991 to 1995, the official
statistics represent data collected only from the non-occupied territory of the
country. Also, maize yields in this period were low mainly due to war-induced
factors and did not result only from weather and soil characteristics. Therefore,
only data for the 1996-2003 period were shown.
Since 1992, according to the new territorial division eastern Croatia includes
five counties (c) with the total area of 12.452 km2: Vukovar-Sirmium (VSc),
Osijek-Baranya (OBc), Brod-Posavina (BPc), Pozega-Slavonia (PSc) and
Virovitica-Podravina (VPc) County. Yield data for the entire region and three
counties (VSc, OBc and VPc) for the 1996-2003 period were shown.
Soil characteristics of the Eastern Croatia
Pedologic characteristics of the Eastern Croatia elaborated in detail by Janekovic
(1971), Kovacevic and Basic (1997). On the Pleistocene terrace and plateaus of
the Eastern Croatia there is a succession of climatozonal soil complexes. From
east to west there is a zonal decrease in soil fertility. As the physical and
chemical soil properties deteriorate, the soil profile is increasingly impaired
(Fig. 1).
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Proceedings of the III. Alps-Adria Scientific Workshop, Dubrovnik, 1-6 March 2004. Croatia.
(Szilvia H and Gyuricza C. Editors) Hungarian Academy of Sciences Budapest. P. 295-299.
Soil types
S = Brown soil
LS = Lessive
brown soil
L = Lessive soil
PG = Pseudogley:
lessive and
marbled PG
Fig 1. Scheme of soil zonality in the Eastern Croatia (Janekovic 1971):
climatogenic zonal soils (I), intrazonal hydrogen soils (II), intrazonal substratogenic
soils of mountain part above 230 mm of sea level (III) and intrazonal substratogenic
soils on relict sand substrate (IV).
Results and discussion
Considerable variation of maize grain yields among years as well as among
different parts of Eastern Croatia for 30-year (1961-1990) period (Table 1) and
for 1996-2003 period (Table 2) were found. Increased yield trends for long
period is possible to explain by improvement of crop and soil management
practices as well as creating of high-yielding hybrids.
Affected by soil characteristics, higher grain yields of maize were found in the
eastern part of the region compared to its western part. For example, mean grain
yield of maize in the DM and PS was 22% lower than in VU and OS area (5.84
and 4.58 t ha-1, respectively). Differences of maize yields were found between
VU and PS areas (6.00 and 4.14 t ha-1, respectively). Yield differences in the
same period for individual parts of province could be explained only by soil
factors, since weather conditions, soil and crop management practices as well as
choice of maize hybrids are similar for the region.
Weather differences among individual growing seasons are more responsible
factor of maize yields for a short period. For example, in the three more
favorable seasons (MFS=1982, 1984 and 1986) mean maize yield in the region
totaled 6.69 t ha-1, whereas in the three less favorable seasons (LFS=1978, 1980
and 1988) it was 5.11 t ha-1 or 24% lower. Analogical data for the VU area were
7.94 and 6.38 t ha-1 and for PS area 5.34 and 4.14 t ha-1, respectively (Table 1).
The amount of precipitation for 4-month period (May-August) was lower in the
LFS (3-year means for four tested localities: 285 and 237 mm, for the MFS and
LFS, respectively), whereas at the same time precipitation in July was nearly
40% lower (65 and 40 mm, respectively).
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Proceedings of the III. Alps-Adria Scientific Workshop, Dubrovnik, 1-6 March 2004. Croatia.
(Szilvia H and Gyuricza C. Editors) Hungarian Academy of Sciences Budapest. P. 295-299.
Table 1. Maize harvested area (ha) and grain yields (t ha-1) in the Eastern Croatia
for the period 1961-1990 (Kovacevic and Josipovic, 2001)
The Eastern Croatia: Maize harvested area (ha) and grain yields (t ha-1)
The 1961-1970 period
The 1971-1980 period
The 1981-1990 period
-1
-1
Year
ha
t ha
Year
ha
t ha
Year
ha
t ha-1
1961 173 579 2.74
1971 208 892 4.06
1981 214 301 5.72
1962 171 546 3.28
1971 195 942 4.67
1982 201 268 6.40
1963 166 810 3.26
1973 216 172 4.30
1983 209 305 6.40
1964 168 346 3.99
1974 192 182 5.16
1984 206 779 7.08
1965 196 690 3.48
1975 221 632 5.14
1985 221 395 6.26
1966 188 918 4.15
1976 201 462 4.76
1986 217 788 6.59
1967 206 666 4.10
1977 196 650 5.80
1987 197 149 5.33
1968 200 333 3.69
1978 180 862 5.14
1988 209 768 4.78
1969 202 920 4.26
1979 196 632 5.87
1989 208 312 5.46
1970 194 981 4.21
1980 189 692 5.42
1990 234 148 4.31
Mean 187 079 3.72 Mean 200 012 5.03 Mean 212 021 5.83
In the 1996-2000 period, maize harvested area in the region decreased about
20% in comparison with 10-year mean of 1981-1990, whereas yields showed
mild increasing trend (Tables 1 and 3). Since 1996 yield variation among years,
as well as its dependences on water regime had similar trend as in the previous
tested periods (Table 2). Especially low maize yield in the region in 2000 (34%
lower in comparison with four previous years) is mainly influenced by water
shortage. For example, the amount of precipitation in Osijek for the period MayAugust in 2000 was 107 mm or only 40% in comparison with 30-year mean
(1961-1990). Under these environmental conditions, maize yield differences
between more fertile aerated soils of the eastern part of the region (e.g. VSc
area) and less fertile compacted soils in its western part (e.g. VPc area) are very
small (Table 3). Main reason for this phenomenon is better ascent of
underground water in compacted soils.
The 2003 growing season was especially unfavorable for maize growing
because of water shortage. For example, precipitation in 4-months May-August
period was only 162 mm (the data of Osijek Waether Bureau) and it is for 40%
lower in comparison with 30-years mean (1961-1990). Under these conditions,
maize yield in Eastern Croatia (Table 3) was only 4.53 t ha -1 or 37% lower in
comparison with previous year (7.21 t ha-1). Yield difference between 2002 and
2003 growing season is mainly affected by precipitation quantity (May-August:
368 and 162 mm, for 2002 and 2003, respectively).
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Proceedings of the III. Alps-Adria Scientific Workshop, Dubrovnik, 1-6 March 2004. Croatia.
(Szilvia H and Gyuricza C. Editors) Hungarian Academy of Sciences Budapest. P. 295-299.
Table 2. Maize grain rain yields (t ha-1) and precipitation for the 1961-1990
period (Kovacevic and Josipovic, 2001)
Maize
grain yields
(t ha-1)*
Precipitation (mm): data of the Weather
Bureaus Vukovar (VU), Osijek (OS), Donji
Miholjac (DM) and Podravska Slatina (PS)
Year
May-August
July
VU OS DM PS VU OS DM PS VU OS DM PS
1961 3.14 3.04 2.03 2.94 163 239 239 320
26 58
62 77
1962 3.73 4.09 3.18 2.89 176 194 256 297 103 119 106 124
1963 4.07 4.15 3.03 3.08 240 272 274 312
44 61
37 58
1964 4.67 4.99 4.27 3.57 294 305 380 358
61 83
94 74
1965 4.09 4.39 4.19 2.98 306 303 354 393
36 56 103 96
1966 5.60 5.41 4.52 3.65 256 276 329 393
99 83 109 144
1967 6.20 5.21 3.81 3.38 224 207 291 289
83 61 159 90
1968 4.73 4.30 3.86 3.21 237 274 256 253
55 41
77 49
1969 5.60 5.27 4.41 3.97 285 314 201 396
27 57
33 57
1970 5.92 4.96 4.60 3.65 405 276 338 308
85 56
55 91
Mean 4.78 4.58 3.79 3.33 258 266 292 332
62 68
84 86
1971 5.43 5.45 4.04 3.89 178 197 218 222
18 29
22 53
1971 6.34 5.61 4.23 3.51 445 503 558 625 185 274 267 289
1973 6.55 5.27 4.56 3.33 296 237 236 221
61 119
94 66
1974 6.38 6.01 5.29 4.56 364 351 484 530
69 62
58 67
1975 6.86 5.80 4.61 4.16 550 373 410 505
97 89
90 81
1976 6.63 5.48 4.56 3.96 373 262 259 288 110 26
31 73
1977 7.46 6.38 5.96 4.68 258 237 276 219
85 57
79 73
1978 6.78 6.07 4.42 3.83 240 248 250 268
27 41
61 58
1979 7.46 6.37 5.34 4.75 270 195 205 270 117 92
87 113
1980 7.02 6.50 5.36 4.05 307 300 217 275
32 58
38 39
Mean 6.69 5.89 4.84 4.07 328 290 311 342
80 85
83 85
1981 6.15 6.10 6.32 4.80 298 280 233 304
28 28
29 28
1982 7.40 7.70 7.12 5.00 294 267 273 353
95 80
73 86
1983 7.57 8.01 6.97 5.41 314 204 324 280 126 43
97 74
1984 8.43 8.30 7.72 5.22 331 237 332 320
53 37
47 75
1985 7.80 6.82 6.71 5.05 257 271 240 274
44 30
29 38
1986 8.00 7.51 7.05 5.81 235 201 248 335
50 41
62 76
1987 6.38 6.17 6.50 5.22 250 309 298 264
20 33
45 33
1988 5.33 5.59 5.06 4.53 161 184 163 237
8 29
43 48
1989 4.46 6.05 6.62 4.60 359 331 337 484
99 15
20 21
1990 3.78 3.74 4.35 4.43 238 208 154 180
53 39
37 41
Mean 6.53 6.60 6.44 5.01 274 249 260 303
58 38
48 52
30-y 6.00 5.69 5.02 4.14 287 269 288 326
67 64
72 74
* the municipality: VU=Vukovar, OS=Osijek, DM=D.Miholjac, PS= P. Slatina
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Proceedings of the III. Alps-Adria Scientific Workshop, Dubrovnik, 1-6 March 2004. Croatia.
(Szilvia H and Gyuricza C. Editors) Hungarian Academy of Sciences Budapest. P. 295-299.
Table 3. Maize harvested area (ha), grain yields (t ha-1) and precipitation (mm)
for 30-years (means) and 1996-2003 periods
Harvested area (ha), maize grain yield (Y) in t ha-1 and precipitation (mm)*
Year Eastern Croatia
County** (Y)
May-Aug. (mm)
July (mm)
ha
Y
VSc OBc VPc SB OS BJ
SB OS
BJ
The counties in
1961
199 704 4.86 Croatia established
269
64
1992
1990
1991
Absence of correspondingly data because of war incidences
1995
1996 154 202 6.30 7.06 6.46 5.84 243 280 271
47
95
59
1997 159 770 7.01 7.29 7.35 6.83 315 256 322 106
91
97
1998 169 935 6.20 6.49 6.53 5.88 276 258 350
88
84
92
1999 177 353 6.50 7.29 6.60 5.82 403 407 415 210
95
93
2000 180 182 4.31 4.72 3.96 4.30 151 107 186
88
63
85
Mean 168 288 6.06 6.57 6.18 5.73 278 261 309 108
86
85
2001 190 136 6.63 7.37 6.79 5.94 310 384 284
57
77
52
2002 185 651 7.21 6.82 7.50 7.67 334 368 475
78
85
78
+
2003 184 270 4.53 5.15 4.32 4.57 241 162 237
61
70
91
* Weather Bureaues Slav. Brod (SB), Osijek (OS) and Bjelovar (BJ)
** Vukovar-Sirmium (VSc), Osijek-Baranya (OBc), Virovitica-Podravina (VPc)
+
estimation of yield data for 2003
References
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Baranje, 17-19. svibanj 1970, Osijek , p.115-176.
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(IPI) Basel.
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