1. INFLUENCES OF IRRIGATION AND N FERTILIZATION ON MAIZE (Zea mays L.) PROPERTIES - Hrvoje PLAVSIC1 - Marko JOSIPOVIC1 - Luka ANDRIC1 - Antun JAMBROVIC1 - Jasna SOSTARIC2 1 Agricultural Institute Osijek, Osijek, Croatia 2 Faculty of Agriculture, Osijek University of Josip Juraj Strossmayer Osijek, Croatia

2. INTRODUCTION WATER quantity, water quality and time of application are very important elements for achieving high yield for most crops WATER quantity, water quality and time of application are very important elements for achieving high yield for most crops MACRONUTRIENTS, especially NITROGEN applied in proper amount and proper time also results by higher yield and beter quality of crops MACRONUTRIENTS, especially NITROGEN applied in proper amount and proper time also results by higher yield and beter quality of cropsCAUTION To much water a) usually resulted by leaching fertilizers and elements which are necesary for growing the plants, especially nitrogen b) some toxic elements leach deeper in the soil and to the groundwater To much nitrogen a) Keeping in the soil b) With to much water = leacing to deeper soil layers and in the groundwater

3. INTRODUCTION Nitrogen is ecologically a very “sensitive” element Nitrogen is ecologically a very “sensitive” element - (Nemeth, 2006) - Applying higher quantities of nitrogen for plant growth and grain yield could cause leaching in the groundwater and no yield increase. - Bertic et al. (2006) confirmed that although the amount of 240 kg of N ha-1 is recommended for the increase of maize grain yield and total above ground mass, the same can be achieved with the optimal N fertilization amount of 120 kg N ha-1 with the sufficient availability of potassium and phosphorus. - Kovacevic (2004) - the results obtained in the research are closely connected that climatic factors have an effect on the efficiency of fertilization.

4. MATERIAL AND METHODS Field trial was set at the Agricultural Institute Osijek, Croatia, Growing seasons were 2000 and 2002 at. Each growing season impact was calculated separately Field trial was set at the Agricultural Institute Osijek, Croatia, Growing seasons were 2000 and 2002 at. Each growing season impact was calculated separately Factor A – Irrigation Factor A – Irrigation A1 – maintining water in the soil from 80% to 100% FWC A2 - maintining water in the soil from 60% to 100% FWC A3 - no irrigation (control) Factor B – Nitrogen fertilization Factor B – Nitrogen fertilization B1 – 100 kg N/ha B2 – 150 kg N/ha B3 – 200 kg N/ha

5. The experiment was set by split-plot method - 4 repetitions The experiment was set by split-plot method - 4 repetitions Maize was sown at the end of April and harvested at the second half of October Maize was sown at the end of April and harvested at the second half of October Plant densities were 65 000 plant per ha Plant densities were 65 000 plant per ha Irrigation rates (IR) and nitrogen fertilization (NF) on maize yield and yield components: plant height, 1000 grain mass, hectolitre mass, grain part in ear and ear length were measured Irrigation rates (IR) and nitrogen fertilization (NF) on maize yield and yield components: plant height, 1000 grain mass, hectolitre mass, grain part in ear and ear length were measured During the vegetation period soil samples (0-35 cm) from each plot of set factors were taken every 10 days for measuring soil water content – by TDR soil moisture meter During the vegetation period soil samples (0-35 cm) from each plot of set factors were taken every 10 days for measuring soil water content – by TDR soil moisture meter Precipitation, air temperature and sunshine hours in the two investigated years were considered, also Precipitation, air temperature and sunshine hours in the two investigated years were considered, also

6. Precipitation (mm) for the period of study (Osijek Weather Bureau)

7. Mean air temperature (°C) for the period of study (Osijek Weather Bureau)

8. Sunshine hours for the period of study (Osijek Weather Bureau)

9. Quantities of applied water during the vegetation period added by IR were as follows : Year IR20002002 A1 280 mm (8 x 35 mm) 175 mm (5 x 35 mm) A2 250 mm (5 x 50 mm) 100 mm (2 x 50 mm)

10. Results and discussions

11. Influences of year, irrigation rate (A) and nitrogen doses (B) on maize properties a) Grain yield of maize, t ha-1 (14% grain moisture basis) 20002002 AB interaction Mean Mean B1B2B3AYearB1B2B3AYear A111,1511,1711,42 11,25 ** 10,64A112,2612,3112,61 12,39 * (A3)12,14 A210,6010,8510,79 10,75* * A211,9412,2512,3212,17 A39,8710,069,939,95A311,8111,8111,9911,87 Mean B 10,5410,6910,71 12,0012,1212,30*(A1) LSD 5% LSD 1% yearAB A x B AB 20000,310,410,650,470,560,91 20020,360,280,540,540,390,77

12. Influences of year, irrigation rate (A) and nitrogen doses (B) on maize properties b) Plant height to the top (cm) of plant 20002002 AB interaction Mean Mean B1B2B3AYearB1B2B3AYear A1253,7258,1258,3 256,7 ** (A2,A3)249,9A1304,1309,1309,3 307,5* * (A3)301,4 A2251,2252,7253,5 252,4* * (A3)A2312,6307,6310,8 310,3 ** (A3) A3241,5238,2241,8240,5A3280,5290,9287,9286,5 Mean B 248,8249,7251,2 299,1302,6302,7 LSD 5% LSD 1% yearAB A x B AB 20002,687,8111,44,0710,715,7 20028,167,5313,412,410,319,0

13. Influences of year, irrigation rate (A) and nitrogen doses (B) on maize properties c) Weight of 1000 grains (g) 20002002 AB interaction Mean Mean B1B2B3AYearB1B2B3AYear A1346,4339,6350,1 345,4 * (A2,A3)334,4A1370,9392,0385,9 382,9 * (A3)374,5 A2330,4323,7337,6330,6A2376,6381,8378,9379,1 A3336,7319,2325,5327,1A3359,0360,2365,1361,5 Mean B 337,8327,5337,8 368,9377,9376,6 LSD 5% LSD 1% yearAB A x B AB 200012,314,123,318,619,332,8 200221,618,333,632,725,147,9

14. Influences of year, irrigation rate (A) and nitrogen doses (B) on maize properties d) Hectolitre mass (kg) 20002002 AB interaction Mean Mean B1B2B3AYearB1B2B3AYear A177,377,577,2 77,3* * (A3)76,9A176,376,476,376,376,1 A276,976,677,176,9A276,076,075,775,9 A376,476,576,676,5A375,876,176,276,0 Mean B 76,976,977,0 76,076,276,1 LSD 5% LSD 1% yearAB A x B AB 20000,480,530,890,730,731,26 20020,710,490,991,070,681,43

15. Influences of year, irrigation rate (A) and nitrogen doses (B) on maize properties e) Grain in ear (%) 20002002 AB interaction Mean Mean B1B2B3AYearB1B2B3AYear A187,987,988,288,087,9A182,984,183,883,683,4 A288,287,487,787,8A283,383,484,483,7 A388,187,687,787,8A382,883,582,382,9 Mean B 88,1*(B2)87,687,9 83,083,7*(B1)83,5 LSD 5% LSD 1% yearAB A x B AB 20000,490,440,790,740,611,23 20021,060,691,451,610,952,09

16. Influences of year, irrigation rate (A) and nitrogen doses (B) on maize properties f) Ear length (cm) 20002002 AB interaction Mean Mean B1B2B3AYearB1B2B3AYear A119,419,219,619,419,4A120,321,321,521,120,9 A219,119,619,919,6A220,521,121,020,8 A319,119,019,519,2A319,820,821,420,7 Mean B 19,219,319,7 20,221,121,3 LSD 5% LSD 1% yearAB A x B AB 20000,930,531,201,410,731,74 20021,520,942,012,301,292,91

17. CONCLUSIONS Results showed statistical differences between 2000. (10,64 t/ha) and 2002. (12,14 t/ha) growing season. Results showed statistical differences between 2000. (10,64 t/ha) and 2002. (12,14 t/ha) growing season. Irrigation variant A1 gave the best results in yield and in all investigated components. Irrigation variant A1 gave the best results in yield and in all investigated components. Medium (B2) and higher nitrogen level (B3) also gave the best results in the research except grain/ear ratio (best 100 kg N/ha). Medium (B2) and higher nitrogen level (B3) also gave the best results in the research except grain/ear ratio (best 100 kg N/ha). The highest level of irrigation and nitrogen level did not give statistically significant higher yield and yield components. The highest level of irrigation and nitrogen level did not give statistically significant higher yield and yield components. Applying 150 kg N/ha in the year 2000. also provide enviromentally suitable quantity of nitrogen on the researched soil since the higher level of N (200 kg/ha) did not increase the yield. Applying 150 kg N/ha in the year 2000. also provide enviromentally suitable quantity of nitrogen on the researched soil since the higher level of N (200 kg/ha) did not increase the yield.

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