Optimum lateral spacing for drip-irrigated corn under Çukurova conditions

ABSTRACTMSc THESISOPTIMUM LATERAL SPACING FOR DRIP-IRRIGATED CORN UNDERCUKUROVA CONDITIONSYeşim BOZKURTDEPARTMENT OF AGRICULTUREL STRUCTURES AND IRRIGATIONINSTITUTE OF NATURAL AND APPLIED SCIENCES UNIVERSITY OFCUKUROVASupervisor : Prof. Dr. Attila YAZARYear : 2005, Pages: 70Jury : Prof. Dr. Attila YAZARProf. Dr. Ahmet Can ÜLGERProf. Dr. Bülent ÖZEK CThis study was carried out to determine yield-water relationships of thesecond crop maize, and to evaluate the effects full and deficit irrigation and differentlateral spacing on yield and yield components under Çukurova region conditions in2003. Experimental site is located at the Research Field of the Agricultural Structuresand Irrigation Department (altitude 20 m sea level above, 36° 59? N and 35° 18? E ) onclay soils in Mutlu Soil series. Pioneer 3394 hybrid corn variety was used in thisstudy.Irrigation management treatments were created as three different lateralspacings ( A1:0.70, A2:1.40, A3: 2.10 m) and two different water levels ( I100, I67 ).The amount of irrigation water applied to treatment of I100 was estimated as thequantity equal to replenishing the soil moisture to field capacity in the 90 cm soilprofile depth. For deficit irrigation treatment of I67, 33% less water was applied ascompared to I100 treatment plots. Maximum water use was determined in the A1I100treatment as 758 mm; and the lowest ET was in the A2I67 treatment with 573 mm.Grain yields varied from 719 to 979 kg/da. The highest grain yield was observed inA2I100 treatment as 979 kg/da, and the lowest yiels was found in A3I67 treatment as710 kg/da. According to research results, optimum lateral spacing for corn plant wasfound to be 1.4 m.Significant second degree polinomial relationships between grain yield (Y)vs irrigation water (I) and grain yield (Y) vs water use (ET) were found as Y=-0.0037I2 + 5.835I-1397.7 (R2=0.6214**); and Y=-0.0039ET2 + 5.926ET-1365.1(R2=0.5438*), respectively. Water use effeciencies (WUE) for the second crop maizevaried from 1.13 kg/m3 to 1.40 kg/m3. The highest WUE was found in A2I100treatment (1.40 kg/m3), the lowest one was found in A1I100 treatment (1.13 kg/m3).Key Words: Drip irrigation, optimum lateral spacing, deficit irrigation, maize