Effect of drip irrigation regimes on yield and quality of field grown bell pepper

Abstract

This study examined the effects of different irrigation regimes on yield and water use of bell pepper ( Capsicum annuum sp. 1 1-B-14) irrigated with a drip irrigation system under field conditions in 2002 and 2003 growing seasons in the Mediterranean region of Turkey. Irrigation regimes consisted of three irrigation intervals based on three levels of cumulative pan evaporation (Epan) values ( I 1, 18–22 mm; I 2, 38–42 mm; and I 3, 58–62 mm); irrigations occurred on the respective treatments when Epan reached target values. Three plant-pan coefficients were evaluated as irrigation levels ( K cp1 = 0.50, K cp2 = 0.75 and K cp3 = 1.00). Irrigation intervals varied from 3 to 6 days in I 1, 6 to 11 days in I 2 and 9 to 15 days in I 3 treatments. Combined variance analysis indicated that experimental years were not significantly different, but both K cp and irrigation intervals ( I) significantly influenced total pepper yields. Maximum and minimum yields were obtained from the I 1 K cp3 and I 3 K cp1 treatments: 33,140 kg ha −1 and 21,620 kg ha −1 in the first experimental year and 35,298 kg ha −1 and 21,010 kg ha −1 in the second experimental year, respectively. As the K cp value decreased the total yields within each irrigation interval also decreased. However, with the lower irrigation frequency ( I 3), lower yields were obtained with all K cp coefficients. Crop evapotranspiration (ET) values in the treatments varied from 365 mm in I 2 K cp1 to 528 mm in I 1 K cp3 in the first experimental year and 309 mm in I 3 K cp1 to 511 mm in I 1 K cp3 in the second experimental year. Significant second degree polynomial relations were found between pepper yield and total water use for each irrigation interval in 2002 and 2003 growing seasons. Different irrigation intervals resulted in similar water use in the treatments with the same K cp value. Water use efficiency (WUE) and irrigation water use efficiency (IWUE) values were significantly influenced by the irrigation intervals, plant-pan coefficients and experimental years ( Y 1: 2002 and Y 2: 2003) at 1% level of significance. WUE ranged from 4.7 kg m −3 in I 3 K cp2 to 7.6 kg m −3 of ET in the I 1 K cp1 in the 2002 growing season and ranged from 6.4 kg m −3 in I 3 K cp3 to 7.9 kg m −3 of ET in the I 2 K cp2 in the 2003 growing season. Maximum IWUE was observed in Y 1 I 1 K cp1 (7.7 kg m −3), and minimum IWUE was in Y 1 I 3 K cp3 treatment (4.8 kg m −3) in the experimental years. K cp coefficients (irrigation amounts) and irrigation frequencies ( I) and years had significantly different effects on quality parameters such as the first and second quality yield, and number of fruit. Both K cp and I significantly influenced the mean fruit weight, pepper length and width, as well as stem diameter and plant height at harvest. In conclusion, I 1 K cp3 irrigation regime is recommended for field grown bell pepper in order to attain higher yields with improved quality.