Effects of wheat row spacing layout and drip tape spacing on yield and water productivity in sandy clay loam soil in a semi-arid region

Abstract

Recent droughts and subsequent reduction of water resources in arid and semi-arid regions have highlighted the necessity of altering surface irrigation techniques to modern methods of irrigation. The present study compares drip irrigation tubes with 60 and 75 cm spacing with the furrow irrigation prevalent in Hamedan province, Iran and investigates the effects of the former form of irrigation on the productivity of wheat crops with various cropping layouts. This experiment was implemented as a field-scale experiment in sandy clay loam texture soil and consisted of the following treatments: 4 cultivated rows with 15 cm spacing on both sides of the drip tape, and 75 cm spacing between tapes (T1); 4 cultivated rows with 20-cm row spacing, and 75 cm drip tape spacing (T2); 3 cultivated rows with 20 cm row spacing and 60-cm drip tape spacing (T3); 4 cultivated rows with 15 cm row spacing and 60 cm drip tape spacing (T4); 2 cultivated rows with 30 cm row spacing and 60 cm drip tape spacing (T5); and furrow irrigation which consisted of 4 cultivated rows with 12 cm spacing on the ridge and 60 cm furrow spacing (F). The results showed that the maximum and minimum value of the two-year average grain yield and irrigation water productivity were those of T1 and F treatments at 7443 and 5996 kg ha−1 and 1.91 and 1.02 kg m−3, respectively. The maximum and minimum values of two-year average weight of 1000 kernels were also obtained from T1 and F treatments at 44.3 and 42.1 g, respectively. The mean irrigation water productivity obtained for drip and furrow irrigation treatments were 1.74 and 1.01 kg m−3, respectively. Results indicated that drip irrigation caused a 33% reduction in applied irrigation water use and a 72% increase in irrigation water productivity in comparison to the furrow irrigation method.