Effects of micro-sprinkling hose length and width on wheat field water condition and flag leaf chlorophyll fluorescence characteristics in different sampling districts

Abstract

A two-year field experiment was conducted in 2014-2015 and 2015-2016 wheat growing seasons to study the effects of micro-sprinkling hose length and width on field water condition, and flag leaf chlorophyll fluorescence characteristics in different sampling districts (D1 to D6 along with the hose laying direction). Six micro-sprinkling hose treatments were set: 60 m (T1), 80 m (T2) and 100 m (T3) lengths under 65 mm width; 60 m (T4), 80 m (T5) and 100 m (T6) lengths under 80 mm width. The results showed that after irrigation at jointing, the Christiansen uniformity coefficient (Cu) of T1 was significantly higher than T2 and T3 under 65 mm hose width. Under 80 mm hose width, T4 and T5 had the highest Cu compared to T6. After irrigation at anthesis, the Cu showed T1>T2>T3 under 65 mm hose width, and T4>T5>T6 under 80 mm hose width. Under 65 mm hose width, the average relative soil water content of 0-40 cm soil layers after irrigation at anthesis, flag leaf ΦPSII, NPQ and ETR at 20 and 30 d after anthesis and the grain yield of different sampling district did not differ in T1; T2 showed the order of D1, D2>D3>D4>D5; T3 showed D1, D2>D3>D4>D5, D6. The average ΦPSII, NPQ and ETR at 20 and 30 d after anthesis, and the average dry matter at maturity of different sampling districts were presented as T1>T2, T3. Under 85 mm hose width, no significant differences were observed in the average relative soil water content of 0-40 cm soil layers after irrigation at ahthesis, flag leaf ΦPSII, NPQ and ETR at 20 and 30 d after anthesis and the grain yield of different sampling districts in T4; in T5, the indexes mentioned above in D1, D2 and D3 sampling districts were significantly higher than those in D4 and D5; in T6, the decreasing order was D1, D2, D3>D4>D5>T6. The average ΦPSII, NPQ and ETR at 20 and 30 d after anthesis, and the average dry matter at maturity of different districts showed the order of T4, T5>T6. The ave-rage grain yield and water use efficiency of T1, T4 and T5 were significantly higher than those in T2, T3 and T6, T1 and T4 had a better irrigation benefit than T5. Under this experimental condition, T1 treatment under 65 mm hose width, T4 treatment under 80 mm hose width were the most recommendable treatments considering high yield and water saving, and T5 treatment was also recommendable under 80 mm hose width.