[Effects of micro-sprinkling hose length and width on wheat field water condition and flag leaf chlorophyll...

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 (C_u) 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 C_u compared to T₆. After irrigation at anthesis, the C_u 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 Φ_PSII, 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 Φ_PSII, 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 Φ_PSII, 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 Φ_PSII, 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.