Study on sugarcane drip irrigation water amount based on water surface evaporation

[Objective]The effects of different irrigation water amount on sugarcane growth were studied to provide references for making simple and easily-operative sugarcane irrigation plan. [Method]An experiment was conducted by single factor randomized plot design. There were three irrigation treatments (A,B,C) and a non-irrigation control (CK). Irrigation amount of treatment A,B and C was 1.25,1.00 and 0.75 times of canopy water surface evaporation. The sprouting rate,tillering rate and growth rate were investigated during process of sugarcane growth. The plant height,stem diameter,number of millable stalks, quality and yield were measured at harvesting stage. The rainfall,evaporation and irrigation water amount were recorded during the whole growth period of sugarcane to assess the effects of different irrigation water amount on sugarcane agronomic traits, yield, quality, sucrose content, and irrigation use efficiency. [Result]The highest sprouting rate was found in treatment A, reaching 73.50%,and the highest tillering rate was found in treatment B,reaching 27.55%. At the sugarcane elongation stage,the plant height grew fast initially but slowed down later in all treatments. The plant height growth increment of drip irrigation treat- ment was significantly higher than that of the control. As to the stem diameter,the sequence was CKACB,but there was no significant difference among them. The yield production of drip irrigation treatment A,B and C was significantly higher than that of the control,which increased by 46.25% ,40.75% and 27.29% , respectively. The highest sucrose content of sugarcane was found in treatment B,which was 13163 kg/ha. The second highest was A, which was 13136 kg/ha. Irrigation water use efficiency and agricultural water use efficiency of treatment B were 49.32 and 56.60 kg/ha·mm, respectively,which were higher than those of treatment A and treatment C. Irrigation water amount of treatment B was 19.89% lower than treatment A. [Conclusion]Comprehensively considering yield,quality,sucrose content and irrigation water use efficiency of sugarcane,irrigation water amount of treatment B was more appropriate. The 1.00 times of 20 cm standard pan evaporation should be suggested as a guideline for drip irrigation sugarcane culture under the similar conditions.