甘蔗节水灌溉及高效施肥关键技术参数研究

Key technical parameters of water-saving irrigation and high-efficiency fertilization for sugarcane

【目的】建立适合广西蔗区生产的甘蔗节水灌溉及高效施肥关键技术体系,为实现糖料蔗的高产优质目标奠定基础。【方法】以甘蔗田间试验为基础,采用蔗区土壤养分及水分系统研究法对甘蔗节水灌溉及高效施肥的参数进行探索,对历时15年的相关研究结果进行总结归纳。【结果】广西蔗区降雨主要集中在5~9月,春秋季干旱及缺水制约着糖料蔗生产;蔗区土壤饱和持水量38%~61%,土壤永久凋萎点2%~21%,土壤田间持水量6%~42%,土壤有效水含量4%~22%。甘蔗需水量1075.0~1231.0 mm,日需水量3.6~5.9 mm,日耗水强度4.0~6.0 mm。不同生长阶段甘蔗吸收氮、磷、钾量和节水灌溉肥料浓度参数存在较大差异,综合考虑甘蔗产量质量、降雨时空、灌溉量等因素,优选出节水灌溉肥料水平为:苗期0.10%~0.20%,分蘖期灌0.20%~0.30%,伸长(拔节)期0.20%~0.30%,成熟期灌溉停止施肥。经实际生产证实,不同灌溉方式中以滴灌甘蔗对水分和氮、磷、钾养分的利用率最高,分别为90.01%、51.32%、30.21%和52.11%;滴灌区采用减量施肥(N 210.00 kg/ha+P2O575.00 kg/ha+K_2O 210.00 kg/ha)能实现糖料蔗的高产优质目标。【结论】广西蔗区生产的甘蔗节水灌溉及高效施肥模式为早春土壤湿润促苗,中期灌溉施肥偶合,后期灌溉防蔗早衰。即甘蔗灌溉频次9次(春季2次、分蘖期2次、伸长期3次、成熟期2次),灌溉总量900.0~1425.0 m^3/ha,每次灌溉量60.0~90.0m^3/ha,用水关键节点在春秋季;轻质土壤的滴灌间隔9~12 d,黏壤土的滴灌间隔12~17 d;灌溉肥料水平为甘蔗苗期0.10%~0.20%、分蘖期0.20%~0.30%、伸长(拔节)期0.20%~0.30%、成熟期灌溉不施肥;以氮、钾肥为主(N∶K_2O=1∶1.6)。

【Objective】The present experiment was conducted to establish water-saving irrigation and high-efficiency fertilization technique system, in order to lay the foundation for achieving high yield and high quality of sugar crop.【Method】Based on sugarcane field experiment, the key technical parameters of water-saving irrigation and high-efficiency fertilization were investigated using research method of sugarcane soil nutrient and water system, the experiment took 15 years, its research results were summarized. 【Result 】The results showed that, the rainfall of sugarcane planting areas mainly concentrated in the months of May to September, the spring and autumn was drought season, and the water shortage restricted the sugarcane production. In sugarcane planting areas, the soil saturated water-holding capacity ranged from^38% to 61%, the permanent wilting point ranged from 2% to 21%, the field capacity ranged from 6% to 42%, the soil water content ranged from 4% to 22%, the available water capacity ranged from 4% to 22%. The water demand of sugarcane was 1075.0-1231.0 mm, the daily water demand of sugarcane was 3.6-5.9 mm, and daily water consumption intensity of sugarcane was 4.0-6.0 mm. In addition, there were some larger differences between fertilizer concentration parameter and amount of nitrogen, phosphorus and potassium absorbed by sugarcane, considering some factors viz., yield and quality of cane, rainfall space time, irrigation water amount etc., so the optimal fertilizer application rates in water-saving irrigation were as follows： 0.10%-0.20% at seedling stage, 0.20%-0.30% at tillering stage, 0.20%-0.30% at elongating stage, but no fertilizer was applied at maturation stage. The actual production confirmed that, among different irrigation methods, drop irrigation made use efficiencies of nitrogen, phosphorus and potassium into be the highest, the use efficiencies of nitrogen, phosphorus and potassium were 90.01%, 51.32%, 30.21% and 52.11%, respectively. And the reducing fertilizer application（N 210.00 kg/ha＋P2O575.00 kg/ha＋K_2O 210.00 kg/ha） could achieve high yield and high quality of sugarcane. 【Conclusion 】The established water-saving irrigation and high-efficiency fertilization mode suitable for Guangxi sugarcane areas is as follows： moist soils in early spring for promoting growth of seedlings, medium-term fertigation, the late irrigation for preventing premature aging. All that sugarcane irrigation frequency was nine times（irrigating 2times in spring, 2 times at tillering stage, 3 times at elongating stage, 2 times at maturation stage）, and the irrigation amount is 60.0-90.0 m^3/ha every time, total irrigation amount is 900.0-1425.0 m^3/ha. And the key seasons for irrigation are spring and autumn, the light soil should be irrigated with drip system at intervals of 9-12 days, the clay loam should be irrigated with drip system at intervals of 12-17 days. Further, the fertilizer application rates in drop irrigation are 0.10%-0.20% at seedling stage, 0.20%-0.30% at tillering stage, 0.20%-0.30% at elongating stage, but no fertilizer is applied at maturation stage. More importantly, the nitrogen-potassium fertilizer（N∶K_2O=1∶1.6）is mainly applied.