田间不同水肥管理下小粒咖啡的生长和光合特性

通过云南5年生田间小粒咖啡(Coffea arabica)进行2种施肥(低肥和高肥)和在干季秸秆覆盖、滴灌、秸秆覆盖+滴灌、对照4种水分处理对植株生长和叶片光合特性影响的测定研究．结果表明，小粒咖啡一年生长周期中最高峰期在雨季始期，次高峰期在雨季中期．水分处理对生长高峰期株高和分枝长度的相对生长率没有显著作用，高施肥量则加大了其相对生长率．干季水分处理提高了叶片的Pn、gs、Tr和WUE，而叶绿素的荧光特征没有受到影响．在湿季，高施肥量使叶片含氮量Pn增加，对gs和Tr的影响较小，从而导致WUE提高,高施肥量显著减小日间光抑制程度，加大了光合机构的实际光化学效率和热耗散能力，提高了对强光环境的适应性，研究表明，小粒咖啡需要高养分的投入和良好的水分管理，湿季是小粒咖啡进行光合和生长的最优季节，干季田间秸秆覆盖+滴灌的效果较好，滴灌和秸秆覆盖的效果相近。

Growth and photosynthetic characteristics of field-grown Coffea arabica under different watering and fertilization managements

Straw mulching and drip irrigation have been widely used for coffee production.In order to know if these techniques are suitable in Yunnan,five-year-old coffee plants were separated into 8 groups to grow in the field under 2 fertilization rates (low and high) and 4 watering regimes:dry straw mulching (M),drip irrigation (I),drip irrigation straw mulching (MI) and control treatment (CK),and the effects of various watering and fertilization treatments on the growth and photosynthetic characteristics of Coffea arabica with the density of 4500 individuals per hectare were measured.The results showed that during one year's growth period,the coffee plants had two growth peaks,one was in May when the rainy season just begun,and the another was in August to September,the middle of rainy season.Higher fertilization promoted the relative height and length growth rates of the branches,but watering treatments hadn't significant effects on them.In dry season,watering significantly promoted the Pn,g s,Tr and WUE,while water status had no significant influence on the internal fluorescence features of PSII.In wet season,high-fertilized plants had a higher leaf nitrogen content and Pn than low-fertilized plants,and Pn was positively correlated with leaf nitrogen content.In both seasons,higher fertilization increased the WUE regardless of the watering treatments.At the same time,the high-fertilization treatment significantly alleviated diurnal photoinhibition,companying with a higher energy utilization through photochemistry and a higher energy dissipation through xanthophyll cycle,which appears that high-fertilized coffee plants have the mechanism to acclimate to strong light environment.All the results indicated that wet season is the optimum time for the photosynthesis and growth of C.arabica,and C.arabica needs a high fertilization investment and fine watering managements during its whole growth period.Among the three man-made watering treatments,MI was the best,M and I had the nearly same effects but the former was more practical than the latter.