[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, gs, 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.
Cai
Chuantao
C
Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China. caict@xtbg.ac.cn
Cai
Zhiquan
Z
Xie
Jiwu
J
Zhou
Qinghui
Q
Cao
Kunfang
K
Yao
Tianquan
T
Wang
Hua
H
D002681:China; D040503:Coffea / Q000254:growth & development* / Q000502:physiology*; D005308:Fertilizers; D010788:Photosynthesis; D014867:Water
D005308:Fertilizers; D014867:Water