Analysis of coffee (Coffea arabica L.) performance in relation to radiation levels and rates of nitrogen supply I. Vegetative growth, production and distribution of biomass and radiation use efficiency

作者：Bote Adugna Debela; Ayalew Biruk; Ocho Fikre L; Anten Niels P R; Vos Jan

来源：European Journal of Agronomy, 2018, 92: 115-122.

DOI：10.1016/j.eja.2017.10.007

• Plagiotropic branch
• Orthotropic stem
• Light extinction
• Radiation interception
• Shade avoidance

Intensively managed full-sun coffee (Coffea arabica L.), is potentially highly productive, but has shown disappointingly low yield performance, as adequate resource supplies (especially plant nutrition) are needed to sustain the productivity. In order to underpin rational radiation and nutrient management, the current study focussed on growth and development of 2.5 years old trees in relation to nitrogen supply in combination with several degrees of radiation. Three coffee varieties were grown under four levels of radiation (30-100% full sun) and four rates of nitrogen supply (0-88 g tree(-1) y(-1)), arranged in a randomized split-split plot design at Jimma University horticultural farm, Ethiopia, and their biomass increment (growth) and allocation, and crown characteristics were measured. Growth responded positively to both radiation and nitrogen supply, with positive interactions for several plant attributes (including number and length of branches, numbers of pairs of leaves per branch, radiation use efficiency). Plant height and area per leaflet declined with higher radiation level, while the positive effect of larger N supply on these attributes declined with increase in radiation. Branch length and leaf dry weight showed the most positive plasticity in response to higher radiation. Specific leaf area declined from 187 in shade (reducing sunlight to 30%) to 109 cm(2) g(-1) in full sun without effect of N. Positive effects of nitrogen on growth and biomass production were mediated through higher radiation-use efficiency, RUE, ranging from 0.23 to 0.46 g MJ(-1) (PAR). Variables associated with dry matter partitioning were modestly responsive to either N or radiation. All these responses were consistent across the three varieties. The study enhanced the understanding of vegetative growth and biomass production of coffee trees and explored traits that underlie these patterns. The study also yielded essential information for managing shade and nitrogen supply in both open sun and agroforestry systems and yielded basic information for developing coffee growth models,

• 出版日期2018-1