Abstract
Planting high density can reduce photosynthetic active radiation due to mutual shading or low light interception. The nature of the canopy and utilization of solar radiation influence the performances of coffee genotype. This study was designed to evaluate the effect of planting density and fertilizer rate on physiological parameters of Arabica coffee seedlings under nursery conditions. It was conducted at the Jimma Agricultural Research Center in southwest Ethiopia in 2018 season. A factorial experimentation in a completely randomized design with three replications was used for the study. The treatments consisted of combinations of two Arabica coffee cultivars (compact-74110 and open-75227), four population densities per polythene tube (one, two, three and four) and three compound NPK fertilizer (22:6:12 + Te) rates (control, 5g and 10g). The most common plant physiological parameters including NAR, AGR, RGR and CGR were estimated and analyzed using standard procedures. The results showed that interaction between cultivar, population density and fertilizer significantly (P ≤0.05) influenced NAR and CGR, and highly significantly (P ≤0.01) influenced AGR and RGR. The highest values of NAR, AGR, RGR and CGR were recorded from the lowest population density (PD1) and increased in the order of PD1 > PD2 > PD3 > PD4 for each parameter. Application of 5g of NPK significantly enhanced NAR, AGR, RGR and CGR as compared with other fertilizer rates, while these parameters were observed to decrease for 10g of NPK perhaps due to toxicity problem. In general, high planting density decrease physiological parameters of the coffee plant, so more attention like intensive coffee tree management practices as well as optimization of population density should be done under field conditions to increase physiological parameters of the coffee plant.
Highlights
Light is the energy source for photosynthesis and an essential prerequisite for plant life
The analysis of variance revealed that the three-way interaction effect of cultivar, population density and fertilizer rate was highly significant (P ≤ 0.01) for absolute growth rate (AGR) and relative growth rate (RGR), whereas significant (P ≤ 0.05) for net assimilation rate (NAR) and crop growth rate (CGR) (Table 1)
Coffee production depends on several factors, among which quality of coffee seedlings to greatly affect the rate of establishment and subsequent growth and yield performance of genotypes
Summary
Light is the energy source for photosynthesis and an essential prerequisite for plant life. Net assimilation rate is affected by different factors; from this light intensity is the major one. Photosynthesis and growth of plants are affected by heavy shade, which reduces light interception of leaves [1]. Planting high density reduces photosynthetic active radiation due to mutual shading or self-shading. The decrease in net assimilation rate (NAR), absolute growth rate (AGR), relative growth rate (RGR) and crop growth rate (CGR), while increasing planting density might be due to the decrease in light interception [2]. Plants undertake certain morphological modifications and physiological adaptations to increase photosynthetic rate like increase leaf area index [3]. Optimum leaf area index is very important; above the critical level may decline yield due to shading and competition for water, nutrients and light [4].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Science, Technology and Society
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
