Effects of shade and fertilizer levels on seedling growth of four Robusta coffee (Coffea canephora Pierre) genotypes
2017
Quilong Quilong, L.M. | Salazar, B.M.
A 4x3x3 factorial experiment in split-split plot experiment was conducted from August 2014 to January 2015 to describe the effects of different shade and fertilizer levels on seedling growth and development of four Robusta coffee genotypes (FRT7, FRT11, FRT23, and FRT65), shade treatments (30%, 55%, and 90% shade) were imposed to two-month old seedlings using black fishnets, while fertilizer treatments were reckoned after the recommended rate (RR) of 120-120-60 (i.e., 0% RR, 100% RR, and 200 RR). Results showed that Robusta coffee genotypes exhibit differential sensitivity to varying levels of shade and fertilizer. FRT 23 seedlings, regardless of shade and fertilizer level, exhibited high mortality (approx 85%) one month after transplanting. Comparable responses were observed in other genotypes when they were provided with high fertilizer dosage (200% RR). Interestingly, zero (0% RR) or normal (100% RR) fertilization seemed to counter the detrimental effects of excessive shade (90% shade) as evidenced by better vegetative growth. Correlation analyses show that shading and fertilization have opposing effects on the growth and development of coffee seedlings. Specifically, shade level has strong negative correlation with plant height, whereas fertilizer level has very strong positive relationship with relative leaf greenness (SPAD value), and strong positive relationship with other growth parameters (i.e., seedling vigor, plant height, rooting intensity number of leaves, internode length, stem diameter, and leaf area). Best vegetative growth was observed in seedlings subjected to medium shade (30% or 50%) in combination with 100% RR fertilization, hence the recommendation for coffee seedling stage prior to field planting.
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