Open AccessEffect of Nypa fruticans pruning regime and soil properties on regeneration of Mangrove species (Rhizophora racemosa) in Eastern Obolo, Akwa Ibom State
Publication year - 2020
Language(s) - English
Resource type - Journals
ISSN - 1597-4488
DOI - 10.36265/njss.2020.300111
Subject(s) - mangrove , rhizophora , randomized block design , pruning , hydraulic conductivity , rhizophora mucronata , horticulture , bulk density , botany , environmental science , biology , soil science , soil water , ecology
The study was conducted to evaluate the effect of Nypa fruticans pruning regimes on the regeneration of mangrove (Rhizophora racemosa) at Okorombokhoin Eastern Obolo, Akwa Ibom State, Nigeria. The Nypa was pruned at a uniformheight of 10 cm and the area protected with used fishing nets against infiltrationby Nypa seeds in tidal floods. Mangrove plants of similar height were interplanted among pre-existing stands, out of which ten plants were tagged in eachsub-plot for the measurement of plant height, leaf area index, and stem girth.Three pruning regimes (0, 4, and 6 weekly pruning (WPR) were adopted and soilsamples were collected from 0-15 and 15-30 cm depths. The study was a 3x2factorial in randomized complete block design with three replications. Soil properties showed consistent differences with depth than with pruning regimes. Bulkdensity (BD) was statistically similar, averaging 1.04 and 1.06 Mgm-3in 0-15 and15-30 cm, respectively, while saturated hydraulic conductivity (Ksat), respectively averaged 0.64 and 0.27 cm h-1. Electrical conductivity (EC), available phosphorous (Av.P) and base saturation (BS) were significantly (p≤0.05) greater in4WPR (5.77 dS m-1; 30.07 mg g-1; 85.4%) than 6WPR (4.54 dS m-1; 25.82 mg g1; 76.2%) and 0WPR (3.57 dS m-1; 23.02 mg g-1; 74.3%). Plant height (PH) ofmangrove averaged throughout the study was significantly (p≤0.05) greater in4WPR (80.3 cm) than 0WPR (62.5 cm) but similar to 6WPR (73.4 cm). Stemgirth (SG) of mangrove was similar but in the order 4WPR (1.06 cm)>6WPR(0.98 cm)>0WPR(0.86 cm). The pattern of variation in other mangrove growthparameters was similar to plant height and stem girth. The study also showed thatPH and SG were negatively correlated with sand, Av.P, and EA but positivelycorrelated with silt and clay, EC, and BS. Results indicated that mangrove species (Rhizophora racemosa) growth was optimum 4WPR than 0WPR and 6WPRand could, therefore, be recommended as a management practice for controllingthe growth of Nypa fruticans and regenerating mangrove (Rhizophora racemosa)in the study area.