Structural demography, modular dynamics and growth patterns of aboveground populations of Scirpus grossus L. on paddy field

B. B. Bakar, A. M. Jaafar, A. Majrashi, M. M. Khandaker, A. N. Boyce

Abstract: Scirpus grossus L. is a principal rhizomatous weed in the rice fields, drainage and irrigation canals, riverbanks, abandoned rice fields and wasteland in Malaysia. This study describes the structural demography, modular dynamics, spatio-temporal growth patterns of aerial plant populations of this scourge on fertilized and unfertilized peat soils. The NPK fertilizer application at 100:30:30 ha-1 resulted in more robust aerial plant growth of S. grossus with gross population of 97.08 ramets m-2 (mean dry aerial biomass of 12.19 g plant-1) compared with 83.67 ramets m-2 (10.89 g plant-1) in unfertilized plots 24 weeks after planting of the mother plant. Mean ramets mortality was significantly higher in unfertilized plots at 8.58 ramets m-2 at %0.7, while in the fertilized plots this was only 5.67 ramets m-2, hence the resultant net populations of 91.41 ramets m-2 and 75.09 ramets m-2 in fertilized and unfertilized plots, respectively. Flowering set in earlier among ramets in fertilized plots with 49.56 ramets m-2 vis-a-vis 47.79 ramets m-2, 24 weeks after transplanting of the mother plant in unfertilized plots. Fertilizer applications did not register any significant difference in mean plant height, chlorophyll contents, and chlorophyll fluorescence measurements vis-a-vis those devoid of fertilizer application. The time- and space-mediated clonal growth of S. grossus did not register any significant preferential directionality and dispersion of aerial plants irrespective of fertilizer regimes, but rather displaying opportunistic resource capture by aerial and sub-terranean modules.

Keywords: fertilizer application; modular growth; modules; Scipus grossus

Date published: 2019-02-27