000			02074nam a2200181Ia 4500
008			220216s9999 xx 000 0 und d
100			_aSamarappuli L
245		0	_aRoot development in Hevea brasiliensis in relation to management practices
260			_bJournal of the Rubber Research Institute of Sri Lanka _c1996
300			_a93-111
520			_aFeeder root density was shown to be significantly different between distances from the base of the rubber plant and in their vertical distribution with the highest percentage of roots being in the surface soil layers, 0-10 cm and 10-20 cm in the region of 120 cm circle. The amount of feeder roots in the surface soil was more than 75;of the total feeder roots and only 17.2;and 1.9;of the total root weights were found in the lower soil layers, 20-50 cm and 50-90 cm, respectively. Statistical calculations (coefficient of variation) of volumetric moisture content data indicated that the distance 60 cm from the tree at surface soil layers would appear to give the highest variation. Significant positive correlations were found between fine sand content (< 200m diameter) and root density, while clay content was nagatively correlated to root density. Root density had the tendency to decrease with increasing soil bulk density, but to increase with increasing soil organic carbon content. There was a significant difference in root density between clones. Vigorous clones like RRIC 102, RRIC 121, RRIC 100 and RRIC 110 had more feeder roots than a less vigorous clone like PB 86. Feeder root development also significantly differed between different establishment practices. Differences in the development of feeder roots were also shown to be significant with different soil moisture levels and potassium levels. Moreover, data obtained show that there was more vigorous feeder root development under mulching than under legume cover or natural cover.
650			_aHevea brasiliensis
650			_aRoot development
700			_aKarunadasa P
700			_aMitrasena U
700			_aYogaratnam N
942			_cJS
999			_c67242 _d67242