Studies on some competing factors in the intercropping systems of rubber (Hevea brasiliensis Muell. Arg)
| dc.contributor.advisor | Vikraman Nair, R | |
| dc.contributor.author | Mathew Joseph | |
| dc.contributor.author | KAU | |
| dc.date.accessioned | 2019-05-18T07:26:25Z | |
| dc.date.available | 2019-05-18T07:26:25Z | |
| dc.date.issued | 1999 | |
| dc.description | PhD | en_US |
| dc.description.abstract | Field experiments were conducted at the Kerala Agricultural University during 1994-97 to study the extent of involvement of root level competition and competition for light in the early years of growth of rubber. Rooting pattern of rubber was studied employing 32p soil injection technique. Activity was applied at varying lateral distances of 50, 100, 150, 200 and 250 cm from the plant and varying depths of 10, 25, 50, 75 and 100 cm. This experiment was laid out in randomised block design and was replicated thrice. In another experiment, rubber was intercropped with banana cv. Poovan under two systems of planting. The extent of root competition was evaluated using 32p soil injection technique. Both rubber as well as banana were treated with the radio label 32p. It was applied in four circles of varying radii of 25,50, 100 and 150 cm around the plant. Along each circle, nine equidistant holes were made and required activity was applied in alternate holes at depths of 25, 50 and, 75 cm. This experiment was laid out in CRD. In a third field experiment, the intensity of light infiltration through rubber canopies of varying ages was studied. For this, fields with one to seven-year-old rubber were selected and in each age group the extent of filtered light was measured. These were related with the biological parameters of rubber plant viz., girth, height and canopy diameter. The most important findings of the investigation are abstracted below. Uptake of soil applied 32p by one-year-old rubber is maximum when the radio chemical was applied in a lateral distance of 50 cm and depth of 25 cm. The interaction between lateral distance and depth of application of 32p was significant. The extent of root activity in one-year-old rubber was confined to a lateral distance of 50 cm and a vertical distance of 25 cm was over 90 per cent. 2 In two-year-old rubber, uptake of soil applied 32p was significant with respect to lateral distance and the highest activity was noticed at 50 cm followed by 100 cm distance. The effect of depth of application was also significant and 50 cm depth recorded maximum recovery of the radio label. The interaction effect was also significant. Regarding the root activity pattern of two-year-old rubber, about 80 per cent activity was confined to a zone of 100 cm lateral distance and 50 cm depth. During the third year, maximum recovery of soil applied 32p was obtained from a lateral distance of 50 cm followed by 100 and 150 cm. Uptake of activity was found to be independent of the depth of application. More than 90 per cent of root activity was concentrated to a lateral distance of 150 cm from the plant. Uptake of 32p by both rubber and banana was higher when these crops were grown alone during the first year of planting. Among the intercropped situations,there was more of sharing of applied activity during first year in the case of the double row system of intercropping banana. Root activity of rubber was reduced to approximately one third by intercropping with a single row of banana and this was further reduced in the double row system. Uptake of 32p by two-year-old rubber was higher when intercropped with single row banana than double row. 3 In the second year also, percentage root activity was more for sole rubber and banana as compared to their mixed stand. The root activity of rubber was reduced to approximately 24 and 16 per cent in rubber mixed with single and double row banana, respectively. In the third year also, sole crops of rubber and banana registered higher uptake rate of radioactivity compared to the intercropped situations. Radio uptake by three-year-old rubber plants under intercropped situation was higher in the single row system of planting banana. Root activity was reduced to 27 and 17 per cent under single row and double row systems of intercropping banana, respecti vel y. Absorption of 32p by banana when intercropped with three-year-old rubber was higher in the single row system than in the double row system of banana. The percentage values were 27 and 8 per cent, respectively. Uptake of activity by banana was maintained at much higher levels during the three years of intercropping under single row system (60 to 27 per cent). But in the double row system the activity was drastically reduced with age. The degree of root competition between rubber and banana was minimum when rubber was intercropped with single row of banana during the initial three years of planting rubber. The growth of rubber tree is closely associated with the steady increase in all the growth parameters during the immature phase. ."', 4 Progressive development of rubber canopy proportionately reduced the light infiltration from 97 per cent at the close of first year to a meagre 7 per cent at the end of the seventh year. All the growth parameters observed were significantly related among themselves and had a negative correlation with the percentage of light infiltration. Reasonably accurate prediction on available infiItered light is possible using the equation y = ab", if only anyone parameter of growth observed is known. It is concluded that the active roots of rubber are concentrated in radial distances of 50, 100 and 150 cm from the plant during the first, second and third years of growth respectively. Majority of roots are found below soil surface to a range of 20-30 cm during the initial three years. Based on these, it can be tentatively recommended that fertilisers for rubber may preferably be placed in basins of proportionate radius and at a depth of 20-30 cm during the first, second and third years respectively. Banana can be grown in the inter row spaces of rubber as a rainfed crop during the initial three years. Insufficiency of filtered light through the rubber canopy will limit the scope for intercropping beyond the third year of growth of rubber. | en_US |
| dc.identifier.citation | 171582 | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810103746 | |
| dc.keywords | Agronomy, rubber, rubber-intercropping system, commercial crop | en_US |
| dc.language.iso | en | en_US |
| dc.publisher | Department of Agronomy, College of Horticulture, Vellenikkara | en_US |
| dc.sub | Agronomy | en_US |
| dc.subject | null | en_US |
| dc.theme | Factors in the intercropping systems of rubber | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Studies on some competing factors in the intercropping systems of rubber (Hevea brasiliensis Muell. Arg) | en_US |
| dc.type | Thesis | en_US |