ISHS Acta Horticulturae 735: I International Guava Symposium
CHANGES IN THE SPATIAL ROOT ACTIVITY DISTRIBUTION AND PLACEMENT OF SUPERPHOSPHATE FOR MAXIMUM ABSORPTION AS INFLUENCED BY AGE OF TREES OF CV. ARKA MRIDULA GUAVA (PSIDIUM GUAJAVA L.) |
| Author: | S.C. Kotur |
| Keywords: | root activity, fertilizer placement |
| Abstract:
Isotope-aided studies were taken up on guava cv. Arka Mridula trees of 7 and 16 years to evaluate the influence of age on root activity distribution and the zone of effective placement of fertilizer. Soil injection of carrier-free 32P was employed for root activity studies and 32P-labelled superphosphate/soil was used to compare different placements of fertilizer. Laterally, the younger trees showed bulk of the active roots (96.10-96.48%, late monsoon and 76.68-82.96%, winter season) up to 150 cm distance, while the root activity was fairly well-distributed up to 240 cm distance indicating that the root system predominantly extended sideways with age. In terms of depth, most active roots resided at 25/30cm depth (45.75-69.72%) during both seasons. At deeper layers, the root activity of the older trees was relatively lower (at 50 cm 30.38-48.60%) due to anisotropism of the soil compared to that of the younger trees (at 45 cm 39.76-54.25%). The zone of fertilizer application showing maximum phosphorus absorption shifted from 100 to 160 cm in 8-yr old plants to 130 to 190 cm lateral distance in 17-yr old plants as a result of extended spread of root activity in the latter trees. | |
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