P32 uptake by cacao and coconut in relation to placement /
by Baudilla B. Siton
- Los Baños, Laguna : University of the Philippines, 1980.
- 99 pages : illustrations ; 28 cm.
Thesis (M.S. - - Horticulture) University of the Phililippines, College, Laguna.
Includes bibliographical references.
SITON, BAUDILLA BARAN, University of the Philippines at Los Banos, June, 1980. p32 Uptake by Cacao and Coconut in Relation to Placement. Major Professor: Dr. Rafael P. Creencia
An experiment was conducted on 6-year old Trinitario? cacao planted under 25-year old "Laguna’ coconuts at Buenavista, Bansalan, Davao del Sur from March to April, 1980 (1) to determine the effect of distance and depth of placement of labelled ordinary superphosphate on the individual and combined p32 uptake by treated cacao, contact coconut, and cacao, and (2) to provide a basis for assessing the manner in which fertilizers can be applied in the field most effectively and economically.
No interference from naturally occurring radio-active sources was noted on observed counts. Five millicuries p32 leaf samplings, and radioassay procedures employed provided comparable results. Fertilizer application in a 2.0 ¥ 0.2m Strip between a cacao and coconut hill benefited not Only these two trees but also the nearest two cacao trees in the same row, Total P content of leaves showed no change during the three sampling periods. High coefficients of variations were only observed at 10-day sampling. p32 uptake in all treatments increased with time. Together, the three contact trees absorbed two to three times more p32 than treated cacao.
Root activity of treated cacao was maximum either at 1.0 m from its base 25 cm from the soil surface or at 1.5 m from its base 5 cm from the soil Surface. Root activity of contact coconut and the combined root activities of treated cacao and contact coconut were highest at 1.5 m from the treated cacao 5 om from the soil surface. Equal distribution on the p32 uptake by the treated cacao and three contact trees was obtained at 1.0 m from treated cacao 25 cm from the soil surface.
Highest combined root activities of the treated cacao and the three contact trees were concentrated at 1.0 m from treated cacao 25 cm from the soil surface. For maximum utilization, fertilizers should be placed at this zone where most active roots are found.