| Author | Boonsong Niyomtham |
| Call Number | AIT Thesis no.AE-84-05 |
| Subject(s) | Rice--Soils
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources & Development |
| Publisher | Asian Institute of Technology |
| Abstract | After flooding the soil pH increased from 4.7 to 6-7 in formerly uncultivated and decreased slightly from 7-8 to 7-7.5 in cultivated soil. P-deficiency reduced the number of tillers and increased the time required between transplanting and maturity, from a minimum of 94 to a maximum of 146 days. Extreme P-deficiency caused plants to die before maturity.
Available soil-P before soil preparation varied from 1.4 to 4.8 and from 2.7 to 8.9 ppm, determined by Bray II and Olsen methods, respectively. At harvest time corresponding variations were 6.1 to 15.4 and 8.4 to 30.8 ppm P. Direct P determinations on wet soil samples from the plots at harvest time gave available soil-P contents from 7.4 to 32.4 (Bray II) and from 12.0 to 71.1 ppm P (Olsen).
Bray II-P was positively and significantly correlated with grain yield at all soil sampling sates, whereas correlations generally were less close with Olsen-P. Correlation coefficients r between grain yield and Bray II-P were 0.74** before soil preparation and 0.60** and 0.89** at harvesting time for dried and wet soil samples, respectively.
Rice yields responded well to increasing soil-and fertilizer-P levels. In the fertilizer-P experiment the highest average grain yield of 4.9 t/ha was obtained with 200 kg/ha of triple superphosphate. In the soil-P experiment the highest grain yield of 6.2 t/ha was obtained in a plot with the highest available soil-P content.
Increasing levels of soil-and fertilizer-P levels. In the fertilizer-P experiment the highest average grain yield of 4.9 t/ha was obtained with 200 kg/ha of triple superphosphate. In the soil-P experiment the highest grain yield of 6.2 t/ha was obtained in a plot with the highest available soil-P content.
Increasing levels of soil-and fertilizer-P increased the P-concentration of plants, as well as Ca and Zn contents, whereas the concentration of N, K, Na, Al, Fe and Mn were decreased. |
| Year | 1984 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Eppendorfer, W.H. |
| Examination Committee(s) | Jensen, Jens Raunso ; Wee, Kok Leong |
| Scholarship Donor(s) | Australian Government |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1984 |