Increasing phosphorus availability from rock phosphate using organic matter in rice (Oryza sativa L.)

Issue Date

9-2009

Abstract

The study was conducted to improve the availability of phosphorus from low-grade rock phosphate (RP) by preparing RP-enriched compost (RP-compost) via mixing RP at the rate of 2 or 4 kg (based on elemental P), 5 kg fresh cow dung and 0.5 kg N as a urea solution per 100 kg of air-dried rice straw. RP-composts had markedly lower electrical conductivity (EC), organic carbon, total nitrogen, water soluble P (WSP), citric soluble P (CSP) and higher total P than straw compost. Statistically, straw compost and RP-compost 2% had similar pH. An incubation experiment was carried out under waterlogged condition to monitor the release of P from P sources. Thus, RP-composts, straw compost, RP and triple super phosphate (TSP) were added to the soil to provide 0, 25 and 50 mg P kg -1 soil. P and pH were determined in the samples after 1, 4, 8, 15, 30, 45, 60, 75 and 90 d at 25 °C. Olsen P increased during the 90-d incubation period and was highest in straw compost compared with the other treatments. The pot experiment on rice showed straw compost had significantly more effect on increasing grain yield than RP-compost 2% (compost with 2% RP) and RP, but no significant difference with TSP and RP-compost 4% (compost with 4% RP). The highest and the lowest straw yields were obtained significantly from TSP and RP, respectively. Statistically, panicle length, 1000-grain weight and grain P concentration were similar among the treatments. Maximum and minimum filled grains were obtained from straw compost and TSP, respectively. The highest plant height was obtained from TSP which was significantly different from RP-composts and RP but not straw compost. The highest root dry weight and productive tillers were obtained from straw compost, which was not significantly different from the other treatments, except RP.

Source or Periodical Title

Philippine Agricultural Scientist, The (Formerly: The Philippine Agriculturist)

ISSN

0031-7454

Volume

92

Issue

3

Page

301-307

Document Type

Article

College

College of Agriculture and Food Science (CAFS)

Frequency

quarterly

Physical Description

graphs; tables; references

Language

English

Subject

enriched compost, Olsen P, organic acids, rice agronomic characteristics, straw compost

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