Nuanchan Eaimpraphan. Effect of mixed nitrogen fertilizer on carbon sequestration of some photo-insensitive rice varieties in paddy field, Pathum Thani province . Master's Degree(Appropriate Technology for Resources and Environmental Development). Mahidol University. : Mahidol University, 2007.
Effect of mixed nitrogen fertilizer on carbon sequestration of some photo-insensitive rice varieties in paddy field, Pathum Thani province
Abstract:
This research studied regarding the carbon sequestration in Clayey, Sulfic Tropaquepts:
Rangsit series in the irrigated paddy fields within the central plain. The objective of this study was to
evaluate the carbon storage within one season of rice cultivation, growing the photo-insensitive
Suphan Buri 1 (SPR1) and Chai Nat 1 (CNT1) varieties. In the sample mixed nitrogen fertilizers
content were applied with different rate at 12, 18, 24 and 30 kg N/rai. The plant samples were
collected during 3 different growth stages which were tillering stage, booting stage and maturing
stage.
The analyses of carbon content were performed from both the plants and the soils. The
evaluation of carbon contents in the plants was done by collecting biomass of the plant both above
ground and below ground, and the samples were oven dried at 70°C for 72 hours in order to find the
dry weight of the plant. Then the biomass was multiplied by carbon coefficient values of plant
biomass using the total organic carbon analyzer (TOC). In addition, organic carbon contents within
the soils were analyzed by the Walkley and Black method (1947).
It was found that the average carbon contents during all seasons of SPR1 and CNT1
cultivation were 9,282.38 and 9,067.01 kg/rai, respectively. Both rice varieties responded best to
mixed nitrogen fertilizer 18 kg N/rai and they yielded highest level of carbon content at 9,505.61 and
9,271.53 kg/rai for SPR1 and CNT1, respectively. SPR1 had the highest carbon storage rate during
the booting stage which was 38.38 kg/rai-day, while the CNT1 had the highest carbon storage rate
during the tillering stage which was 32.64 kg/rai-day. The leaf color was related to nitrogen content
which had an impact on photosynthesis and biomass production. The SPR1 variety demonstrated a
higher color value than CNT1 variety and was directly related to the rate of mixed nitrogen fertilizer.
The leaf color value was more significant during booting stage than maturing stage. The sample soil
properties changed according to growth stages of the rice. However, rice varieties and mixed nitrogen
rate had no effects on the paddy soil properties.