Phakamas, Nittaya

Preferred name

Phakamas, Nittaya

Alternative Name

Phakamas, N.

Main Affiliation

School of Agricultural Technology

nittaya.ph@kmitl.ac.th

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Application of soil test kit for evaluating nitrogen fertilizer requirement of Napier Pakchong 1 grass in Thailand
(2018-12-01)
Phakamas, N.
;
Yampracha, S.
A soil test kit may be applicable for nitrogen management in pasture grass production. The nitrogen fertilizer requirement of Napier Pakchong 1 grass (Pennisetum purpurem ×Pennisetum amenicanum cv. Pakchong 1) was evaluated by using a soil test kit (STK). Result showed that the application of nitrogen fertilizer in the forms of urea and ammonium sulphate increased in dry mater yield of Napier Pakchong 1 grass, whereas application of cattle manure at both recommended rates and the recommended rate by STK gave the dry matter yield similar to the unfertilized control. Application of ammonium sulphate gave better than application of urea. The clay soil with moderate soil fertility and high soil moisture content, the soil test kit provided the acceptable guideline for nitrogen management in Napier Pakchong 1 grass. The application of the soil test kit for nitrogen fertilizer management of Napier Pakchong 1 grass in other soil types are noted.
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Assessment of antioxidant enzymes in response to exogenous titanium dioxide (TiO2) nanoparticles in Chainat 1 rice cultivar
(2018-01-01)
Samart, Sutichai
;
Phakamas, Nittaya
;
Chutipaijit, Sutee
Antioxidant enzymes are important to prevent the destruction of photosynthetic pigments in plant cells. There have been reported that ZnO nanoparticles can promote activities of antioxidant enzymes in rice, but should not use in high activities because it can cause toxicity. Therefore, the objective of this study was to investigate the effect of titanium dioxide (TiO<inf>2</inf>) nanoparticles on the activities of antioxidant enzymes in Chainat 1 rice cultivar. Rice plants were treated with TiO<inf>2</inf> nanoparticles using different concentrations i.e., 0, 100, 200, 400, 600 and 800 mg.L-1 for every 7 days-interval. Photosynthetic pigment contents (chlorophyll A, chlorophyll B and carotenoid) and activities of antioxidant enzymes (catalase and peroxidase) were recorded at 37, 44 and 51 days after planting. The results showed that the treatment of TiO<inf>2</inf> nanoparticles was not effect on the quantities of chlorophyll A, chlorophyll B and carotenoids, but found that the activities of peroxidase and catalase enzymes were significant affected at all growth stages. Especially, at a concentration of 200 mg.L-1 TiO<inf>2</inf> found that rice plants contained the highest activities of peroxidase enzyme and significant difference from control treatment. However, the treatments of higher dose than 200 mg.L-1 TiO<inf>2</inf> would have a chance to meet toxicity in rice plants as the activities of antioxidant enzymes were decreased.
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Estimation of solar radiation based on air temperature and application with the DSSAT v4.5 peanut and rice simulation models in Thailand
(2013-10-15)
Phakamas, Nittaya
;
Jintrawet, Attachai
;
Patanothai, Aran
;
Sringam, Prakan
;
Hoogenboom, Gerrit
Estimation of solar radiation (SRAD) from daily air temperature by the modified Bristow-Campbell (B-C) model requires three empirical coefficients that are area specific. Previous estimates of these coefficients for Thailand were based on limited data without any evaluation. Accurate estimation of solar radiation has become more important with the wider application of environmental models. The objective of this study was to calibrate and evaluate the coefficients for Thailand with a broader range of data. Meteorological data from 2008 to 2011 were obtained from eight weather stations, three in the North (Chiang Mai, Chiang Rai and Nakhon Sawan), two in the Northeast (Khon Kaen and Ubon Ratchathani), one in the Central (Lop Buri) and two in the South (Chumporn and Surat Thani). Data for 2010 for all locations except Chiang Rai were used for calibration of the coefficients and the remaining data were used as independent data sets for evaluation. The coefficient of determination (R2), root mean square error (RMSE) and normalized root mean square error (RMSEn) were used as indicators of the agreement between the observed and the calculated SRAD. The results showed that the calibration was acceptable (R2=0.56, RMSE=3.07MJm-2d-1 and RMSEn=17.5%). The derived values are a=0.63, b=1.89 and c=1.54. These new coefficients performed well during evaluation with the 13 independent data sets from the eight locations for all four regions, with the R2, RMSE and RMSEn values in the range of 0.39-0.70, 2.42-3.79MJm-2d-1 and 14.0-21.7%, respectively. In addition, simulations using estimated SRAD from the derived values provided high R2 values for peanut and rice yield and total dry matter. These new coefficient values can be used to estimate solar radiation from air temperature data for all locations in Thailand and similar environments in Southeast Asia. © 2013 Elsevier B.V.
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Effects of different forms nitrogen fertilizer on growth and yield of four tropical pasture grasses
(2018-12-01)
Buamool, P.
;
Phakamas, N.
Nitrogen fertilizer is an essential plant nutrient of tropical pasture crops. The effect of nitrogen fertilizer in forms of urea and ammonium sulphate on growth and yield of four tropical pasture grasses was determined. The results showed that four tropical pasture grasses were significantly different for tiller number, SCMR, CGR during the regrowth, fresh weight yield and dry matter yield, when different forms of nitrogen fertilizer were applied. Application of urea resulted in higher fresh yield (9.6-10.7 t/ha/time) and dry matter yield (1.3-2.0 t/ha/time) than did application of ammonium sulphate and control. Application of urea also had higher tiller number and higher crop growth rate during the regrowth period after each cutting time than application of ammonium sulphate and unfertilized control. Application of urea at the rate of 62.5 kg N/ha is recommended for growing Purple Guinea, Mombasa Guinea, Ruzi and Mulato II in Thailand. The interaction between pasture grass and nitrogen form was not significant in this study.
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Evaluating the effect of zinc oxide nanoparticles on the physiological responses of nine non-photoperiod sensitive rice cultivars
(2017-01-01)
Samart, Sutichai
;
Chutipaijit, Sutee
;
Phakamas, Nittaya
The effects of nanopaticles on plant growth and metabolites have been reported in previous studies, but knowledge of the potential impacts of physiological responses is still unclear. Therefore, this study focused on the effect of exposure of zinc oxide (ZnO) nanoparticles on photosynthetic pigment contents (chlorophyll A, chlorophyll B and carotenoids) and the antioxidant enzyme activities (catalase and peroxidase) in nine non-photoperiod sensitive rice cultivars consisting of RD41, RD49, Chai Nat 1, Suphan Buri 1, Suphan Buri 2, Suphan Buri 3, Pathum Thani 1, Pathum Thani 80 and Phitsanulok 2. Rice plants were treated with 200 mg L-1 ZnO nanoparticles for every 15 days-interval. Rice plants were collected at 37, 44 and 51 days after planting for the evaluation of ZnO nanoparticles toxicity. The results showed that nine non-photoperiod sensitive rice cultivars treated with ZnO nanoparticle, as determined by the reduction of photosynthetic pigment contents. The activities of antioxidant enzymes protected plant cell when exposed to the toxicity of ZnO nanoparticles. This study showed that the supplementation of ZnO nanoparticles was no significant difference in photosynthetic pigment contents of rice cultivars. The results indicated that the accumulation of antioxidant enzyme activities could be protecting damage of the photosynthetic pigments in plant cells.

Phakamas, Nittaya

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