• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.952-954
• /
• 2003

In this paper, we present the different characteristics of NDVI fluctuation pattern between irrigated and non-irrigated area in Suphanburi province, in Central Thailand. For non-irrigated rice cultivation area, there is a strong correlation between NDVI fluctuation and peak rainfall, while there is a lower correlation with irrigated area. In this study, the 'peak detector' classifier was developed to identify the area of non-irrigated and irrigated cropping and its cropping intensity (number of crops per year). This classifier was created based on cropping characteristics such as number of crops, time or planting period of each crop and its relationship with the peak of rainfall. The classified result showed good accuracy in identification irrigated and nonirrigated rice cultivation areas.

• Journal of Environmental Science International
• /
• v.33 no.1
• /
• pp.27-41
• /
• 2024

In this study, we evaluated productivity, soil physiochemical properties, and soil microbial characteristics in Kimchi cabbage(Brassica rapa subsp. pekinensis) cultivation within a highland environment during summer. Specifically, we examined the effect of different cropping systems, namely monoculture and rotation with soybean, over an 8-year cropping period. The results of our investigation revealed that significant differences were absent in terms of yield and soil physiochemical properties between the two cropping systems. However, microbial characteristics exhibited distinctive patterns. Bacterial diversity was significantly higher in the rotation system that in the monoculture, whereas fungal diversity demonstrated a preference for rotation although the result was not significant. Our findings identified the presence of Bradyrhizobium stylosanthis, a nitrogen-fixation symbiont, as an indicator ASV (amplicon sequence variant) in the rotation system, where it displayed significantly higher abundances. These observations suggest a potential positive effect of the rotation system on nitrogen fixation. Notably, throughout the cultivation period, both cropping systems did not exhibit critical disease incidences. However, Fusarium oxysporum, a well-known pathogen responsible for inducing fusarium wilt disease in Kimchi cabbage, was detected with significantly higher abundance in the monoculture system. This finding raises concerns about the potential risk associated with Kimchi cabbage cultivation in a long-term monoculture system.

• Plant Resources
• /
• v.3 no.3
• /
• pp.194-199
• /
• 2000

The result of this experiment which are conducted, to improve the cultivation technology of Alisma plantago, to increase its quantity and to contribute for stable production with Yongiun local group by examining the optimal planting density and transplanting period of double cropping of Alisma plantago in the southern region. The characters of plant height, leaf width and length tend to be reduced as the seeding period is later by the order of the 10th, 20th and 30th of July. The period required for flowering is reduced as the transplanting period is later and dense planting is applied. Plant height, the number of leaves and yield of dry root have much quantity at the dense planting density of 20$\times$ 15cm as they are transplanted later in the 30th of August or the 10th of September, but they are rather less in sparse planting density of 20$\times$25cm or 20$\times$35cm.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2001.10a
• /
• pp.484-487
• /
• 2001

Runoff, sediments and nutrient losses were studied under different patterns of paddy field management: (1) fall and spring plowing (PL); (2) fall plowing for half of plot and spring plowing (SPL); (3) no-till for fall and spring plowing (NPL) during the non-cropping period in the southern Korea. Sediment losses from PL plot were 25% more than those from NPL plot. There was significant difference in nutrient losses via runoff water and sediment according to plowing practice (P < 0.01). Losses of total-N, ammonia-N, nitrate-N, total-P from NPL plot were larger than PL and SPL plots during study period. Sediment and total-P losses from SPL plot were close to those of PL plot.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2001.10a
• /
• pp.394-398
• /
• 2001

The study was carried out to investigate the water balance and losses of nutrients from paddy fields during cropping period. The size of paddy fields was 95 ha and the fields were irrigated from a pumping station. The runoff loading was the highest in June because of the high concentrations of nutrients due to applied fertilizer. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 39.1 % to 42.5 % of nitrogen lost via runoff while runoff losses of phosphorus account for 6.3 % to 8.0 % of the total applied amount during cropping period. When the ratio was calculated between nutrients losses by infiltration and the applied of chemical fertilizer, two year results showed 9.1 % to 10.7 % for nitrogen and 0.2 % for phosphorus, respectively.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2001.10a
• /
• pp.451-455
• /
• 2001

This study was performed to examine water and nutrient balance during rice cropping period using difference fertilization paddy plot in ground water irrigation region. The experimental rice paddy consist of three plot, Treatment of Excess fertilization(TEF) and Treatment of Standard Fertilization(TSF) and Treatment of Reduce Fertilization(TRF). As result, input amount to rice paddy was almost rainfall and output was direct runoff through drainage. nutrient input amount was upper paddy in case COD and fertilization in case Total nitrogen and total phosphorus, and output was drainage in all nutrient.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.72-72
• /
• 2022

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.2
• /
• pp.218-225
• /
• 2016

This experiment was conducted in Suwon and Iksan city from 2012 to 2014 to evaluate soil erosion and nutrient loss from irrigated paddy fields during cropping period. Rainfall amount and rainfall erosivity of $EI_{30}$ were, on average, 1,026 mm and $3,922mm\;ha^{-1}yr^{-1}hr^{-1}$ for the cropping period, respectively, and the rainfall event with maximum $EI_{30}$ occurred in July. Annual average of runoff was $2,508MT\;ha^{-1}yr^{-1}$ in Suwon and $3,375MT\;ha^{-1}yr^{-1}$ in Iksan, accounting for 36% of rainfall of the cropping period. Nutrient loss by runoff, on average, was $7.0kg\;N\;ha^{-1}yr^{-1}$, $1.3kg\;P\;ha^{-1}yr^{-1}$, and $16.6kg\;K\;ha^{-1}yr^{-1}$; N, P, and K loss were 5.0, 0.6, and $8.3kg\;ha^{-1}yr^{-1}$, respectively, in Suwon and 8.9, 1.9, and $16.7kg\;ha^{-1}yr^{-1}$ in Iksan. Soil loss in Korean paddy rice was evaluated as $0.33MT\;ha^{-1}yr^{-1}$ ranging from $0.05MT\;ha^{-1}yr^{-1}$ to $0.88MT\;ha^{-1}yr^{-1}$. Amount of soil loss, however, depended on areas and year influenced by variation of rainfall amount and intensity. Interestingly, soil erosion in Iksan in 2012 was remarkably greater than those in other periods due to heavy rainfall between late May and June with soil flake dispersion right after the rice-planting season.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.43 no.5
• /
• pp.153-162
• /
• 2001

A study was carried out to investigate the water balance and losses of nutrients at a paddy plot located at the southern Korea. The observed amount of precipitation, irrigation, runoff, evapotranspiration and percolation for the experimental paddy plot during cropping period were 1,030, 566, 701, 551. and 310 mm for 1999 and 1.214, 413, 710, 682, and 234 mm for 2000 year, respectively. The measured input quantities of N and P into the paddy field during cropping period were 122 to 140 kg N $ha^-1$ and 29 to 30 kg $P_2O_5$ kg $ha^-1$ by chemical fertilizer, 20 to 28 kg N $ha^-1$ and 0.35 to 0.36 kg P $ha^-1$ by precipitation, and 26 to 35 kg N $ha^-1$ and 0.57 to 0.72 kg P$ha^-1$ by irrigation water. respectively. The output amounts of N and P from paddy field were measured as follows. They were 48 to 52 kg N $ha^-1$ and 1.1 to 1.6 kg P $ha^-1$by runoff water, and 9 to 12 kg N $ha^-1$ and 0.04 to 0.05 kg $ha^-1$ by percolation water. When the runoff losses of nutrients were compared to applied chemical fertilizer. it was found that 34.3 % to 42.6 % of nitrogen lost via runoff while runoff losses of phosphorus account for 3.8 % to 5.3 % of the total applied amount. When the ratio was calculated between nutrients losses by percolation water and the applied of chemical fertilizer, two year results showed 6.4 % to 9.8 % for the nitrogen and 0.1% to 0.2% phosphorus, respectively.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.44 no.7
• /
• pp.53-63
• /
• 2002

Runoff, sediments and nutrient losses were studied under different patterns of paddy field management: (1) fall and spring plowing (Plowing)i (2) fall plowing for half of plot and spring plowing (Semi-plowing); (3) no-till for fall and spring plowing (Un-plowing) during the non-cropping period in the southern Korea for two years. The runoff amount and initial abstract were significantly affected by plowing practices. Un-plowing plot showed the highest runoff amount among treatments. The concentrations of sediment from Plowing plot were much higher than those from Un-plowing plot, especially after (all plowing. Sediment losses from Plowing plot were 25% more than those from Un-plowing plot. There was significant difference in nutrient losses via runoff water and sediment according to plowing practice. Two-year average of losses of N from paddy field during non-cropping period were 9.42 kg ha$\^$-1/, 8.17kg ha$\^$-1/, and 7.76 kg ha$\^$-l/ for Un-plowing, Semi-plowing, and Plowing plot, respectively, while losses of P were 0.64 kg ha$\^$-1/, 0.58 kg ha$\^$-1/, and 0.58 kg ha$\^$-1/ for each tillage system. Losses of total-N, ammonia-N, nitrate-N, Total-P from Un-plowing plot was larger than those from Plowing and Semi-plowing plots during study period.