The growth, yield and chemical properties of waxy corn Sonjajang~timesKNU-7 and Asan~timesKNU-7 planted in different dates and mulch types in a converted paddy field was investigated. Experiment was carried out in a randomized complete block design in a split split-plot arrangement with four replications. Planting dates (D) [May 16 (D1, early), June 1 (D2, middle), June 6 (D3, late)] represented main plots, plastic mulch (M) [(BM, black mulch; TM, transparent mulch)] for subplots while waxy corn crosses [Sonjajang~timesKNU-7 (‘Sonja’) and Asan~timesKNU-7 (‘Asan’)] for sub-subplots. Results showed that D had a significant effect on growth characters except emergence, ear quality except ear diameter, and yield whereas M showed significant effect on growth characters only. Superior growth and ear quality performance were recorded in D1 and BM. In terms of crosses, ‘Sonja’ had better growth performance than ‘Asan’ regardless of D and M, but performed better at D1 and BM. Highest yield was obtained in D1 for BM (2,131 kg 10a-1 ) and TM (1,655 kg 10a-1 ) but no significant difference in the yield across V was recorded. In terms of starch and sugar contents, a decreasing trend was observed from D1 to D3 regardless of M and V.

2003년에 이상적으로 많이 발생하여 벼에 심각한 피해를 가져온 혹명나방의 재배방법별, 엽록소 함량별 피해실태를 조사하여 피해에 따른 수량반응, 미질변화 등을 구명하고자 조사한 결과는 다음과 같다. 1. 혹명나방의 피해가 심할수록 벼의 등숙비율, 천립중의 감소와 복백립 등 미숙립의 증가에 따른 완전미 비율이 감소되어 완전미 수량이 피해가 심한 곳에서 36% 감소되었다. 2. 혹명나방의 피해가 심할수록 쌀의 외관상 품위가 떨어질 뿐만 아니라 단백질함량이 높아져 식미치는 감소되어 미질이 급격히 저하되었다. 3. 질소질 비료의 시용량이 증가할수록 혹명나방에 의한 피해는 증가하였으며, 특히 주남벼의 경우 질소량이 증가할수록 피해가 급증하였다. 4. 질소 시비량이 추천 시비량인 11 kg/10a를 초과시 피해엽율이 60% 이상으로 급증하였고, 60% 이상 피해를 입은 엽의 비율도 25%이상으로 늘어나 수량 감수 요인으로 작용하였다.

The aim of this study was to isolate chicken feather-degrading bacteria with high keratinolytic activity and to investigate cultural conditions affecting keratinolytic enzyme production by a selected isolate. A chicken feather-degrading bacterial strain CH3 was isolated from poultry wastes. Isolate CH3 degraded whole chicken feather completely within 3 days. On the basis of phenotypical and 16S rDNA studies, isolate CH3 was identified as Bacillus thuringiensis CH3. This strain is the first B. thuringiensis described as a feather degrader. The bacterium grew with an optimum at pH 8.0 and 37℃, where maximum keratinolytic activity was also observed. The composition of optimal medium for keratinolytic enzyme production was feather 0.1%, sucrose 0.7%, casein 0.3%, K2HPO4 0.03%, KH2PO4 0.04%, MgCl2 0.01% and NaCl 0.05%, respectively. The keratinolytic enzyme had a pH and temperature optima 9.0 and 45℃, respectively. The keratinolytic activity was inhibited ethylenediaminetetraacetic acid, phenylmethylsulfonyl fluoride, and metal ions like Hg2+, Cu2+ and Zn2+. The enzyme activated by Fe2+, dithiothreitol and 2-mercaptoethanol.

A field experiment was conducted to investigate effects of application time and rate of biofertilizer alone and in combination with chemical NPK fertilizer on growth, yield and quality of rice. The biofertilizer used composted food waste as substrate and added with effective microorganism. The treatments included recommended NPK fertilizer(RF, 11-5.5-4.8kg~;10a-1 ), half recommended NPK fertilizer(HRF, 5.5-2.8-2.4kg~;10a-1 ), half recommended NPK fertilizer plus 250kg~;10a-1 biofertilizer(HRF+Bio 250) and 500kg~;10a-1 biofertilizer(HRF+Bio 500). The biofertilizer treatments were applied at 0, 5 and 10 days before transplanting(DBT). Grain yield of HRF+Bio 250 at 5 DBT(648.4kg~;10a-1 ) was statistically similar to the highest obtained in the RF(654.1kg~;10a-1 ). Tiller numbers at HRF plus biofertilizer treatments were already high during the maximum tillering stage, and were similar with that of the RF and higher than that of the HRF during heading stage. Likewise, ripening ratio at HRF plus biofertilizer treatments was similar with that of the RF and higher than that of the HRF. Furthermore, all the biofertilizer treatments improved protein content but reduced the amylose content and palatability compared to treatments with chemical NPK fertilizer alone. Thus, HRF+Bio 250 at 5 DBT can be used to save 50% chemical NPK fertilizer and at the same time obtain an improved rice grain yield and quality.

The effect of mixed treatments of wood vinegar and sulfonylurea-based herbicides on weed control, yield and yield components, and quality of rice was investigated. Two herbicides were tested namely: imazosulfuron-ethyl+thiobencarb[ethyl-1-(2-chloroimidazo[1,2-α ]pyridin-3-ylsulfonyl)-3-(4,6-dimethoxypyrimidin-2-yl) urea+S-4-chlorobenzyl diethyl(thiocarbamate)], and bensulfuronmethyl+butachlor [methyl α -[(4,6-dimethoxypyrimidin-2-ylcarbamoyl)sulfamoyl]-o-toluate+N-butoxymethyl-2-chloro-2',6'-diethylacetanilide]. The experiment was carried out in a randomized complete block design with 3 replications and 5 treatments. Treatments used were recommended(RH: 100%) and half-recommended(HRH: 50%) application rates of each herbicide. Half-recommended application rates were combined with 1 mL wood vinegar 500mL~;water-1 (500) and 1 mL wood vinegar 1000mL~;water-1 (1000) wood vinegar. Plots for no herbicide treatments were also prepared and used as control. Results showed that wood vinegar significantly increased efficacy of HRH in bensulfuron-methyl+butachlor while high efficacy was already obtained in HRH treatment of imazosulfuron-ethyl+thiobencarb. Wood vinegar did not improve the efficacy of imazosulfuron-ethyl+thiobencarb but improved rice yield. Significantly similar rice yields were obtained in the HRH+1000 WV and RH treatments of both herbicides. There were no significant variations in the yield components among the treatments; however, differences in yield can be attributed to the variations in the spikelet number and ripening ratio. Data on rice quality analysis did not show clear trend on the effects of the treatments on grain appearance and nutritional quality.

The effect of biofertilizer in enhancing nutrient quality and antioxidant property of rice grain was investigated. The experiment was carried out in a randomized complete block design with 3 replications and 7 treatments namely : RF = N-P2O5-K2O(11-5.5-4.8kg~;10a-1); half of the recommended fertilizer rate, HRF=N-P2O5-K2O(5.5-2.75-2.4kg~;10a-1): HRF+Bio 250=HRF combined with 250 kg Biofertilizer 10 a-1 ; HRF+Bio 500=HRF combined with 500 kg Biofertilizer 10 a-1; Bio 250=250 kg Biofertilizer 10 a-1; Bio 500=500 kg Biofertilizer 10 a-1; and NF=No Fertilizer. Results showed that HRF+Bio 500 obtained a significantly higher protein content but a significantly lower amylose content compared with RF and NF treatments. Highest phytic acid content was recorded in NF treatment while the lowest was observed in HRF+500 treatment. The highest values in both electron donating ability and reducing power were obtained in HRF+Bio 500 treatment. All treatments obtained higher reducing power than that of the RF treatment and that NF treatment showed comparable values in both electron donating ability and reducing power with those of the treated plots. Highest antimutagenicity property was also observed in HRF+Bio 500 treatment followed by Bio 500 treatment. This study showed the possibility of using biofertilizer to enhance nutritional quality and antioxidant property of rice.