: An estimation of the requirement of minerals based on growth stage and cropping pattern is very important for greenhouse zucchini. This study was performed at farmer's field which was applied with a fertigation system and a semi-forcing cultivation from Feb. to July in 2014, and nitrogen levels were set up with x0.5, x0.75, x1.0 and x1.5 of the NO3-N-based soil-testing recommendation for zucchini cultivation. Top dressing of nitrogen (basal : top = 4 : 6) and potassium (basal : top = 3 : 7) was applied with an interval of every two weeks from two and six weeks after transplanting, respectively, and phosphorus was totally supplied with basal dressing. The nitrogen uptake was the order of x1.0, x0.75, x1.5 and x0.5, phosphorus, x1.0, x0.75, x0.5 and x1.5, and potassium, x0.75, x1.0, x1.5 and x0.5. From these results, it was suggested that highest mineral uptake could be reached between x0.75 and x1.0 of the NO3-N-based soil-testing recommendation. In conclusion, nutrient management based on the growth stage was proven to be better method for favorable growth and yield of zucchini.
An estimation of optimal requirement of additional N by cropping pattern and growth stage is very important for greenhouse watermelon. The objectives of this study were to estimate an amount of optimal additional N based on growth, N uptake and yield of watermelon. In order to achieve these goals, we performed the study at farmer's greenhouse with a fertigation system and watermelon was cultivated three times (spring, summer and autumn) in 2015. The levels of additional N were set up with x0.5, x0.75, x1.0 and x1.5 of the NO 3 -N-based soil-testing N supply for watermelon cultivation. The trends of growth and N uptake of watermelon markedly differed from cropping pattern; spring (sigmoid), summer and autumn (linear). The yield of watermelon was the highest at summer season and followed by autumn and spring. Also, the x1.5N showed a significantly higher yield compared to other N treatments. On the basis of growth, N uptake and yield of watermelon, we estimated an optimal level of additional N by cropping pattern and growth stage as follows; 1) spring (transplanting ~ 6 WAT : 6 ~ 14 WAT : 14 ~ harvest = 5 : 90 : 5%), summer (transplanting ~ 4 WAT : 4 ~ 8 WAT : 8 ~ harvest = 25 : 50 : 25%) and autumn (transplanting ~ 4 WAT : 4 ~ harvesting : 50 : 50%). In conclusion, nutrient management, especially N, based on cropping pattern and growth stage was effective for favorable growth and yield of watermelon.
BACKGROUND:Cultivation of alternative crops in paddy fields is necessary because of the decrease in rice consumption and the increase in excess stock of rice. The study was conducted to investigate the effects of alternative crops cultivation in paddy fields on soil physico-chemical characteristics and crop yield. METHODS AND RESULTS: Soybean (Glycine max), red-clover (Trifolium pratense), and water convolvulus (Ipomoea aquatica) were selected for alternative crops in the first and/or second year and rice was planted in the third year. When alternative crops were cultivated in the previous year, soil bulk density, soil hardness, and water content were lower than those for rice cultivation. Water-depth decreasing rate and aggregate content were greater for the upland-upland-paddy cropping system than upland-paddypaddy cropping system. Cultivation of red-clover and water convolvulus for two years resulted in the high soil organic matter content. In the third year, available phosphate, exchangeable potassium, and soil cation exchange capacity were relatively high when soybean was cultivated in the previous year. In the first year, water convolvulus cultivation showed greater productivity than red-clover cultivation while the opposite pattern was found in the second year. Rice yield in the third year was greater for soybean or red-clover as a previous crop than for water convolvulus as a previous crop. CONCLUSION : The results suggest that cultivation of alternative crops in paddy fields can improve soil physical properties including bulk density, hardness, water content, and aggregate content as well as rice productivity.
It is known that the poor soil fertility of newly reclaimed saline soils is due to the lack of organic matter and available mineral nutrients for crop production. The effect of green manuring with Sesbania aculeata in combination with five rates of urea-N treatments (N0. N25, N50, N75, N100) on the productivity of a subsequent whole-crop barley and the fertility of the reclaimed saline soil in Saemangeum was evaluated in the field during 2013-2014 growing season. Sesbania was grown during summer season (June to October). The amount of Sesbania incorporated was 16.2 Mg ha . Apparent N recovery (ANR) of whole-crop barely showed decreased with sesbania plus increasing rates of N fertilizer. Despite higher yield with sesbania manuring plus increasing N rates, the contributions of N from Sesbania with increasing N rates to whole-crop barley were decreased, whereas those from fertilizer increment due to excessively mineralized Nitrogen. Considering yield, ANR, N contribution from Sesbania and nitrogen fertilizer, the optimum N rate was N50 rate following sesbania incorporation.Key words: Green manuring, Sesbania, Seamangeum, NitrogenResponse of whole-crop barley to N fertilizer rates following sesbania incorporation (actual N fertilizer rates to whole-crop barley were N0-N100 : 0, 37.5, 75.0, 112.5, 150 kg ha ).
It is important to increase the area of potato cultivation in the fall season for a stable year-round supply system in Korea. Saemangeum reclaimed land has the potential to extension of potato cultivation area with appropriate practices. This study was performed to test applicability of fertilizer recommendation in southern coastal area to the Saemangeum area. Two experiments were conducted: one experiment compared the yield response of potato between standard rates of N-P-K (SR) and recommendation rates of N-P-K based on soil test (STR) and the other experiment analyzed yield response to 4 different levels of N, P, K, respectively. The potato yield in SR was 6.05 Mg ha -1 on average and varied from 1.68 Mg ha -1 to 11.80 Mg ha -1 . The potato yield in STR, meanwhile, ranged from 8.13 Mg ha -1 to 12.17 Mg ha -1 with a mean value of 9.65 Mg ha -1 . Potato yield was increased linearly with N fertilization rates but P and K fertilization did not have any significant effect on potato growth. The N fertilization rate (NFR) and the soil available phosphate content (Av. P 2 O 5 ) had significant positive corelation with potato yield (p < 0.01). Based on stepwise multiple regression analysis, partial regression coefficient was 0.30 for NFR and 0.08 for Av. P 2 O 5 ; Y = 19.6 X 1 + 34.9 X 2 + 1,410, where Y, X 1 , and X 2 mean potato yield, NFR, and Av. P 2 O 5 , respectively. Conclusively, STR was strongly recommended for potato in the Saemangeum reclaimed land and the conventional standard fertilization rate was hardly applicable to the area, especially for nitrogen.
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