• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.105-112
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• 1988

Experiment was conducted to elucidate the effect of various nitrogen fertilizers on the growth and yield of soybean cv. Backwoon in field, and to examine soybeans produced with different nitrogen fertilizers for their nutritional constituents and protein digestibility. Soybean plants were generally similar in growth among fertilizers applied, and plants with non-nitrogen and with ammonium sulfate showed tendency to have fewer internodes. Nodule number and nodule weight also were lower in plants with non-nitrogen and with ammonium sulfate. Nitrogen fixation ability per nodule number were similar at an early growth stage and at flowering stage treatments and were relatively higher with newly developed complex fertilizer at pod elongation stage. With newly developed complex fertilizer and with non-nitrogen, there were slight increase and in 100 grain weight and yield per 10a, respectively. Crude protein contents in soybeans with nitrogen fertilizers were higher than that with non-nitrogen, and the reverse were true for crude fat. Crude ash contents were relatively similar among the treatment. Crude fiber contents were higher with readily used complex fertilizer than with the others. The contents of inorganic constituents were of the same sort among the treatments, that of Fe with non-nitrogen being much lower than with the others. Protein digestibility was the highest in the non-nitrogen treated soybean.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.50-55
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• 1983

Effects of nitrogen applied to grown alone and in mixture with grass and legumes of forage crops on the yield of dry matter, absorptivity, and the amount of nitrogen fixation were studied using $^{15}N$ ammonium sulfate. 1. The amount of nitrogen fixation in legume was decreased in order of alfalfa > red clover > birdsfoot trefoil, and red clover gave highest soil-nitrogen dependency. 2. Fertilizer nitrogen for the yield of dry matter was highly effective only in orchardgrass, and effective at the early stages of alfalfa and birdsfoot trefoil in case of a mixed sowing. 3. Alone and mixed sewings showed the yield of dry matter in decreasing order of alfalfa > red clover > orchardgrass > birdsfoot trefoil and orchardgrass + alfalfa > orchardgrass + red clover > orchardgrass + birdsfoot trefoil, respectively. 4. The plot of with nitrogen showed greater nitrogen uptake than the plot of without-nitrogen throughout the plots. In case of grown alone, however, difference in the absorptivity of various forage crops was decreased in order of alfalfa > red clover > orchardgrass > birdsfoot trefoil. 5. Regardless of nitrogen application, nitrogen uptake amount of orchardgrass was higher in the plot of mixture then in the plot grown alone, except the with nitrogen plot of red clover grown in mixture at the ratio of 3 : 7.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.594-597
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• 2014

Crop yields depend on the limiting factor of crop growth; Liebig law of minimum. Identifying the kind and the necessary amount of the limiting factor is essential to increase crop yield. Although nitrogen is the most essential nutrient, N application does not always bring about yield increases when other elements are limiting in rice cultivation. Two experiments were compared to elucidate the effect of soil testing on rice yield response to N level. The one was an experiment about yield response of 3 rice cultivars to 7 levels of N application, which was conducted from 2003 to 2004 in 25 farmer's fields without ameliorating soil conditions by soil testing and the other was a demonstration experiment on N fertilizer recommendation equation by 0, 0.5, 1.0, and 1.5 times of N recommended level in 5 soil types from 30 fields after ameliorating soil conditions by soil testing. The N response patterns of the experiments conducted without soil testing showed a Mitscherlich pattern in some cultivars and soil types, but did not in the others. The N response patterns of the demonstration experiment showed a Mitscherlich pattern in all soil types. Because these results indicated that N was the minimum nutrient in the demonstration experiment by ameliorating soil conditions with soil testing, but not in the other experiment without soil testing, the supply of minimum nutrients by soil testing could increase the efficiency of N-fertilization.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.153-161
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• 2007

Field experiments were conducted to determine the physiological and biochemical basis of the interactive effect of sulphur (S) and nitrogen (N) application on seed and xanthotoxin yield of Ammi majus L. Six treatments were tested ($T_1$ = control-without manure and fertilizers, $T_2$ = manure @ 9 kg $plot^{-1}-10\;t\;ha^{-1},\;T_3=A_0N_{50}K_{25}P_{25},\;T_4=S_{40}N_{50}K_{25}P_{25},\;T_5=S_{40}N_{100}K_{25}P_{25}\;T_6=S_{20+20}N_{50+50}K_{25}P_{25})$). Nitrate reductase (NR) activity and ATP-sulphurylase activity in the leaves were measured at various phonological stages, as the two enzymes catalyze rate-limiting steps of the assimilatory pathways of nitrate and sulphate, respectively. The activities of these two enzymes were strongly correlated with seed and xanthotoxin yield. The highest nitrate reductase activity, ATP-sulphurylase activity and xanthotoxin yield were achieved with the treatment $T_4$. Any variation from this treatment decreased the activity of these enzymes, resulting in a reduction of the seed and xanthotoxin yield in Ammi majus L. The higher seed and xanthotoxin yield achieved in Ammi majus L. at treatment $T_4$ could be due to optimization of leaf soluble protein and photosynthetic rate, as these parameters are Influenced by S and N assimilation.

• Journal of Ecology and Environment
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• v.36 no.3
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• pp.167-172
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• 2013

A Two-year field experiment was carried out in 2009 and 2010 to evaluate the effects of different densities of wild oat and nitrogen (N) rates on oilseed rape yield and yield components. Experimental design was split plot with three replications. Increased nitrogen rates up to 150 kg N/ha caused an increase in oilseed rape grain yield in weed-free plots (4.26 t/ha; 1t = $10^3kg$), while even at the lowest density of wild oat (15 $plants/m^2$), increasing N fertilizer only up to 50 kg/ha led to a significant increase in grain yield. Wild oat growth was favored by high levels of N. Intraspecific competition reduced biomass, 100-seed weight and number of tillers of wild oat. Both lower N rate and intraspecific competition had negative effect on wild oat growth but the weed was still able to produce a considerable number of tillers and vigorous seeds. It showed that wild oat possess a notable adaptive plasticity and can allocate a greater proportion of its resource toward reproductive organs even under resource shortage conditions and, thus, it may increase the competitive ability of the weed over the crop.Our results suggest that effective weed management should be done to prevent wild oat seed production in crops preceding oilseed rape as well as to control the weed at early season in oilseed rape fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.247-255
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• 2005

ice yield and plant growth response to nitrogen (N) fertilizer may vary within a field, probably due to spatially variable soil conditions. An experiment designed for studying the response of rice yield to different rates of N in combination with variable soil conditions was carried out at a field where spatial variation in soil properties, plant growth, and yield across the field was documented from our previous studies for two years. The field with area of 6,600 m2 was divided into six strips running east-west so that variable soil conditions could be included in each strip. Each strip was subjected to different N application level (six levels from 0 to 165kg/ha), and schematically divided into 12 grids $(10m \times10m\;for\;each\;grid)$ for sampling and measurement of plant growth and rice grain yield. Most of plant growth parameters and rice yield showed high variations even at the same N fertilizer level due to the spatially variable soil condition. However, the maximum plant growth and yield response to N fertilizer rate that was analyzed using boundary line analysis followed the Mitcherlich equation (negative exponential function), approaching a maximum value with increasing N fertilizer rate. Assuming the obtainable maximum rice yield is constrained by a limiting soil property, the following model to predict rice grain yield was obtained: $Y=10765{1-0.4704^*EXP(-0.0117^*FN)}^*MIN(I-{clay},\;I_{om},\;I_{cec},\;I_{TN},\; I_{Si})$ where FN is N fertilizer rate (kg/ha), I is index for subscripted soil properties, and MIN is an operator for selecting the minimum value. The observed and predicted yield was well fitted to 1:1 line (Y=X) with determination coefficient of 0.564. As this result was obtained in a very limited condition and did not explain the yield variability so high, this result may not be applied to practical N management. However, this approach has potential for quantifying the grain yield response to N fertilizer rate under variable soil conditions and formulating the site-specific N prescription for the management of spatial yield variability in a field if sufficient data set is acquired for boundary line analysis.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.44-49
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• 2015

Urea has been the most useful N-source, due to lower cost per unit of N. But nitrogen use efficiency of urea may be reduced because of losses from agricultural system by volatilization of ammonia to atmosphere. This study was conducted to evaluate the nitrogen efficiency and growth of hot pepper (Capsicum annuum L.) by mixed treatment with nitrogen and zeolite. They were treated with N $161kg\;ha^{-1}$, N $230kg\;ha^{-1}$, nitrogenzeolite mixture (NZM) $161kg\;ha^{-1}$, NZM $230kg\;ha^{-1}$ and N $0kg\;ha^{-1}$, respectively. In the soil chemical properties after experiment, soil pH decreased but available $P_2O_5$, EC and total nitrogen increased in nitrogen-zeolite mixture treatment. $NO_3-N$ content in the soil showed the highest level in NZM $230kg\;ha^{-1}$. NZM $161kg\;ha^{-1}$ treatment increased growth and yield of hot pepper compared to urea alone. Nitrogen utilization efficiency of hot pepper plant was 47.15% at the treatment of NZM $161kg\;ha^{-1}$, while 36.74% at N $230kg\;ha^{-1}$. These results showed that application of mixture of nitrogen and zeolite had positive influence to improve the efficiency of nitrogen utilization and increase of red pepper yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.30-34
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• 2006

The effect of N-fertilization on yield, milling characteristics and quality of Samcheonbyeo, an early maturing rice variety, was investigated in 2002 to 2004. The study was carried out in the southern alpine area of Un-bong Sub-Station, Honam Agricultural Research Institute. Higher nitrogen levels increased number of panicle and grain per unit area, but lowed ripening rate and decreased 1,000-grain weight. Higher nitrogen levels of up to 90 kg/ha also increased head rice yield. A nitrogen level of 90 kg/ha was found optimal for increasing ripening rate and head rice yield, and rice palatability.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.269-277
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• 2012

In order to investigate the effects of different maize-bean intercropping patterns, and of nitrogen fertilizers on morphological and yield related traits, a factorial study based on Randomized Complete Block Design (RCBD) was performed during the 2010 and 2011 growing seasons in a research filed of Shiraz University, Iran. The first factor of the study was seven different ratios of Maize-Bean intercropping system (Maize sole cropping, Bean sole cropping, and intercropping of maize/bean at the ratios of 1/3, 1/1, 2/3, 3/2 and 3/1) and the second factor was three nitrogen (N) fertilizer application levels (0, 100 and 200 kg N/ha). Results showed that with respect to increasing the levels of N fertilizer, the yield of bean sole cropping decreased but the yield of maize sole cropping increased. On the other hand, in intercropping systems with N fertilizer application, the yield of both crops increased. Results of total land equivalent ratio (LER) for both crops showed that the highest LER value under both 100 and 200 kg N/ha application was that of M1B1 (1 seed of maize after 1 seed of bean, consecutively, on a row with same distance). Under no N fertilizer application the highest LER value was that of M2B3 (2 seeds of maize after 3 seeds of bean, consecutively, on a row with same distance). Overall, it can be concluded that M1B1 is the best intercropping pattern in maize-bean intercropping systems and that the application of N fertilizer can be effective within practical settings of intercropping agriculture, resulting in higher yields.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.8
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• pp.1093-1097
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• 2004

This study was aimed to establish the amount of enzose (corn dextrose) for optimum N fixation in urea treated corncobs (UTC) and their dietary effect on nutrient intake, digestibility and milk yield in crossbred cows. Corncobs were treated with 5% urea and ensiled in laboratory silos with 0, 2, 4 and 6% enzose for 15 days. Total nitrogen (N), neutral detergent fiber (NDF) and neutral detergent insoluble N contents were increased in UTC with the level of enzose. Five early lactating crossbred cows (Sahiwal$\times$Holstein Frisian) were used in a 5$\times$5 Latin Square Design to see the influence of UTC ensiled with 6% enzose on nutrient intake, digestibility, milk yield and its composition. Five iso-nitrogenous and iso-caloric diets were formulated. The UTC30 (control), UTC40, UTC50, UTC60 and UTC70 diets contained 30% UTC ensiled without enzose and 40, 50, 60, 70% UTC ensiled with 6% enzose, respectively. Dry matter, NDF and ADF intakes were increased with the increasing level of UTC ensiled with enzose in the diets of cows. Dry matter, NDF and ADF digestibilities were significantly higher with diets containing UTC ensiled with enzose. Milk yield was significantly higher in cows fed UTC70 compared to those fed on other diets. The milk crude protein percentage was significantly different across treatments. However, milk fat, total solids, solid not fat, true protein and non-protein nitrogen contents of milk remained similar across all diets. Ensilation of UTC with 6% enzose improved the nitrogen retention and thus enhanced the feeding value of UTC for lactating cows.