Amount Of Nitrogen Application Research Articles

Water and nitrogen supply on photosynthetic physiological response of sugar beet (Beta vulgaris) under mulched drip irrigation

Sugar beet is a characteristic cash crop in Inner Mongolia, and water and fertilizer is an important management measure in sugar beet planting. The interaction between water and nitrogen is of practical significance in regulating the growth of sugar beet. The coordinated relationship between water and fertilizer can achieve the purpose of water saving, fertilizer saving, cost saving and efficiency increasing. The cultivation method of drip irrigation under plastic mulch was adopted in this study. The effects of water nitrogen supply on water metabolism and photosynthetic performance of sugar beet were studied through two years of field experiments in order to provide theoretical basis for improving the utilization efficiency of water and fertilizer and rational fertilization and irrigation. The results showed that the water nitrogen supply level and its proportion had influence with the water potential, Transpiration rate (Tr), Photosynthetic rate (Pn) and stomatal Conductance (Cond) of sugar beet leaves. And they were significantly positively correlated with the yield of sugar beet. When the water potential of sugar beet leaves was −0.38 ∼ −0.23 MPa in the period of leaf fast growth, root and sugar growth, and −0.45 ∼ −0.38 MPa in the period of sugar accumulation, the yield and sugar content were the highest. Under the coupling condition of water and nitrogen, the irrigation amount of sugar beet was 1350 ∼ 1427 m3·ha−1, and the nitrogen application amount was 150 ∼ 179.22 kg·ha−1. Sugar beet has the highest utilization rate of light energy and yield and sugar content.

Simulation of the responses of spring wheat yield to the rates and depths of nitrogen application in dryland based on APSIM model

Nitrogen limitation is an important factor for the improvement of crop water production potential in rain-fed areas of the Loess Plateau. The reasonable deep application of nitrogen fertilizer is a promising method to increase yield of rain-fed crop. Based on APSIM model, this study simulated spring wheat yield under different nitrogen application rates and depths, by using meteorological observation data from 1990 to 2020 in the semiarid areas of central Gansu Province, aiming to provide theoretical reference for optimizing wheat fertilization strategy. The results showed that the determination coefficient of simulated spring wheat yield, biomass and soil water content in 0-200 cm soil profile was greater than 0.80, the normalized root mean square error was less than 0.2, and the model validity index was greater than 0.5. These results indicated that the model had good fitting and adaptability in the test area. Across all the levels within the experimental design, increasing nitrogen application rates could significantly increase the yield of spring wheat in different precipitation years, and increasing nitrogen application depth could significantly increase spring wheat yield in wet and normal years, but had no effect in dry years. The rate and depth of nitrogen application had significant interaction effects on spring wheat yield in wet and normal years, but not in dry years. According to the binary quadratic regression fitting equation, when the potential maximum yield reached 2749 kg·hm-2 in wet year, nitrogen application depth was 22.7 cm, and nitrogen application rate was 245 kg·hm-2. When the maximum potential yield reached 2596 kg·hm-2 in normal year, nitrogen application depth was 20.6 cm, and nitrogen application rate was 235 kg·hm-2. Integrating the effects of nitrogen application rate and depth on yield, biomass and agronomic efficiency of nitrogen fertilizer, and farmer's fertilizer application habits, the recommended nitrogen application depth was 20-23 cm, and nitrogen application amount was 120-150 kg·hm-2, which could further improve water productivity and nitrogen use efficiency of spring wheat in arid areas of central Gansu Province.

Effects of different amounts of straw return and nitrogen fertilizer application on soil CO2 emission from maize fields.

Understanding the effects of different amounts of straw returning and nitrogen fertilizer application on soil CO2 emission from maize field can provide theoretical support for carbon sequestration and CO2 emission reduction and the implementation of black soil region conservation plan. Three rates of straw returning were set up in the semi-arid area of northwest Liaoning Province, China, i.e. 3000 (S1), 6000 (S2) and 9000 kg·hm-2(S3, full amount of straw returned to the field); crossed with three nitrogen fertilizer application rates in the sub-region, respectively, i.e. 105 (N1), 210 (N2, conventional nitrogen application rate) and 420 kg N·hm-2(N3). In addition, there was a control treatment (CK) without nitrogen fertilizer and straw returning. Soil samples were collected after 4 years field experiment with maize plantation. The influence of different treatments on maize field soil CO2 emission and the relationship between CO2 emission and soil dissolved organic carbon (DOC) and microbial biomass carbon (MBC) were investigated in an incubation experiment. The results showed that both of straw returning and nitrogen fertilizer application promoted soil CO2 emission in maize field, which were increased significantly with the increases of straw returning amount and nitrogen application amount. Nitrogen fertilizer application was the most important factor promoting soil CO2 emission in maize field. Straw returning combined with nitrogen fertilizer promoted soil CO2 emission by increasing microbial biomass and increasing DOC consumption. MBC and DOC stimulated soil CO2 emission significantly in maize field, and were mainly affected by their contents in the early stage of incubation. From the perspective of ensuring the fertilization of straw return to the field while reducing CO2 emissions, results from our experiment showed that 210 kg N·hm-2 conventional nitrogen application in combination with 6000 kg N·hm-2 straw returning (N2S2) was the most promising mode in the semi-arid area of northwest Liaoning Province.

Effects of Nutrient Management Strategies on Yield Formation of Dryland Wheat in the Loess Plateau of China

In order to explore the optimum amount of nitrogen application of winter wheat, a field experiment was conducted at Wenxi experimental site of Shanxi Agriculture Wenxi. Nitrogen application significantly increased the Net Photosynthesis Rate (PN), intercellular carbon dioxide concentration (Ci) and transpiration rate (E) of post-anthesis flag leaves. Compared to other nitrogen application rates, 210 kg ha–1 was the best compared to other nitrogen application rates, with the nitrogen of 210 kg ha–1 nitrogen application increased nitrogen accumulation in all growth stages. The content of each protein component increased. With 210 kg ha–1 of nitrogen application, the albumin, globulin, prolamin, and glutenin was high in content and showed no significant with those of 240 kg ha–1 application rate. The protein yield at 210 kg ha–1 were significantly improved compared to other nitrogen application rates. The prolamin and glutenin (storage protein) were the highest at 210 kg ha–1. Significantly improved the protein yield at 210 kg ha–1 compared to other nitrogen application rates.

Effects of Shallow Groundwater Depth and Nitrogen Application Level on Soil Water and Nitrate Content, Growth and Yield of Winter Wheat

The large amount of nitrogen application on the North China Plain has caused a serious negative impact on the sustainable development of regional agriculture and ecological environmental protection. Our aim was to explore the effects of nitrogen fertilization rate and groundwater depth on growth attributes, soil-water and soil-fertilizer contents, and the winter wheat yield. Experiments were carried out in micro-lysimeters at groundwater depths of 60, 90, 120, and 150 cm on the basis of 0, 150, 240, and 300 kg/ha nitrogen fertilization rates in the growth season for winter wheat. Results showed that plant height, leaf area index, soil plant analysis development, and yield without nitrogen application increased significantly with increases in groundwater depth. The optimal groundwater depths for growth attributes and yield were 60–120 cm and tended to be shallower with added nitrogen application. Soil moisture was lowered significantly with groundwater depth, adding a nitrogen application reduced soil moisture, and excessive nitrogen input intensified soil drought. Nitrate-N accumulation at the 120–150 cm depths was significantly higher than that at the 60–90 cm depths, and a 300 kg/ha (traditional nitrogen application rate) treatment was 6.7 times greater than that of 150 kg/ha treatment and increased by 74% more than that of the 240 kg/ha treatment at 60–150 cm depth. Compared with the yield of the 300 kg/ha rate, the yield of the 240 kg/ha rate had no significant difference, but the yield increased by 3.90% and 11.09% at the 120 cm and 150 cm depths. The growth attributes and yield of winter wheat were better, and the soil nitrate-N content was lower, when the nitrogen application rate was 240 kg/ha. Therefore, it can be concluded that nitrogen application can be reduced by 20% on the North China Plain.

Effects of nitrogen application and brackish water irrigation on yield and quality of cotton

In order to alleviate the shortage of water resources for cotton (Gossypium hirsutum L.) planting in Xinjiang of China, a reasonable amount of nitrogen application under brackish water irrigation was sought. A two-year field experiment was conducted to investigate the effects of nitrogen application rate and irrigation water salinity on seed cotton yield, nitrogen partial factor productivity and fiber quality in Xinjiang under mulched drip irrigation in 2019 and 2020. In this study, we selected four nitrogen application rates (i.e., 100, 200, 300, and 400 kg N ha−1, respectively) and three irrigation water salinity (i.e., 1, 3, and 5 g L−1, respectively). Our results showed that nitrogen application rates and irrigation water salinity significantly affected the seed cotton yield, nitrogen partial factor productivity, micronaire, fiber length, fiber strength, uniformity index and elongation. As the salinity of irrigation water increased, seed cotton yield and nitrogen partial factor productivity increased first and then decreased, micronaire decreased, but fiber length, fiber strength, uniformity index and elongation increased. Moreover, seed cotton yield, micronaire, fiber length, fiber strength, uniformity index and elongation increased first and then decreased, and nitrogen partial factor productivity decreased with the amount of nitrogen application. The optimal combination of nitrogen application rate and irrigation water salinity were 200 kg N ha−1 and 5 g L−1 by principal component analysis. We concluded that the normalized relative value of seed cotton yield and comprehensive evaluation value was 0.85, when the nitrogen application rate and the irrigation water salinity were 197.04 ⁓ 237.94 kg N ha−1 and 3.60 ⁓ 3.88 g L−1, respectively.

Seed mixture of oats and common vetch on fertilizer and water-use reduction in a semi-arid alpine region

The overuse of synthetic fertilizers damages terrestrial and aquatic ecosystems on the Tibetan plateau. We conducted this study to investigate the possibility of reducing fertilizer use by applying cereal-legume mixture planting in forage crops cultivation. A field experiment was conducted in 2017 and 2018 at Jintai farm in the northeast of the Tibetan plateau. The experiment was a randomized complete block design with four treatments: sole oat with nitrogen application rate of 120 kg ha−1, sole oat with a lower nitrogen rate of 60 kg ha−1, and oat and common vetch mixtures applied with those two nitrogen levels. Results showed that forage biomass production of oat-common vetch mixture was comparable or higher than that of corresponding sole oat under different nitrogen levels. Nitrogen uptake of the mixture was 19.6–81.7% higher than that of sole oat under high nitrogen fertilization and was 107.3–144.6% higher under low nitrogen. Biological nitrogen fixation of common vetch in mixture stands ranged from 11.1 to 59.1 kg ha−1. Nitrogen use efficiency in the mixture was lower than that in sole oat under both nitrogen levels. However, the partial factor productivity of applied nitrogen (PFPN) in the mixture was higher than that in sole oat. Mixture with low nitrogen application attained the highest PFPN of 102.8 and 150.6 kg kg−1 in 2017 and 2018 respectively. The mixture system depleted much more soil water storage than sole oat in both years. Water use efficiency based on biomass production in the sole and mixture systems were comparable. However, that based on crude protein production was far greater in the mixture system, and the advantage of the mixture under low nitrogen level was more significant compared to that under high nitrogen level. Therefore, we conclude that practicing cereal-legume mixture planting in forage production could improve nitrogen and water use efficiencies, maintain forage production and improve forage quality. We suggest applying the mixture planting system and reducing the amount of nitrogen application in forage production in the semi-arid farming area on the Tibetan Plateau and similar alpine regions worldwide.

A comprehensive method to increase yield and narrow the yield gap of winter wheat for sustainable intensification.

The agricultural production system is facing increasing demand pressure and environmental pressure. Green and efficient production methods are urgently needed in order to further enhance the yield of winter wheat and reduce the negative impact on the environment. Here, we analyzed the potential yield and yield gap of winter wheat in Shandong Province of China from 1981 to 2009. Meanwhile, we specified the effects of sowing time, irrigation and fertilization scheme, and variety characteristics on winter wheat. In the past 29 years, the yield gap in most areas of Shandong has become smaller, because the actual yield has increased and the potential yield has changed little under the background of climate change. In addition, it is found that delaying sowing date is beneficial to increase yield by helping winter wheat avoid adverse climate conditions. Also, an irrigation amount of 240 mm and nitrogen application amount of 180-210 kg ha-1 are best to maintain high yield, high resource utilization rate and low environmental pollution in this area. These suggested levels are lower than those currently used by many local farmers. Wheat varieties with longer grain-filling period and photoperiod response, higher grain-filling rate and grain weight were more adaptable to climate change. Improving agronomic management measures can significantly increase the yield of winter wheat and narrow the yield gap. This study can provide valuable information for improving the production potential of winter wheat, and for reducing the damage of agricultural activities to the environment. © 2022 Society of Chemical Industry.

Interactive effects of level of nitrogen and irrigation application on maize yield

Maize (Zea mays L.) yields are recognized to be sensitive to both the level of nitrogen fertilization and irrigation that is applied to the crop. However, there are virtually no studies where experimental results are analyzed to quantitatively explore directly the interactive influence of these two resources on yield. As a consequence, it is difficult to sort out the optimum management regime for the available resources. A polynomial regression analysis was applied to results from seven field experiments involving several nitrogen and irrigation treatments. The polynomial equation included for each resource a linear term and second-order term plus a multiplicative term of the two resources. The polynomial regression fit very well the results of all experiments (R2 ≥ 0.86). The impact of irrigation included the linear term in all experiments (p ≤ 0.017). In all but one experiment, yield was also linearly dependent on amount of nitrogen application. The polynomial expression led to determination of the nitrogen fertilization required for maximum yield as being dependent on level of irrigation. In all cases, increased irrigation amounts resulted in an increased nitrogen requirement to achieve maximum yield. Another important outcome of the analysis was that the multiplicative term for irrigation x nitrogen was generally important in describing yield. These results demonstrate the inadequacy of attempting to define the results of such multiple-factor experiments based on a single limiting-factor approach.

Characteristics of root‐associated bacterial community and nitrogen biochemical properties of twoJaponicarice cultivars with different yields

AbstractRoot‐associated microbiomes play pivotal roles in rice plant nutrition and productivity. We studied how the Liaoxing 1 and Akitakomachi rice cultivars, which are characterized by high and low yields, respectively, modified the nutrient content, enzymatic activities in the rhizosphere, and bacterial community structure in the root endosphere, rhizosphere, and bulk soil with and without nitrogen application. Rice genotype and nitrogen application amount are both essential driving factors for changes in the nutrient content, enzymatic activities, and bacterial community. Bacterial community structure varied significantly across the three root‐associated compartments, and rhizosphere and bulk soil harbored significantly higher diversity and richness of bacteria than root endophytes. Bacterial communities in the root endosphere are mainly structured by rice cultivars. Nitrogen fertilization application influenced the compositions and functions of bacterial groups across the three compartments.Prolixibacteriaceae, as nitrogen‐fixing bacteria, were significantly enriched in the rhizosphere, and the relative abundance in the rhizosphere of the high‐yield cultivar was higher than that of the low‐yield cultivar. Rice genotype and nitrogen application amount are both essential driving factors for changes in nutrient content and enzymatic activities. In this study, it was found that the higher available nitrogen content and soil enzymatic activities in the rhizosphere of the high‐yield rice cultivar promoted rice nitrogen use, and they ultimately formed a positive feedback loop. Our results indicated that root‐associated bacterial communities combined with soil enzymatic activities strengthen the transformation of nitrogen nutrients, suggesting that the interactions could represent a mechanism for enhancing rice yield.

Does nitrogen application rate affect the moisture content of corn grains?

Nitrogen fertilizer application is an important measure to obtain high and stable corn yield, and the moisture content of corn grains is an important factor affecting the quality of mechanical grain harvesting. In this study, four different nitrogen fertilizer treatments from 0 to 450 kg ha–1 pure nitrogen were set for a planting density of 12.0×104 plants ha–1 in 2017 and 2018, and 18 different nitrogen fertilizer treatments from 0 to 765 kg ha–1 pure nitrogen were set for planting densities of 7.5×104 and 12.0×104 plants ha–1 in 2019, to investigate the effect of nitrogen application rate on the moisture content of corn grains. Under each treatment, the growth of corn, leaf area index (LAI) of green leaves, grain moisture content, and grain dehydration rate were measured. The results showed that, as nitrogen application increased from 0 to 765 kg ha–1, the silking stage was delayed by about 1 day, the maturity stage was delayed by about 1–2 days, and the number of physiologically mature green leaves and LAI increased. At and after physiological maturity, the extreme difference in grain moisture content between different nitrogen application rates was 1.9–4.0%. As the amount of nitrogen application increased, the corn grain dehydration rate after physiological maturity decreased, but it did not reach statistical significance between nitrogen application rate and grain dehydration rate. No significant correlation was observed between LAI at physiological maturity and grain dehydration rate after physiological maturity. In short, nitrogen application affected the grain moisture content of corn at and after physiological maturity, however, the difference in grain moisture content among different nitrogen application rates was small. These results suggest that the effect of nitrogen application on the moisture content of corn grains should not be considered in agricultural production.

Response of yield, yield components and water-nitrogen use efficiency of winter wheat to different drip fertigation regimes in Northwest China

Understanding the response of spike density (SD), grain number per spike (GN), and thousand kernel weight (TKW) to the application amount of nitrogen and irrigation, and clarifying the contribution of nitrogen and irrigation to the increased yield are vital for achieving high grain yield (GY), water and nitrogen use efficiency (WUE and NUE) in precision agriculture. A two-year (2018–2020) drip fertigated winter wheat experiment was conducted with three irrigation levels (rain-fed (RF), deficit irrigation (DI, 75% ETc) and full irrigation (FI, 100% ETc)) as main plot and four nitrogen levels (0 (NN), 85 (N3), 170 (N2) and 255 (N1) kg N hm−2) as subplot in Northwest China. The results showed that the tillers per plant (TP) significantly increased with increasing nitrogen application amount (0–255 kg hm−2), but the SD had insignificant difference between N1 and N2 levels due to lower effective spike rate (ESR) of N1. The GN firstly increased and then decreased with increasing nitrogen application amount. However, the TKW continued to decrease with increasing nitrogen application amount. Irrigation significantly increased SD and GN, but the impact on TKW showed uncertainty during two growing seasons. The structure equation model showed that both irrigation and nitrogen indirectly affect GY by affecting yield components, and nitrogen had the stronger influence to SD, GN and TKW than irrigation in this study. The highest GY (9.10 and 9.28 t hm−2 in 2018–2019 and 2019–2020, respectively) was observed at DIN2, which increased by 200% and 277% in 2018–2019 and 2019–2020 growing seasons compared with RFNN treatment, respectively. And among these increased yield, more than 65% and approximately 20% were contributed by the application of nitrogen and irrigation, respectively. In addition, DIN2 also obtained the highest WUE and higher NUE due to lower actual evapotranspiration and nitrogen application amount. Therefore, deficit drip irrigation (75%ETc) coupled with 170 kg N hm−2 was the best management strategy of irrigation and nitrogen under drip fertigation in Northwest China.

Influence of Different Nitrogen Application Levels on Dry Matter Accumulation and Distribution of Silage Corn

The clarification of the dry matter accumulation, distribution law and yield differences of silage corn under different nitrogen application rates will provide theoretical basis for determining the optimal nitrogen application rates of silage corn under drip irrigation in central Inner Mongolia. In this study, Zhongxing silage 1 was selected as the experimental variety. This paper systematically analyzes the dry and fresh weight accumulation and growth rate, dry matter distribution and yield index of silage corn in the whole growth period under the condition of six different nitrogen application amount in two consecutive years of 2018 and 2019. The results indicated that the application of nitrogen fertilizer increased the whole plant fresh weight and dry matter content in different growth stages after the seedling stage of silage corn, and the whole growth period from the seedling stage to the harvest stage, the fresh weight and dry matter accumulation rate of N16 and N20 treated plant were higher than other treatments in 2018 and 2019. Except for the leaves at the trumpet period, the dry matter distribution ratio of each organ was not affected by nitrogen application level before tasseling stage. In the silage harvest period, the biological fresh weight and biomass yield of silage corn were the highest in N16. It can be concluded that N16 (240kg N ha−1) is the best nitrogen application rate for silage corn under drip irrigation in central Inner Mongolia by means of comprehensively comparing the dry matter accumulation rate, distribution and yield under different nitrogen rates.

Effects of biochar application combined with nitrogen fertilizer on soil physicochemical pro-perties and winter wheat yield in the typical ancient region of Yellow River, China

The aims of this study were to reveal the effects of biochar application combined with nitrogen fertilizer on soil physicochemical properties and crop yield in the typical ancient region of Yellow River, and to clarify the dynamics of carbon and nitrogen content and soil physicochemical properties with different treatments of biochar and nitrogen, which could provide scientific basis for reasonable fertilization of soil, quality improvement of cultivated land, and yield increase of winter wheat. A two-year field experiment was conducted with different biochar applications (0, 15, 30 t·hm-2) combined with different nitrogen levels (N 270, 330 kg·hm-2) to investigate their effects on soil physicochemical property in the typical ancient of Yellow River. After 2-yr biochar application, the generalized soil structure index (GSSI) was increased and three-phase structure distance index of soil (STPSD) was decreased, and three-phase ratio was significantly improved. The most ideal state of three-phase ratio was in the condition of 30 t·hm-2 biochar application. Soil compactness and bulk density was decreased, total porosity and capillary porosity was increased, water holding capacity was improved, water and gas permeability was enhanced, and soil hardening was relieved. The composition of soil aggregate was also changed. Soil aggregate >0.25 mm particle size was increased by 70.6%-94.4%, and mean weight diameter (MWD) was improved by 24.0%-48.0%. Biochar application significantly increased organic carbon content by 15.8%-67.0%, adjusted soil C/N, reduced nitrogen release intensity, improved utilization rate of nitrogen fertili-zer, and enhanced soil fertility. However, it didn't increase soil pH. Soil pH showed a significant downward in 10-20 cm layer. With the same amount of nitrogen application, biochar application significantly increased average yield of winter wheat by 9.6%-25.6% in two years. With the same amount of biochar application, average yield of winter wheat with high nitrogen application was 2.5%-4.4% higher than that with conventional nitrogen application. In summary, combined biochar and nitrogen application could improve soil micro-environment, soil fertility and crop yield. Comprehensively considering soil modification, crop yield improvement and input cost, the optimum amount of fertilization was biochar application (30 t·hm-2) combined with nitrogen fertilizer (330 kg·hm-2).

Effect of Water-Fertilizer-Gas Coupling on Soil N2O Emission and Yield in Greenhouse Tomato

To reveal the effect of water, fertilizer, and gas coupling on soil N2O emissions in greenhouse tomato soil and suggest appropriate measures for increasing yield and reducing N2O emissions, static chamber-gas chromatography was used to study the effects of soil N2O emissions. The variation laws of soil temperature, water-filled pore space (WFPS), NO3--N content, and O2 content and the influence mechanism of N2O emission under the condition of water-fertilizer-gas coupling were analyzed. Aerated conditions comprised two water levels, 0.6 W and 1.0 W (representing 40% deficit irrigation and full irrigation, W represents when sufficient irrigation water was available), and three nitrogen levels (120 kg·hm-2, 180 kg·hm-2, and 240 kg·hm-2, representing low, medium, and high nitrogen, respectively, with 50% F, 75% F, and F, F is the recommended amount of nitrogen application locally). Three levels of fertilization were used as controlled unaerated full irrigation (O representing aeration, and CK representing conventional drip irrigation). Nine treatments were designed in the experiment. The results showed that the tomato field cumulative emission of N2O under full irrigation (W2F1O, W2F2O, and W2F3O) increased by an average of 55.7% compared with the corresponding treatment at W1 level (P<0.05). The N2O emissions of W1F3O, W2F3O, and W2F3CK fields significantly increased by 13.4% and 43.8% compared with medium nitrogen W1F2O, W2F2O, and W2F2CK and low nitrogen W1F1O, W2F1O, and W2F1CK treatments, respectively (P<0.05).Compared with the corresponding unaerated full irrigation, the emissions (W2F1O, W2F2O, and W2F3O) significantly increased by 11.2% (P<0.05). Aeration, the increase of nitrogen rate, and irrigation amount resulted in the increment of tomato yield and yield-scaled N2O emissions. Compared with medium nitrogen, the yield and yield-scaled N2O emission of high nitrogen treatment increased by 12.5% (P<0.05) and 3.9% (P>0.05), respectively. Compared with low nitrogen treatment, the yield and yield-scaled N2O emission of high nitrogen treatment increased by 30.4% and 9.6% (P<0.05), respectively. The yield and yield-scaled N2O emissions of aerated full irrigation significantly increased by 29.7% and 18.7%, respectively, compared with aerated deficient irrigation. Compared with unaerated irrigation treatment, the yield under aerated treatment increased by 10.4% (P<0.05), and the yield-scaled N2O emission increased by 3.9% (P>0.05). Under the conditions of increasing irrigation water, decreasing fertilizer application, and aeration, partial factor productivity, and irrigation water use efficiency (IWUE) can be significantly increased. After comprehensive consideration of cumulative N2O emissions, tomato production, nitrogen fertilizer utilization efficiency, IWUE, and yield-scaled N2O emission, it can be concluded that aerated low nitrogen full irrigation is an optimal management mode. The results provide reference for increasing yield and reducing emissions of greenhouse tomato.

Farklı Azot Dozlarının Krotalarya (Crotalaria juncea L.)’da Verim ve Diğer Bazı Verim Özellikleri Üzerine Etkisi

Bu araştırma, farklı azot dozlarının (0, 3, 6, 9, 12, 15 kg/da) Krotalarya (Crotalaria juncea L.) bitkisinde verim ve bazı verim özellikleri üzerine olan etkisini incelemek amacıyla 2018 yılında Ege Üniversitesi Ziraat Fakültesi Tarla Bitkileri Bölümü’nün Bornova/İzmir’deki deneme alanlarında yürütülmüştür. Araştırmada; bitki materyali olarak yurtdışından temin edilen Tillage Sunn çeşidi kullanılmış ve bitki boyu, sap çapı, dal sayısı, yaprak sayısı, yeşil ve kuru ot verimi, kuru madde oranı ve kuru madde verimi gibi özellikler incelenmiştir. Elde edilen verilere göre; 12 kg/da azot uygulamasında 5221 kg/da ile en yüksek yeşil ot verimi, 1553 kg/da ile en yüksek kuru ot verimi, 216,4 cm ile en yüksek bitki boyu, 13,67 mm ile en yüksek sap çapı, 5,73 adet ile en fazla dal sayısı, 167,9 adet ile en fazla yaprak sayısı elde edilmiş ve Krotalarya yetiştiriciliğinde optimum miktarda azot uygulamasının gerekli olduğu ve Akdeniz iklim koşulları altındaki Bornova ovasında en ideal azot dozunun 12 kg/da olduğu sonucuna varılmıştır.

パン用コムギ「せときらら」の収量と開花期追肥量による子実タンパク質含有率の予測

パン用コムギ「せときらら」の収量と開花期追肥量による子実タンパク質含有率の予測

Effects of nitrogen application on growth and yield of maize

The effects of different nitrogen application levels on growth, dry matter accumulation, SPAD value, leaf area index and yield of maize were studied to provide theoretical basis for rational and efficient nitrogen application management of crops. In the field experiment, 225, 337.5, 450, and 675 kg ·hm−2 nitrogen application levels were set, respectively expressed by N1, N2, N3, and N4. N0without nitrogen fertilizer was used for the control experiment. During the growing period, plant height, leaf area index and SPAD were observed, and dry matter accumulation, yield and yield components were counted. The growth index, dry matter accumulation, yield and yield components of maize were influenced by different fertilization levels. When the nitrogen application amount is greater than 225 kg · hm−2, it could significantly promote the growth and development of corn and increase the yield. Through comparative analysis, it was concluded that when the nitrogen application amount was 280kg·hm−2, it was the optimal nitrogen application amount for the efficient production of corn in the experimental area.

Soil acidification of alfisols influenced by nitrate and ammonium nitrogen level in tea plantation

Nitrogen is an important fertilizer in tea production, but it is also an important factor in tea garden soil acidification. The relationship between absorption and transport of different forms of nitrogen in the tea plant and soil acidification is still unknown. In order to explore the different characteristics of absorption, utilization and distribution of nitrogen, stable isotope 15N tracer technique was used to measure the absorption, utilization and allocation of nitrate nitrogen (NO3-15N) and ammonium nitrogen (NH4-15N) under the same nitrogen application amount of tea tree seedlings as experimental materials. The results showed that the tea seedlings had the same pattern of nitrogen application: tissue nitrogen content increased after fertilization, remarkable rising at 7 d and the absorption speed increased quickly after 28 d, finally reached its maximum at 56 d. The nitrogen use efficiency of two nitrogen sources in two kinds of soil varied not significantly. The maximum NUE of NO3-15N reached 12.66%, and at the same time NH4-15N utilization rose up to 11.54%. According to the absorption of soil nitrogen and nitrogen fertilizer in the two kinds of soil, it is concluded that the soil nitrogen cannot meet the growth needs of tea tree and extra nitrogen supply was required. The declined soil pH indicated that fertilizer should be used in moderation, which can not only satisfy the growth of tea tree but also to restrict soil acidification. Keywords: tea tree, 15N, nitrate nitrogen, ammonium nitrogen, soil acidification DOI: 10.25165/j.ijabe.20181104.2078 Citation: Wang H, Zhang H, Zhao Y, Xu R K. Soil acidification of alfisols influenced by nitrate and ammonium nitrogen level in tea plantation. Int J Agric & Biol Eng, 2018; 11(4): 168-172.

Effects of different nitrogen application rates on low temperature resistance of late rice at heading and flowering stage.

Four levels of nitrogen application (N1, low nitrogen, 90 kg N·hm-2; N2, normal nitrogen, 180 kg N·hm-2; N3, high nitrogen, 250 kg N·hm-2; N4, ultra high nitrogen, 330 kg N·hm-2) were set to examine the effects of nitrogen application on the growth and development, yield formation and related physiological characteristics of late rice under low temperature condition during heading and flowering stage, with super hybrid late rice variety Wufengyou T025 as test material. The results showed that yield of all treatments decreased in different degrees under the low temperature conditions, with the yield of N2 being the highest, and N1 the lowest. The effective panicles per plant and total grains per panicle in N3 and N4 were higher than those of the other treatments, but their seed setting rate and harvest index were significantly decreased. With the increases of nitrogen application rates, pocketed panicle rate, the total dry mass and chlorophyll contents (SPAD value) increased to different extent, while the panicle dry mass of N2 was the highest. After low temperature, chlorophyll content, net photosynthetic rate and transpiration rate of the total treatments decreased to varying degrees, and the declined range of the net photosynthetic rate and trans-piration rate in N3 and N4 were higher than other treatments. The contents of free proline, malondialdehyde and peroxidase activity of all treatments increased to varying extent, while superoxide dismutase, catalyes activities and the soluble protein contents decreased, with the magnitude of variation in N3 and N4 being the greatest. It demonstrated that high amounts of nitrogen application were unfavorable to late rice to resist low temperature at heading and flowering stage and thus misuse of nitrogen fertilizer application should be avoided in production. The suitable amount of nitrogen application in double cropping late rice was not more than 180 kg·hm-2.