Increasing Nitrogen Fertilization Research Articles

Influence of Foliar Nitrogen and Magnesium Fertilization on Concentration of Ash Micronutrients in Potato Tubers

Abstract: The paper contains a discussion of the results of an experiment concerning the effect of foliar nitrogen and magnesium fertilization on the concentration of ash macronutrients in edible potato tubers of a medium-early cultivar called Zebra. The trials were based on a three-year, two-factorial field experiment, carried out in 2005–2007 at the Research Station in Tomaszkowo, owned by the University of Warmia and Mazury in Olsztyn. The applied fertilization consisted of 80 kgN, 35 kgP and 100 kgK ha. The first experimental factor comprised foliar nitrogen fertilization in the range of doses (8; 40) kgN ha accompanied by simultaneously diminished doses of soil nitrogen fertilization. The second factor included three series: without magnesium, with magnesium introduced to soil in a rate of 24 kg ha and with magnesium sprayed over potato leaves in a rate of 12 kgMg ha. Tuber samples were analyzed for the concentrations of phosphorus, potassium, magnesium and sodium. The content of these macronutrients tended to decrease under the influence of the increasing nitrogen fertilization, with the exception of phosphorus, whose concentration rose in the series unfertilized with magnesium under the effect of 8 and 16 kgN, and the concentration of sodium, which continued to increase in the Mg fertilized series up to the rate of 24 kg of N applied as a foliar fertilizer. The mean Ca : P = 0.28, Ca : Mg = 0.39 and K : Ca = 11.9 ratios suggest very poor calcium supply of the potato cultivar. In contrast, very broad ratios between K : (Ca + Mg) = 3.32 and K : Mg = 4.60 prove that the concentrations of potassium and magnesium were relatively high. The foliar application of nitrogen, tested in this experiment, had a significant effect on the ratios between ash elements in tubers. It has been demonstrated that as the top-dressing rate of nitrogen increased, the Ca : P and Ca : Mg ratios narrowed while the ratios of K : (Ca + Mg) and K : Ca were broader. The applied fertilization had no effect on the K : Mg ratio.

EFFECT OF NITROGEN FERTILIZER RATES AND SOME GROWTH REGULATORS TREATMENTS ON SUGAR BEET

Two field experiments were carried out at El – Hamoul, Kafr El – Sheikh Governorate in 2009 / 2010 and 2010 / 2011 seasons to study the effect of four nitrogen fertilizer rates (0, 70, 90 and 110 kg N / fed) and five growth regulators treatments (sprayed plants with tap water (control), Mepiquate Chloride (pix) at the concentration of 1000 and 2000 ppm and Indole acetic acid (IAA) at the concentration of 100 and 200 ppm on yield of sugar beet. The experiments were laid out in split plot design. The obtained results showed clearly that average root / top ratio, sucrose %, potassium %, sodium %, top yield / fed, root yield / fed and sugar yield / fed were significantly affected by nitrogen fertilizer rates in both seasons. Increasing nitrogen fertilizer from 0 to 110 kg N / fed caused 102.14 and 103.53 %, 112.55 and 118.18 % as well as 136.70 and 142.60 % increases in top yield / fed, root yield / fed as well as sugar yield / fed compared to plants grown on the control treatment (no added nitrogen) in 2009 / 2010 and 2010 / 2011 seasons, respectively. Results recorded indicated that all studied traits were significantly affected by growth regulators treatments in both seasons. Sugar beet plants sprayed with IAA at the concentration of 200 ppm gave the highest top yield / fed 5.75 and 5.86 tons, root yield / fed 27.65 and 28.98 tons as well as sugar yield / fed 4.46 and 4.70 tons compared to other treatments in 2009 / 2010 and 2010 / 2011 seasons, respectively. The interaction effect between nitrogen fertilizer rates and growth regulators treatments was significant on all studied traits in both seasons, except sodium % in 2009 / 2010 seasons. Fertilizing sugar beet plants by nitrogen fertilizer at the rate of 110 kg N / fed and sprayed with IAA at the concentration of 200 ppm gave the highest top yield / fed 7.73 and 7.83 tons, root yield / fed 36.90 and 39.84 tons as well as sugar yield / fed 5.65 and 6.13 tons as compared to all other this interaction treatments in 2009 / 2010 and 2010 / 2011 seasons, respectively. Generally, it could be recommended that fertilized sugar beet plants with 110 kg N / fed and sprayed by IAA at the concentration of 200 ppm increased root and sugar yields/ fed at El-Hammoul, Kafer El-Sheikh Governorate conditions.

Impacts of Nitrogen (Urea) Fertilization on Cadmium Accumulation Nitrate Contents and Nutritive Values in Chinese Cabbage

Pot-mode cultivation experiments were carried out to study the impacts of nitrogen（urea）fertilization in different level on Cadmium (Cd) accumulation, nitrate contents and nutritive values in Chinese cabbage, The results showed that: at different level of Cd artificial enriched soil, with applied urea increased, the accumulation of Cd in edible part of Chinese cabbage gradually decreased. Nitrate Contents in edible part have a positive correlation with the concentration of Cd in soil and the nitrogen fertilizer applied. In the natural soil (with contaminated Cd in concentration of 0.18 mg/kg), when the urea was fertilized by 255 kg/hm2 to 330 kg/hm2, Cd and nitrate contents of edible parts of cabbage were within the national food security limits, which could guarantee the food security of Chinese cabbage. Increasing nitrogen fertilization in the form of urea has a certain effect on amino acids contents but little effect on soluble sugar contents in Chinese cabbage, when the concentration of urea was 320 kg/hm2, amino acids contents of cabbage reached the highest level of 355 mg/kg1. Increasing nitrogen fertilization could lower down the contents of water-soluble Cd and the available Cd in soil, thereby reduce the absorption of Cd by Chinese cabbage. To a certain extent, increasing nitrogen fertilization could increase the food security of Chinese cabbage.

Effects of irrigation and fertilization coupling on protein and amino acids contents in grains of winter wheat

To evaluate effects of different water,nitrogen and phosphorus fertilizers and their interactions on grain quality of winter wheat in semiarid region,the experiment was carried out in rain-sheltered condition in Luoyang,west part of Henan Province during crop season of 2009～2010.Grain protein content and contents of amino acid components were tested.The results indicated that irri-gation,application of nitrogen had significant effects on grain protein and amino acids contents(P≤0.01) of winter wheat.The in-teraction of irrigation and nitrogen fertilization also presented significant effects(P≤0.05 or ≤0.01).No significant effect of P fer-tilization on protein and amino acids contents was observed.Protein and amino acids contents in wheat grains increased with in-creasing nitrogen fertilization rate,but dropped with increasing of irrigation amount.However,as irrigation amount was above 282.0 mm,and nitrogen fertilization rate was above 179.2 kg·hm 2,the changes became less obvious.Protein content decreased as the ni-trogen fertilization rate above 179.2 kg·hm 2.The trend of ETT/ATT(percent of essential amino acids to total amino acids) was con-trary to that of amino acids contents.The contents of protein and amino acids in wheat grains reached the highest in treatment of N105P42W127 with nitrogen fertilization rate of 105 kg(N)·hm 2,phosphorus fertilization rate of 42 kg(P2O5)·hm 2 and irrigation amount during growing season of 127 mm.While ETT/ATT reached the highest in treatment of N30.8P126W282 with nitrogen fertiliza-tion rate of 30.8 kg(N)·hm 2,phosphorus fertilization rate of 126 kg(P2O5)·hm 2 and irrigation amount during growing season of 282 mm.The grain yield increased with the increasing of irrigation,and water use efficiency was higher with high yield.Overall,N179.2P126W282 with nitrogen fertilization rate of 179.2 kg(N)·hm 2,phosphorus fertilization rate of 126 kg(P2O5)·hm 2 and irrigation amount during growing season of 282 mm was the best treatment.

Inlfuence of increasing nitrogen fertilization on content of microelements in grasses cultivated on ornamental lawns

The main aim of the study, conducted in 2007-2008, was to define the influence of nitrogen levels 0, 50, 100, 150, 200 mg N dm –3 applied to grass lawns on the content of metallic microelements: iron, manganese, zinc and copper and on their quantitative ratios in turf grass. The study was carried out on a 2-year-old lawn, composed of a mixture of lawn grasses species and varieties: perennial ryegrass (Lolium perenne L.) var. Grasslands Nui (45%), tall fescue (Festuca arundinacea Schreb) Finelawn (25%), red fescue (Festuca rubra Hack.) Olivia (10%), red fescue (Festuca rubra Hack.) Boreal (15%) and Kentucky bluegrass (Poa pratensis L.) Balin (5%). With the exception of copper, the nitrogen fertilization raised the content of iron, manganese and zinc in aerial plant parts. The application of nitrogen (as ammonium nitrate) increased the uptake of nutrients by aerial plant parts: Fe to 143.0%, Mn – 227.2%, Zn – 233.3% Cu – 180.7%, and modified the ratios between amounts of the microelements. In general, it has been demonstrated that nitrogen nutrition of plants grown on ornamental lawns, within ranges of N – 150 to N – 200, increased the ratios of Fe : Mn : Zn : Cu. The best ornamental quality of lawns was obtained where the aerial plant parts contained (in mg kg–1 d.m.): Fe 231.6-292.8, Mn 35.6-50.5, Zn 26.5-47.5 and Cu 16.9-17.6. These ranges could be recommended as preliminary guidelines for ornamental lawns. In practice, considering the positive and stimulating influence of nitrogen nutrition on crops, the chemical composition of plants and the uptake of microelements by a mixture of grasses on ornamental lawns, it is crucial to monitor actual fertilization by taking into account losses of nutrients. These losses are caused by intensive uptake of nutrients by the aerial plant parts and due to the leaching of nutrients from the rhizosphere. It is necessary to replenish lost elements using mineral fertilizers.

Effects of Irrigation Volume and Nitrogen Fertilization on Redglobe and Michele Palieri Table-Grape Cultivars

The effects of water management and nitrogen fertilization, on yield, quality, and sensory profile of the red table-grape cultivars Redglobe and Michele Palieri were studied. Two irrigation volumes (1000 and 2000 m³/ha) and two nitrogen levels (120 and 180 kg/ha) were imposed. The effects of these parameters were cultivar-dependent. For Redglobe, irrigation resulted in significant increases in soluble solids and titratable acidity and significant decreases in resistance to compression and resistance to penetration. Increased nitrogen fertilization level exerted a significant effect only on titratable acidity (increased) and resistance to compression (decreased). Significant interactions between the two practices were demonstrated for soluble solids, pH, and resistance to compression. For Michele Palieri, increased irrigation resulted in significant decreases in soluble solids and resistance to penetration and significant increases in resistance to compression. Higher nitrogen caused decreases in berry weight but increases in soluble solid content and resistance to mechanical stress. Significant interactive effects were highlighted on yield, cluster weight, titratable acidity, and resistance to penetration. The lack of a significant correlation between physical/chemical and sensory results indicated that the changes induced by the agricultural practices on composition and mechanical behavior of berries were not perceptible by a trained panel.

Contrasted responses of Botrytis cinerea isolates developing on tomato plants grown under different nitrogen nutrition regimes

The nutritional status of a plant is known to influence its susceptibility to pathogens. In the case of Botrytis cinerea, the role of nitrogen fertilization of various host plants on disease development appears to be variable. This study was carried out to characterize possible variability associated with isolates and inoculum density of B. cinerea in its ability to infect leaf‐pruning wounds and to develop stem lesions on tomato plants, as affected by the nitrogen input. Six isolates differing in their aggressiveness to tomato were compared. They all had similar reaction patterns in vitro in response to differential nitrogen levels. In tests on plants grown with contrasted regimes of nitrate fertilization, overall disease severity was lower for all isolates on plants with higher nitrogen inputs, regardless of inoculum concentration. However, differences among isolates were observed in the effect of plant nitrogen nutrition on infection and on lesion expansion. Disease onset was delayed on all plants with higher nitrogen inputs, but the response was greater for isolates with lower aggressiveness on tomato. The highest contrast among isolates was observed with the colonization of stems. The daily rate of stem lesion expansion decreased with increasing nitrogen fertilization levels for the more aggressive isolates, while it increased for the less aggressive isolate. Hypotheses to explain these results are discussed in light of the possible physiological effects of nitrogen fertilization on nutrient availability for the pathogen in the host tissue and of possible production of defence metabolites by the plant.

EFFECT OF NITROGEN FERTILIZER RATES AND FOLIAR FERTILIZATION ON GROWTH, YIELD AND YIELD COMPONENTS OF SUNFLOWER

Two field experiments were carried out in 2006 and 2007 summer seasons at Sakha Agric. Res. Station (ARC) to study the effect of soil and foliar fertilization on growth, yield and its components of sunflower c.v. Sakha 53. Nitrogen fertilizer rates at 15, 30 and 45 kg N/fed were applied alone or along with foliar spray of urea (2%), single superphosphate (4%) and a mixture of micronutrients (100 ppm Fe + 140 ppm Zn + 120 ppm Mn). Results indicated that vegetative growth traits at 65 days after planting were significantly affected by nitrogen fertilizer rates and foliar spray nutrient application. Plant height, leaf area and dry matter/plant, as well as chlorophyll a and total photosynthetic pigments in leaves were significantly increased with increasing nitrogen level. Foliar nutrient application of urea remarkably improved growth traits. Flowering date was delayed with increasing nitrogen rates and foliar spraying of micronutrient. Increasing nitrogen fertilizer up to 45 kg N/fed led to significant increases in plant height, stem diameter, head diameter, 100-seed weight, seed yield/plant and seed yield/fed However, seed oil% was decreased with increasing nitrogen fertilizer rates. Oil yield/fed was significantly increased with increasing fertilizer nitrogen rate. It could be concluded that nitrogen applied at of 45 or 30 kg/fed with spraying with urea (2%) gave the highest oil yield/fed.

EFFECT OF PRECEDING WINTER CROPS, RELAY CROPPING, INTERCROPPING SYSTEM AND NITROGEN FERTILIZER RATES ON SOME SOIL PHYSICAL, HYDROPHYSICAL AND CHEMICAL PROPERTIES

Field experiments were carried out on clay soil at the experimental farm of El-Gemmeiza Agricultural Research Station, El-Gharbia governorate, during two years (2006 and 2007), to investigate the effect of preceding winter crops, relay cropping, intercropping system and N fertilization levels on soil properties. The experiments were conducted in randomized complete block design in a split–plot, with three replicates, where preceding winter crops (i.e., wheat, sugar beet and faba bean) occupied the main plots and nitrogen fertilizer rates for maize plant (90, 105, 120 and 135 Kg N/fed.) were assigned to the sub plots, in both years. Results can be summarized as follows:- 1- All preceding winter crops induced significant changes in all soil properties under study, but faba bean was more effective than wheat or sugar beet on decreasing the values of soil bulk density (Db), settling %, water consumption (CU), soil reaction (pH), soluble Ca, Mg and HCO3 andC/N ratio of the soil, where take the following order: faba bean > sugar beet > wheat. On the other hand, the effects of preceding winter crops on total porosity (E), void ratio (e), pore size distribution (>9µ, 9-0.2 µ and <0.2 µ), hydraulic conductivity (Kh), soil moisture content (θw) just before harvesting, saturation percentage (SP), field capacity (FC), wilting point (WP), available water (AW), water use efficiency (WUE), soil salinity (EC), soluble Na, K, Cl, SO4, total N, organic carbon (OC) and availability of soil macronutrients (N, P and K) were increased these characters and take the same order. 2- Faba bean planting as a preceding winter crop with the addition of 90 Kg N/fed to maize in summer season gave the lowest values of (CU), while faba bean with 135 Kg N./fed to maize was the best treatment, since it gave the highest value of (WUE) in the first and second years. 3- The addition of 135 Kg N/fed resulted in a decrease of (pH), soluble HCO3 and C/N ratio of the soil and increase in (WUE), total N, organic carbon (OC) and availability of soil macronutrients (N, P and K). 4- It could be concluded that the sowing of faba bean, sugar beet and wheat plants in winter season, relay cropping and intercropping system with increasing nitrogen fertilizer for summer crops led to a markedly improvement in soil physical, hydrophysical and chemical properties as well as the status of nutrients which reflect on higher yield of summer season crops.

Triangular Transplanting Pattern and Split Nitrogen Fertilizer Application Increase Rice Yield and Nitrogen Fertilizer Recovery

Field experiments were conducted to evaluate the effects of improved crop management (OPT) for irrigated rice (Oryza sativa L.) on grain yield and N recovery efficiency in southwestern China. In the OPT treatment, rice seedlings were transplanted in a triangular spatial pattern and the N fertilizer was split, based on the difference between the estimated total N requirement and the soil and environmental N supply. Fine‐tuning of application rates was achieved using leaf greenness measurements. The performance of OPT was tested in two adjacent fields in which the crops preceding rice were wheat (Triticum aestivum L.; Rw) and rapeseed (Brassica napus var. napus; Ro). The OPT and traditional farming practice (TRA) treatments both gave higher average grain yields than zero‐N controls (CK). Rice yields were considerably smaller in Rw than Ro under CK. Compared with TRA, OPT led to significantly higher aboveground N uptake, biomass accumulation, and grain yield in Rw Over the 2 yr of the study, average rice grain yields under OPT increased by 19 and 22% compared with TRA and 30 farmers' fields, respectively. The OPT treatment performed better than TRA in 15N recovery efficiency. Compared with TRA, OPT led to increased 15N fertilizer recovery efficiency from 19% in TRA to 42% in OPT, and decreased loss from 68% in TRA to 39% in OPT. In conclusion, OPT practice is a feasible means to attain increased yield with efficient N use. This study provides guidance for farmers using rice‐based cropping systems, especially in southwestern China.

EFFECT OF RIDGE WIDTH, HILL DISTANCE AND NITROGEN FERTILIZER RATES ON GROWTH, YIELD AND QUALITY OF STEVIA PLANT

Two field experiments were laid out at El-Bakatoush Village, Kafr El-Sheikh Governorate, Egypt in 2005/2006 and 2006/2007 seasons to study the effect of two ridge width (40 and 50 cm), three hill distances (15, 20 and 25 cm) and three nitrogen fertilizer rates (0, 30 and 45 kg N/fed/cut) as well as their interactions on growth, yield and quality of stevia plant (Stevia relebaudiana Bertoni) c. v. Spanti. The experiments were laid out in split- split plot design with three replications. The obtained results showed that plants sown on narrow ridge (40 cm) gave the highest values of leaf area index per plant, leaves dry weight cut/feddan, stevioside percentage at all cuts, total leaves dry weight per feddan and stevioside yield per feddan in both seasons. On the other hand, ridge width at 50 cm gave the highest number of leaves per plant at all cuts in both seasons. The closer hill spacing (15 cm apart) exceeded the middl and widest hill spacing at (20 and 25 cm which) in all previously mentioned traits, except number of leaves per plant was higher at the wider hill spacing (25 cm apart) at all cuts in both seasons. Increasing nitrogen fertilizer rates up to 45 kg N/fed/cut increased values of all studied characters at all cuts in both seasons. Planting stevia plants on ridging width 40 cm and hill distance 15 cm gave the highest values of all studied characters at all cuts in both seasons, except number of leaves per plant. Planting stevia plants on narrow ridge (40 cm) and fertilized with 45 kg N/fed/cut gave the highest averages of all studied characters at all cuts in both seasons, except number of leaves per plant was highest with 50 cm ridge width and 45 kg N/fed/cut. Plants having the close hill (15 cm) and fertilized by 45 kg N/fed/cut gave the highest values of all studied parameters except, number of leaves in both seasons. The highest total leaves dry weight per feddan and stevioside yield per feddan was recorded by sowing plants on narrow ridge (40 cm) and closer hill (15 cm) as well as fertilized by 45 kg N/fed/cut in both seasons.

Improvement of yield and botanical composition in meadows: effects of N fertilisation, irrigation on locations having different water table levels

Meadows dominated by native herbaceous species and having a high water table are an important source of feed for livestock in semi-arid regions of Turkey. This research investigated the effects of nitrogen fertilisation (ammonium sulfate) on two meadows having different water table levels and different soils. Dry matter production was 8868 kg ha–1 at location 1 and 7276 kg ha–1 at location 2. The application of 225 kg N ha–1 increased the crude protein content of the forage from 7.1 to 10.8%. A level of 150 kg ha–1 (CP 9.6%) is recommended as a result of this study. Crude protein yield increased from 303 to 1113 kg ha–1 with the highest rate of nitrogen application. The percentage of grasses in the forage averaged 92.5% and the weeds averaged 7.5%. Increasing nitrogen fertilisation resulted in an increase in the grass percentage and a decrease in the proportion of weeds. The differences in water table depth between location 1 and location 2 were not consistent between the years, and these differences influenced the irrigation applications which were applied according to soil moisture criteria.

EFFECT OF NITROGEN FERTILIZATION ON NITROGEN ABSORPTION EFFICIENCY BY WEAT PLANTS AND OR THEIR PHENOLOGICAL AND PRODUCT IONAL PROPERTIES UNDER THE CONDITIONS OF Al-Furat lower Basin.

Two varieties of wheat plants, i.e., Acsad 65 and Cham 3 were cultivated inDeirezzor to Governorate study effect of applied different rates of nitrogen fertilizer onthe chemical and fertility properties of soil as well as the economical return of thestudied two grown varieties.The obtained results showed that applying mineral fertilizer gaves areal increasein the wheat yield, while this didn't occur when phosphorus was applied alone. Also,increasing the rate of nitrogen fertilizer within the complete fertilization equation gave areal increase increment in wheat yield reached of about 310.08 kg/donum in case ofCham-3 as compared to the control treatment, while increasing nitrogen fertilizer rateover the optimal limits didn't give any real increase in both of the studied wheatvarieties.Response of Cham-3 to the increase of nitrogen fertilizer rates was clearly obviousthan of Acsad-65, as shown in treatment -3, where yield of Sham-3 reached 460.93kg/donum.It is noteworthy to mention that available nitrogen in the experimental soilincreased with increasing the applied nitrogen fertilizer rates, the reverse was true foravailable phosphor, however its amount decreased with increasing nitrogen fertilizerrates within the fertilizer equation.

INFLUENCE OF DIFFERENT LEVELS AND APPLICATION DATES OF NITROGEN FERTILIZER ON GROWTH OF TWO

Afield experiment was conducted to investigate the effect of varieties, nitrogen fertilizer levels and their application dates on growth characters of corn (Zea mays L.). The split -split plot design in RCBD with three replications was used. The experiment included two corn varieties (Buhooth 106 and Tallar) and four nitrogen fertilizer levels (0,80,120,160 kg N/ha) and three application dates of fertilizer (half of recommended level was added at sowing and other half after 30 days from sowing, half of recommended level was added at sowing and other half after 60 days from sowing, one fourth of the quantity was added at sowing and half after 30 days from sowing and the last quarter after 60 days from sowing. The varieties ,nitrogen fertilizer levels and application dates, represented as main plot , sub plot and sub-sub plot, respectively. The result indicated that the varieties Buhooth 106 was significantly superior than Tallar variety for grains yield and components with the exception of number of rows per ear and harvest index .Tallar variety was significantly exceeded than Buhooth 106 in crude protien , oil yield and percentage .Increasing nitrogen fertilizer rates caused continuous increase in all grains yield and components and continuous singnificant increase in grain quality with the exception of oil percentage.Application dates of nitrogen affected significantly all grains yield and components. Partitioning nitrogen to three batches gave higer grains yield and components , crude protien and oil .

ROLE OF NON-SYMBIOTIC N2-FIXING BACTERIA IN OPTIMIZING THE MINERAL NITROGEN FERTILIZER USE OF WHEAT PRODUCTION

Two field trails were carried out at Sakha Agricultural Research Station Farm through the two successive growing seasons of 2006/2007 and 2007/2008 to study the effects of fertilization with five nitrogen levels of 0, 25, 50, 75 and 100 kg N/fed. and applying azospirillum bacteria as effective biofertilizer on yield, yield components, nitrogen percentage and grain protein content of wheat .Split plot design was used, the main plots were assigned by N levels and the sub plots were assigned by biofertilization. The obtained results can be summarized as follows: Inoculation with biofertilizer high significantly increased wheat grain yield from 1.32 to 2.13 ton fed.-1 in the first season and from 1.31 to 2.2 ton fed-1 in the second season. Increasing nitrogen fertilizer rates high significantly increased grain yield. The highest mean values of 2.26 and 2.6 ton fed-1 were obtained with 100 kg N fed-1 in the first and second season, respectively. Obtained data clearly illustrated that the mean values of straw yield tons/fed. were increased by increasing nitrogen does up to 100 kg/fed. The highest mean values were recorded and they are 3.03 and 3.12 ton/fed. in the first and second growing seasons, respectively. On the contrary, the lowest mean values were recorded under the control treatment (without nitrogen) of 1.32 and 1.28 ton/fed. in the two growing seasons. The mean values of nitrogen and protein percentages were increased by increasing both of mineral and biofertilizer applications. The mean values for plant height were increased by increasing application of both mineral and biofertilizer. The mean values under biofertilizer application were 96.36 and 97.23 cm. But under non-application treatments the mean values were 62.12 and 61.04 cm in the first and second seasons, respectively. Also, application of mineral fertilizer up to 100 kg/fed. increased wheat plant height. The highest mean values were recorded with 100 kg N fed.-1. The mean values of 1000 grain weight, number of tillers and number of spikes were incased by increasing nitrogen dose up to 100 kg N/fed. Also, application of biofertilization led to increasing the studied parameters in comparison with non-application treatments.

Effects of Nitrogen Application Time on Caryopsis Development and Grain Quality of Rice Variety Yangdao 6

A pot experiment was conducted to study the effects of different nitrogen application time (during the tillering or the booting stages) with the same nitrogen rates on the caryopsis development and grain quality of rice variety Yangdao 6. The increased nitrogen fertilizer (urea), especially applied during the booting stage, could evidently increase the milled rice rate, head rice rate and protein content in rice grains compared with the control (no nitrogen application), and decrease chalky grain rate and amylose content. Moreover, the increased nitrogen fertilizer significantly affected the caryopsis development and enhanced the grain weight when nitrogen applied during the tillering and the booting stages, especially during the booting stage. During caryopsis development the increased nitrogen fertilizer applied during the tillering and booting stages could obviously decrease the total starch and amylose contents, but not obviously for the amylopectin content in rice grain. Increased topdressing of nitrogen fertilizer, especially applied during the booting stage, had significant effect on the development and structures of amyloplasts and proteinoplasts. That is, it could change the distribution, number and shape of amyloplasts and proteinoplasts in the endosperm cells especially in grain abdomen. Compared with the control the arrangements of amyloplasts and proteinoplasts were closer, with more numbers, higher density and less interspaces each ohter. Furthermore, most amyloplasts showed polyhedron under the increased nitrogen fertilizer level.

Monitoring leaf nitrogen status with hyperspectral reflectance in wheat

The objectives of this study were to determine the relationships of leaf nitrogen concentration on a leaf dry weight basis (LNC) and leaf nitrogen accumulation per unit soil area (LNA) to ground-based canopy hyperspectral reflectance and derivative parameters, and to establish quantitative models for real-time monitoring of leaf N status with key hyperspectral bands and estimation indices in wheat ( Triticum aestivum L.). Three field experiments were conducted with different N application rates and wheat cultivars across three growing seasons, and time-course measurements were taken on canopy hyperspectral reflectance, LNC and leaf dry weights under the various treatments. The results showed that LNC and LNA in wheat increased with increasing nitrogen fertilization rates, and changes in canopy hyperspectral reflectance under varied N rates were all highly significant, with consistent patterns across the different cultivars and years. The sensitive spectral bands occurred mostly within visible light and near infrared regions, and a close correlation existed between red-edge district and LNC or LNA. An integrated linear regression equation of LNC to spectral parameters REIPle and λ o well described the dynamic pattern of LNC changes in wheat, giving the determination of coefficients ( R 2) as 0.831 and 0.834, and the standard errors (SE) as 0.405 and 0.403, respectively. The hyperspectral parameters MSS-SARVI and FD742 were linearly related to LNA, with R 2 as 0.861 and 0.873, and SE as 1.11 and 1.06, respectively. When independent data were used to test the derived equations, the R 2 values between the measured and estimated LNC from spectral parameters REIPle and mND705 were 0.752 and 0.695, with the average relative errors (RE) as 14.4% and 16.5%, respectively. For spectral parameters FD742 and SDr/SDb, the R 2 values between the measured and estimated LNA were 0.872 and 0.828, with RE as 14.1% and 15.2%, respectively. The high fit between the measured and estimated values indicated that the present models based on hyperspectral reflectance could be used for reliable estimation of the leaf N status in wheat plant under different growing conditions.

Green‐maize potential of hybrid and open‐pollinated cultivars at varying levels of applied nitrogen: relationship with grain yield

AbstractTwo sets (white‐ and yellow‐kernelled) of six cultivars of field‐maize, each comprising three hybrids and three open‐pollinated (OP) varieties, were evaluated for green‐maize productivity under three levels of nitrogen fertilisation (0, 60 and 120 kg ha−1) at two locations in southwestern Nigeria. The relationship between green‐maize and grain yield was also investigated. Numbers of marketable ears and marketable‐ear yield were significantly correlated. Green‐maize traits and grain yields showed different responses to increased nitrogen fertiliser application: grain yield was significantly greater at 120 kg ha−1 than at 60 kg ha−1 whereas marketable‐ear yield was not significantly changed by the higher rate. The hybrids showed higher green‐maize and grain yield responses than the OPs to fertiliser application. At 60 kg ha−1 nitrogen application, marketable‐ear yield averaged 0.620 kg m−2 and 0.567 kg m−2 for white hybrids and OPs, respectively, and 0.576 kg m−2 and 0.439 kg m−2 for yellow hybrids and OPs. Marketable‐ear yield was significantly correlated with grain yield for both the white and yellow cultivars. Regressions of grain yield on marketable‐ear yield were significant and such regression equations can thus be used to estimate marketable‐ear yield potential from grain yield data. Copyright © 2008 John Wiley &amp; Sons, Ltd

Grain yield and quality of winter wheat inoculated with a mixed culture of Pseudomonas bacteria against the background of increasing nitrogen fertilizer rates

The effect of a mixed culture of non-nitrogen fixing bacterium Pseudomonas fluorescens 20 and nitrogen-fixing bacterium Pseudomonas putida 23 on winter wheat grain yield, nitrogen removal by plants, and content of protein and ash elements in grain against a background of nitrogen fertilizer was studied in a microplot experiment on gray forest soil.

Nitrogen fertilization at the rice panicle differentiation stage to compensate for rice water weevil (Coleoptera: Curculionidae) injury

A three-year study was conducted to determine the effect of nitrogen fertilizer rates applied at the panicle initiation stage of rice, Oryza sativa L., and insecticide applications on yield loss caused by rice water weevil, Lissorhoptrus oryzophilus Kushel, damage. Our estimates of yield loss caused by L. oryzophilus injury were, at the recommended nitrogen rate of 191 kg N per ha, 1.7% in 1997, 11.8% in 1998, and 9.9% in 1999. In 1998, doubling the panicle differentiation nitrogen rate from 67 to 134 kg N per ha significantly increased yield by 591 kg per ha, averaged across insecticide treated and untreated plots. In both 1998 and 1999, reducing nitrogen rate below the recommended rate significantly ( P<0.05) reduced rice yield, indicating the value of providing the rice plant with sufficient levels of nitrogen. In 1998 and 1999, insecticide treatment increased yield by 570 and 830 kg per ha, respectively. The interaction between insecticide treatment and fertilizer rate was not significant ( P>0.05) for yield in any year of our study, suggesting that increasing nitrogen at the panicle differentiation stage does not have a major impact on compensation of the rice plant for L. oryzophilus injury. Our results indicate that farmers should not increase nitrogen fertilizer at the panicle differentiation stage to compensate for L. oryzophilus damage.