Different Amounts Of Nitrogen Fertilizer Research Articles

Biological soil conditioner with reduced rates of chemical fertilization improves soil functionality and enhances rice production in vegetable-rice rotation

Soil is an essential source of nutrients for crop growth, but excessive chemical fertilizer can lead to soil acidification and decreased sustainability. Organic fertilizer helps improve soil physicochemical properties and increase soil utilization efficiency. However, soil functionality and crop sustainability response to organic fertilizers need further research. In this study, multiple fertilizer practices (including different amounts of nitrogen fertilizer or soil conditioners, traditional organic fertilizer), various rice varieties, and other rotation systems were applied to test the effects of soil conditioners on crop yield and soil fertility. The results showed that crop yield sustainability and stability were significantly positively correlated with soil pH, EC value, and nitrogen (Pearson r > 0.5). In addition, improving soil quality was beneficial to increasing crop yield sustainability and stability (R2 > 0.5). Chemical fertilizers and soil conditioners can increase soil nutrient content and improve crop yield sustainability index (>0.8). Applying soil conditioners can enhance the activity of soil catalase and urease in paddy soil, especially in the 12 and 15 m3 ha−1 soil conditioner treatments due to soil microbial activity being affected by soil salinity and organic matter content. Soil conditioners increase the mass of Nitrospira species in soil, decompose nitrogen in the soil, and reduce soil nitrate and nitrite content, thereby improving soil pH and reducing the risk of soil acidification caused by excessive chemical fertilizer. Combining soil conditioners and chemical fertilizer (20 % less than traditional fertilization) can promote soil quality and fertility while improving crop yield sustainability and stability.

Investigation of Nitrogen Losses, Corn Yield and Yield Components Under Different Amounts of Nitrogen Fertilizer and Fertigation Management Via Furrow Irrigation

Investigation of Nitrogen Losses, Corn Yield and Yield Components Under Different Amounts of Nitrogen Fertilizer and Fertigation Management Via Furrow Irrigation

Effect of Preceding Crop Type and Different Amounts of Nitrogen Fertilizer on the Yield and Quality of Rapeseed Oil

Effect of Preceding Crop Type and Different Amounts of Nitrogen Fertilizer on the Yield and Quality of Rapeseed Oil

Elucidating the effect and interaction mechanism of fulvic acid and nitrogen fertilizer application on phosphorus availability in a salt-affected soil

The present study was performed to investigate the effects of the interaction of fulvic acid (FA) with different amounts of nitrogen fertilizer (N) on soil phosphorus availability and transformation in a salt-affected soil and to obtain the direct and indirect relationships between inorganic phosphorus (Pi) fractions and Olsen-P. An incubation experiment was conducted to evaluate the effects of nitrogen addition (215, 183, and 151 mg kg-1, referred as N100, N85, and N70), fulvic acid addition (30 and 60 mg kg-1, referred as F1 and F2), and their interactions on phosphorus availability (based on soil Olsen-P and inorganic P fractions). The results indicated that the application of N100 significantly reduced the release and availability of phosphorus (P). However, the phosphorus recovery (PR) as Olsen-P was significantly enhanced in the N100F1 and N100F2 treatments. The P kinetics was best described by the power function model. Moreover, labile Ca2-P and Ca8-P contents decreased as N application rate increased. Combined application of FA and fertilizer N increased the percentage of Ca2-P and decreased the percentage of Ca10-P at the end of the incubation period. According to the correlation analysis and path analysis, the direct effects of Ca2-P, Fe-P, and O-P on Olsen-P were significant after 112 days of incubation (P<0.05). The indirect effects of Ca2-P (R21Py1 = 0.57) and Fe-P (R24Py4 = 0.19) were essential contributors to the correlation between Ca8-P and Olsen-P. Additionally, the indirect effect of Ca8-P (R41Py1 = 0.53) contributed significantly to the correlation between Fe-P and Olsen-P. In conclusion, our results show that the availability of phosphorus can be improved by reducing the amount of nitrogen fertilizer applied in salt-affected soils. Integrating FA and inorganic N fertilizer enhances the release and availability of phosphorus, when excessive amounts of N fertilizers are applied to salt-affected soils.

The Effect of Periodic Irrigation and Different Amounts of Nitrogen Fertilizer on Yield and Yield Components of Rice

ABSTRACT A split-plot experiment was conducted in a completely randomized block design with three iterations for 2 years in Gilan province (Iran) to investigate the effect of periodic irrigation and different amounts of nitrogen fertilizer on yield and yield components of the rice plant. In the present research, the main factor was irrigation at five levels, and the secondary factors included nitrogen fertilizer at six levels. The simple effect of irrigation on all tested traits was significant and the simple effect of nitrogen was significant on all traits except for emptiness percentage and harvest index. Interaction of irrigation and nitrogen had a significant effect on seed yield, plant height, number of tillers, 1000-seed weight, emptiness percentage, number of seeds per panicle, biological yield, as well as harvest index. Regarding the higher yield in 5-day irrigation (3278 kg ha−1) than flooding irrigation (3081 kg ha−1), this irrigation interval is recommended for maximum yield and water saving. Under low-stress conditions (daily and 5-day irrigations), given the significant low difference between the amount of nitrogen fertilizer 75 and 90 kg ha−1, environmental considerations, besides reduction of planting costs, an amount of 75 kg ha−1 fertilizer urea can be recommended.

Effects of straw returning combined with nitrogen fertilizer on spring maize yield and soil physicochemical properties under drip irrigation condition in Yellow River pumping irrigation area, Ningxia, China

Soil compaction and nutrient deficiency are common problems in Ningxia Yellow River pumping irrigation area, which adversely affect crop yield. A two-year (2017-2018) field experiment of straw returning combined with nitrogen fertilizer were designed. Four nitrogen application levels (pure N with 0, 150, 300 and 450 kg·hm-2) were set under the condition of full smashing of maize straw (12000 kg·hm-2) returning, with the conventional nitrogen application (pure N with 225 kg·hm-2) without straw returning as the control (CK) to investigate the effects of straw returning combined with different amounts of nitrogen fertilizer on soil physical and chemical properties and maize yield under drip irrigation condition. The results showed that, compared with no-straw returning treatment, the treatments of straw returning combined nitrogen fertilizer with 300 and 450 kg·hm-2 reduced soil bulk density (0-20 cm) by 3.3% and 5.4%, but increased soil porosity by 3.7% and 7.1%, respectively. Straw returning combined with nitrogen with 300 kg·hm-2 and 450 kg·hm-2 was the best treatment which increased soil organic matter content, available K, P, alkaline N and total N in 0-40 cm soil layer. Compared with the non-returning treatment, straw returning combined with nitrogen fertilizer 300 kg·hm-2 significantly increased soil water storage by 13.6% and 22.1%, increased maize yield by 31.1% and 46.0 % in 2017 and 2018, respectively. The analysis of yield components showed that the high maize yield was achieved mainly by increasing grain number and the100-grain weight. Curve fitting showed that the optimum amount of nitrogen fertilizer was 260 kg·hm-2. Our results provide important basis for soil fertility improvement and sustainable production.

Growth and yield responses of two forage sorghum cultivars to different nitrogen fertilizer rates

In order to evaluate the impact of different amounts of nitrogen fertilizer on growth and yield of two forage sorghum cultivars, a 2-year field experiment was carried out at the College of Agriculture, Shiraz University, Shiraz, Iran during 2010 and 2011 growing seasons. Two factorial experiments were carried out in randomized block design with three replicates, in which the treatments included nitrogen fertilizer at three levels: 69 (N1), 138 (N2) and 205 (N3) kg N ha-1 and two sorghum cultivars: Pegah and KFS2. The results showed that nitrogen fertilizer enhanced plant height, leaf area index, fresh weight, total dry weight and biological yield significantly so that these traits were higher in N3 as 5.71, 22.8, 8.13, 22.5, and 8.7% than N1, respectively. Furthermore, increasing nitrogen rate had additive effect on crop growth rate, relative growth rate, biomass duration and leaf area duration. Comparing the cultivars, it was found that, plant height, fresh weight, total dry weight and biological yield were higher in Pegah than KFS2 cultivar. Results also showed that most of the studied traits were superior for Pegah under N3 treatment; so, Pegah cultivar and application of 205 kg N ha-1 might be offered for similar agro-climatic conditions.

Application of Instrument-Based Multiple Texture Measurement of Cooked Milled-Rice Grains to Rice Quality Evaluation

The subject of this study was to examine a method of multiple texture measurement of cooked milled-rice grains and to develop techniques for quality evaluation on the basis of the method. The low-and high-compression (LHC) test, which measures surface and overall texture properties (25% and 90% compression ratios for the single grain thickness after cooking), was effective in enhancing the classification accuracy of the texture. A multiple regression model based on surface texture properties indicated higher prediction accuracy for palatability than that with using overall texture properties. The surface adhesion distance was adopted for distinguishing stickiness. Concerning the effect of protein content on texture among the samples of the same cultivar given different amounts of nitrogen fertilizer, the protein content showed a higher correlation with surface hardness than with overall hardness. Surface hardness was a more reliable indicator of protein content and palatability in the same cultivar. It revealed that the surface texture can be used as a key quality index. A multiple regression model of the LHC test was able to predict amylose content more precisely than using the conventional method. It was possible, using the single-grain method with the LHC test, to evaluate not only grain texture but also many other qualities such as protein content, palatability and amylose content.

Estimating Canopy Light Interception and Absorption Using Leaf Mass Per Unit Leaf Area in Solanum melongena

Knowledge of canopy light interception and absorption is fundamental for understanding many aspects of crop growth and productivity, and for crop modelling. Light interception is commonly measured with expensive equipment or estimated with elaborate models; simpler and more economical ways of estimation would be advantageous. Since leaf mass per unit leaf area (MA) is closely related to long-term light interception by leaves, the latter can be estimated by measuring MA. In this study, partitioning of leaf area into one of six classes ofMA was used to estimate canopy light interception and absorption in aubergine (Solanum melongena L.) grown with different amounts of nitrogen fertilizer and with or without artificial shade. Although plants grown with ample fertilizer had a greater leaf area index (LAI) than those grown with less nitrogen, the increase in leaf area occurred in the lower and intermediate MAclasses, while the leaf area in the two highest MAclasses was similar. Artificially shaded plants had more leaf area in the lower MAclasses and less in the higher classes compared to unshaded plants, showing acclimation to low light conditions. The amount of light intercepted daily by leaves in eachMA class was estimated using the previously determined light:MArelationship. Canopy light interception was calculated as the sum of intercepted light for all MAclasses, and canopy light absorption was estimated from light interception data assuming a constant absorption coefficient (82%). To validate the results, the estimated values were compared to those calculated from independent measurements of light absorption carried out in the same field. Results indicate that it is possible to estimate canopy light interception and absorption from the partitioning of leaf area into MAclasses.

Levels of Nonstructural Carbohydrate in Leaves and Roots and Some Characteristics of Chloroplasts after Application of Different Amounts of Nitrogen Fertilizer to Peach Seedlings.

The effects of different amounts of nitrogen, applied in the soil, on the accumulation of nonstructural carbohydrate in leaves and roots were determined as well as on some characteristics of chloroplasts in one-year-old peach trees (Prunus persica) grown in 500-ml pots. The amounts of nitrogen, applied as NH4NO3, were as follows : 0 mg/pot (N-0), 75 mg/pot (N-75), 150 mg/pot (N-150), 300 mg/pot (N-300), and 600 mg/pot (N-600). The weights of stems and leaves and shoot length were greatest in N-150 and N-300 trees, whereas root weights were heaviest in N-75 and N-150 trees. Shoot and root growth was significantly reduced in N-0 and N-600 trees. Leaf chlorophyll content (μg cm-2), total soluble sugar (% dry weight), and nitrogen content (% dry weight) of leaves and roots increased with increased application of nitrogen, whereas starch content of leaves was inversely proportional to the amount of nitrogen administered. The amount of sorbitol (% fresh weight) in leaves was proportional to the growth rate of the trees. Chlorophyll was stained more heavily by 4', 6-diamidino-2-phenylindole in N-600 leaves than in N-0 leaves ; the staining concentrated at the periphery of chloroplasts, indicating an accumulation of starch. The level of the enzyme, ribulose-bisphosphate carboxylase-oxygenase (RuBisCO), increased with increased applied nitrogen, reaching maximum at N-300 and N-600. Total soluble sugar in roots was high in vigorous trees, where root starch content was inversely proportional to root growth.

Changes in Carbohydrate and Ribulose Bisphosphate Carboxylase-Oxygenase Contents in Peach Leaves after Applications of Different Amounts of Nitrogen Fertilizer.

The effects of applying different amounts of nitrogen on the accumulation of nonstructural carbohydrate and ribulose bisphosphate carboxylase-oxygenase (RuBisCO) and on some characteristics of peach leaves were determined on young trees. The leaf nitrogen contents of trees supplied 0 and 1.5g N/pot (N-0 and N-1.5, respectively) were lower than were those administered 9.0g/pot (N-9). On a dry weight (DW) basis, leaves sampled from N-0 trees and N-9 trees were 1.8% and 4.0%, respectively. The chlorophyll content per unit leaf area increased with increased nitrogen applied. The starch content on a dry weight basis was inversely proportional to the amount of nitrogen administered, whereas total soluble sugar per unit dry weight was proportional. The sorbitol and sucrose contents per unit leaf fresh weight were the lowest in leaves from N-0 trees. The RuBisCO content detected by immunoblotting after SDS-polyacrylamide gel electrophoresis as well as by immunostaining of sections under the light microscope increased with the increase in the amounts of nitrogen applied.

Simulation model of Oulema melanopus in the winter-wheat ecosystem

Simulation system sonches (Simulation of Nonlinear Complex Hierarchical Ecological Systems) is a tool for computer-aided experimental investigation of the dynamic behaviour of ecological systems. A winter-wheat agroecosystem was modelled with the help of sonches. The whole model consists of several submodels. One of them is the growth-development model of winter wheat itself. The others are pest models. The model of cereal leaf beetle (Oulema melanopus) was investigated. The main driving force in the model is daily mean temperature. The temperature inside the plant canopy is different from the temperature outside it (at the meteorological station). A microclimate model was used to modify the measured temperature values. Simulation experiments were carried out to show the effect of using microclimate data instead of standard meteorological data. The difference between the temperature inside and outside the canopy depends on radiation. The days of the vegetation period were classified by sunshine duration: clear, cloudy and overcast days. Winter wheat treated with different amounts of nitrogen fertilizer has a different canopy structure. The microclimate inside the canopy alters according to density. Results of simulation experiments in the form of population dynamics are presented.

Relationship between Japanese Pear Scab Development and Nutrients Content in Leaves on Trees Given Different Amounts of Nitrogen Fertilizer.

The correlation between the development of Japanese pear scab (caused by Venturia nashicola) on leaves and the content of total nitrogen, total carbon, phosphorus, potassium, calcium, magnesium, iron and manganese in the leaves on trees given different amounts of nitrogen fertilizer was investigated. With an increase of nitrogen fertilizer, the content of total nitrogen and manganese in leaves increased while calcium content decreased. The content of total carbon, phosphorus, potassium, magnesium and iron did not show any obvious change. The ratio of diseased leaves, degree of disease development and degree of conidial formation increased with increasing amounts of given nitrogen fertilizer. Significant correlation (P=0.05) were recognized between total nitrogen content and the degree of disease development on 3rd and 7th position leaves from top leaf, the degree of conidial formation on 11th position leaf, calcium content and degree of disease development on 7th position leaf, and manganese content and degree of conidial formation on 7th position leaf. These results show that with an increase in nitrogen fertilizer there is an increase in total nitrogen and manganese content and a decrease in calcium content in leaves, and a higher susceptibility to Japanese pear scab was induced.

Field measurements of the photosynthetic rate of potatoes grown with different amounts of nitrogen fertilizer

SummaryThree experiments are reported in which the photosynthetic rates of potatoes grown with various amounts of applied nitrogen (N) fertilizer were measured. Rates of photosynthesis in leaves of plants grown without applied N reached levels as high as those receiving N in all experiments. The rate of photosynthesis in the uppermost leaves of the variety Pentland Crown was found to increase during the season, whereas in Estima rates remained the same. Decline in the rate of photosynthesis with leaf age was more rapid in strongly shaded leaves than in less shaded leaves which were found to be photosynthetically active 8 weeks after expansion.

Decomposition and nutrient release in needle litter from nitrogen‐fertilized scots pine (pinus sylvestris)stands

Decomposition of Scots pine needle litter originating from five stands treated with different amounts of nitrogen fertilizer was measured over a 4‐year period in a mature Scots pine forest. The litter types, which differed in initial concentrations of nitrogen, phosphorus, potassium, and sulfur, but not in gross organic composition, were studied with respect to mass loss, ingrowth of total fungal mycelium, and net release of nutrients. During the first year of decomposition, rates of mass loss and ingrowth of fungal mycelium were highest in the nutrient‐rich litter. Phosphorus concentration was found to be the main factor affecting mass‐loss rate, and the rate of fungal ingrowth was positively correlated with initial nitrogen concentration. After this initial period, decomposition rates decreased, and after 4 years, accumulated mass loss and amounts of fungal mycelium were similar in all five litter types. These findings may be due, in part, to a lower rate of lignin decomposition in nitrogen‐enriched litter. Of the elements, potassium and magnesium were most rapidly lost from the litter, and their release was most pronounced during the first year. Calcium release was proportional to the loss in organic matter. Initially, the release of nitrogen and phosphorus was positively related to their concentrations in litter, however, during later stages of decomposition the differences among litter types levelled out. There was a tendency for concentrations of all elements, except nitrogen, in the different litters to approach similar levels as decomposition proceeded. Thus, after 4 years the nutrient composition of the various litter types was very similar, except for higher nitrogen concentrations in the originally most nutrient‐rich litters. The importance of the results in terms of substrate quality in fertilized as well as in non‐fertilized forests is discussed.

Nitrogen fertigation of Shamouti oranges

The effects of different amounts of nitrogen fertilizer supplied in the irrigation water on nitrogen uptake, orange yield and quality of Shamouti oranges was studied in a field experiment in a mature orange grove. Nitrogen was supplied as ammonium nitrate in three concentrations (15, 35 and 60 ppm) resulting in resp. 100, 170 and 310 kg N/ha. Significant effects of nitrogen were found during four years of fruit yields and on the number of fruits per tree. The average fruit weight was not affected. The high nitrogen rates caused thicker peels and later development of orange colour. The leaf nitrate content was closely related to the fruit yield. Soil solution samples taken with ceramic cups gave a good indication of the soil nitrate content. It was shown that the spring flush of leaves is based mainly on tree nitrogen reserves, and not on nitrate uptake from the soil.

Dark Respiration of Several Varieties of Winter Wheat Given Different Amounts of Nitrogen Fertilizer

Carbon dioxide production in the dark by ears and by the rest of the shoot of winter wheat grown in the field was measured in 2 years during grain growth. The respiration rate per g d. wt of the ears was increased by nitrogen fertilizer. Ears of the semi-dwarf varieties Maris Fundin and Hobbit respired more slowly than ears of Maris Huntsman and Cappelle-Desprez. Respiration rates of the rest of the shoot were unaffected by nitrogen or variety. The amount of carbohydrate required to provide the CO2 respired during the whole period of grain growth varied from 163 to 443 g m−2, or 42 to 76 per cent of the dry weight of the grain. More than half the CO2 lost was respired by the ear. The addition of 180 kg N ha−1, which increased grain yield by 78 per cent in 1975, almost trebled the amount of CO2 lost by the ears. The semi-dwarf varieties lost less CO2 from ears and shoots than did the taller ones, and had larger yields of grain. Respiration was also estimated from the difference between the 14C contents of shoots sampled immediately after a 30 s exposure to 14CO2 and at maturity. When 14C was supplied 10 days after anthesis, the loss by maturity amounted to 16–28 per cent of that initially absorbed by flag leaves and 40 per cent of that absorbed by the leaf below the flag leaf. Most of the loss occurred in the first day. The loss of 14C by maturity was significantly increased by nitrogen fertilizer in 1975.

Storage fungi of onion and their control

Botrytis allii Munn caused total onion damages of 15—20 % during storage in 1975—1979, and was present on 80—90 % of the spoilt onions. The proportion of damage caused by Fusarium oxysporum Schl. was 0—5 % and was present in 0—10 % of the spoilt onions. The early weight losses during storage of the onions were mostly due to storage pathogens which spread via the onion sets used as propagation material. This can be prevented very effectively by soaking the sets in benomyl solution before planting out. The unusually high fungus content of the sets resulted in a reduced yield. Spraying with fungicide early on in the growing season and applying different amounts of nitrogen fertilizer had no significant effect on the number of storage pathogens. A low stroge temperature did not inhibit the development of storage pathogens, it merely slowed it down.

The Effect of Ethirimol Seed Dressings on Yield of Spring Barley grown with Different Amounts of Nitrogen Fertilizer 1969–71

SUMMARYEthirimol seed dressings usually increased the yields of Zephyr and Sultan barley more than those of other cultivars less susceptible to mildew. However, Julia and Vada also responded well, especially in experiments where brown rust was common. Julia and Vada have some resistance to foliage diseases other than mildew and this may affect their apparent response to fungicides applied to control mildew. Different amounts of nitrogen fertilizer affected the benefit from ethirimol seed dressings as well as total yield.

Studies on the Methods to Evaluate the Availability of Phosphatic Fertilizers (Part 1) : Phosphorus Availability of Phosphatic Fertilizers in Relation to the Growth of Plants Varied by Applying Different Amounts of Nitrogen Fertilizer

Studies on the Methods to Evaluate the Availability of Phosphatic Fertilizers (Part 1) : Phosphorus Availability of Phosphatic Fertilizers in Relation to the Growth of Plants Varied by Applying Different Amounts of Nitrogen Fertilizer