Amount Of Nitrogen Fertilizer Research Articles

Determination of the Nitrate Sufficiency Limit Value for Nitrogenous Fertilization Use in Wheat Grown on a Calcareous Soils Through Application of Mitscherlich-Bray Equation

ABSTRACT This study was carried out to determine the optimum levels of NO3-N (nitrate – nitrogen) in soils. According to the randomized complete block design, increased N applications (0, 40, 80, 120, 160, 200 and 240 kg N ha−1) were applied as urea (46% N) in 10 locations with different amounts of nitrate-nitrogen in the soil profile (0–100 cm). As a result, statistically significant relationships were determined between the maximum product increase in wheat and NO3-N amount determined by the phenoldisulfonic acid method at 0–20, 0–40, 0–60, 0–80 and 0–100 cm depths of the trial field soils. Considering these relationships, Mitscherlich–Bray equation was expressed as [log (A-y) = log A – 0.048*b – 0.007*x] for the bread wheat plants grown in the calcareous soils under irrigated conditions. The levels of NO3-N in the soil and consequently the amount of nitrogen fertilizer to be applied in calcareous soils varies according to the economically acceptable rate of maximum yield of bread wheat. Hence, the values of NO3-N determined at 0–20 cm depth was categorized as insufficient (<20 kg ha−1), sufficient (20.1 to 34 kg ha−1) and excessive (>34 kg ha−1).

15N fate in maize cropping system in response to black soil fertility improvement in China

AbstractApplications of high amounts of nitrogen (N) fertilizer are essential for obtaining sustainable maize (Zea mays L.) yields but also result in low N‐use efficiency (NUE) and cause a series of environmental problems. To optimize fertilizer management, it is necessary to determine the effects of soil fertility improvement on NUE and the fate of N fertilizer. In this study, we conducted a 15N tracer pot experiment involving five different fertilizer treatments in soils with five different total organic carbon levels under field conditions. The average NUE ranged from 36 to 56% 15N‐urea and 0.1 to 0.2% residual N in the first and second seasons. The N retained in the soil ranged from 10 to 28%, and the N lost to water and the atmosphere ranged from 29 to 39% in the five soils. Compared with that in the low‐fertility soils, NUE in the high‐fertility soils was 20–45% greater, and N loss was 1 –6% lower. The results showed that higher soil fertility corresponded to higher NUE and lower N loss. We suggest that although the local customary N fertilizer application rate (N3; 165 kg N/ha) in the study area is reasonable for low‐fertility soils, after soil fertility improvements, an approximately 50% reduction of N fertilizer should be implemented.

The use of the data derived from the PlanetScope satellite and unmanned aerial vehicles to estimate crop yield as dependent on the amount of nitrogen fertilizer applied

The purpose of the present study is to show the usefulness of the satellite data and the data derived from unmanned aerial vehicles (UAVs) for estimating the relationship between cereal grain crop yield and the amount of nitrogen fertilizer applied. The study was conducted on the land of the Kuraginskoye Research Farm. The study material was spring barley cv. Biom. Three test plots were studied; mineral fertilizer, urea, was used in different quantities for foliar application in June; applications were performed at equal intervals. Multispectral images were based on PlanetScope satellite data, with the 3 m spatial resolution, and the data derived from the DJI Phantom 4 Multispectral UAV, with the 10 cm resolution. The satellite and UAV data were used to calculate spectral vegetation index (NDVI) (Normalized Difference Vegetation Index). A high correlation was obtained between the NDVI values calculated using satellite data and UAV data. The satellite data provided the basis for assessing barley crop yield as dependent on the amount of foliar-applied urea during the growing season. Maps of the spatial distribution of barley NDVI were constructed using the Phantom UAV data; they showed that the third foliar application of the fertilizer was not economically justified.

Seasonal Nitrous Oxide Emissions From Hydroponic Tomato and Cucumber Cultivation in a Commercial Greenhouse Company

Nitrous oxide (N2O) is considered as the most critical greenhouse gas (GHG) emitted by agricultural and horticultural food production. Hydroponic vegetable cultivation in greenhouse systems has a high potential for N2O emissions due to the intense application of nitrogen-containing fertilizers. Previous studies on model hydroponic systems indicate that N2O emissions per unit area can be several times higher than typically found during field cultivation. However, reliable data from production-scale hydroponic systems is missing. Here we report our findings from monitoring the N2O emissions in a commercial production greenhouse, located in the east of Germany, over a period of 1 year. We used the static chamber method to estimate N2O fluxes in the root zones of hydroponic tomato and cucumber cultures on rock wool growing bags with drip fertigation. Regular sampling intervals (weekly-biweekly) were used to calculate whole season cumulative N2O emissions and N2O emission factors (EFs) based on the amount of nitrogen fertilizer applied. Our results indicate that the seasonal N2O emissions from hydroponic greenhouse cultivation are considerably smaller than expected from previous studies. In total, we estimated average cumulative N2O emissions of 2.3 and 1.5 kg N2O–N ha−1 yr−1 for tomato and cucumber cultures, respectively. Average EFs were 0.31% for tomato cultivation with drain re-use (closed hydroponic system), and 0.13% for cucumber cultivation without drain re-use (open hydroponic system). These values lie below the general EF for N2O from agricultural soils, noted with 1% by the intergovernmental panel on climate change (IPCC). In conclusion, considering the high yield of greenhouse cultivation, hydroponic systems provide a way of producing vegetables climate-friendly, in terms of direct GHG emissions. Further attention should be given to reducing energy inputs, e.g., by using regenerative sources or thermal discharge from industrial processes, and to increasing circularity, e.g., by using recycling fertilizers derived from waste streams. Especially in urban and peri-urban areas, the use of hydroponics is promising to increase local and sustainable food production.

Biomass and Yield Estimation of MR219 and MR220 of Paddy Varieties using Terrestrial Laser Scanning Data

Rice (Oryza Sativa L.) is the main food source in Malaysia. Thus, to fulfill the needs, continuous rice production is required. Appropriate amount of nitrogen (N) fertilizer is needed to ensure high production of rice. In this research, the effect of N to plant height, SPAD reading, biomass and yield were firstly studied. It was later followed by the estimation of biomass and yield using Terrestrial Laser Scanning (TLS) data. Different amount of N i.e. 0 kg/ha, 85 kg/ha, 170 kg/ha and 250 kg/ha were applied to MR 219 and MR 220 paddy. The 2-way ANOVA results showed that all parameters were significantly different at each N level. The highest reading was achieved at 250 kg/ha of N level; 70.46 cm (plant height), 39.13 (SPAD reading), 927.29 g/m2 (biomass) and 830.99 g/m2 (grain yield) respectively. Therefore, these parameters can be used to indicate the level of input nitrogen at the plant. Later, the plant height calculated using developed Crop Surface Model (CSM) of the Terrestrial Laser Scanning (TLS) data was used to evaluate the biomass and grain yield of paddy. Results has shown that high correlations and regression were accomplished for CSM plant height and biomass (R2 = 0.809). However, the results between CSM plant height and grain were lower (R2 = 0.582). In accordance with the outcome, biomass and yield were best estimated at 94 Day After Sowing (DAS). An estimation model for biomass and grain yield using linear equation was developed. Then a t-test was done to test the estimated and measured biomass and grain yield. The outcome showed that there was no significance difference between measured and estimated values. The values for both parameters were 1 (p≥0.05). Thus, it can be said that CSM plant height can be used to estimate biomass and grain yield.

Where can we find the fertilizer?

Bioenergy Crops One strategy for meeting our future energy needs without fossil carbon is the use of plantations of bioenergy crops such as fast-growing trees or grasses. However, such intensive growth operations are not inherently sustainable and will require fertilization to maintain productivity. Li et al. estimated that in some scenarios, the amounts of nitrogen, potassium, and phosphorous fertilizer that would be required to balance their removal by biomass is nearly half of their current use for all agricultural purposes. Fertilizer supplies are already under pressure. New strategies will be required if bioenergy crops are to be sustainable. Environ. Sci. Technol. 10.1021/acs.est.1c02238 (2021).

English

Nitrogen (N), one of the most important elements for plant growth, is needed by plants in large quantities. However, this nutrient has limited supply in the soil. Arbuscular mycorrhizal fungi (AMF) are known for their ability to form symbiotic association with plants and transfer the mineral nutrients to the host plants. To validate this hypothesis on sorghum plants, three ecotypes of this cereal (3p4, 3p9 and 4p11) were cultivated with and without AMF under low nitrogen concentration (0.5 mM NH4+). Growth parameters were determined and key enzymes responsible for nitrogen and carbon metabolisms such as glutamine synthetase (GS), glutamate dehydrogenase (GDH), phosphoenolpyruvate carboxylase (PEPC), isocitrate dehydrogenase (ICDH), malate dehydrogenase (MDH) and asparate aminotransferase (AAT) were measured. For the three sorghum ecotypes, mycorrhizal plants showed a higher plant growth compared to the control plants. The biochemical parameters revealed a significant increase in the nitrogen assimilatory enzymes; GS and GDH in the leaves and roots of mycorrhizal plants. Furthermore, mycorrhizal fungi also appear to have a significant effect on carbon assimilatory enzymes. These enzymes are known to have a cardinal role in the provision of carbon skeletons essential for the assimilation of ammonium and thus, amino acids synthesis. Our study indicates clearly that AMF can be an efficient way to optimize nitrogen uptake and/or assimilation by plants and thus improve the crop yields with lower amount of nitrogen fertilizers. © 2021 Friends Science Publishers

Agronomical traits associated with yield and yield components of winter wheat as affected by nitrogen managements.

Nitrogen fertilizer is one of the key elements to increase the yield and significance of winter wheat. The experiment was established in the split zone design and was repeated three times. The nitrogen application level is set to 4 treatments, 75, 150, 225 and 300 kg ha−1 are arranged in the main plot, and different nitrogen application ratios are arranged in the sub-plots, respectively 5:5 (50%+50%) and 6: 4 (60%) + 40%). Nitrogen fertilizer was applied before sowing, jointing stage, flowering stage and filling stage. The experimental plot is 12 m2 (3 m × 4 m). The results showed that under the conditions of 225 kg/hm2 nitrogen application and 60%+40% nitrogen application rate, the yield of Jintai 182 was the highest compared with other treatment groups. With the increase of nitrogen application rate, the number of ears, grains per ear, thousand-grain weight and grain yield all increase first and then decrease. Each factor reached the highest 225 N kg / hm2, 417.17, 30.74, 40.96 g and 6182.11 kg / hm2. Compared with 75 kg/hm2 topdressing fertilizer, 225 kg/hm2 is a more suitable nitrogen fertilizer application rate for winter wheat. Within a reasonable range of nitrogen fertilizer application, there is a significant positive correlation between nitrogen content and winter wheat yield. By studying the amount of nitrogen fertilizer and a reasonable ratio of base fertilizer to topdressing, the utilization rate of nitrogen fertilizer can be maximized and excessive application of nitrogen fertilizer can be avoided.

Encourage farmers to adopt sustainable water and nutrient management in arid agroecosystems: problems, solutions and future studies

Crop production is seriously threatened by drought. Greater availability of nitrogen and phosphorus through intercropping with grain legumes and incubation with Phosphate Solubilizing Bacteria (PSB) can alleviate the negative effect of water stress on some crops. However, row crop-grain legume intercropping and using PSB bacteria is not welcomed or widely accepted by smallholder farmers in arid regions. The problem is that N-fixation by grain legumes cannot complementarily satisfy nitrogen demand of row crop especially in low phosphorus soils of these regions under restricted irrigation. The efficiency of PSB bacteria also is very low in the alkaline soil of this region. It suggests that some amount of nitrogen fertilizer should be used in this intercropping system. Nitrogen also consumption improves the efficiency of PSB bacteria. So, consumption of some nitrogen, and incubation with PSB bacteria meet entirely the need for phosphorus fertilizer. Significant water saving by restricting irrigation without significant yield loss in row crop and grain legumes can be regarded as an advantage of this method. So, farmers can cultivate more land with the same amount of water. In such a situation, even small foliage of the grain legumes, as green manure can convince the farmers to use the row crop -grain legumes intercropping system even under restricted irrigation conditions. Futures studies must focus on a better understanding of competition and facilitation of two crops for water and nutrients. They also must pay attention to nitrogen × PSB bacteria, and Phosphorus × rhizobacteria synergic interactions on yield of and sources use efficiency of both crops. These studies may help to better water and plant nutrition management in a way that is environmentally safe and economical for farmers.

Growth Performance Can Be Increased Under High Nitrate and High Salt Stress Through Enhanced Nitrate Reductase Activity in Arabidopsis Anthocyanin Over-Producing Mutant Plants

Nitrogen is one of the most important macro-nutrients for plant growth and crop productivity. The amount of synthetic nitrogen fertilizers supplied to crops has dramatically increased, leading to a notable rise in crop yields. However, excessive nitrogen use has an enormous negative impact on ecosystems and human health through the emission of intense greenhouse gases, such as nitric oxide derived from the nitrate (NO3–) assimilation cascade. Additionally, owing to the development of extensive irrigation in agriculture, crops are known to suffer from high salt stress. The effect of excessive nitrogen fertilizer application has been studied in some crops, but the effect of high nitrate level and salt stress on plant stress tolerance has not been studied in detail. Therefore, in this study we aimed to study the effects of high concentrations of NO3– on salt stress tolerance in Arabidopsis. In addition, since anthocyanin functions as a reactive oxygen species (ROS) scavenger under abiotic stress conditions, we investigated whether enhanced anthocyanin content helps Arabidopsis to withstand higher salt stress levels under high NO3– concentrations by using pap1-D/fls1ko double mutant plants, which accumulate excessive amount of anthocyanin. We found that Col-0 plants are more sensitive to salt stress under high NO3– concentrations. Although both the pap1-D/fls1ko and fls1ko plants accumulated higher anthocyanin levels and radical scavenging activities than Col-0 plants under both normal and salt stress conditions, the fls1ko plants exhibited much better growth than the pap1-D/fls1ko plants. It appears that the enhanced NR activities and transcript levels of NIA1 and NIA2 in pap1-D/fls1ko and fls1ko plants led to an increase in the synthesis of proteins and proline, which increases osmolytes against salt stress. Our results demonstrate that optimal levels of anthocyanin accumulation can enhance growth performance of plants under high NO3– and salt stress conditions.

Evaluation of Forage Productivity and Nutritional Value of Kenaf (&lt;i&gt;Hibiscus cannabinus&lt;/i&gt; L.) at Different Fertilizer Application Amounts and Different Stages of Maturity

The purpose of this study was to assess the forage productivity and nutritive value of kenaf at different fertilizer application amounts and various stages of maturity. The experiment was conducted from May to September 2020, the amount of 80 kg of kenaf seed/ha was supplied with different types and amounts of nitrogen fertilizer and the plants were harvested at 10-day intervals from different harvesting dates (24th August and 3rd, 13th, 23rd September). According to the different fertilizer types and application amounts, the highest kenaf height was recorded in the inorganic fertilizer amounts of 200 and 250 kg N/ha and the fresh and DM yield were significantly improved in the inorganic nitrogen amount of 250 kg N/ha. The highest CP and TDN content in the leaf was achieved in the inorganic fertilizer amounts of 150 and 200 kg N/ha, respectively; and the highest TDN content in the stem was also found in the inorganic fertilizer amount of 200 kg N/ha. According to the different harvesting dates, the highest DM ratio was found in the harvesting date of 13th September, the leaf ratio increased with advanced maturity, whereas the stem ratio decreased significantly and the highest DM yield of kenaf was recorded in the harvesting dates of 13th and 23rd September. Besides, the highest CP, CF, CA, ADF, NDF and TDN content in the leaf as influenced by different harvesting dates was 15.4, 31.8, 10.2, 22.1, 34.7 and 76.5%, respectively, and the CP, CA, ADF and TDN in stem decreased significantly with advanced maturity of kenaf. In conclusion, the optimal fertilizer amounts and the appropriate harvesting dates for a high forage yield and high-quality kenaf as livestock feed were the inorganic fertilizer application amounts of 200-250 kg N/ha and from 13th and 23rd September, respectively.

INFLUÊNCIA DA ADUBAÇÃO NO TEOR DE NITRATO NAS PASTAGENS E NO LEITE AO LONGO DO ANO NO OESTE DE SANTA CATARINA

The indiscriminate use without criteria of nitrogen fertilization can lead to an accumulation of nitrate in pastures, animal poisoning and potential increase in residual content of this compound in milk. The objective of this study was to determine the residual levels of nitrate throughout the year in pastures and milk from small farms in western Santa Catarina (SC) that use high levels of nitrogen fertilization. The experiment was carried out from April/2018 to March/2019 on 10 dairy farms in the municipality of Riqueza (SC). Two annual collections of water samples and monthly collections of pastures and milk were carried out, in addition to obtaining information on the property and management of pasture fertilization through a structured questionnaire. Nitrate was also evaluated in pastures using the diphenylamine test. Temperature and rainfall data were obtained daily by a weather station. The average amount of nitrogen fertilizer used in the properties was 654 ± 176 kg/ha/year. The average nitrate content in the drinking water of the animals was 1.5 ± 1.4 mg/L, in the pasture it was 270 ± 76 mg/kg DM, while in milk it was 2.0 ± 0.3 mg/L. There was seasonal variation with an increase in nitrate content in pastures and milk in autumn, a period of the experiment in which low rainfall was observed. It was concluded that despite being dairy properties with high use of nitrogen fertilization, safe milk is produced in terms of nitrate levels, even in times of the year with adverse climatic conditions. The diphenylamine test has a good ability to discriminate the nitrate content in pastures and can be indicated as a quick test to verify the presence of high levels of nitrate in the pasture.

Effect of Ammonium Sulfate Application Levels on the Growth and Yield of IR-28 Rice

The study was conducted in JICA Tsukuba experimental rice field RE-2 from April 2018 to September 2018, to determine the effect of different levels of nitrogen fertilizer (Ammonium sulfate) application, on the growth and the yield of IR-28 rice. Four levels of nitrogen fertilizer were applied; 0kg.ha-1 (N0), 40kg.ha-1(N40), 60kg.ha-1(N60) and 80kg.ha-1(N80). For each of the four levels, part of the fertilizer was applied as basal dressing prior to transplanting, and the rest was applied as top-dressing at the panicle initiation stage. The experimental design was a Randomized Complete Block Design (RCBD) with four treatments and three replications. The plant length, the tiller number and the leaf colour were measured for growth data. The number of panicles per m2, the number of spikelets per panicle, the spikelet fertility rate, the 1000 grains weight, and the calculated yield were determined for yield components assessment. The plant length and the tiller number were significantly higher in N80 and N60 compared to N40 and N0, and N80 showed the highest values. There was no significant difference among the four nitrogen levels in terms of the number of panicles per m2 and the number of spikelets per panicle. The spikelet fertility rate and the 1000 grains weight were significantly higher in N80, N60 and N40 compared to N0, and no significant difference was observed among the three. Calculated yield values were higher in N80 (5.74 tons.ha-1) and N60 (5.38 tons.ha-1) compared to N40(4.88 tons.ha-1) and N0 (4.36 tons.ha-1), but there were no significant differences among the four treatments (5% Level of HSD). These results suggest that a high yield of rice can be achieved through the application of high amounts of nitrogen fertilizers. N60 nitrogen level can be recommended for optimum yield of IR-28. Although N80 showed higher yield and yield components, N60 is the best and the most economical nitrogen level required for optimum yield of IR-28.

Progress and Prospect of Breeding Utilization of Green Revolution Gene SD1 in Rice

Rice (Oryza sativa L.) is one of the most important cereal crops in the world. The identification of sd1 mutants in rice resulted in a semi-dwarf phenotype that was used by breeders to improve yields. Investigations of sd1 mutants initiated the “green revolution” for rice and staved off famine for many people in the 1960s. The smaller plant height conferred by sd1 allele gives the plants lodging resistance even with a high amount of nitrogen fertilizer. Guang-chang-ai-carrying sd1 was the first high-yielding rice variety that capitalized on the semi-dwarf trait, aiming to significantly improve the rice yield in China. IR8, known as the miracle rice, was also bred by using sd1. The green revolution gene sd1 in rice has been used for decades, but was not identified for a long time. The SD1 gene encodes the rice Gibberellin 20 oxidase-2 (GA20ox2). As such, the SD1 gene is instrumental in uncovering the molecular mechanisms underlying gibberellin biosynthesis There are ten different alleles of SD1. These alleles are identified by genome sequencing within several donor lines in breeding for semi-dwarf rice. Apart from breeding applications and the molecular mechanism of GA biosynthesis, the SD1 gene is also involved in the molecular regulation of other important agronomic traits, like nitrogen fertilizer utilization. The dentification of new alleles of SD1 can be obtained by mutagenesis and genome editing. These new alleles will play an important role in improving the resource diversity of semi-dwarf breeding in the future.

Bacterial Diversity and Community in Response to Long-Term Nitrogen Fertilization Gradient in Citrus Orchard Soils

Citrus orchards receive increasing amounts of nitrogen fertilizer for the purpose of optimal yields and good quality of citrus fruits. Although the effects of increased nitrogen fertilizer on citrus fruit trees have been reasonably well studied, few comparable studies have examined impacts on soil bacterial communities and diversity, even though they play critical roles in orchard ecosystem functioning. In our study, Illumina MiSeq sequencing was used to investigate bacterial community structure and diversity under 5-years long-term nitrogen fertilization gradients (N0, N1, N2, N3, N4, and N5) in citrus orchard soils. The sequencing result showed that nitrogen fertilizer addition increased bacterial diversity along the N0 to N3 gradient but decreased bacterial diversity along the N3 to N5 gradient. The increase in the nitrogen fertilizer rate altered bacterial community composition by increasing the relative abundance of Delta-proteobacteria, Nitrospirae, SBR1093, and Latescibacteria and decreasing the relative abundance of Alpha-proteobacteria. Finally, regression analysis revealed that bacterial diversity and the relative abundance of Nitrosomonadales, Rhodobiaceae, Gemmatimonas, and Variibacter exhibited a significant positive correlation with citrus yield. The study revealed that a reasonable nitrogen fertilizer rate applied to citrus orchards could improve bacterial community structure and diversity and increase citrus yield.

Early rotation biomass and nutrient accumulation of Pinus radiata forests after harvest residue management and fertiliser treatment on contrasting types of soil

The productivity of planted forests depends upon the maintenance of soil fertility and an understanding of the relationships between site fertility and stand productivity. The effects of harvest residue and forest floor management, and fertiliser additions on ecosystem biomass, carbon and nutrient accumulation were evaluated 5 years after establishment of Pinus radiata stands growing on four contrasting soil types at Woodhill, Tarawera, Kinleith, and Golden Downs forest in New Zealand. The harvest residue removal treatments were stem only harvest, whole tree harvest, and whole tree harvest combined with forest floor removal, all with and without mostly urea-nitrogen fertiliser additions (cumulative range across the four sites 400–1150 kg N ha−1). Woodhill forest biomass and nutrient stock results at age 5 years have been previously reported and were added to with new carbon and nitrogen analysis. The results showed for all sites except on recent sands at Woodhill, where soil nutrients were very low, that harvest residue and forest floor removal had limited impact on 5 year old P. radiata productivity, above ground live biomass and nutrient accumulation, and mineral soil nutrient concentrations. Across all sites the whole tree harvest combined with forest floor removal negatively impacted the 5 year old forest floor biomass and nutrient stocks, with variable impact due to whole tree only removal. The addition of large experimental amounts of mineral nitrogen fertiliser increased tree productivity across sites, which was reflected in tree biomass for all sites except Tarawera. Based on these relatively short-term findings, when P. radiata forests in New Zealand are experiencing a peak nutrient demand (highest nutrient demand amount per year), there were limited negative impacts of harvest residue and forest floor removal on forest productivity, tree biomass and nutrient accumulation, and mineral soil nutrient concentrations. The exception was for a sand dune derived soil that had very low soil nutrients resulting in a greater proportion of the forest ecosystem nutrient pool to be held within the tree and forest floor biomass, emphasising the importance of harvest residue and forest floor retention at low nutrient sites.

Nitrogen Uptake Efficiency of Olive Cultivars

Maximizing nitrogen uptake efficiency is a sustainable objective to reduce the amount of nitrogen fertilizers applied in olive orchards. Many factors affect this parameter, but nothing is known about whether there are differences among cultivars related to nitrogen uptake efficiency in the olive, and if there are interactions with soil type. To clarify these questions, two groups of experiments were conducted. In the first group, four experiments were carried out in which 20 olive cultivars were compared. In the second group, three experiments were carried out to study the interaction with the type of soil. In all experiments, mist-rooted olive cuttings were growing in 1.1 L pots containing a mixture of sand and peat (2:1 by volume). Depending on the experiment, plants were placed in a shadehouse or in growth chambers at 25/15 °C (day/night) with a 14 h photoperiod and 70% humidity. Plants received weekly applications of 100 ppm N throughout the irrigation water, alternating with one or two applications of 150 mL of tap water. Some plants of each cultivar did not receive nitrogen and served as a control for NUE calculation. A nutrient solution without nitrogen was applied every four weeks to prevent nutritional deficiencies. Results indicated that there are differences among cultivars in the efficiency of uptake nitrogen. The Spanish cultivars ‘Picual’, ‘Arbequina’ and ‘Manzanilla de Sevilla’, together with the Greek cultivar ‘Koroneiki’ and the Italian ‘Frantoio’, were the cultivars with high NUE in this work. Soil type did not affect NUE, and no interaction between soil type and cultivar was observed.

The Effect of Biofertilizer of Azola, Phosphate and Nitrogen Fertilizers on Yield and Grain Quality of Rice

A field experiment was carried out during the summer season of 2019 in one of the fields of Al-Tahiniah village - Al-Mahanawiya district which is 36 km away from the Diwaniyah governorate center, to study the effect of Azola, phosphate and nitrogen fertilizers and the interactions between them on yield components, yield and grains quality of the rice grown in water logging conditions. The experiment was arrangement as factorial experiment according to Randomized Complete Blocks Design (RCBD) at three replications. The experiment included three factors, the first factor included the application of Azolla (Azolla pinnata L.) at 20 tons ha-1 and the control treatment (without application of Azolla), while the second factor included application three levels of phosphate fertilizer (21, 42 and 84 kg P ha-1) as well as the control treatment (without application of phosphate fertilizer), whereas the third factor included application two levels of nitrogen fertilizer (92 and 184 kg N ha-1) as well as the control treatment (without application of nitrogen fertilizer). The results showed that the application of Azolla pinnata L. achieving the highest results of the number of panicles per plants, number of grains per panicle and grain yield by 30.30, 6.37 and 7.80% respectively compared with control treatment that achieved the lowest results for all traits respectively. Also, the application of phosphate fertilizer at half recommended amount (42 kg P ha-1) was significantly superior and gave the highest results of the number of panicles per plant, number of grains per panicle and grain yield with a significant increase of 35.29, 4.76 and 7.55 respectively compared with control treatment. In addition to, the application of nitrogen fertilizer at the recommended amount (184 kg N ha-1) had the highest results of the number of panicles per plant and number of grains per panicles by 48.29 and 5.75% respectively, without significant difference on the application of nitrogen fertilizer at half the recommended amount (92 kg N ha-1) which had the highest mean of the grain yield by 4.94% compared with control treatment which had the lowest results for all traits respectively. The interaction between the application of Azola and the levels of phosphate fertilizer, application of Azola and the levels of nitrogen fertilizer, application of phosphate and nitrogen fertilizers as well as the tri-interaction between three factors had significant effect in all the studied traits except the weight of 1000 grains. We can concluded that the application of Azolla pinnata L. reduced the amounts of phosphate and nitrogen fertilizer by 50% of Recommended amounts and led to improvement the yield and yield components of rice in addition to grain rice quality.

Energy Use and Econometric Evaluation of Sweet Sorghum in China

Energy productivity and consume sensitivity of sweet sorghum were investigated in comparison with maize, sunflower, and soybean at Wuyuan and Moqi County, Inner Mongolia Province, China. We got the data from 83 farmers who did grow sweet sorghum at Wuyuan and Moqi County by face-to-face survey. The sweet sorghum showed an expressively higher total energy-consume than sunflower at Wuyuan and soybean at Moqi, but less total energy-consume than maize at Moqi. Sweet sorghum had an expressively higher energy-production and net-energy than soybean, maize and sunflower. Among all the consumes, nitrogen fertilizer expended the highest portion of the total energy for almost the all crops except the diesel consume of sweet sorghum at Moqi which was a little higher than nitrogen fertilizer fraction. Compared with the conference crops, sweet sorghum showed higher diesel energy percentage at both sites (p < %) for a higher machinery level during harvesting season. The renewable energy was expending much lower than non-renewable. Same increase among all the consumes diesel will bring much more production based on Cobb-Douglas manufacture model. The sweet sorghum and conference crops displayed a growing return to scale. These means that production could be improved substantially by a modification of the nitrogen fertilizer amounts and information support systems.

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.