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1.
ABSTRACT

A pot experiment was conducted to study the influence of four nitrogen (N) fertilizer forms [Urea; calcium nitrate, Ca(NO3)2; ammonium sulfate, (NH4)2SO4; and organic N] on growth, photosynthesis, and yield of rice under two cadmium (Cd) levels (0 and 100 mg Cd kg?1 soil). Cadmium addition significantly reduced photosynthetic rate, and the reduction varied with N fertilizer form, with ammonium (NH4 +)-N and urea treated plants having more reduction. Nitrogen form had a distinct effect on SPAD value, and the effect was also dependent on Cd level and growth stage. Cadmium-stress significantly reduced flag leaf area, but for the second leaf, only the plants supplied with organic N showed the reduction. There was a significant difference in plant height among four N forms, with NH4 +- and nitrate (NO3 ?)-treated plants having the highest and lowest height, respectively. Cadmium stress caused significant reduction in grains per panicle and total plant weight, and the reduction varied with N form, with organic N treatment showing more reduction. There were significant differences among N forms in N and Cd concentrations of the plants subjected to Cd stress, with NH4 +-N treated plants having highest N and lowest Cd concentrations and NO3 ?-treated plants having lowest N and highest Cd uptake. The results showed that the inhibition of Cd stress on growth and yield formation of rice is closely related to N fertilizer form.  相似文献   

2.
In this study, the yields, nutritional qualities and nitrate (NO3) content of Chinese kale were studied with two cultivars, following partial replacement of nitrate (20%) with ammonium (NH4), urea and glycine in hydroponics. The results showed that, compared with the full nitrate treatment, ammonium replacement increased the fresh weight by 18.1% and 8.0% of ‘Zaobao’ and ‘Lvbao’ cultivars respectively, whereas urea and glycine replacements decreased the biomass significantly. Adding different nitrogen (N) forms significantly improved the contents of vitamin C, soluble sugar, free amino acid, protein, soluble phenol and flavonoids in Chinese kale. Adding the three alternative N forms also reduced nitrate content significantly, in which glycine replacement was the lowest. According to the results obtained, different forms of N replacement could be used for different purposes. Glycine replacement could be the best alternative only to improve qualities, while ammonium replacement could be the best alternative to improve both the yield and qualities.  相似文献   

3.
Abstract

The changes in availability and uptake of boron (B) by M.26 apple rootstocks as affected by applications of different forms and rates of nitrogen (N) were examined. The study was carried out in a greenhouse using soil with low contents of organic matter, clay, calcium carbonate, NH4‐oxalate soluble aluminum (Al) and iron (Fe), NH2OH·HCl extractable manganese (Mn), poor cation exchange capacity and low pH. Soil N application was in the form of urea, calcium nitrate, ammonium sulphate, or ammonium nitrate at rates of 0, 17, 34, and 51 mg N kg?1. After 1, 3, and 5 days of N application, soil B fractions were determined: B in soil solution, B specifically and non‐specifically adsorbed on soil surfaces, B occluded in Mn oxyhydroxides, and B occluded in crystalline Al and Fe oxides. The results showed that N as calcium nitrate and ammonium nitrate increased B both in soil solution and non‐specifically adsorbed on soil surface and decreased B concentration on Al and Fe oxides. This indicates that N‐NO3 inhibited B sorption on Fe and Al oxides. Maximum B desorption from Fe and Al oxides was obtained within one day after N‐NO3 was supplied. Nitrogen application as calcium nitrate and ammonium nitrate increased availability and uptake of B by plant roots. Thus, it was concluded that apple trees planted on coarse‐textured soils where risk of B deficiency is high, calcium nitrate or ammonium nitrates would be appropriately to apply to keep B more available.  相似文献   

4.
Nitrogen (N), ammonium (NH4+) and nitrate (NO3?), is one of the key determinants for plant growth. The interaction of both ions displays a significant effect on their uptake in some species. In the current study, net fluxes of NH4+ and NO3? along the roots of Picea asperata were determined using a Non-invasive Micro-test Technology (NMT). Besides, we examined the interaction of NH4+ and NO3? on the fluxes of both ions, and the plasma membrane (PM) H+-ATPases and nitrate reductase (NR) were taken into account as well. The results demonstrated that the maximal net NH4+ and NO3? influxes were detected at 13–15?mm and 8–10.5?mm from the root apex, respectively. Net NH4+ influx was significantly stimulated with the presence of NO3?, whereas NH4+ exhibited a markedly negative effect on NO3? uptake in the roots of P. asperata. Also, our results indicated that PM H+-ATPases and NR play a key role in the control of N uptake.  相似文献   

5.
Field experiments were conducted to determine the effect of nitrogen (N) fertilizer forms and doses on wheat (Triticum aestivum L.) on three soils differing in their ammonium (NH4) fixation capacity [high = 161 mg fixed NH4-N kg?1 soil, medium = 31.5 mg fixed NH4-N kg?1 soil and no = nearly no fixed NH4-N kg?1 soil]. On high NH4+ fixing soil, 80 kg N ha?1 Urea+ ammonium nitrate [NH4NO3] or 240 kg N ha?1 ammonium sulfate [(NH4)2SO4]+(NH4)2SO4, was required to obtain the maximum yield. Urea + NH4NO3 generally showed the highest significance in respect to the agronomic efficiency of N fertilizers. In the non NH4+ fixing soil, 80 kg N ha?1 urea+NH4NO3 was enough to obtain high grain yield. The agronomic efficiency of N fertilizers was generally higher in the non NH4+ fixing soil than in the others. Grain protein was highly affected by NH4+ fixation capacities and N doses. Harvest index was affected by the NH4+ fixation capacity at the 1% significance level.  相似文献   

6.
ABSTRACT

Black walnut (Juglans nigra L.) half-sib 1+0 seedlings were exponentially fertilized with ammonium (NH4 +) as ammonium sulfate [(NH4)2SO4], nitrate (NO3 ?) as sodium nitrate (NaNO3), or a mixed nitrogen (N) source as ammonium nitrate (NH4NO3) at the rate of 0, 800, or 1600 mg N plant?1 and grown for three months. One month following the final fertilization, N concentration, growth, and photosynthetic characteristics were assessed. Compared with unfertilized seedlings, N addition increased plant component N content, chlorophyll content, and photosynthetic gas exchange. Net photosynthesis ranged from 2.45 to 4.84 μmol m?2 s?1 for lower leaves but varied from 5.95 to 9.06 μmol m?2 s?1 for upper leaves. Plants responded more favorably to NH4NO3 than sole NH4 + or NO3 ? fertilizers. These results suggest that N fertilization can be used to promote net photosynthesis as well as increase N storage in black walnut seedlings. The NH4NO3 appears to be the preferred N source to promote black walnut growth and physiology.  相似文献   

7.
Co-composting of chicken slurry and rice straw with clinoptilolite zeolite and urea as additives was conducted to determine the characteristics of a compost and their effects on controlling ammonium (NH4+) and nitrate (NO3?) losses from urea. Quality of the compost was assessed based on temperature, moisture content, ash, pH, electrical conductivity, carbon/nitrogen (C/N) ratio, NH4+, NO3?, macronutrients, heavy metals, humic acid, microbial population, germination index, and phytotoxicity test. Moisture content and C/N ratio of the compost were 43.83% and 15, respectively. Total N, humic acid, ash, NH4+, NO3?, phosphorus (P), calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na) increased after co-composting rice straw and chicken slurry. Copper, iron (Fe), manganese (Mn), zinc (Zn), and microbial biomass of the compost were low. The germination rate of Zea mays on distilled water and Spinacia oleracea growth on peat-based growing medium (PBGM) and compost were not significantly different. Urea amended with compost reduced N loss by retaining NH4+ and NO3? in the soil.  相似文献   

8.
Ammonium and nitrate are the major forms of nitrogen (N) present in tropical soils. An experiment was conducted to assess the influence of nitrate and ammonium forms (NO3?, NH4+, and mix of NO3? + NH4+), and levels (1.5–12.0 mM) of N on the growth and nutrition of cacao (Theobroma cacao L). Growth parameters were significantly influenced by N forms, and nitrogen supplied as NH4+ proved better for the growth of cacao compared with NO3? form and mixtures of these two forms. Irrespective of the forms of N, levels of N had no significant effect on plant growth parameters. Nutrient efficiency ratios (NERs) (shoot dry matter produced per unit of nutrient uptake) for macronutrients were sulfur>phosphorus>calcium>magnesium>nitrogen>potassium (S>P>Ca>Mg>N>K) and for micronutrients NERs were in the order of copper>boron>zinc>iron>manganese (Cu>B>Zn>Fe>Mn).  相似文献   

9.
10.
Pot experiments were conducted on three soils differing in their ammonium (NH4 +) fixation capacity [high = 161 mg NH4-nitrogen (N) kg?1 soil; medium = 31.5 mg NH4-N kg?1 soil; and no = no NH4-N was additionally fixed], and the effect of N fertilizer forms and doses on wheat (Triticum aestivum L.) was investigated. Grain yields responded to almost all forms of N fertilizer with 80, 160, and 240 kg N ha?1 in the high, medium, and no NH4 + fixing soil process, respectively. Agronomic efficiency of applied N fertilizers was significantly greater in the no NH4 + fixing soil. Thousand grain weights (TGW) of wheat grown on the high and medium NH4 + fixing soil decreased with increasing N. Grain protein increased with increasing NH4 + fixation capacity. Nitrogen doses and the forms of N fertilizers affected grain protein at a significance level. The combination of urea + ammonium nitrate (NH4NO3) was most effective in increasing grain protein content.  相似文献   

11.
It is well known that plants are capable of taking up intact amino acids. However, how the nitrogen (N) rates and N forms affect amino acid uptake and amino acid nutritional contribution for plant are still uncertain. Effects of the different proportions of nitrate (NO3?), ammonium (NH4+) and 15N-labeled glycine on pakchoi seedlings glycine uptake were investigated for 21 days hydroponics under the aseptic media. Our results showed that plant biomass and glycine uptake was positively related to glycine rate. NO3? and NH4+, the two antagonistic N forms, both significantly inhibited plant glycine uptake. Their interactions with glycine were also negatively related to glycine uptake and glycine nutritional contribution. Glycine nutritional contribution in the treatments with high glycine rate (13.4%–35.8%) was significantly higher than that with low glycine rate (2.2%–13.2%). The high nutritional contribution indicated amino acids can serve as an important N source for plant growth under the high organic and low inorganic N input ecosystem.  相似文献   

12.
Abstract

While it is known that superoptimal concentrations of the nitrate (NO3 ?) ion in solution culture do not increase NO3 ? uptake or dry matter accumulation, the same is not known for the ammonium (NH4 +) ion. An experiment was conducted utilizing flowing solution culture with pH control to investigate the influence of superoptimal NH4 + concentrations on dry matter, nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) accumulation by nonnodulated soybean plants. Increasing the NH4 + concentration in solution from 1 to 10 mM did not affect dry matter or N accumulation. Accumulations of K, Ca, and Mg were slightly decreased with the increased NH4 + concentration. The NH4 + uptake system, which is saturated at less than 1 mM NH4 +, is able to regulate uptake of NH4 + at concentrations as high as 10 mM.  相似文献   

13.
Abstract

Root‐tip, 1‐cm of Sorghum bicolor (L.) Moench cv SC283, SC574, GP‐10, and Funk G522DR were exposed to calcium (45Ca2+) at pH 5.5 for 2‐hr in the presence of nitrate‐nitrogen (NO3?‐N) or ammonium‐nitrogen (NH4+‐N). Nitrate (0.1 mM) induced significantly increased 45Ca uptake in Funk G522DR, SC283, and GP‐10 while 0.01 mM NO3 ?‐N induced significantly increased 45Ca'uptake in SC574, but 45Ca absorption was significantly decreased at 1 mM NO3—N. In the presence of the NH4+ ion, 45Ca uptake was increased up to 8X that of the NH4 +‐N untreated roots. When ammonium chloride (NH4CI) was used, the Cl? tended to induce an increased 45Ca uptake. Cultivar variation was present.  相似文献   

14.
Many bryophytes rely to a large extent on atmospheric deposition for their nutrient uptake.However, increasing levels of atmospheric ammonium NH 4 + and nitrate NO 3 - attract concern as to the possible harmful effects onbryophytes from these two nutrient sources. Changes in nitrate reductase (NR) activities, cation(Ca, K and Mg), total nitrogen (N) and organic acid concentrations were investigated for themosses, Racomitrium lanuginosum, Rytidiadelphus loreus and Philonotis fontana, in response to asingle field misting with 3 mol m-3 NH 4 + and NO 3 - . Increases of 20% were recordedfor tissue N content, 48 hr after misting with N containing solutions. When labelled NH 4 + or NO 3 - were applied to R. Lanuginosum at 1, 3 and 6mol m-3 concentrations, partitioning ofincorporated 15N between different tissueregions occured, with the highest N uptake in the upper stem and leaves. High concentrations ofapplied N resulted in reduced efficiency of N uptake. NH 4 + applications caused declines in NR activities, organic acidsand cations, whereas, NO 3 - treatments causedthe reverse response. Changes in cation contents, organic acids and NR activity reflect short-termregulation of N metabolism in the presence of defined N sources, as well as potential mechanismsof regulating cell pH homoeostasis. The consistency of physiological responses, especially NRactivities, over short-term pollution episodes, provides evidence for their use as indicators of both NH 4 + and NO 3 - pollution.  相似文献   

15.
ABSTRACT

Understanding how plants use of various nitrogen (N) sources is important for improving plant N use efficiency in organic farming systems. This study investigated the effects of farming management practices (organic and conventional) on pakchoi short-term uptake of glycine (Gly), nitrate (NO3 ?) and ammonium (NH4 +) under two N level conditions. Results showed that plant N uptake rates and N contributions from the three N forms in the low N (0.15 μg N g?1 dry soil) treatment did not significantly differ between the organic and conventional soils, except the significantly greater Gly contribution in organic soil at 24 h after tracer addition. Under high N (15 μg N g?1 dry soil) conditions, the N uptake rates, uptake efficiencies, and N contributions of Gly and NH4 +-N were significantly greater in pakchoi cultivated in the organic soil compared to conventional soil, whereas the N uptake rates and N contributions from NO3 -N decreased in pakchoi cultivated in the organic soil. The greater Gly-N uptake in plants grown in high-N treated organic soil may be related to the greater gross N transformation, Gly turnover rate and the increased expression of an amino acid transporter gene BcLHT1. Intact Gly contributed at most 6% to Gly-derived N at 24 h after tracer additions, which accounting for about 1.24% of the total N uptake in organic soil. Our study suggested that Gly-N and other organic source N might serve as a more important compensatory N source for plants in organic farming.  相似文献   

16.
ABSTRACT

The interactions between salinity and different nitrogen (N) sources nitrate (NO3 ?), ammonium (NH4 +), and NO3 ? + NH4 + were investigated on Indian mustard (Brassica juncea cv. RH30). Treatments were added to observe the combined effect of two salinity levels (8 and 12 ds m? 1) and three nitrogen sources (NO3 ?, NH4 +, and NO3 ? + NH4 +) on different growth parameters and mineral composition in different plant parts, i.e., leaves, stem, and root. Salinity has been known to affect the uptake and assimilation of various essential nutrients required for normal growth and development. Different growth parameters, i.e., leaf area, dry weight of different plant parts, absolute growth rate (AGR), relative growth rate (RGR), and net assimilation rate (NAR) declined markedly by salinity at pre-flowering and flowering stages. All growth indices were less sensitive to salinity (12 d s m? 1) with the nitrate form of nitrogen. It is pertinent mention that a high dose (120 kg ha? 1) of nitrogen in ammonium form NH4 +, acted synergistically with salinity in inhibiting growth. Plants fed with combined nitrogen (NO3 ? + NH4 +) had an edge over individual forms in ameliorating the adverse effects of salinity on growth and yield. Under salt stress, different nutrient elements such as N, phosphorus (P), potassium (K+), and magnesium (Mg2 +) were decreased in different plant parts (leaves, stem, and root). The maximum and minimum reduction was observed with ammoniacal and combined form of nitrogen, respectively, while the reverse was true of calcium (Ca2 +), sodium (Na+), chloride (Cl?), and sulfate (SO4 2?) at harvest. Nitrogen application (120 Kg ha? 1) in combined form had been found to maintain highest concentrations of N, P, Mg2 +, and Ca2 + along with reduced concentrations of Na+, Cl?, and SO4 2 ?. However, reverse was true with ammoniacal form of nitrogen.  相似文献   

17.
几种蔬菜对硝态氮、铵态氮的相对吸收能力   总被引:25,自引:1,他引:24  
采用溶液培养方法探讨了莴笋、菠菜、小白菜和大青菜 4种蔬菜作物对硝、铵态氮的相对吸收能力以及这两种氮源对它们生长发育的影响。结果表明 ,单独供给NO3-N ,4种作物均生长发育良好 ;供给NO3--N +NH4+-N(NO3-∶NH4+=1∶1) ,生长量均有所下降 ,而单独供给NH4+-N时 ,生长量则大幅度下降。莴笋单独供给NO3--N时 ,其吸氮量显著高于供给NO3--N +NH4+-N的处理 ,大青菜、菠菜供给NO3--N +NH4+-N与单独供给NO3--N相比吸氮量大体相当 ;小白菜同时供应NO3--N +NH4+N时吸氮量最高 ,供给NO3--N时次之 ,供给NH4+-N时显著降低。供给NH4+-N时 4种作物吸氮量均比其它氮源显著降低。 4种作物对NO3--N与NH4+-N的吸收具有明显的偏向性。供给等氮量铵、硝态氮 (NO3--N +NH4+-N处理 )时 ,菠菜、小白菜吸收的NO3-N显著多于NH4+-N ,表现出喜硝性 ,莴笋则与此相反 ,表现出喜铵性 ;而大青菜对两种形态氮素的吸收量相差不多 ,表现出兼性吸收的特点。但上述偏向性具有阶段特点 ,即喜硝作物可能在某一阶段表现出喜铵性状  相似文献   

18.
Controlled-release urea (CRU) and its placement method in rice production were investigated during 2007 and 2008 seasons. Controlled-release urea was applied at 62.5, 125, and 187.5 kg nitrogen (N) ha?1, and the urea was 187.5 kg N ha?1. All the CRU treatments were applied to the nursery beds once, and they were brought into the paddy field during transplanting, while the urea treatment was split into three applications from the plowing to the harvest. The results showed that rice seedlings with CRUs germinated and grow well and there was no salt damage at the nursery stage. The CRU treatment with 125 kg N ha?1 had 33% less N than urea treatment (187.50 kg N ha?1), but it produced significantly higher grain and straw yields, higher total N uptake and total apparent N uptake efficiency. In addition, all the CRU treatments effectively decreased floodwater ammonium (NH4 +)-N and nitrate (NO3 ?)-N concentrations, pH, and N runoff.  相似文献   

19.

Purpose

A laboratory incubation under constant temperature and humidity was conducted to estimate the impacts of nitrogen (N) fertilizers on the acidification of two acid soils (Plinthudult and Paleudalfs) in south China.

Materials and methods

The experiment had three treatments, i.e., control (CK), addition of urea (U), and addition of ammonium sulfate (AS). We measured soil pH, nitrate (NO3 ?), ammonium (NH4 +), exchangeable hydrogen ion (H+), and aluminum ion (Al3+) concentrations at various intervals during the 90 days of incubation. Soil buffering capacity (pHBC) was also measured at the end of the experiment.

Results and discussion

The application of N fertilizers resulted in soil acidification. The U treatment caused greater acidification of the Plinthudult soil than the AS treatment, while there were no differences between U and AS treatments on the acidification of the Paleudalfs. At the end of the trial, the pHBC of Plinthudult in AS treatment was greater than that in CK and U treatments, which may be due to the buffering system of NH4 + and NH4OH. However, the pHBC of Paleudalfs was unchanged between treatments. The dynamics of exchangeable H+ and Al3+ corresponded to that of soil pH. Correlation analysis showed that both soil exchangeable H+ and soil exchangeable Al3+ were significantly related to soil pH.

Conclusions

Application of urea and ammonium sulfate caused acidification in both soils and increased soil exchangeable Al3+ and H+ concentrations in the Paleudalfs. The application of urea increased exchangeable Al3+, and ammonium sulfate increased pHBC in the Plinthudult.  相似文献   

20.
The aim of this study was to evaluate the sustainability of an agro-industry sludge as a nitrogen (N) fertilizer in perennial crops by assessing its dynamics of release of: 1) N as ammonium (NH4+)- and nitrate (NO3?)-N, and 2) carbon as soil respiration. In incubation assay, application of agro-industry sludge promoted the maximum NH4+-N concentration (50 mg kg?1) 2 h after application, then it decreased with time until day 26. NO3?-N increased, reaching the maximum between day 60 and day 100, according to a second degree function. Agro-industry sludge showed a slower release of NO3?-N compared with urea. Soil basal respiration and cumulative amount of carbon dioxide were higher in sludge from day 71 on. In field, soil NO3?-N increased after fertilization treatments and was higher in Calcari Stagnic Cambisols soil. Sludge showed a potential lower environment impact in terms of mineral N release, than urea.  相似文献   

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