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1.
ABSTRACT

This experiment was conducted in a greenhouse in Vinces Los Rios (Ecuador). The aim of this work is to evaluate the relationship between different parameters and the nutrient demand of a greenhouse soilless cucumber production system in a tropical climate as well as to propose an empirical model for the design of the nutrient supply to the system. Considering the results obtained in this experiment, there was a high correlation between nutrient demands of the system with nutrient supplies and water uptake but not with leaf area index. With respect to the models, nutrient supplies and leaf area index were the most significant variables for nitrate (NO3?), chloride (Cl?) and manganese (Mn). For calcium (Ca2+), magnesium (Mg2+) and zinc (Zn), nutrients supply was the most significant variable and for the rest of nutrients [phosphates (H2PO4?), sulfates (SO42)?, potassium (K+), sodium (Na+) and iron (Fe)], the three variables assessed were significant.  相似文献   

2.
The aim of this trial was to study the spatio-temporal variability in solution nutrient concentration under intensive greenhouse tomato production, to determine the number of suction-cups needed to obtain a representative sample and the influence by the position in the greenhouses. Twenty sampling points were selected within the greenhouse with one suction-cup per sampling point. One soil solution were sampled per point at weekly intervals to analyze for pH, electrical conductivity, chloride, nitrate, phosphate, sulfate, sodium, potassium, calcium, and magnesium (EC, Cl?, NO3?, H2PO4?, SO42—, Na+, K+, Ca2+, and Mg2+) concentrations. The pH, Cl?, H2PO4?, and SO42? concentrations showed no spatio-temporal variation but EC, NO3?, and K+ showed temporal variation. The spatial variability in EC, K+, Na+, Mg2+, and Ca2+ can be influenced by microclimate and topography. The numbers of suction cups required for a representative sample ranged from 1 to 10 depending on nutrient.  相似文献   

3.
The phytotoxicity of salts in composted sewage sludge (CSS) was evaluated. Concentrations of sodium (Na+), chloride (Cl?1), calcium (Ca2+), and magnesium (Mg2+) were present at levels that would induce salt stress in plants. Nutrient imbalances were also found that would adversely affect the use of CSS as a growth medium. To further understand the phytotoxic nature of these salts, sodium chloride (NaCl), calcium nitrate [Ca(NO3)2] and magnesium nitrate [Mg(NO3)2] solutions were used to simulate the composition of salts found in CSS in an investigation of radish (Raphanus sativus L.) seed germination. High concentrations of Ca2+ (92.1 mmol.L?1) and Mg2+ (27.4 mmol.L?1) inhibited seed germination to an equal extent as did Na+ (40.6 mmol.L?1). The lower concentration of Ca2+ (10 mmol.L?1), however, significantly relieved the stress caused by NaCl. These results indicated that the composition and total amount of Na+, Cl?1, Ca2+, and Mg2+ in CSS should be carefully monitored before it is used as a soil amendment or growth medium.  相似文献   

4.
Abstract

Leaching of nutrients and major ions from a tile-drained arable field was evaluated over a 25-year period (1980–2005). The soil, classified as a Gleyic Cambisol, received moderate applications of fertilizers. During later years the soil was more frequently under ley, and since 2002, an area of ravine (29% of the total field) has been managed as a permanent fallow with annual cutting without removing the grass material. A decrease in the concentration of nitrate nitrogen (NO3?N) in the drainwater was estimated in 1980–2005, based on non-parametric tests on concentrations flow-normalized with a robust fitting curve procedure. The average concentration of soluble reactive phosphorus after pre-filtration (RPf) of 0.030 mg l?l corresponded to a calculated degree of phosphorus saturation (DPS) of 6% in acid extract of ammonium lactate from the topsoil. Between 1995 and 2005, concentrations of suspended solids (SS), RP and total organic carbon (TOC) decreased significantly in the drainage water from the entire field. Throughout the entire period, there was a negative net accumulation of the major ions to the soil. The order of decrease in relative terms was calcium (Ca2+)>magnesium (Mg2+)>sulphate (SO4 2?)>chloride (Cl?)>potassium (K+). In addition, the soil phosphorus (P) balance was negative. A significant reduction in ion concentrations in the drainwater, including sodium (Na+) and hydrogen carbonate HCO3 ?, was estimated. The order of reduction in relative terms was: SO4 2?>Mg2+>Ca2+>HCO3 ?>Cl?>NO3 ?>Na+>HPO4. Altogether these trends were equal to approximately 0.1 mmolc l?1. yr?1 of positively and negatively charged ions. Based on measured concentrations, decreasing trends in SO4 2? and Ca2+ were also observed in the shallow groundwater (3.6 m below the soil surface), while K+, Na+ and HCO3 ? tended to increase. Trends of cations in deeper groundwater (5.8 m below the soil surface) were in some cases the opposite of the trends in the drainwater.  相似文献   

5.
This study was carried out to evaluate acid depositions and to understand their effect. Wet precipitation has been collected at twenty-four sites in Korea for one year of 1999. The ion concentrations such as H+, Na+, K+, Mg2+, NH4 +, Ca2+, Cl?, NO3 ? and SO4 2? were chemically analyzed and determined. Precipitation had wide range of pH(3.5～8.5), and volume-weighted average was 5.2. The contribution amounts of Cl?, SO4 2? and NO3 ? in anion were shown to be 54%, 32%, and 14%, respectively and those of Na+ and NH4 + in cation were 32% and 25%. The ratios of Cl? and Mg2+ to Na+ in precipitation were similar to those of seawater, which imply that great amount of Cl? and Mg2+ in precipitation could be originated from seawater. The concentration of H+ is little related with SO4 2?, NO3 ? and Cl? ions, whereas nss?SO4 2? and NO3 ? are highly correlated with NH4 +, which could suggest that great amount of SO4 2? and NO3 ? exist in the form of ammonium associated salt. The annual wet deposition amounts (g m?2year?1) of SO4 2?, NO3 ?, Cl?, H+, NH4 +, Na+, K+, Ca2+ and Mg2+ were estimated as 0.88～4.89, 0.49～4.37, 0.30～9.80, 0.001～0.031, 0.06～2.15, 0.27～4.27, 0.10～3.81, 0.23～1.59 and 0.03～0.63.  相似文献   

6.
Hydroponic production of rocket as a salad vegetable has become increasingly important in recent years. Rocket is known to be a high nitrate (NO3–)-accumulating vegetable, which can be grown throughout the year. In the present study, rocket was grown in a floating hydroponic system at three levels of nitrogen (N) and sodium chloride (NaCl). The highest yield was obtained at 14 mM N, whereas the yield was lower at 20 mM and 40 Mm NaCl. Leaf elongation was more sensitive to salinity than leaf differentiation. Adding NaCl to the nutrient solution increased the relative chlorophyll content. Na+ and Cl– concentrations increased as salinity increased. NO3? levels in fresh biomass increased with increased amounts of NO3? in the nutrient solution, and plants at 18 mM N were able to maintain a higher NO3? : Cl? ratio than those at 10 mM N.  相似文献   

7.
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   

8.
The aim of this trial was to study the variability of anions and cations concentrations in the different petiole samples: young leaves (YL), mature leaves (ML) and aged leaves (AL). The experimental design consisted of four blocks and four plants per block being each plant one replication. In each plant, petiole samples were collected at 135 days after transplanting (DAT) to determine chloride, nitrate-nitrogen, phosphate-phosphorus, sulfate-sulfur, sodium, potassium, calcium, and magnesium (Cl?, NO3–N, H2PO4–P, SO42–S, Na+, K+, Ca2+ and Mg2+) concentrations. Our results showed that the selection of sample petiole in the tomato crop did not modify the Ca2+, Cl?, SO42–S and Na+ concentrations, while NO3–N, K+, Mg2+ and H2PO4–P concentrations showed a great variability due to the selection of the sample petiole, therefore it is necessary to be careful with the sample selection.  相似文献   

9.
The salinity tolerance of nine grape genotypes was studied. Salinity was applied as nutrient solutions containing 0, 25, 50, and 100 mM sodium chloride (NaCl) for two weeks. Growth was significantly reduced by salinity, whereas chloride (Cl?) and sodium (Na+) contents increased. Sodium ion accumulation exceeded that of Cl? in all treatments. Shirazi and H6 had higher and lower Cl? concentrations in their lamina than others. There were significant positive correlations (P < 0.01) between Cl? and Na+ and negative correlation between Na+ and potassium (K+) in roots and laminas of all genotypes. Soluble sugars, proline, and glycine betaine contents increased in laminas of all of the genotypes with moderate salinity. There were positive correlations (P < 0.01) between lamina and root Na+ and Cl? contents and compatible solutes in all genotypes. Overall results revealed that unlike Shirazi with higher Na+ and Cl? accumulation in shoot, H6 showed a higher capacity to restrict Na+ and Cl? transport to shoot.  相似文献   

10.
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11.
A greenhouse experiment was conducted to investigate the impact of water and salt stress in Quinoa plants (Chenopodium quinoa Willd.). Irrigation treatments using saline solutions of 0 (control), 50(T1), 200(T2), 400(T3), 600(T4), and 800(T5) mM sodium chloride (NaCl) were adopted. The results indicated that quinoa plants can tolerate water stress (50%FC) when irrigated with moderately saline water (T1 and T2, respectively). Salinity stress increases quinoa drought tolerance in terms of biomass production. Neither osmotic stress nor ions deficiency/toxicity seems to be determinant under T1 and 100%FC. Salinity induced a significant increase of sodium (Na+) and chloride (Cl?), while reduced magnesium (Mg2+) and calcium (Ca2+) in stems, leaves, seed’s coating, and seeds. The potassium (K+)/Na+ ratio never fell below 1 with T1; yet, fell to 0.78 and 0.89 with T2 for 100% and 50%FC, respectively. The seed coat limited the passage of possibly toxic concentrations of Na+ and Cl? to seed interior, as high Na+ and Cl? was found in the seed coat.  相似文献   

12.
In order to study the effects of salinity and water stress on growth and macronutrients concentration of pomegranate plant leaves, a factorial experiment was conducted based on completely randomized design with 0, 30, and 60 mM of salinity levels of sodium chloride and calcium chloride (1:1) and three irrigation intervals (2, 4, and 6 days) with 3 replications on ‘Rabab’ and ‘Shishegap’ cultivars of pomegranate. The results of the shoot and root analysis indicated that the salinity and drought affected the concentration and distribution of sodium (Na+), potassium (K+), chloride (Cl?), calcium (Ca2+), magnesium (Mg2+), and phosphorus (P+) in pomegranate leaves. Mineral concentrations of sodium (Na+), chloride (Cl-), potassium (K+), in shoots and roots were increased with increasing salinity. Drought treatments increased the concentration of Cl?, Na+, and Mg2+ in the shoot. Both cultivars showed significant differences in the concentrations of elements, however the most accumulation of Na+ and Cl? was observed in ‘Rabab,’ while the ‘Shishegap’ cultivar had the most absorption of K+. ‘Shishegap’ cultivar showed higher tolerance to salinity than ‘Rabab’ through maintaining the vegetative growth and lower chloride transport to the shoot, and improvement of potassium transport to shoot.  相似文献   

13.
The reduction in tiller number is a major reason for a decrease in grain yield of wheat. Thus, we hypothesize that the limiting growth of tillering of wheat plant under saline conditions may be due to a different distribution of ions among tillers, which may be tested by tiller removal. Two contrasting spring wheat (Triticum aestivum L.) genotypes were subjected to five levels of detillering treatments under saline or non-saline conditions grown in a greenhouse. Sodium (Na+), potassium (K+), calcium (Ca2+), chloride (Cl?), and nitrate (NO3 ?) concentrations in the top leaves of tillers were determined at plant maturity. Regardless of genotypes, the moderate salinity significantly increased the Na+ and Cl? concentrations in the top leaves and the decreased NO3 ? in the mainstem, subtillers and whole plant. Potassium and Ca2+ concentrations in leaves were not affected or slightly increased by salinity. Under moderate salinity, Na+ and/or Ca2+ concentrations in mainstem, subtillers and the whole plant were increased with a decrease in tiller removal for both genotypes, while there was almost no effect of tiller removal on Cl? and NO3 ? concentration. The tiller removal increased the tolerance of wheat to tissue Na+ content, especially for the salt sensitive genotype. Thus, the salt-specific effects in wheat plant could be alleviated by fewer tillers per plant through the removal for the salt-sensitive genotype. However, our study did not show the competition for the mineral nutrients among tillers under saline conditions. Thus, we speculate that there is a competition for photoassimilates among the tillers under saline conditions, especially for the salt sensitive genotype, which needs to be investigated further.  相似文献   

14.
This study reports the evaluation of chemical composition of a Black Vistula and White Vistula streams’ waters taking into consideration both geological conditions of the stream’s catchment area and different water’ level related to seasonal variations in particular catchment ecosystem (high stage: beginning of the vegetation period; medium stage: vegetation period; low stage: final time of vegetation period). The complex data matrix (744 observations), obtained by the determination of major inorganic analytes (Cl?, NO3 ?, SO4 2?, NH4 +, Na+, K+, Ca2+, Mg2+) in water samples by ion chromatography was treated by linear discriminant analysis and non-parametrical testing. In case of both streams obtained results indicate presence of two discriminant functions (DFs). The data variance explained by DFs is as follows: Black Vistula stream—first DF: 93.5%, second DF: 6.5%; White Vistula stream—first DF: 66.3%, second DF: 33.7%. In case of Black Vistula stream first DF allows distinction of medium, high and low waterstage related samples while second DF between high/low and medium water stage related samples. In case of White Vistula stream first DF allowed to distinguish between medium/high and low water stage related samples while second DF between medium and high water level samples. In case of both streams, the most informative DFs were related to geological conditions of investigated catchments (contents of Cl?, Na+, K+, Mg2+, Ca2+, SO4 2?), while the second to nutrient biocycle (mainly NH4 + and NO3 ?) related to slope’s exposition and inclination.  相似文献   

15.
Chemical and Statistical Analysis of Precipitation in Singapore   总被引：1，自引：0，他引：1  
The results of chemical analyses of precipitation samples collected in Singapore between August 1997 and July 1998 are presented. Major inorganic and organic ions were determined in 169 rain samples collected using an automated wet-only sampler. The daily sample pH values ranged from 3.49 to 6.54 with a volume-weighted mean of 4.50, and about 88% of the samples had pH values less than 5.0 Nss-SO4 2? accounted for about 53 % of the sum of anions in rain, whereas chloride, nitrate, formate, and acetate accounted for the remainder. Rain chemistry data were analyzed using principal component analysis to find possible sources of the measured chemical species. Three components that accounted for 83.5% of the total variance were extracted: sea-spray (Na+, Cl? and and Mg2+) and soil particles (Ca2+ and K+), acid factor (nss-SO4 2?, NO3 ?, NH4 +, and H+), and biomass burning (HCOO? and CH3COOO?).  相似文献   

16.
Osmotic and specific ion effects are the most frequently mentioned mechanisms by which saline substance reduces plant growth. However, the relative importance of osmotic and specific ion effect on plant growth seems to vary depending on the salt tolerance of the plant under study. Tall wheatgrass (TW), perennial ryegrass (PR), African millet (AM) and Rhodesgrass (Rh) were grown in nutrient solution with sodium chloride (NaCl), sodium sulfate (Na2SO4), potassium chloride (KCl), and potassium sulfate (K2SO4) salinity up to electrical conductivity (EC) 27 dS m?1. Growth of all plant species decreased significantly at high level (EC 27 dS m?1) of NaCl and Na2SO4 salts. However, the growth of none of the plant species was affected significantly by KCl and K2SO4 at any level. Even leaf and shoot fresh weights were enhanced by K2SO4 in all plant species, except AM. Chlorine (Cl) was taken up in similar quantities from KCl and NaCl solutions and the content of the respective cations was similar to each other. Further sensitivity to sulfate and chloride was equal when sodium concentrations in shoots were equal, regardless of the anion composition of the media. The sodium (Na) concentration of the leaves of the plant species increased with increased NaCl and Na2SO4 levels in the nutrient solutions. The leaf Na concentration of TW was lower than that of the other plant species. However, the root Na concentration of TW was higher than that of the other plant species. Increased NaCl and Na2SO4 concentrations had a marked effect on leaf water potential of all plant species, and the TW showed higher leaf water potential at all levels of salts. Tall wheatgrass adjusted osmotically by accumulating electrolytes from the nutrient solution and by accumulation of glycinebetaine. Sodium was generally found more injurious than Chloride in all the four forage species. Salt tolerance could be ascribed as greater exclusion of Na ion.  相似文献   

17.
The Nandong Underground River System (NURS) is located in Southeast Yunnan Province, China. Groundwater in NURS plays a critical role in socio-economical development of the region. However, with the rapid increase of population in recent years, groundwater quality has degraded greatly. In this study, the analysis of 36 groundwater samples collected from springs in both rain and dry seasons shows significant spatial disparities and slight seasonal variations of major element concentrations in the groundwater. In addition, results from factor analysis indicate that NO 3 ? , Cl?, SO 4 2? , Na+, K+, and EC in the groundwater are mainly from the sources related to human activities while Ca2+, Mg2+, HCO 3 ? , and pH are primarily controlled by water–rock interactions in karst system with Ca2+ and HCO 3 ? somewhat from anthropogenic inputs. With the increased anthropogenic contaminations, the groundwater chemistry changes widely from Ca-HCO3 or Ca (Mg)-HCO3 type to Ca-Cl (+NO3) or Ca (Mg)-Cl (+NO3), and Ca-Cl (+NO3+SO4) or Ca (Mg)-Cl (+NO3+SO4) type. Concentrations of NO 3 ? , Cl?, SO 4 2? , Na+, and K+ generally show an indistinct grouping with respect to land use types, with very high concentrations observed in the groundwater from residential and agricultural areas. This suggests that those ions are mainly derived from sewage effluents and fertilizers. No specific land use control on the Mg2+ ion distribution is observed, suggesting Mg2+ is originated from natural dissolution of carbonate rocks. The distribution of Ca2+ and HCO 3 ? does not show any distinct land use control either, except for the samples from residential zones, suggesting the Ca2+ and HCO 3 - mainly come from both natural dissolution of carbonate rocks and sewage effluents.  相似文献   

18.
This trial was carried out to study the evolution of the nutrient parameters of the nutrient solution applied to tomato plants (Lycopersicum sculentum Mill. Forteza) cultivated in Mediterranean greenhouse conditions under different fertigation management models. The dynamic model is based on soil water content, which was measured by tensiometers, and on soil solutions obtained with suction cups (porous ceramic cup water samplers). The local traditional method consists of following technical recommendations, and the classical model requires the estimation of Crop Factor (Kc) and knowing the nutrient extraction. Nutrient solution and water applied are functions of the fertigation management criteria. The water used for fertigation was classified as C4-S3 according to the Riverside classification system. The cultivation period lasted from 15 August to 20 April. The nutrient parameters studied in nutrient and soil solution were pH, electrical conductivity (EC), nitrate (NO3 ?), phosphate (H2PO4 ?), potassium (K+), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), and chloride (Cl?). The pH shows similar trends under the different treatments. Electrical conductivity is in the range of 2.8–4.5 dS m?1. Chloride, sodium, magnesium, and sulfate are exclusively modified by the salt concentration in the irrigation water, so it can be assumed that the three treatments vary equally. Nitrate, potassium, phosphate, and calcium are modified depending on each fertigation management method. Soil solution is modified by the nutrient solution applied. Dynamic management allows low nutrient concentration in the nutrient solution to be maintained and keeps soil nutrient concentration low, reducing fertilizer losses and therefore aquifer contamination.  相似文献   

19.
Fog water and precipitation were collected and analyzed to study fog and precipitation chemistry. The research was carried out through one year from April 1997 to March 1998 at Mt. Rokko in Kobe. Higher fog occurrence and larger volume of fog water were observed in summer, corresponding to the trend of seasonal variation in precipitation amount. The annual mean pH value of fog water (3.80) was lower by ca. one pH unit than that of precipitation (4.74). The concentration of chemical species in fog water was ca. 7 times that in precipitation. The highest anion and cation concentrations were SO4 2? and NH4 + in fog water and Cl? and Na+ in precipitation, although the Cl?/Na+ equivalent ratio in both fog water and precipitation was almost the same value as that in sea water. It is considered that in the longest fog event, NH4 + and nss-SO4 2? in fog water mainly scavenged as (NH4)2SO4, mainly derived from (NH4)2SO4 (aerosol) in the atmosphere, NH3 was scavenged at the growing stage, and SO2 was also scavenged after the mature stage. NO3 ? in this fog event was mainly absorbed as HNO3.  相似文献   

20.
Elution of Cl?, SO4 2?, NO3 ?, and H+ often occurred in that order at a site in the central Sierra Nevada, California, that receives an annual average of 1000 cm of snowfall which is low in acidic components. During eight winter periods of above-base level snowpack outflow, and one spring melt period, on the average 25% of the ions were discharged at the following percentages of outflow volumes: Cl? at 11%, NO3 ? at 13%, SO4 2? at 18%, and H+ at 20%. Seven of eight winter outflows were associated with low ionic strength rainfall onto the snowpack. Mean solute concentrations during the first 25% and first 50% of the total outflow were significantly greater than during the last 75% and last 50% of the total outflow for Cl?, NO3 ?, and SO4 2?, but not for H+. Maximum solute concentrations were up to 2.9 times the overall event volume-weighted mean concentrations for Cl?, 3.7 times for NO3 ?, 3.0 times for SO4 2?, and 2.9 times for H+.  相似文献   

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