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1.
The effects of the interaction between sodium chloride, nitrate, and concentrations on growth and internal ion content of faba bean (Vicia faba L.) plants were studied, to understand the relationship between the above parameters and salt tolerance. Increased salinity substantially reduced the dry weight of roots and shoots and increased the root/shoot biomass ratio. Additional nitrate‐N considerably moderated the salinity effects on these parameters. The promotive effects of nitrate‐N were more pronounced on shoot dry weight. These results suggest that an exogenous supply of nitrate‐N would improve the vegetative growth of V. faba plants by moderating the suppresive effects of salinity. The evolution of the root and shoot content in potassium (K), sodium (Na), magnesium (Mg), calcium (Ca), and nitrogen (N) was monitored during vegetative growth. A high correspondence between total N and Ca content was found. The acquisition of Ca and K in response to salt and nitrate was similar in shoots and roots, whereas Mg uptake showed notable differences in the two organs. In salt‐affected plants, the roots were found to be high in accumulated Na while the shoots exhibited the lowest Na concentration. Potassium accumulation was higher in the shoots. In this way, there was an antagonistic effect between Na and K uptake. Analyses of the nutrient contents in plant organs have provided a data base on salt‐tolerance mechanisms of V. faba plants.  相似文献   

2.
Growth, ion balance, water relations and leaf photosynthesis of canola (Brassica napus L., cv. Excel) and wild mustard (Brassica kaber L. C. Wheeler) grown under a mixture of sodium and magnesium sulphate salts were examined using a hydroponic system in a growth chamber. Wild mustard was less salt tolerant than canola, based on the growth responses. Salinity caused large accumulation of sodium (Na) and magnesium (Mg) ions, but reduced calcium (Ca) and potassium (K) concentrations in the shoots and roots. Water potential, osmotic potential, transpiration, stomatal conductance and hydraulic conductance decreased to a greater extent in canola than in wild mustard, indicating salinity imposed a smaller osmotic effect on the wild species. Calcium addition improved the growth of wild mustard more than canola but it had no effect on water relations. The growth reduction in these species under salt stress resulted from a combination of ion toxicity, insufficient nutrient ion availability and altered water relations. Supplemental Ca improved growth by reducing Mg and increasing Ca content in plant tissues, ameliorating salinity‐associated ion toxicity to photosynthesis, and possibly through an indirect effect on cell growth.  相似文献   

3.
Investigations on the significance of the nutritional status of plants for their salt tolerance In order to explain the causes of salt damages on crops in the Sibari Plain (Southern Italy) the nutrient contents of plants were used in addition to soil data. Increasing Na- and Mg-salinity reduced the K-contents of wheat plants during sprouting below the (preliminary) critical value of 30%o and the Ca-contents below the value of 3%o in spite of high gypsum contents and optimum K-supply of the soils (compared to soils with low salt contents). The content of nutrient elements can be improved by an increased nutrient supply up to the optimum range, and the content of detrimental elements in plants can be reduced below toxic limits. The specific toxicity of Mg-salts (believed to be especially high) could be prevented by optimum nutrition of the plants until general salt effects became dominant factors of damage. At optimum nutrient supply 6–7%o Mg in the tops of corn plants were toxic in greenhouse experiments. In the field even at high Mg-supply of the soils no more than 2,5%o Mg were found in cereals. At optimum K-supply more than 1–2%o Na in wheat plants reduced the yield. The salt tolerance of plants, therefore, can be increased by proper fertilisation.  相似文献   

4.
The effect of varying hydrogel (0, 0.5, and 1.0% w/w) supply on some agro-physiological properties, such as dry matter, nutrient contents, chlorophyll contents, proline content, and ionic balance of bean plants in different salt sources and stress due to doses were investigated. Plants were treated with eight salt sources [sodium chloride (NaCl), sodium sulfate (Na2SO4), calcium chloride (CaCl2), calcium sulfate (CaSO4), potassium chloride (KCl), potassium sulfate (K2SO4), magnesium chloride (MgCl2), magnesium sulfate (MgSO4)] and four concentrations (0, 30, 60, and 120 mM doses) for 60 days in a growth media. Salt type, doses, and hydrogel (HG) affected the soil electrical conductivity. Soil salinity affected the parameters considered, and changed the nutrient balance of plants. High salt concentration caused substantial reduction in plant growth. Different salt concentrations negatively affected plant dry weight. The highest decrease of plant root dry weight was obtained with NaCl application followed by Na2SO4, CaCl2, CaSO4, MgCl2, MgSO4, KCl, and K2SO4, and similarly NaCl, Na2SO4, CaCl2, CaSO4, KCl, K2SO4, MgCl2, and MgSO4 in root dry weight. Total chlorophyll and nitrate contents of plants decreased with increasing salt doses, and the lowest value was obtained for NaCl application. Proline contents of plants were increased with increasing salt doses, and the highest value was obtained with the NaCl application. The effects of salt concentrations in nitrogen (N), potassium (K), and phosphorus (P) content of plants were significant. The presence of salt in the growth medium induced an important decrease the macro nutrient of the root and shoot part of plant such as N, P, K, calcium (Ca), and magnesium (Mg) content, but the N and P content of root and shoot part of the plant were increased with increasing of the HG application doses. The highest N and P increases were obtained with the 1.0 HG application for all salt types for both the root and shoots of plants. The HG added to saline soil significantly improved the variables affected by high salinity and also increased plant N and P, reduced soil electricity conductivity, nitrate, proline, and electrolyte leakage of plants, enhanced plant root and shoot dry weight by allowing nutrients and water to release to the plant as needed. The results suggested that HG has great potential for use in alleviating salinity stress on plant growth and growth parameters in saline soils of arid and semi-arid areas. This HG appears to be highly effective for use as a soil conditioner in vegetable growing, to improve crop tolerance and growth in saline conditions. It is intended to confirm the results of these studies by field trials.  相似文献   

5.
Studies were carried out in the glass house using sand culture to find out the specific ion effect on the accumulation of abscisic acid in wheat. Seeds were sown in sixteen different solutions of chloride, sulphate, nitrate, carbonate salts of sodium, potassium, calcium and magnesium used each at ‐2 bar osmotic potential. The leaf samples taken after 25 days of sowing indicated that osmotic as well as salt stress increased significantly the accumulation of abscisic acid. The accumulation of abscisic acid was significantly less under potassium and calcium salt ions as compared to that under sodium and magnesium salts ions. Overall effect of anions showed that accumulation of abscisic acid was more under PEG (osmotic stress and chloride salts but it was less under sulphate and nitrate salts and was the least under carbonate salts. The accumulation of abscisic acid was exceptionally high under potassium dihydrogen phosphate. In general, the accumulation of abscisic acid‐a growth inhibitor varied not only with the type of the cation but also depended on the accompanying anion indicating differential growth response of plants under different types of saline conditions having dominance of different salt ion(s).  相似文献   

6.
A two years lysimeter experiment was carried out using wheat plants (Triticum aestivum L. cv. Lotti) on two texturally contrasting soils. The main purpose of this study was to evaluate the influence of increasing applications (5,10, 15,20, and 25 t.ha‐1) of solid phase (SP) from pig slurry on soil nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) content, nitrate‐N (NO3‐N) leaching as well as on wheat composition and yield. As the control, a basic dressing of NPK fertilizer was applied. Results showed that plant growth was stimulated by increasing amounts of SP, yet the additions of 15 to 20 t SP ha‐1 led to similar effects on yield as that for the control. An accumulation of P on both soils was observed as well as a significant increase on NO3‐N leaching due to increasing rates of SP added to the soils. The N and P content in wheat plants (straw and grain) increased with increasing rates of applied SP.  相似文献   

7.
《Journal of plant nutrition》2013,36(8):1581-1593
Abstract

In order to improve determinations of nutrient critical levels using growth response curves, a detailed study of magnesium (Mg) deficiency on pepper (Capsicum annuum L.) biomass allocation was performed. For each growth parameter, data were fitted using the modified Mitscherlich's model and Mg‐critical level was calculated. Under Mg‐deficiency, pepper plants showed a decrease in their relative growth rate (RGR), total dry weight (DW), stem and root mass fractions (SMF and RMF), total leaf area, specific leaf area (SLA), and unit leaf rate (ULR), whereas leaf mass fraction (LMF) and shoot to root ratio increased. Growth response coefficient (GRC) analysis indicated that the decrease in RGR was mainly due to a decrease in ULR. When the interval time between two harvests was ≥10 days, determination of Mg‐critical level (x c ) using the modified Mitscherlich's model showed that the best growth parameter for early detection of Mg‐deficiency in pepper plants was total DW (x c  ≈ 0.21%), whereas other parameters underestimated Mg‐critical level.  相似文献   

8.
The appropriate supply of magnesium (Mg) to the common bean (Phaseolus vulgaris L.) according to the requirements of each variety increases the productivity and nutritional value of grains. However, there are few studies on soil's ability to provide the adequate amount of the nutrient and on the reaction of plants with different Mg concentrations. The present study analyzed the response of the common bean plant to soil fertility, grain yield (GY), shoot dry weight (SDW) yield, nutritional status and the response of physiological components of the plant to the concentrations of Mg applied to the tropical soil. Thus, an experiment was conducted in a completely randomized design, in 5 × 4 factorial arrangement, with three replicates. The varieties BRS Estilo, IAPAR 81, BRS Ametista, IPR Campos Gerais (CG) and IPR Tangará were cultivated in an Ustoxix Quatzipsamment with five rates of Mg [0, 50, 100, and 200 mg kg?1, source magnesium chloride (MgCl2)]. The common bean varieties and the Mg rates significantly affected the soil chemical properties. Photosynthetic rate, stomatal conductance, transpiration rate, intercellular concentration of carbon dioxide (CO2), and total soluble sugars significantly correlated with common bean GY and SDW yield. The nutrient content in leaves and grains showed difference responses among the varieties. IAPAR 81 showed the highest rate of mobilization of nitrogen, phosphorus, magnesium, sulfur, boron, copper and zinc (N, P, Mg, S, B, Cu, and Zn) for grains, being an important factor in studies of crop biofortification.  相似文献   

9.
The effect of salinity on growth response, nitrogen (N) fixation and tissue mineral content was investigated for four legumes: faba bean (Vicia faba L), pea (Pisum sativum L), soybean (Glycine max L), and common bean (Phaseolus vulgaris L). Plants were grown in a vermiculite culture system supplied with a N‐free nutrient solution with the addition of 0, 50, and 100 mM NaCl. Plants were harvested at the beginning of the flowering period and the dry weights of shoots and roots and acetylene reduction activity (ARA) were evaluated at the same time plant tissues were analysed for N, potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) contents.

The depressive effect of saline stress on ARA of nodules was directely related to the salt induced decline in dry weight and N content in shoots. Growth inhibition by NaCl treatments was greater for the pea than for other legumes, whereas the soybean was the most salt‐tolerant Saline stress also affected the N content in shoots and roots. In general the N content accumulated in the shoot and Na in the roots of the four legumes tested, while K accumulated both organs. The acquisition of other macronutrients differed according to the legume species. The legumes most sensitive were P. sativum and V. faba which accumulated Ca in shoot and Mg both in the shoot and the roots. On the contrary, in G. max and P. vulgaris, the two most salt tolerant legumes, accumulated Mg in the roots and Ca in both vegetative organs. Our results suggest a relationship between the salt‐tolerant range in legumes and the macronutrient accumulation in vegetative organs.  相似文献   

10.
Abstract

The effect of salinity on the growth and yield of tomato plants and mineral composition of tomato leaves was studied. Five tomato (Lycopersicon esculentum Mill) cultivars, Pearson, Strain B, Montecarlo, Tropic, and Marikit, were grown in sand nutrient culture. The nutrient solutions applied consisted of a modified half‐strength Hoagland solution with 50 mM sodium chloride (NaCl), 3 mM potassium sulphate (K2SO4), 1.5 mM orthophosphoric acid (H3PO4), and 10 mM calcium sulphate (CaSO4). Stem height and number of leaves of tomato plants were not found to be significantly different but leaf and stem dry weight were reduced significantly in plants irrigated with saline nutrient solution in contrast with control plants. The total yield was reduced in plants that received saline treatments, but there was no significant difference in fruit number and fruit set percentage. The fruit electrical conductivity and total soluble solids were increased in plants irrigated with saline nutrient solution. Fruit pH was not found to be significantly different among salinity treatments. Mineral composition of tomato leaves were increased by addition of potassium (K), phosphorus (P), and calcium (Ca) to the saline nutrient solution. The addition of K to the solution resulted in an increase in sodium (Na) leaf content. The amounts of K and magnesium (Mg) were not significantly different among salinity treatments. Calcium content was increased when CaSO4 was added. Application of H3PO4 resulted in the highest amount of P in tomato leaves under saline conditions. The present study revealed that application of K, P, and Ca under saline conditions improved fruit electrical conductivity and total soluble solids. Sufficiency levels of the mineral nutrients K and P were obtained in tomato leaves when the appropriate nutrient was used in the saline solution.  相似文献   

11.
The effects of varying fertilizer application rates [100–15–100 or 300–46–300 mg L‐1 of nitrogen (N)‐phosphorus (P)‐potassium (K)] and pinching dates on nutrient uptake patterns of poinsettias were studied. During the first seven weeks after potting, varying the N‐P‐K fertilization rate from 100–15–100 to 300–46–300 mg L‐1 N‐P‐K had no effect on plant height, dry weight, nutrient concentration, or nutrient content of poinsettias. The uptake ratios for NO3‐N, K, calcium (Ca), and magnesium (Mg) all were <40% of the amount that was available at the 100 mg L"1 N and K fertilization rate, indicating that poinsettias require lower levels of NO3‐N, K, Ca, and Mg than what was available from the 100–15–100 mg L"1 N‐P‐K fertilization rate. The higher uptake ratios of >60% and >70%, respectively, for NH4‐N and P at the 100 mg L"1 N and K fertilization rate indicated the plants utilized a higher percentage of the available NH4‐N and P, indicating that an application rate >18 mg L‐1 NH4‐N and >15 mg L‐1 P would be required by poinsettias from the week before the plants were pinched through three weeks after pinching. The 300–46–300 mg L‐1 N‐P‐K fertilization rate provided excessive nutrients that were not utilized by the plants during the early stages of plant growth.  相似文献   

12.
Mycorrhizal fungi affect growth and nutrition of host plants positively. In this research, influence of vesicular-arbuscular mycorrhiza (VAM) ongrowth, chlorophyll content, and potassium (K) and magnesium (Mg) uptake in maize seedlings in pot culture was studied. This experiment was performed using natural soil containing a mixture of spores of Glomus spp. Mycorrhizal spores were exposed to four concentrations of K solution, i.e. 0.61 (soil K content), 0.92, and 1.23 meq/L and three concentrations of Mg, i.e. 4.8 (soil Mg content), 7.2, and 9.6 meq/L concurrently. Plants were watered every 4 days for 16 days with 50 mL distilled water. A pot with sterilized soil was used as negative control. For study of mycorrhizal colonization, very thin manually prepared longitudinal sections of plant roots (>1 mm in diameter) were stained with lactophenol-cottonblue and examined microscopically. Percentage of mycorrhizal colonization was determined using the grid-line intersect method. Samples from root and shoot of maize were collected for further analysis. Results showed mycorrhizal plants had significantly higher dry and fresh weight and chlorophyll content than plants grown in sterilized soil (p ≤ 0.05). Treatments with concentrations of 7.2 meq/L of magnesium alone and in combination with 0.92 meq/L of potassium with7.2 meq/L of Mg had better effect on morphological characters (dry and fresh weight of root and shoot). Mycorrhizal colonization increased Mg uptake but decreased K uptake.  相似文献   

13.
Excessive sodium (Na) accumulation in soil, which can be a problem for production agriculture in arid and semiarid regions, may be ameliorated by calcium (Ca). The mechanisms of Ca amelioration of Na stress in plants have received much more attention than has the effect of the anion of the Ca salt. Our objective was to determine the relative effects of the chloride (Cl‐) and sulfate (SO4 2‐) anions on Ca amelioration of Na stress. We exposed Phaseolus vulgaris L., cv. Contender seedlings growing in 1‐L styrofoam pots under greenhouse conditions to sodum chloride (NaCl) or sodium sulfate (Na2SO4) at concentrations of 0, 15, 30, 45, and 60 mmol/L combined with either 15 and 30 mmol/L of calcium sulfate (CaSO4) or calcium chloride (CaCl2). Plants in each styrofoam pot were irrigated with 300 mL of salt solution (leaching fraction = 0.25) every fourth day for four weeks. Increasing Na concentration decreased shoot dry weight, number and weight of pods, and number of nodules. The photo‐ synthesis rate was affected by all levels and types of Na salts. Calcium sulfate treatments ameliorated Na‐induced salinity in snapbeans more than did comparable CaCl2 treatments. The thermodynamic activity of Ca, Na, and Cl was linearly related to the tissue content of each ion.  相似文献   

14.
Abstract

White Rose potato plants (Solanum tuberosum, L.) were grown outdoors, without tuber formation, in a modified Hoagland's nutrient solution with 9 treatments of KH2PO4 ranging from 0 to 4.0 mmoles per liter. Deficiency symptoms ranged from very severe to none at harvest after 27 days of growth. Growth of the potato plants increased with increased P supply and was associated with an increased P content of the plant tissues. The critical H2PO4‐P concentration at a 10% reduction of top growth, based on a second leaf analysis, was about 1,000 ppm for the petiole and terminal bladelet and about 1,200 ppm for the lateral bladelet, dry weight basis.

Phosphorus nutrition had only a slight effect on the K, Na, Mg and NO3‐N concentrations of the root tissues but Ca increased as phosphate increased which suggests a calcium phosphate precipitation. Phosphorus stress lowered the K, Na, Ca, Mg and NO3‐N concentrations of the petiole tissues of the recently matured leaf which suggests that P increases salt accumulation. Phosphorus nutrition had only a slight effect on the concentrations of K, Na, Mg and Ca of the blade tissues of the recently matured leaf but NO3‐N increased greatly with P supply.  相似文献   

15.
Ion relations, water content, leaf water potential, and osmotic adjustment were determined for cultivated barley (cv Harrington) and wild barley grown under mixed sulphate (SO4) salts with varied calcium (Ca) supply using a hydroponic system. Salinity induced significant increases of leaf, stem and root sodium (Na) concentrations in both species. Salt‐stressed wild barley roots accumulated more Na than shoots, and transport of Na from roots to shoots was low compared to Harrington. Cultivated barley had lower Ca concentrations than wild barley, especially in the low Ca salt treatment. Although potassium (K/Na) and Ca/Na ratios were higher in control wild barley plants than in Harrington, they declined under salt stress, irrespective of Ca supply. Major osmotica in wild barley leaves were K, sugars, organic acids, and quaternary ammonium compounds, while in Harrington they were cations, including Na, K and Mg, and anions such as phosphate (PO4) and SO4. Wild barley maintained better water status than Harrington under low Ca salt treatment. Supplemental Ca improved water status more in Harrington than in wild barley. Lack of osmotic adjustment to salinity in wild barley apparently resulted from its ion exclusion. Low Ca salt treatment caused Ca deficiency, Na toxicity, and loss of turgor in Harrington. In the high Ca salt treatment, Harrington had improved water and ion relations, as well as positive turgor.  相似文献   

16.
Abstract

The large amounts of coal combustion by‐products (CCBs) generated by coal burning power plants must be utilized or discarded, and beneficial use of these materials are desired. One beneficial use of CCBs could be application to agricultural land. Information about the use of one kind of CCB (flue gas desulfurization by‐product, FGD‐BP) on soil is limited. Maize (Zea mays L.) was grown (greenhouse) on an acid soil [Umbric Dystrochrept, pHCa (1:1, soil: 10 mM CaCl2) 4.2] amended with two high CaSO4 FGD‐BPs (5 and 15 g#lbkg‐1 soil) and CaCQ3 (2.5 and 5.0 g#lbkg‐1 soil) at varied calcium/magnesium (Ca/Mg) equivalency ratios (0/0, 1/0, 1/0.01, 1/0.05, 1/0.1, and 1/0.5) to determine treatment effects on growth traits [shoot and root dry matter (DM) and total and specific root length (RL)], mineral concentrations in leaves, and soil pH and electrical conductivity [(EC) 1:1, soil:water]. Magnesium deficiency symptoms were induced on leaves of plants grown with and without low Mg, and the Mg to Ca ratio in each amendment needed to be about 1 to 20 to alleviate Mg deficiency. Shoot and root DM and total RL of plants grown with FGD‐BPs became higher as Mg increased. Specific RL (total RL/root DM, root fineness) was not affected by FGD‐BP and only slightly by Ca/Mg ratio. Shoot concentrations of Mg increased; Ca, phosphorus (P), and manganese (Mn) decreased; and potassium (K), sulfur (S), iron (Fe), zinc (Zn), and copper (Cu) remained relatively constant as amendment and Mg increased. On unamended soil, aluminum (A1) and Mn concentrations in shoots were above normal. Enhancement of growth was closely related to increased soil pH compared to added Mg for CaCO3 amended soil and to increased Mg compared to increased soil pH for FGD‐BP amended soil. Except at the highest level of Mg where soil pH increased, added FGD‐BPs and Mg had only limited effect on increasing soil pH. Soil EC increased from added FGD‐BPs but not from added Mg, and EC was not sufficiently high to be detrimental to plants. Maize grown on this acid soil amended with FGD‐BPs received benefits when caution was used to alleviate mineral deficiencies/toxicities inherent in the soil.  相似文献   

17.
Abstract

Some irrigation waters have a high Mg/Ca ratio. The objective of the experiment reported herein was to compare the effect of high Mg in combination with different anions and different EC levels on the growth of corn (Zea mays L.). Corn was grown in the greenhouse in a calcareous soil equilibrated and irrigated with the following waters: 1) tap water (check, EC = 0.078 dS/m, SAR = 0.1); 2) Mg(HCO3)2, EC=1 dS/m; 3) Mg(HCO3)2, EC = 3; 4) MgSO4) EC=1; 5) MgSO4, EC=3; 6) MgSO4, EC = 6; and 7) and 8) mixed salts (Ec = 3 & 6 dS/m, SAR = 5, Ca: Mg = 3: 1, Cl: SO4 = 2: 1). Yield depressions of top growth caused by mixed‐salt waters (EC = 3 & 6) were 17 and 26%, respectively, compared to yields obtained with tap water. Single‐salt MgSO4 waters (EC = 1, 3 & 6) reduced corn tops 19, 38, and 59%, respectively, more than the mixed‐salt solutions at equivalent soil salinity levels probably due to Mg‐induced Ca deficiency. The Mg(HCO3)2 waters (EC = 1 & 3) reduced top growth 45 and 87% more than the mixed salt solutions. Thus Mg (HCO3)2 was more than twice as depressive on corn top growth as MgSO4. Corn root growth depression was similar to top growth depression. Leaf Ca: Mg ratio was related to their ratio in the soil solution. The leaf Ca and Mg concentrations were almost the same for plants irrigated with Mg(HCO3)2 or MgSO4 at EC = 1. Therefore, Mg: Ca ratio of leaves did not explain the yield differences between the two Mg salts. Nutrient imbalances and a high pH of 9 were possibly responsible for the lower yields in the presence of Mg(HCO3)2.  相似文献   

18.
Abstract

Greenhouse‐pot experiments were conducted to compare wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merrill] in terms of their potassium (K) and magnesium (Mg) uptake. Previously, a field study indicated that various rates of K and Mg fertilization did not produce a significant wheat‐yield response. However, a yield increase with residual K and Mg was measured for the subsequent soybean crop. The 0 to 15 cm layer of Norfolk loamy fine sand (fine loamy, siliceous, thermic Typic Kandiudult) from two different sites was used for the pot experiments. Soil from both sites had a pH of 5.1. Potassium as potassium sulfate (K2SO4) was mixed into the soil from the K‐deficient site and Mg as magnesium sulfate (MgSO4) was mixed into the soil from the Mg‐deficient site. ‘Florida 301’ wheat and ‘Cobb’ soybean were grown in winter and summer, respectively.

Soybean and wheat were similar in K uptake/g of roots on the first and second sampling dates. However, by the third sampling date, K uptake/g of wheat roots was about twice as high as for soybean. Potassium uptake/cm of soybean roots was two to five times that of wheat at each sampling date. Magnesium uptake/g of soybean roots was about four to five times as high as wheat on each sampling date. Similarly, Mg uptake/cm of soybean roots was 10 to 30 times higher than for wheat. Soybean showed higher total K and Mg content than wheat, suggesting that soybean has a higher demand for both K and Mg. The higher demand for K and Mg by soybeans than by wheat suggests that wheat could meet its demand for K and Mg at much lower soil levels than that for soybean. This would also explain a grain‐yield response to K and Mg by soybeans in the previously reported field study, despite a lack of yield response by wheat grown on the same site.  相似文献   

19.
Abstract

Forage intake with potassium/(calcium + magnesium) [K/(Mg + Ca)] values in excess of 2.2 are associated with grass tetany and Mg deficiencies in ruminants. This study was conducted to determine the degree to which forage K and Mg concentrations and K/(Ca + Mg) ratios could be predicted from soil bicarbonate (HCO3) extractable phosphate‐phosphorus (PO4‐P), and saturation extract Ca, Mg, K, sodium (Na), and nitrate‐nitrogen (NO3‐N) concentrations. Crested wheatgrass (Agropyron spp) strains and cultivars representing four ploidy levels were grown in the greenhouse on eight calcareous soils with different saturation extract Ca, Mg, K and K/Mg ratios. The plants were harvested three times. Soil solution K/(Ca + Mg) and K/Mg ratios were the only measured soil parameters that showed a consistent correlation with plant K/(Ca + Mg) ratios. Bicarbonate extractable soil P was positively related to plant P and K uptake in the first harvest, but was not related in the second and third harvests nor was soil P related to plant Ca or Mg content. There was a tendency for the higher ploidy level entries to have higher plant K/(Ca + Mg) ratios. It was concluded that soil K/(Ca + Mg) ratios can be used to predict relative forage K/(Ca + Mg) ratios for grasses grown under similar conditions.  相似文献   

20.
An antagonistic reaction between calcium (Ca) and magnesium (Mg) and potassium (K) may lead to low absorption of K and Mg by plants from soils with high Ca contents even when levels of K and Mg should be adequate. Two separate field studies were carried out in 2009 and 2010 to determine the effects of potassium (0, 40, 80, 120 kg K2O ha?1; as potassium sulfate) and magnesium (0, 20, 40, 60 kg magnesium oxide (MgO)ha?1; as magnesium sulfate) applied to a soil with high lime content either separately or in combinations, on the grain yield and yield components of maize for grain in semi-arid Central Anatolia in Turkey. One dose of the K, Mg-fertilizers was applied during sowing in both years. According to the results, increasing the dosage of K increased yield components more than increases in Mg dosages. Combinations of K and Mg tended to maximize the yield components. Moreover, the greatest plant heights, first ear lengths, grain weights per ear and protein ratios were obtained for the K80Mg40 dose.  相似文献   

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