首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
A study was conducted to examine the impact of land use on soil fertility in an Entisol in the Jalpaiguri District of humid subtropical India. The natural forest served as a control against which changes in soil properties were compared. Soil samples were collected from four different depths (0–25, 25–50, 50–75, and 75–100 cm) of soil from four land uses (viz. forest, home garden, arecanut plantation, and agriculture) and examined for pH, organic carbon (OC), electrical conductivity (EC), cation exchange capacity, available nitrogen (N), phosphorus (P), exchangeable calcium (Ca), magnesium (Mg), potassium (K), aluminum (Al), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and dehydrogenase activity (DHA). Soil pH (5.7), OC (2.29%), N (386 kg ha?1), and P (22.54 kg ha?1) were greatest in forest soil, followed by soil from arecanut plantation, agriculture, and home garden. The greatest Ca (0.892 cmol kg?1), Mg (0.527 cmol kg?1), and Al (1.86 cmol kg?1) were found in the arecanut plantation, whereas K (0.211 cmol kg?1) was greatest in forest. The greatest content of diethylenetriaminepentaacetic acid–extractable copper, zinc, manganese, and iron (2.25, 1.66, 4.86, and 7.65 ppm, respectively) were found in forest. MBC (558 mg kg?1), MBN (26.67 mg kg?1), and DHA (33.03 μg TPF 24 h?1 g?1) was greatest in forest soil. Soil fertility index varied from 13.13 in arecanut plantation to 18.49 in forest. The soil evaluation factor ranged from 5.32 in agriculture to 6.56 in forest. Pearson's correlation matrix revealed strongly significant positive correlation of soil fertility index and soil evaluation factor with soil properties.  相似文献   

2.
Mineral N accumulates in autumn under pastures in southeastern Australia and is at risk of leaching as nitrate during winter. Nitrate leaching loss and soil mineral N concentrations were measured under pastures grazed by sheep on a duplex (texture contrast) soil in southern New South Wales from 1994 to 1996. Legume (Trifolium subterraneum)‐based pastures contained either annual grass (Lolium rigidum) or perennial grasses (Phalaris aquatica and Dactylis glomerata), and had a control (soil pH 4.1 in 0.01 m CaCl2) or lime treatment (pH 5.5). One of the four replicates was monitored for surface runoff and subsurface flow (the top of the B horizon), and solution NO3– concentrations. The soil contained more mineral N in autumn (64–133 kg N ha?1 to 120 cm) than in spring (51–96 kg N ha?1), with NO3– comprising 70–77%. No NO3– leached in 1994 (475 mm rainfall). In 1995 (697 mm rainfall) and 1996 (666 mm rainfall), the solution at 20 cm depth and subsurface flow contained 20–50 mg N l?1 as NO3– initially but < 1 mg N l?1 by spring. Nitrate‐N concentrations at 120 cm ranged between 2 and 22 mg N l?1 during winter. Losses of NO3– were small in surface runoff (0–2 kg N ha?1 year?1). In 1995, 9–19 kg N ha?1 was lost in subsurface flow. Deep drainage losses were 3–12 kg N ha?1 in 1995 and 4–10 kg N ha?1 in 1996, with the most loss occurring under limed annual pasture. Averaged over 3 years, N losses were 9 and 15 kg N ha?1 year?1 under control and limed annual pastures, respectively, and 6 and 8 kg N ha?1 year?1 under control and limed perennial pastures. Nitrate losses in the wet year of 1995 were 22, 33, 13 and 19 kg N ha?1 under the four respective pastures. The increased loss of N caused by liming was of a similar amount to the decreased N loss by maintaining perennial pasture as distinct from an annual pasture.  相似文献   

3.
The objective of this study was to investigate the changes in the chemical partitioning of Cu, Pb, Cr and Zn within a column of soil incubated with an anaerobic sewage sludge (ANSS) for 2.5 months. The soil was irrigated during the incubation period. A sequential extraction method was used to fractionate these metals into exchangeable, weakly adsorbed, organic, Al oxide, Fe–Mn oxide, and residual, respectively. ANSS was applied at a loading rate of 69 Mg ha?1. The soil is a Dystric Cambisol with low pH (<3.8), low CEC [<10 cmol(+) kg?1 below the first 4 cm depth], and low base saturation (<7%). The addition of the ANSS caused a decrease in concentrations of Cu, Pb, and Cr in the A1 horizon, and an increase in the concentrations with depth. Below the A1 horizon, concentrations of Cu increased uniformly (~1 mg cm?1), and the greatest increases were observed in the residual, Fe–Mn oxides, and weakly adsorbed fractions. Maximum increases in Pb occurred at 4–9 cm of depth (1.6 mg cm?1), and mainly affected the weakly adsorbed fraction. Chromium essentially accumulated at the limit between the A2 and the Bw horizons (1.1–1.5 mg cm?1) as residual and organic bound forms, probably through particulate transport. Zinc mainly accumulated in the A1 horizon (2.9 mg cm?1) as exchangeable Zn. At depth, Zn increments were predominantly observed in the residual fraction. The results of this study thus demonstrate the redistribution of contaminants into different chemical pools and soil layers after sludge amendment.  相似文献   

4.
Phosphorus (P) inputs (wet deposition and fertilizer P) and outputs (animal product and drainflow) were studied on reseeded grazed grassland swards receiving different nitrogen (N) inputs (100–500 kg N ha?1 year?1) for 10 years (March 1989–February 1999), at an experimental site in Northern Ireland. All plots received the same maintenance application of P fertilizer (8.5 kg P ha?1 year?1) to meet grass requirements, to minimize the P surplus and to quantify the impact on P losses to land drainage water. The annual flow weighted mean total P concentrations in drainflow ranged from 187 to 273 μg P litre?1 and were well above the concentrations believed to trigger eutrophication. Annual total P lost to drainage water ranged from 0.28 to 1.73 kg P ha?1, but was unaffected by N input. As the average annual P balance was zero, there was no significant change in total P in the top 15 cm of soil. However, there was a highly significant redistribution of P to the soil surface from the 10–15 cm depth, possibly as a result of root acquisition and earthworm activity. Total P in the top 5 cm of soil increased from 0.85 g kg?1 to 1.04 g kg?1, over the 10 years of the study, despite there being no net P input. This P accumulation in the top few cm of soil is likely to exacerbate P losses in overland flow and make improvements in water quality difficult to achieve.  相似文献   

5.
Are Indicators for Critical Load Exceedance Related to Forest Condition?   总被引：1，自引：0，他引：1  
The aim of this study was to evaluate the suitability of the (Ca?+?Mg?+?K)/Al and the Ca/Al ratios in soil solution as chemical criteria for forest condition in critical load calculations for forest ecosystems. The tree species Norway spruce, Sitka spruce and beech were studied in an area with high deposition of sea salt and nitrogen in the south-western part of Jutland, Denmark. Throughfall and soil water were collected monthly and analysed for pH, NO3-N, NH4-N, K, Ca, Mg, DOC and Altot. Organic Al was estimated using DOC concentrations. Increment and defoliation were determined annually, and foliar element concentrations were determined every other year. The throughfall deposition was highest in the Sitka spruce stand (maximum of 40 kg N ha?1yr?1) and lowest in the beech stand (maximum of 11 kg N ha?1yr?1). The Sitka spruce stand leached on average 12 kg N ha?1yr?1 during the period 1988–1997 and leaching increased throughout the period. Only small amounts of N were leached from the Norway spruce stand whereas almost no N was leached from the beech stand. For all tree species, both (Ca?+?Mg?+?K)/Al and Ca/Al ratios decreased in soil solution at 90 cm depth between 1989 and 1999, which was mainly caused by a decrease in concentrations of base cations. The toxic inorganic Al species were by far the most abundant Al species at 90 cm depth. At the end of the measurement period, the (Ca?+?Mg?+?K)/Al ratio was approximately 1 for all species while the Ca/Al ratio was approximately 0.2. The lack of a trend in the increment rates, a decrease in defoliation as well as sufficient levels of Mg and Ca in foliage suggested an unchanged or even slightly improved health condition, despite the decreasing and very low (Ca?+?Mg?+?K)/Al and Ca/Al ratios. The suitability of these soil solution element ratios is questioned as the chemical criteria for soil acidification under field conditions in areas with elevated deposition rates of sea salts, in particular Mg.  相似文献   

6.
This study was conducted to: (1) determine the probable cause of several areas of stressed and dead vegetation adjacent to a 15-yr-old reject coal pile in western South Carolina and (2) identify the factors limiting successful revegetation of the site. Data from an earlier study suggested that solution pH, total dissolved solids (TDS) and electrical conductivity (EC), and/or elevated trace element concentrations may have contributed to the stress and dieback. Soil water in the two vegetation kill zones is saline (TDS>10 000 mg L?1 and EC>4 dS m?1), highly acidic (soil pH<3.5), and high in Al and Mn (Al conc.>200 mg L?1 and Mn conc.>10 mg L?1). Soil water in areas of sparse vegetation is brackish (TDS>1000 mg L?1 and EC>2 dS m?1) and acidic (soil pH<4.0), with elevated Al values (> 40.5 mg Al L?1). Tissue samples were collected from volunteer loblolly pine (Pinns taeda L.) seedlings growing in the study area and analyzed for essential and non-essential elements. Seedling tissues did not contain abnormal concentrations of nutrients or trace elements. The strong relationship between the zones of vegetation stress and dieback and solution pH and soluble salt concentrations, and the lack of excessive metal accumulations by tree seedlings which have become established in the less toxic portions of the study area, suggest that low solution pH and high soluble salts are more important factors limiting plant establishment on this site than solution metal concentrations. The results of this study demonstrate the importance of site hydrology in determining the impacts of coal waste disposal on adjacent ecosystems.  相似文献   

7.
Abstract

The objective of this research was to assess the long‐term effects of broiler litter applications on soil phosphorus (P), copper (Cu), zinc (Zn), manganese (Mn), and arsenic (As) concentrations in Chesapeake Bay watershed Coastal Plain soils. Litter and soil samples were collected from 10 farms with more than 40 years of broiler production and from wooded sites adjacent to fields and were analyzed for P and metal contents. Averaged over farms, total P and metal concentrations in the litter were 12.8 g kg?1 P and 332, 350, 334, and 2.93 mg kg?1 Cu, Zn, Mn, and As, respectively. Surface (0–15 cm) soil pH values were greater than (5.7–6.4) the 0‐ to 15‐cm depth at wooded sites (3.5–4.3). Surface soil Bray 1 P values (149–796 mg kg?1) in amended fields were greater than wooded sites (4.4–17 mg kg?1). The 1N nitric acid (HNO3)–extractable metal concentrations were higher in amended soils than in wooded areas and were 7.7–32, 5.7–26, 12.3–71, and 0.6–3.0 mg kg?1 for Cu, Zn, Mn, and As, respectively, compared to 0.76–14, 4.6–22, 1.6–70, and 0.14–0.59 mg kg?1 for the same metals, respectively, in wooded areas. Results from this study demonstrated that long‐term broiler litter applications have altered the chemical properties of the Coastal Plain soils of the Maryland Eastern Shore. Metal concentrations were low in the surface layer of amended fields and typically decreased with depth. Phosphorus additions rather than metals are most likely to contribute to the degradation of the Chesapeake Bay watershed.  相似文献   

8.
No‐tillage (NT) cropping systems are becoming increasingly important in the Brazilian savanna. To evaluate their sustainability we compared soil chemical properties in 1‐ to 3‐year‐old NT systems following 9 to 11 years of conventional tillage (CT) with systems where CT was continuously in place for 12 years. In the rainy season 1997/98, NT was cropped with soybean and CT with corn while in the rainy season 1998/99 both systems were cropped with soybean. Soil solid phase samples were taken from the 0—0.15, 0.15—0.3, 0.3—0.8, 0.8—1.2, and 1.2—2 m layers on three spatially separated plots under each of NT and CT. Soil solution samples were collected weekly at 0.15, 0.3, 0.8, 1.2, and 2 m soil depth during two rainy seasons (14 October to 28 April 1997/98 and 1998/99). We determined soil moisture contents, pH, the concentrations of exchangeable cations, the electrical conductivity (EC) of the soil solution, and the concentrations of Al, C, Ca, Cl—, K, Mg, Mn, Na, NH4+, NO3—, P, S, and Zn in solid soil and soil solution samples. Differences in soil solid phase properties and moisture content between NT and CT were small, few were significant. Under NT, the average solution pH was significantly lower (5.5), Al (26 μg l—1), Mn (17 μg l—1) and total organic C concentrations (TOC, 6.5 mg l—1) were higher than under CT (pH: 6.0, Al: 14μg l −1, Mn: 14μg l −1, TOC: 5.5 mg l −1). Irrespective of the different crops in the first rainy season, under NT, the EC (205 μS cm—1), Ca (17 mg l—1), and Mg (2.9 mg l—1) concentrations at 0—0.3 m depth were lower than under CT (EC: 224 μS cm—1, Ca: 25 mg l—1, Mg: 5.6 mg l—1). At 1.2—2 m depth, the reverse order was observed (EC: 124 μS cm—1 under NT and 84 μS cm—1 under CT, Ca: 11 mg l—1 under NT and 7.5 mg l—1 under CT, Mg: 3.1 mg l—1 under NT and 1.8 mg l—1 under CT). Our results indicate that enhanced soil acidification because of higher rates of organic matter mineralization and a more pronounced nutrient leaching because of increased pore continuity may limit the sustainability of NT.  相似文献   

9.
The impact of 60‐year‐old reforestation on soil evolution was studied by following the evolution of Fe and Al distribution as an indicator of early podzolization. We determined the distribution of Al and Fe in soils by combining sequential and kinetic extractions. We extracted the soil sequentially with: 1 mol litre?1 sodium acetate at pH 5.5 (stage 1); twice with 0.1 mol litre?1 sodium pyrophosphate at pH 10 (stage 2 and 2b); and with 1 mol litre?1 hydroxylamine in 4.3 mol litre?1 acetic acid solution at 90°C (stage 3). For each, we drew a kinetic‐extraction curve. We show that no re‐adsorption, precipitation or complexation with dissolved organic matter occurred for the reaction times recommended in this procedure, that is 6 hours for stage 1, 1.5 hours for stage 2 and 2b and 3 hours for stage 3. For a given extraction, the kinetic curves have the same shape for all samples, that is their behaviour is similar for a given reagent. Sequential extraction can therefore be used to compare the speciation of metals in different samples taken from the same soil. In addition, 60 years after reforestation by beech, a decrease of 12 and 17% is noted in the total Fe and Al contents, respectively, in the 0–10 cm layer, accompanied by a re‐distribution of these elements within the different soil compartments: a decrease of the Fe and Al bound to oxy‐hydroxide in favour of organic complexes and more soluble forms. Sequential extraction is therefore a good indicator of the first pedogenetic modifications induced by human intervention through reforestation.  相似文献   

10.
Leaching of Cd and Zn in polluted acid, well‐drained soils is a critical pathway for groundwater pollution. Models predicting future groundwater contamination with these metals have rarely been validated at the field scale. Spodosol profiles (pH 3.2–4.5) were sampled in an unpolluted (reference) field and in a field contaminated with Cd and Zn through atmospheric deposition near a zinc smelter. Average metal concentrations in the upper horizons were 0.2 mg Cd kg?1 and 9 mg Zn kg?1 in the unpolluted field, and 0.8 mg Cd kg?1 and 71 mg Zn kg?1 in the contaminated field. Isotopic dilution was used to measure the labile concentration of Cd and Zn, and the metal transport was modelled using measured sorption parameters that describe the distribution between the labile metal pool (instead of the total metal pool) and the solution phase obtained by centrifugation. Solutions were also collected by wick samplers in two polluted and one unpolluted profile at a depth of 70 cm. Concentrations in these solutions were in the order of 15 µg Cd litre?1 and 0.8 mg Zn litre?1 for the polluted profiles, and 1 µg Cd litre?1 and 0.04 mg Zn litre?1 for the unpolluted profile. The concentrations in these solutions agreed well with those in soil solutions obtained by centrifugation, which supported the use of the local equilibrium assumption (LEA). Present‐day Cd profiles in the polluted field were calculated with the LEA, based on the emission history of the nearby smelter and taking spatial variability into account. Observed and predicted depth profiles agreed reasonably well, but total Cd concentrations in the topsoil were generally underestimated by the model. This may be attributed to the presence of non‐labile Cd in the atmospheric deposition, which was not accounted for in the retrospective modelling. The large concentrations of non‐labile Zn in the topsoil of the polluted field were also indicative that metals in the atmospheric deposition were (partly) in a sparingly soluble form, and that release of these non‐labile metals is a slow process. The presence of non‐labile metals should be taken into account when evaluating metal mobility or predicting their transport.  相似文献   

11.
Acid irrigation (pH 2.7 to 2.8; mean annual input 4.1 kmol H+ ha?1 as H2SO4) has caused significant changes in the chemistry of the soil of a mature Norway spruce stand (Picea abies [L.] KARST.) after 4 years of treatment. In the surface humus layer around 20% of the exchangeable Ca, Mg, K and Mn ions were leached. This was connected with a decrease of pH and cation exchange capacity. In the mineral soil no changes of pH and cation adsorption were observed. However there was a significant increase of Al3+ ions in the soil solution, exceeding 20 mg L?1, mainly caused by dissolution of Al-hydroxides and Al-hydroxosulphates. Also the concentrations of ionic Cu, Zn and Cd were nearly doubled. Manganese concentrations are fluctuating according to periods with and without acid irrigation, showing reduction and oxidation phases. In contrast to microorganisms, certain moss species and Oxalis acetosella, the mature spruce stand was not severely damaged up to now. It is hypothesized that Ca/Al and Mg/Al ratios of single horizons are insufficient for characterizing Al stress in the field. Liming (4 Mg ha?1) led to a significant increase of dissolved organic C, which is associated with mobilization of metals such as Pb, Cu and Al in organic complexation. Also nitrification increased in the surface humus layer. As a consequence the nitrate concentrations in the seepage water exceeded 250 mg NO3 L?1.  相似文献   

12.
‘Acid-flush’ events, monitored in an upland catchment in the Cairngorm Mountains (Scotland) at the time of the spring-thaw, are associated with an increase in stream discharge and raised concentrations of both major ions (Ca, Mg, Na, Cl, N03, and SO,) and trace-elements (Al, Cd, Cu, Fe, Mn, and Pb), in addition to H+. The streamwater chemistry is determined by the hydrological pathways which are operative in the catchment during these periods of snowmelt, and reflects both the meltwater composition and the influence of the soils within the catchment. Aluminium, in particular, is leached from the soils and high concentrations (up to 330 μg L?1) occur in the streamwaters. The presence of frozen soils, which result largely due to the influence of meteorological conditions prior to the accumulation of the snowpack, is likely to have a large impact on the Al concentrations in the streamwaters. The low concentrations of Ca monitored in the stream during the periods of snow-melt (<0.2 mg L?1) may promote subsequent toxic effects of the Al to aquatic life forms.[/p]  相似文献   

13.
Runoff from a highway interchange in western Maryland had Al concentrations averaging about 50 mg L?1, with a maximum of 206 mg L?1. As an alternative to expensive chemical treatment of this Al-rich water, in August 1984, the drainage was diverted through a 500 m2 man-made wetland, constructed from organic peat. For a 10 week period, Al concentrations in water leaving the wetland averaged 1.5 mg L?1. as compared to Al concentrations at the two major inflows to the wetland of 35.3 and 6.6 mg L?1. However, effective treatment of the drainage by the wetland was not observed over the entire 27 mo sampling period. Peat chemical analysis indicated that over the 27 mo, total Al concentration in the peat increased from 2375 μg g?1 to 13 634 μg g?1. Of this increase 5.5 % was contributed by exchangeable Al, 4.3% by adsorbed Al, 39.8% by organically bound Al, 33.1% by oxide bound Al, and 17.2% by precipitated and residual Al. Changes in Fe, Mn, Ca, Mg, K, and Na chemistry in the peat associated with Al retention are discussed.  相似文献   

14.
Abstract

Concentrations of N, P, K, Ca, Mg, and Mn were determined in one‐, two‐, and five‐year‐old needles from upper and lower crowns of declining and healthy red spruce (Picea rubens Sarg.) to assess nutritional deficiencies as causes of severe defoliation in upper‐elevation forests in western Massachusetts. Concentrations of N and K did not differ between stands or positions in crowns but decreased with leaf age. In declining stands, mean Ca concentrations were the same in the upper and lower crowns (3.2 mg g‐1), whereas in healthy stands, Ca was higher in the lower crown (4.8 mg g‐1) than in the upper crown (3.9 mg g‐1). Five‐year‐old needles of healthy trees had higher Ca than those of declining trees (6.0 and 3.8 mg g‐1, respectively). Mean concentrations of P and Mg in declining trees were 0.9 and 0.5 mg g‐1, respectively, with each element being at threshold levels of sufficiency. Mean concentrations of P and Mg, respectively, were 0.3 mg g‐1 and 0.2 mg g‐1 lower in needles of declining trees than in healthy trees. Five‐year‐old needles of declining trees were lower in P and Mg than those from healthy trees. Mean Mn concentrations were lower in needles of declining trees than in healthy trees (0.4 vs 1.3 mg g‐1). The results suggest that low P, Mg, and possibly Ca concentrations in needles of declining trees may contribute to the decline.  相似文献   

15.
Oil palm (Elaeis guineensis Jacq.) is a heavy feeder of nutrients and requires balanced and adequate supply of nutrients for optimum growth and yield. Information regarding soil nutrient status and leaf nutrient concentration is very much required for proper fertilizer application. Therefore, a survey was conducted for assessment of soil nutrient status and leaf nutrient concentration in 64 oil palm plantations in the state of Goa lying in the west coastal region of India. Soil pH, electrical conductivity (EC), organic carbon (OC), available potassium (K) (ammonium acetate-extractable K) (NH4OAc-K), available phosphorus (P) (Bray’s-P), exchangeable calcium (Ca) (Exch. Ca) and magnesium (Mg) (Exch. Mg), available sulphur (S) (calcium chloride-extractable S) (CaCl2-S), and hot water soluble boron (B) (HWB) in surface (0–20 cm depth) soil layers ranged from 4.25 to 6.77, 0.05 to 1.06 dS m–1, 5.07 to 48.4 g kg–1, 58.1 to 1167 mg kg–1, 1.80 to 415 mg kg–1, 200 to 2997 mg kg–1, 36.0 to 744 mg kg–1, 3.00 to 87.7 mg kg–1 and 0.09 to 2.10 mg kg–1, respectively. Diagnosis and Recommendation Integrated System (DRIS) norms were established for different nutrient expressions and were used to compute DRIS indices. As per DRIS indices, the order of requirement of nutrients in the region was found to be P > Mg > K > nitrogen (N) > B. Optimum leaf nutrient ranges as per DRIS norms varied from 1.64 to 2.79%, 0.36 to 0.52%, 0.37 to 0.75%, 0.89 to 1.97%, 0.35 to 0.63%, 0.89 to 1.50%, 3.10 to 13.9 mg kg?1, 7.50 to 32.2 mg kg?1, 35.0 to 91.1 mg kg?1, 206 to 948 mg kg?1, and 895 to 2075 mg kg?1 for N, P, K, Ca, Mg, S, B, copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) respectively. On the basis of DRIS-derived sufficiency ranges, 14, 5, 11, 6, 6, 6, 8, 2, 3, 6, and 16% of leaf samples had less than optimum concentrations of N, P, K, Ca, Mg, S, B, Cu, Zn, Mn, and Fe respectively. The optimum ranges developed can be used as a guide for routine diagnostic and advisory purpose for balanced utilization of fertilizers.  相似文献   

16.
Negative impacts of land‐applied aluminum (Al)–rich water treatment residuals (WTRs), which have been suggested to improve soil phosphorus (P) sorption, could include excessive immobilization of plant‐available P and Al phytotoxicity. We studied the impacts of an Al‐rich WTRs on agronomic returns and plant Al concentrations in glasshouse and field studies. The glasshouse study was a 4 × 2 × 3 factorial experiment with one control in a randomized complete block design and three replicates. Four sources of P were each applied at two agronomic rate [44 kg P ha?1, P‐based rate; and 179 kg plant‐available nitrogen (PAN) ha?1, N‐based rate] to topsoil (0–15 cm) of a sandy, siliceous, hyperthermic Arenic Alaquods. Three WTR rates (0, 10, and 25 g kg?1 oven‐dry‐weight basis) were further applied, whereas the control received neither P source nor WTRs. Bahiagrass (Paspalum notatum Fluggae), ryegrass (Lolium perenne L.), and a second bahiagrass crop were continuously grown in succession for 18 months. Applied WTRs increased soil Al but not plant Al concentrations (22–80 mg Al kg?1), which fell within the normal concentration range for pasture plants. In the glasshouse, when WTRs were incorporated with the soil, bahiagrass dry matter (DM) accumulation was reduced, but ryegrass DM was not affected even at 25 g kg?1 WTR. A 2‐year field study, with same treatments but two rates of WTRs (0 and 10 g kg?1 WTR) surface applied to established bahiagrass on the same soil type (Spodosols) showed neither reduced yields nor increased plant Al phytoavailability in the WTR treatments. The studies show no increase in plant Al is associated with Al‐WTRs applied to reduce excess soil‐soluble P and P losses but plant DM accumulation may be reduced.  相似文献   

17.
《Journal of plant nutrition》2013,36(10):2315-2331
ABSTRACT

Split root solution culture experiments were conducted to study the effects of the rare earth element lanthanum (La) on rice (Oryza sativa) growth, nutrient uptake and distribution. Results showed that low concentrations of La could promote rice growth including yield (0.05 mg L?1 to 1.5 mg L?1), dry root weight (0.05 mg L?1 to 0.75 mg L?1) and grain numbers (0.05 mg L?1 to 6 mg L?1). High concentrations depressed grain formation (9 mg L?1 to 30 mg L?1) and root elongation (1.5 mg L?1 to 30 mg L?1). No significant influence on straw dry weight was found over the whole concentration range except for the 0.05 mg L?1 treatment. In the pot and field experiments, the addition of La had no significant influence on rice growth.Lanthanum had variable influence on nutrient uptake in different parts of rice. Low concentrations (0.05 mg L?1 to 0.75 mg L?1) increased the root copper (Cu), iron (Fe), and magnesium (Mg), and grain Cu, calcium (Ca), phosphorus (P), manganese (Mn), and Mg uptake. High concentrations (9 to 30 mg L?1) decreased the grain Ca, zinc (Zn), P, Mn, Fe and Mg, and straw Ca, Mn, and Mg uptake. With increasing La concentration, root Zn, P, Mn, Cu, and Ca concentrations increased, and grain Ca and Fe, and straw Mn, Mg, and Ca concentrations decreased. Possible reasons are discussed for the differences between the effects of La in nutrient solutions and in pot and field experiments.  相似文献   

18.
The comparative efficacy of bioorganic nutrients on cropping behavior and soil properties of apricot trees was studied. Bioorganic nutrient sources, namely, vermicompost (VC), biofertilizers (BF), cow urine (CU), and vermiwash (VW), were evaluated in 13 treatment combinations. The treatment application of VC at 50 kg, BF at 60 g, CU at 12.5%, and VW at 12.5% significantly improved cropping and soil properties over nitrogen–phosphorus–potassium (N–P–K) chemical fertilizers. Available macronutrient contents of soil (viz., N, P, and K) increased by 25.50, 70.90, and 6.44%, respectively. Diethylenetriaminepentaacetic acid–extractable micronutrients (Fe, Cu, Zn, and Mn) increased by 15.45, 35.90, 80.36, and 40.12%, respectively. Microbial biomass of Pseudomonas, Bacillus, Azotobacter chroococcum, and arbuscular mycorrhizal (AM) fungi improved 51.83, 122.78, 60.93, and 2.91 times, respectively. This superior combination also resulted in considerably greater amounts of leaf macro- and micronutrients: N (2.34%), P (0.34%), K (3.71%), iron (Fe; 172.83 mg kg?1), copper (Cu; 12.79 mg kg?1), zinc (Zn; 25.49 mg kg?1), and manganese (Mn; 54.32 mg kg?1), which might be responsible for better cropping behavior and productivity in apricot trees.  相似文献   

19.
The aim of the current study was to identify major soil and leaf factors accounting for low natural rubber (NR, Hevea brasiliensis) productivity on tropical acid Acrisols in Vietnam. Twenty NR plots were measured with NR productivity, leaf factors (N, P, K, Ca, Mg, Mn, Cu, Fe, and Zn), soil factors (pH, particle size distribution, total C, N, P, K, exchangeable K, Ca, Mg, Al, Mn, Fe, Zn, available P). Cluster analysis showed that NR productivity could be separated into three clusters with low (23.2), medium (38.2), and high (61.3 g tree?1 harvest?1) yield. High-yield cluster had higher leaf P concentration and soil pH, while low-yield cluster had higher leaf Mn, soil exchangeable Al, and Mn concentration. Simple and multiple linear regression analysis applied with backward elimination procedure suggested that leaf and soil toxic concentration may be responsible for low NR productivity in the study soil.  相似文献   

20.
‘Helleri’ holly (Ilex crenata Thunb. ‘Helleri') plants were grown in solution culture at aluminum (Al) concentrations of 0, 6, 12, 24, and 48 mg.L‐1 for 116 days. Aluminum did not affect root or crown index, stem length growth, plant dry weight, or leaf area. Aluminum treatments significantly increased Al uptake and reduced nutrient uptake of magnesium (Mg), calcium (Ca), zinc (Zn), and copper (Cu) on some sampling dates. Iron (Fe) and manganese (Mn) uptake decreased on most sampling dates but increased on some with Al treatments. Potassium (K), phosphorus (P), and boron (B) uptake were significantly affected by Al, decreasing and increasing at different sampling dates. Although plants preferentially took up ammonium‐nitrogen (NH4 +‐N) in all treatments (including 0 Al controls), neither NH4 +‐N nor nitrate‐nitrogen (NO3 ‐N) uptake were affected by Al. Tissue concentrations of P, K, B, Zn, and Al increased with Al treatment; whereas tissue Ca, Mg, and Cu concentrations decreased with increasing Al. Iron and Mn tissue concentrations exhibited increases and decreases in different tissues. Results indicated that ‘Helleri’ holly was tolerant of high concentrations of Al.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号