D. C. Martens

Accumulation and transport of nickel in relation to organic acids in ryegrass and maize grown with different nickel levels

Difference in Ni tolerance/accumulation in plant genotypes might be used to identify or develop plants for remediation of high Ni soils. Ryegrass was shown to be more sensitive to Ni toxicity and accumulated much more Ni in shoots than maize. The objectives of this study were to examine the relationship of organic acids to Ni accumulation and xylem transport of Ni in ryegrass (Lolium perenne L.) and maize (Zea mays L.). The results showed that accumulation of Ni in shoots was 5 to 7 fold higher in ryegrass than in maize grown at 20 to 80 µM Ni, whereas Ni concentration in ryegrass roots was only 1 to 2 fold higher at 0.1 to 40 µM Ni and 1.5-fold lower at 80 µM Ni than that of maize roots. Xylem transport rates of Ni increased with increasing Ni supply for both species, and were about 2 to 7 times higher in ryegrass than in maize. Shoot concentrations of citric, malic, oxalic and cis-aconitic acids increased at Ni levels above 20 µM, and were about 2 to 6 times higher in ryegrass than in maize. Whereas, maize roots accumulated greater amount of malic, oxalic, and cis-aconitic acids than ryegrass roots, especially at Ni levels of 40-80 µM. The rate of Ni exudation by roots in the two species was significantly correlated with root Ni concentrations. It could be concluded that high Ni accumulation in shoots was closely related to high xylem transport rates of Ni and that the accumulation of organic acids, citric and malic acid in particular. A high root exudate rate of Ni and the enhanced accumulation of organic acids, malic acid in particular, in roots might be among the important factors which are associated with the tolerance of crops to toxic Ni levels.

Plant tolerance to nickel toxicity: II nickel effects on influx and transport of mineral nutrients in four plant species

Abstract Nickel (Ni) is an essential micronutrient for higher plants but is toxic to plants at excess levels. Plant species differ extensively for mineral uptake and accumulation, and these differences often help explain plant tolerances to mineral toxicities/deficiencies. Solution culture experiments were conducted under controlled conditions to determine the effects of Ni on influx into roots (IN) and transport from roots to shoots (TR) of zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), calcium (Ca), magnesium (Mg), phosphorus (P), and sulfur (S) in white clover (Trifolium repens L.), cabbage (srassica oleracea van capitata L.), ryegrass (Lolium perenne L.), and maize (Zea mays L.). Nickel decreased both IN and TR of Zn, Cu, Ca, and Mg, but only TR of Fe and Mn in white clover. Both IN and TR of Cu, Fe, Mn, Mg, and S were markedly decreased by Ni >30 μM in cabbage, whereas IN and TR of P increased with Ni treatment. For ryegrass, TR of Cu, Fe, Mn, Ca, and Mg was decreased, but IN of these elements ex...

Influx, transport, and accumulation of cadmium in plant species grown at different Cd2+ activities

Abstract Cadmium (Cd) has no known essential biological function, but it is toxic to plants, animals, and humans. A promising approach to prevent Cd from entering the food chain would be to select and/or create Cd‐accumulating plants to remediate contaminated soils or to develop Cd‐excluding plants to reduce Cd flow from soils into foods. The present study was undertaken to examine the differences in Cd influx, transport, and accumulation among five plant species in relation to plant tolerance to Cd toxicity. Ryegrass (Lolium perenne L.) had the least reduction in dry matter which may be due to its lowest Cd transport rate (TR) to shoots at all Cd levels among the plant species tested. White‐clover (Trifolium repens L.) was the most sensitive species to Cd toxicity, likely because of its highest Cd influx rate (IR) and high TR when plants were grown at low Cd2+ activity (≤8 μM). The high tolerance of cabbage (Brassica oleracea var. capitata L.) to moderate Cd toxicity (≤14 μM) appeared to be mainly due to...

Plant tolerance to nickel toxicity: I. Influx, transport, and accumulation of nickel in four species

Abstract Plant tolerance to nickel (Ni) toxicity depends on plant differences for uptake and distribution within tissues. Differences among and within species for Ni tolerance/accumulation might be used to identify or develop plants for remediation of high Ni soil conditions. Solution culture experiments were conducted under controlled conditions to determine influx (IN) into roots, transport (TR) from roots to shoots, and accumulation of Ni in four plant species grown at different Ni levels. White clover (Trifolium repens L.) had high dry matter (DM) at high Ni levels because of its low IN and TR of Ni. At Ni levels <60 μM, maize (Zea mays L.) had high DM probably because of its low TR even though it had high IN of Ni. Ryegrass (Lolium perenne L.) was sensitive to Ni toxicity because of its high IN and TR of Ni. The sensitivity of cabbage (Brassica oleracea var. capitata L.) to Ni toxicity was correlated with high TR even though it had low IN of Ni. Nickel accumulation in shoots was relatively high for c...

Effect of soil application of fly ash on chemical composition and yield of corn (Zea mays L.) and on chemical composition of displaced soil solutions

SummaryField investigations were initiated in 1971 to study the effect of a weathered fly ash sample on yield and nutrient concentration of corn (Zea mays L.) and on composition of displaced soil solutions, and to determine rates of fly ash that could be applied to soils without adversely affecting plant growth. Application of weathered ash at rates ranging from 18 to 288 metric tons/ha did not decrease corn grain yields on either Groseclose silt loam or Woods-town loamy fine sand. Corn grain yields were increased on the Woodstown soil in 1972 where cumulative rates of 216 and 288 metric tons/ha of fly ash were applied, which was attributed in part to increased soil moisture. Plant analysis data indicated that B and Mn concentrations were not increased to toxic levels as had been reported in other investigations with unweathered fly ash. Soil solution data verified that toxic amounts of these elements were not released from the weathered ash sample.Calcium content of displaced soil solutions was increased by fly ash application but was not sufficiently high to effect increases in Ca content of corn tissue. The data suggest that the weathered fly ash under study could be applied to soils at cumulative rates of 288 metric tons/ha without inimically affecting crop growth.

Accumulation and movement of phosphorus from poultry litter application on a Starr clay loam

Abstract The poultry industry faces tremendous challenges for the economically sound and environmentally safe disposal of the massive amounts of waste it generates during production processes. This study was conducted to investigate the accumulation and downward movement of phosphorus (P) from surface application of poultry litter (PL) on a Starr clay loam (fine‐loamy, mixed, thermic Fluventic Dystrochrepts). Poultry litter was surface applied to unimproved pasture at rates of 5.8, 11.4, 17.2, 22.9, and 28.7 mt/ha in 1991 and 4.1, 8.0, 12.1, 16.1, and 20.2 mt/ha in 1992, respectively. Cumulative P levels supplied by the PL over the two‐year period were 105.8, 211.7, 317.5, 423.3, and 529.1 kg/ha. Phosphorus from both PL and inorganic sources accumulated in the zone of application. The Mehlich 3 (M3)‐extractable P levels varied with rate of P application for each of the two years of this study. In 1992, M3‐extractable P levels were increased by 2‐, 4‐, 6‐, and 8‐fold over the control by PL application in t...

Plant availability of applied and native boron in soils with diverse properties

Laboratory and greenhouse research was conducted to study effects of soil properties on the availability of native and applied B in 14 Virginia soils. Boron absorption could be described by the Langmuir equation in 12 of the 14 soils, and maximum B adsorption (Vmax) in these 12 soils ranged from 3.3 to 26.5 mg kg−1. A multiple regression equation, −19.3+3.51 pH+0.048 clay content, accounted for 89.6% of the variation in Vmax for the 12 soils. Curvilinear relationships (α=0.01) occurred between B in corn (Zea mays L.) tissue from native B and hot-water soluble B, mannitol exchangeable B, and NH4-acetate and Mehlich III extractable B. Among these four procedures, mannitol exchangeable B correlated most closely (r=0.923) with B in corn tissue from native B. From 0.4 to 13.5% of the applied B was absorbed by corn plants and translocated to shoots. Curvilinear relationships (α=0.01) occurred between B in corn tissue from applied B and soil clay content, NH4-oxalate extractable Al and Fe, and acidified NH2OH·HCl extractable Mn. It is evident from these relationships that soil clay and oxyhydroxides of Al, Fe, and Mn have an affinity to adsorb B in somewhat unavailable forms.

Effect on soil and plant mineral levels following application of manures of different copper contents

SummaryManure from finishing pigs fed diets with and without a growth stimulating level of added copper (250 ppm in 1972, 370 ppm in 1973 and 300 ppm in 1974) was incorporated into a Groseclose silt loam at the rate of 15.5, 12.9 and 15.7 metric tons of dry matter per hectare, respectively, for 1972, 1973 and 1974. A third treatment was no manure. The manure was applied between rows when corn was about 10 cm tall and worked into the surface 10 cm of the soil with a rotary tiller. The average composition of the manure for the three years on a dry basis was 3.6 per cent nitrogen, 2.87 per cent calcium, 0.93 per cent magnesium, 2.22 per cent phosphorus, 1.30 per cent potassium, 648 ppm zinc, 2191 ppm iron. The copper content was 73 ppm for control manure and 1719 ppm for high copper manure. The copper content in the upper 10 cm of the soil was significantly increased each year when high copper manure was applied. During one growing season, copper did not appear to move down, however, plowing after the first year increased the copper level in the 10–20 cm depth with a small increase in the 20–30 cm depth. Potassium, zinc, phosphorus, calcium and magnesium levels of the soil were increased when manure was applied. There was a small increase in the copper content of the maize ear leaf (average of one ppm per year) when manure from pigs fed diets containing high copper was applied. Copper in the washed roots of the mature maize plants was doubled (5.6 vs 11.2 ppm) when the high copper manure was added. The copper content of grain from plants grown on soil receiving high copper manure was not different from that of grain from soil receiving no manure. The zinc, potassium and phosphorus contents of the maize ear leaf were increased a small amount when both control and high copper manure were applied with the effect of potassium and phosphorus carrying over to the grain. The iron and calcium contents of the ear leaf were not affected by application of manure, but there was a decrease in calcium content of the grain from the application of control and high copper manure. re]19750305

Poultry litter effects on unmanaged pasture yield, nitrogen and phosphorus uptakes, and botanical composition

Abstract The poultry industry must dispose vast amounts of waste, mainly litter (PL), generated during production processes. This study was conducted to investigate the short‐term effects of various rates of PL application, i.e., cumulative 2‐year totals of 9.9, 19.4, 29.3, 39.0, and 48.9 mt ha‐1, to unmanaged pasture on a Starr clay loam (fine‐loamy mixed thermic Fluventic Dystrochrepts). Dry matter yield, N and P concentrations, and changes in botanical composition were measured on a mixed species, tall fescue (Festuca arundinacea Schreb.) and bluegrass (Poa pratensis L.) pasture. Dry matter yields (r2 = 0.99*), N uptake (r2 = 0.99*), and P uptake (r2 = 0.99*) increased curvilinearly with rate of PL application in both years. Yield increase was attributed to correction of N deficiency in pasture by the PL application. Lower levels of PL increased forage yields in 1992 compared with 1991, due to the residual effect of unmineralized N from PL applied in 1991. Nitrogen concentration in tissue increased wit...

Effect of byproduct, nitrogen fertilizer, and zeolite on phosphate rock dissolution and extractable phosphorus in acid soil

Coal combustion by products (BP) and phosphate rock (PR) have been widely used as cost-effective amendments for acid soils. Information is needed on the proper combination of BP with chemical fertilizers or other organic and inorganic amendments to improve the productivity of acid soils. Chemical analysis and soil incubation studies were carried out to examine the effect of BP, N fertilizers, and zeolite on dissolution of PR and on the status of extractable P in acid soil. Several kinetic models were compared for describing PR dissolution in acid soils that received different amounts of BP, different forms of N fertilizer, and zeolite. PR dissolution in acid soil measured by 0.5 M NaOH extraction was best described by a Langmuir kinetic model (r2=0.988**, followed by an Elovich (r2=0.950**), a two-constant rate (r2=0.947**), a parabolic diffusion (r2=0.905**), and a first-order reaction equation (r2=0.637*). A second-order reaction equation was the poorest among various models tested (r2=0.484). Addition of BP, N fertilizers, and zeolite to the PR-amended soil did not affect the good fitness of PR dissolution to these kinetic equations. Increasing BP addition decreased initial and average dissolution rate and potential maximum dissolution of PR during the incubation period of 132 days as calculated from the Elovich and Langmuir kinetic models. In general, NH4NO3 and (NH4)2SO4 increased the initial rate and decreased slightly the average PR dissolution rate due to a rapid but short-term acidifying effect. On the other hand, urea and zeolite decreased the initial rate of PR dissolution due to higher pH and increased the average PR dissolution rate because of long and persistent acidification by urea and slow but continued removal of Ca by zeolite. The effect of N fertilizers and zeolite on the potential maximum dissolution of PR was related to amounts of BP added. Extractable P in the PR-amended soils as determined by 0.5 M NaHCO3 was closely correlated with P released by PR dissolution. The ratio of increased NaHCO3-extractable P due to PR application divided by the total amount of P released from PR dissolution measured by NaOH extraction might reflect relative availability of P from PR dissolution. This ratio was increased by addition of BP, urea, and zeolite but decreased by NH4NO3 and (NH4)2SO4.