Allen V. Barker

Sodium accumulation in soils and plants along Massachusetts roadsides

The most common de-icing material applied by the Massachusetts state highway department is sodium chloride (NaCl). In Massachusetts, the rate of application of de-icing agents is about 240 lb (110 kg) of sand and 12 lb (5.5 kg) of NaCl per lane mile (1.6 km). The objective of this research was to examine injury to plants along roadsides and to assess relationships of damage to the amount of Na detected in plants and soils. The damage on most plant species was manifested as burning or browning of the leaves or needles. Coniferous species, especially pines (Pinus spp.), were sensitive to NaCl injury. In coniferous species, the damage appeared as browning on the ends of the needles, but new growth was not affected. Most of the damage occurred on the needles on the tree side that faced the road and where salt spray from cars or plows could have been a factor in the degree of damage. Widespread damage was also seen on spruce (Picea spp.), sumac (Rhus typhina), and mountain laurel (Kalmia latifolia) along roadsides. With sumac, injured plants had only 10% of the foliage as uninjured plants. Some salt-tolerant species, apparently undamaged by NaCl, in the same vicinity as the damaged plants, were various oaks (Quercus spp.), maples (Acer spp.), grasses (mixed species), ferns (mixed species), and yarrow (Achillea millefolium). The Na concentrations in the leaves of pines, sumacs, grasses, and oaks decreased as the distance from the road increased. The Na concentrations in pine needles were 3356 mg kg− 1 at 10 feet, 1978 at 15 feet, and 1513 mg kg− 1 at 20 feet. The Na concentrations in maple leaves decreased with the Na concentrations being 249 mg kg− 1 at 10 feet and falling to 150 mg kg− 1 at 30 feet. The concentrations of Na in roadside soil ranged from 101 mg kg− 1 at 5 feet to 16 mg kg− 1 at 30 feet from the roadside, with a marked decrease in the Na concentration in the soil after 15 feet. The pH decreased as the distance from the road increased ranging from 7.60 at 5 feet to 5.78 at 30 feet. The electrical conductivity values decreased as the distance from the road increased and ranged from 0.16 dS m− 1 at 5 feet to 0.12 dS m− 1 at 30 feet. This study suggests a relationship between Na accumulation, in leaves and in soil, and injury to roadside plants.

THE EFFECTS OF NITROGEN SOURCE AND CONCENTRATION ON THE GROWTH AND MINERAL COMPOSITION OF PRIVET

Nursery crops are fertilized with nitrogen (N) to enhance their growth and appearance, and crop responses to fertilization vary with form of N supplied and with plant species. This experiment, conducted in a greenhouse, examined privet (Ligustrum ibolium L.) growth and composition as affected by three N sources: 100% of the N as nitrate, 100% of the N as ammonium and a 50%–50% mixture of nitrate-N and ammonium-N. Nine different concentrations (in treatments incrementally ranging 0 to 300 mg N/L) of the three N regimes on privet growth and composition were studied in sand culture. After 240 days of treatment, total growth (mass or shoot extension) of privet did not differ among the three N sources. However, growth increased with increased N concentration with maximum growth occurring between 50 and 250 mg N/L. Although root mass did not vary among the N sources during the experiment, privet grown with ammonium nutrition had more blackened, discolored roots than plants grown with nitrate or mixed nutrition; however, N concentrations above 200 mg/L with each source of N resulted in discolored roots. Concentration of N in privet did not differ with N source but increased as N fertilization increased. Critical N concentration was 3.35% in leaf tissue, 2.40% in stem tissue, and 1.94% in root tissue and was obtained from fertilizer solution concentrations above 100 mg N/L. Concentrations of potassium (K), calcium (Ca), and magnesium (Mg) generally were lower in plants grown with all ammonium or mixed nutrition than in plants grown with all nitrate nutrition. Effects of N supply on plant manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), and molybdenum (Mo) varied with N source and plant tissue, with increases of these elements occurring in root tissue of plants grown on ammonium nutrition relative to the other N treatments. This experiment suggests that privet will grow well with nitrate, ammonium, or mixed ammonium-nitrate nutrition. The results also suggest that ammonium nutrition should be monitored more carefully that nutrition with the other sources, because of the acidifying effects of ammonium nutrition on the rhizosphere, effects of ammonium on nutrient accumulation, and root stress imparted by ammonium nutrition.

Foliar ammonium accumulation as an index of stress in plants

Abstract Foliar ethylene evolution is used as a bioassay to index physiological stress in plants. Accumulation of uncombined ammonium frequently precedes or coincides with ethylene evolution by stressed plants and also may serve as an index of stress. The objective of this research was to assess the relationship between ethylene evolution and ammonium in plants stressed by toxicity. Ethylene evolution and ammonium accumulation by tomato (Lycopersicon esculentum Mill.) foliage were measured for plants grown in a greenhouse with nutrition from ammonium‐ or nitrate‐based nutrient solutions. Foliar symptoms of stress from ammonium toxicity appeared on plants growing on ammonium‐based solutions. Ethylene evolution increased in response to a progressive array of foliar ammonium accumulation, which varied with source of N and duration of the treatments. Above a threshold of about 0.2 mg NH4‐N g‐1 fresh weight, ethylene evolution rose sharply and linearly with ammonium accumulation. Ammonium accumulation in folia...

Growth of corn in varying mixtures of paper mill sludge and soil

To evaluate different levels of paper mill sludge as a soil amendment for the production of corn (Zea mays L.), sludge was added to 15-cm pots of soil in a greenhouse experiment. Mixtures were made from paper mill sludge (0 to 560 Mg ha− 1 wet weight) mixed with field soil (Hadley fine sandy loam with coarse, mixed, mesic, Fluventic, Dystrochrept deposits). Nitrogen (N) was added as ammonium nitrate at 0 or 200 kg N ha− 1. Eight corn seeds of ‘Pioneer Max 21’ were seeded into each pot immediately after mixing the paper mill sludge and soil or at 21 days after mixing the media. Seven days after sowing, seedlings were counted in each pot to assess germination (emergence). Delaying of sowing of seeds for 21 days increased the number of seeds that germinated. Corn plants were harvested after 35 days of growth. Plant biomass declined as amounts of sludge increased. Adding N and delaying sowing for 21 days produced the greatest amount of dry mass. Tissue (leaf) total N decreased with increasing amounts of sludge. Addition of N to the mixtures increased the average total N in corn leaves. However, leaf total N still decreased with increasing amounts of sludge added even if N at 200 kg ha− 1 was added to the media. Sowing immediately after setup showed the highest leaf total N if no sludge was added to the mixture. Sowing immediately after setup of the experiment and adding paper mill sludge at 560 Mg ha− 1 produced the lowest total N in corn leaves. Generally, the phosphorus (P) concentration in plants increased as the amount of paper sludge increased, but the increase was less with N added than in treatments without N added. At 21 days, carbon:nitrogen, pH, and salinity of the media declined relative to the initial values. Total N in the media was higher after a 21-day delay than immediately after setup. Organic matter content increased with increasing amounts of paper sludge. Results indicated that addition of paper sludge to soil increased media organic matter and P contents. Germination was hindered when seeds were sown immediately after setup of the experiment, but delaying seeding for 21 days eliminated the germination problem. Nitrogen deficiency was problematic, and more than 200 kg ha− 1 of supplemental N is recommended to overcome immobilization of N.

Ethylene evolution and ammonium accumulation by nutrient-stressed tomato plants

Abstract Environmentally stressed plants frequently have elevated rates of ethylene evolution and high accumulation of free ammonium by their foliage. The objective of this study was to investigate ethylene evolution and ammonium accumulation by nutrient‐deficient and ammonium‐stressed tomato plants (Lycopersicon esculentum Mill. ‘Heinz 1350’ and neglecta‐1) grown in a greenhouse. In soil culture, ‘Heinz 1350’ was more sensitive to ammonium toxicity and had higher ethylene evolution than neglecta‐1. High ethylene evolution corresponded with appearance of ammonium toxicity symptoms in both lines. In sand culture, ‘Heinz 1350’ and neglecta‐1 grown with K, Ca, or Mg deficiency in NO3 ‐‐based nutrient solutions had higher ammonium accumulation and higher ethylene evolution than plants grown with complete nutrition. P‐deficient plants had elevated ammonium accumulation but low ethylene evolution. Plants grown on NH4 +‐based nutrition with pH buffering by CaCO3 had lower ethylene evolution and lower ammonium ac...

Ammonium accumulation and ethylene evolution by tomato infected with root‐knot nematode and grown under different regimes of plant nutrition

Abstract Ammonium accumulation and ethylene evolution are common phenomena with plant tissues under physiological stress. Enhanced ethylene evolution has been detected with tomato (Lycopersicon esculentum Mill.) infected with root‐knot nematode (Meloidogyne spp.). The present investigation addressed a linkage between ammonium accumulation and ethylene evolution by tomato infected with root‐knot nematode [Meloidogyne incognita Kofoid & White (Chitwood)]. At 6 weeks after infection, an array of foliar symptoms resembling those of ammonium toxicity developed on infected plants. Increased severity of symptoms was accompanied by a concomitant increase in foliar ammonium accumulation and by enhanced ethylene evolution. Stimulation of ammonium accumulation appeared to precede ethylene evolution. Plants grown on different nutritional regimes showed different responses to nematode infection with respect to shoot growth and injury, ammonium accumulation, and ethylene evolution. Relative to nitrate nutrition, ammoni...

A single plant tissue digestion for macronutrient analysis

Abstract A method was tested for determinations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) in one single digestion of plant tissue. Traditionally, for determinations of these five elements in plant tissue, at least two digestion or ashing procedures are used, totaling about 6 hours of tissue mineralization time. The method tested involved using a digesting medium of concentrated H2SO4 and a mixed catalyst of Na2SO4 and CuSO4. The total digestion time was about 60 minutes on a hot plate. After tissue digestion, determinations were by volumetric analysis (N), colorimetry (P), and atomic absorption (Ca, Mg) or emission spectrophotometry (K). Leaves of eight different species, including one standard tomato leaf sample and one internal quality‐control apple leaf sample were analyzed. High correlations occurred between the results obtained with the new procedure and with the standard digesting methods (furnace ashing and Kjeldahl digestion). The new method used much less re...

Effects of ammonium on elemental nutrition of red spruce and indicator plants grown in acid soil

Abstract Decline of high elevation red spruce (Picea rubens Sarg.) forests in the northeastern United States has been related to Ca and Mg deficiencies induced by input of air‐borne nitrogenous nutrients into the forest ecosystem. This research investigated the effects of N nutrition on mineral nutrition of red spruce and radish (Raphanus sativus L.), as an indicator plant, grown in acid forest soil. Red spruce and radishes in the greenhouse were treated with complete nutrient solutions with 15 mM N supplied as 0, 3.75, 7.5, 11.25, or 15 mM NH4 + with the remainder being supplied as NO3. Growth of each species was chlorotic and stunted by increased NH4 + in the nutrient solution. Increasing NH4 + from 0 to 15 mM depressed soil pH by about 1 unit (from 4.5 to an average of 3.5). Accumulation of N, K, Ca, and Mg by each species was restricted as the proportion of NH4 + increased, although the magnitude of these restrictions were small. The restrictions in growth were attributed directly to NH4 + toxicity an...

Evaluation of ammonium and soluble salts on grass sod production in compost. I. Addition of ammonium or nitrate salts

Abstract Inhibitions in seed germination and in plant growth in some composts have been associated with high concentrations of ammonium or soluble salts in the media. This experiment was conducted to determine changes in ammonium and soluble salts in fertilizer‐amended compost with time and their impacts on plant growth. Turfgrass (Lolium perenne L.) was seeded into an ammonium‐depleted municipal solid waste (MSW) or leaf composts or into MSW or leaf composts with 1,500 or 2,300 mg N/kg (dry weight) from (NH4)2SO4 or Ca(NO3)2 added to simulate immature composts. Seeding occurred on the day that the composts were treated and applied to flats. Ammonium‐nitrogen (N) and nitrate‐N concentrations and electrical conductivity were measured on the day of seeding and after 3, 7, 14, 21, and 28 days. Germination or growth was assessed after 7, 14, 21, and 28 days. Ammonium‐N in the compost declined with time, whereas nitrate‐N and electrical conductivity initially increased then decreased with time. Ammonium‐N from...

Evaluation of ammonium and soluble salts on grass sod production in compost. II. Delaying seeding after compost application

In some composts, seed germination and plant growth have been inhibited by high concentrations of ammonium or soluble salts. Ammonium and salt concentrations in media decrease with time after appli...