Yolo Loam Soil Research Articles

Simulated Transport of Multiple Cations in Soil Using Variable Selectivity Coefficients

AbstractA chromatographic model for describing the transport of multiple cations in soil was modified to include both mobile‐immobile flow regions and variable ion exchange selectivity coefficients Kij for each binary combination of cation species in a ternary soil‐water system. The model was evaluated by comparing simulated results with published breakthrough curves (BTC) for Na+ and Mg2+ concentrations in effluent from columns of Yolo loam soil initially saturated with Ca2+ ions. Experimental BTC for the relatively uncompetitive Na+ species were adequately described when either constant or variable values of Kij were used in the model. For the more competitive Mg2+ species however, simulations using constant Kij coefficients described the relative location for maximum concentration but underestimated tailing for the BTC. When all of the soil solution was assumed to be mobile, description of tailing for Mg2+ BTC was improved by the use of variable Kij values in simulations, but retardation for Mg2+ transport tended to be overestimated. The combined use of mobile‐immobile liquid regions and of variable selectivity coefficients provided the observed tailing in Mg2+ BTC but minimized overestimation of retardation.

Tractive characteristics of radial ply and bias ply tyres in a California soil

Four tyres (18.4-38, 18.4R38, 14.9-28, 14.9R28) were tested using the UCD single wheel traction tester. Each tyre was tested at two different inflation pressures and three different vertical loads at each inflation pressure. All tests were conducted in a well tilled Yolo loam soil. A dimensional analysis procedure was used to design and analyse the experiment. Two models were considered: (A) using inflation pressure as a variable, and (B) using tyre deflection as a variable. The effect of tyre type, tyre size, tyre inflation pressure and dynamic load on (1) net traction ratio at 20% slip and (2) average tractive efficiency in the 0–30% slip range were investigated using an ANOVA technique. An estimate of the possible energy savings due to the use of radial ply tyres instead of bias ply tyres in California agriculture was made.

Sources of variability in traction data

Abstract A 18.4R38 tyre was tested at 124 kPa inflation pressure, approximately 24 kN axle load in a firm and in a tilled Yolo-loam soil using (i) constant slip, (ii) constant draught, (iii) varying slip and (iv) varying draught tyre testing procedures. The results indicated that the constant slip test procedure leads to repeatable and consistent results whereas a variable slip test procedure leads to considerable scatter in the data. The constant draught test procedure yielded acceptable results. Varying slip appeared to influence the system dynamics much more than varying draught during tyre testing. An accurate method of predicting “true rolling radius” and “true slip” for an assumed zero condition is presented. The concept of motion resistance, its variability due to assumed zero conditions, and possible interpretations are discussed. The traction test data indicates that the motion resistance is not constant but varies with slip.

A WATER FUNCTION APPROXIMATION TO DEGREE OF ANAEROBIOSIS ASSOCIATED WITH DENITRIFICATION

Using the acetylene blockage method, we measured denitrification gas flux at 64 locations along a 45-m transect on Yolo loam (Typic Xerorthents) soil, to develop an empirical function indirectly accounting for the degree of anaerobiosis in the field. The function was dependent upon the relative soil

SODIC HAZARD

The authors studied the effect of salinity and sodium adsorption ratio (SAR) on the modified Gapon selectivity coefficient (k/sub g/') using Yolo loam soil and two (sodic) coal mine overburden materials designated surface and deep. The SAR treatments varied in value from 5 to 80 (mmol/L)/sup 1/2/ in an electrolyte solution (NaCl + CaCl/sub 2/) concentration range of 10 to 500 meq/L. When all treatment effects were combined, the k/sub g/' values were 0.0097, 0.0087, and 0.0079 (mmol/L)/sub -1/2/ for Yolo loam, surface, and deep overburden, respectively. In contrast to the other two systems, the deep overburden exhibited a steadily declining value of k/sub g/' (0.014 to 0.0055 (mmol/L)/sup -1/2/ with increasing electrolyte concentration. In all cases the k/sub g/' values were found to be less than the commonly used value of 0.015 (mmol/L)/sup -1/2/. 13 references, 5 figures, 7 tables.

Effect of liming of soil on additive, synergistic and protective interactions of some multiple trace element combinations and on iron and calcium interactions for a dicot and a monocot plant species

Abstract Corn (Zea mays L. cv. Golden Cross N.C.) and soybeans (Glycine max L. iron‐inefficient cv. PI54619–5–1) were grown in soil contaminated with combinations of Co, Ni, Cd, Li, Zn and Cu in Yolo loam soil with and without lime amendment. The objective was to further test the ability of lime (increased soil pH) to protect plants against additive and synergistic effects of combinations of multiple trace elements simultaneously. With soybeans the liming changed some additive and synergistic effects to one of protective but not in all cases. With one combination the effect was protective with and without liming. With corn the interactions tended to be protective without the liming but liming tended to increase the protective nature of the interaction. The effect of protection was characterized by. one of the various trace elements causing an antagonism against the other and not necessarily due to the decreased uptake resulting from liming. The combinations of various trace metals tended to decrease Mn up...

Influence of Atrazine on Denitrification in Soil Columns

AbstractThe effects of the herbicide atrazine (2‐chloro‐4(ethylamino)‐6‐(iso‐propylamino)‐s‐triazine) on denitrification was evaluated during steady transport of 15N‐nitrate through 0.15 m long columns of San Cataldo silt loam (Fluvisol, according to the FAO world map legend) and Yolo loam soil (Typic Xerorthents). The soil atmosphere was maintained at a small O2 partial pressure by flowing a gas mixture of 70% He and 30% N2 through plastic jackets surrounding the plastic soil columns, which had many holes (1 mm diam) drilled through the column sides. This column design allowed evolved N2 and N2O gases to be measured in the effluent gas of each column. The nitrate (NO3−) concentration in the solution effluent and the evolved gases from columns with added atrazine (3 mg kg−1) were compared with that from columns without atrazine. Nitrate reduction rates were determined from a mathematical solution of transport and transformation of nitrate according to first‐order kinetics. The presence of atrazine in the soils resulted in slightly increased nitrate reduction rates over that of the controls. Atrazine caused a decrease in the N2/N2O ratio of the evolved gases. A small amount of NO was also detectable in San Cataldo column without atrazine. The apparent inhibition of N2O reduction by atrazine may have environmental implications in relation to N2O release from the soil to the atmosphere.

Studies on use of DTPA and eddha chelates to supply micronutrients to plants in soils includingsimulated drip irrigation

Abstract In an experiment with calcareous Hacienda loam soil and simulated drip irrigation, FeEDDHA was far superior to FeDTPA in supplying Fe to T203 soybeans. The FeEDDHA applied at constant low levels also increased the Zn, Cu and Mn contents on the per plant basis implying that the procedure is not likely to induce deficiencies of those micronutrients. In an experiment with Yolo loam soil which was not calcareous, ZnDTPA and MnDTPA in the irrigation water did increase micronutrient contents of com growing in the soil. With small peach trees grown in the glasshouse in soil, ZnDTPA and MnDTPA resulted in increased uptake of Zn and Mn and often increased uptake of Fe and Cu. When high levels of both ZnDTPA and MnDTPA were applied, there was additive‐type toxicity.

The utilization of thermal infrared radiation measurements from grain sorghum crops as a method of assessing their irrigation requirements

Field studies on irrigated grain sorghum (Sorghum bicolor L. Moench) crops were conducted in California for three years to evaluate the use of thermal infrared measurements to estimate water use and detect crop stress. These studies were conducted on a Yolo loam soil with different rooting volumes to limit the water availability. Data show that the stress-degree-day index (midday comparison of canopy-air temperature differences) provides a valid indicator of crop stress, and that the canopy-air temperature difference increases rapidly above zero when more than 65% of the available water is depleted. The canopy-air temperature difference is also related to leaf-water potential, with an increase above zero when the potential decreases below − 1.1 MPa (=11 bars). Improvement of the performance of the stress-degree-day index through compensation for environmental variability was achieved by including measurements of the plant water stress which are related to available water extracted. It is concluded that remote sensing of emitted thermal radiation offers a promising technique which can be incorporated into irrigation management programs.

Growth and yield response of two potato cultivars to various levels of applied water

The effects of six levels of irrigation water supply on the growth and yield of two potato cultivars, Kennebec and White Rose, were examined in a field experiment conducted on a deep Yolo loam soil. Seasonal patterns of soil water depletion, water-use efficiency, leaf area development, and dry matter partitioning were evaluated.

SODIUM RELATIONS IN DESERT PLANTS

Atriplex canescens (Pursh) Nutt. ssp. canescens (Calligonum c. Pursh.) and Atriplex polycarpa (Torr.) Wats. (Obione p. Torr.) plants were grown in Yolo loam soil in a glasshouse with different levels of sodium salts. Both species tolerated concentrations of salt equivalent to seawater, using either NaCl or Na2SO4. Vegetative yields were slightly higher with chloride, particularly with stems of A. polycarpa; SO42- decreased calcium and magnesium concentrations. Atriplex canescens leaves contained less Na, total cations, Cl, S, and Si, but more N than did those of A. polycarpa. The A. polycarpa would have high concentrations or organic acids in leaves. Chloride decreased N concentrations in leaves of A. polycarpa.

THE EFFECT OF STABLE STRONTIUM SUPERIMPOSED UPON SOIL UNIFORMLY CONTAMINATED WITH STRONTIUM-85 ON UPTAKE OF STRONTIUM-85 BY BUSH BEAN PLANTS

Bush bean plants were grown for 14 days in Yolo loam soil to which strontium-85 had been blended uniformly. Stable Sr was additionally applied at rates of 0, 10, 25, and 100 micrograms per gram of soil. The results in uptake of 85Sr and stable Sr implied that there was somewhere around 8 ±g available native Sr per g soil. Without added Sr, bush beans contained 72, 30, and 64 ±g/g stable Sr per g for primary leaves, trifoliate leaves, and stems, respectively. The addition of stable Sr was reflected in increased plant uptake of stable Sr. It was postulated that native soil Sr would have much greater effect on radioactive Sr transport than would soil Ca. The Y value for Sr uptake was near In 2.

Effect of liming on two trace element stresses including induced iron deficiency on bean plants

Abstract Bush bean plants were grown in Yolo loam soil with excess levels of manganese, copper, cobalt, nickel and cadmium and with combinations of manganese and the other four trace elements. Without liming, the effect of two trace elements on yield was synergistic. With liming, however, the effect for two elements tended towards protective. The line decreased the effect of all added trace elements by decreasing their uptake. The effect of the trace elements on calcium concentrations in leaves closely paralleled that of yields. A portion of the two‐element interaction was iron chlorosis which contributed to the synergism. Nickel plus Mn in nonlimed soil decreased Fe concentration of leaves most and the effect was synergistic. Liming and combined trace elements also decreased silicon concentration of leaves.

EFFECT OF VARIOUS CONCENTRATIONS OF DTPA CHELATING AGENT IN SOIL ON UPTAKE AND DISTRIBUTION OF 241Am IN BUSH BEAN PLANTS

We grew bush bean plants in pots containing Yolo loam soil in a glasshouse for 15 days with a uniformly applied level of 241Am in soil (14 000 dpm/g soil) and with various concentrations of DTPA applied to the soil. The objective was to demonstrate that the effects assigned to this chelating agent on uptake of 241Am by plants will vary with concentration of the chelating agent. Under some waste management conditions, this could be of importance. On a concentration basis, the DTPA resulted in transport of much more 241Am into primary leaves than into trifoliate leaves. The maximum increase was about two orders of magnitude. The ratio of 241Am in primary leaves to that in trifoliate leaves increased with increasing concentration of DTPA. The concentration ratios in each plant part also increased with increasing DTPA. Without DTPA, the CR values were around 3 × 10−2 for these young plants.

Effect of zone placement in soil on trace metal uptake by plants

Abstract Corn (Zea mays L. cv. Golden Cross N.C.) was grown in Yolo loam soil (fine‐silty, mixed, thermic Typic Xerorthents) in pots in a glasshouse with different trace metals in excess in different zones of the soil. In one experiment, five different trace metals were applied simultaneously: in ng/g 13 Li, 200 Zn, 100 Ni, 200 Cu, and 75 Co all as sulfates. In another experiment they were applied separately. Trace elements were applied variously to the top half of the soil, the bottom half of the soil, one half of the soil vertically, all of the soil or none of the soil. When the top half or the side half of the soil was free of the trace metals, plants grew as well as where no trace metals had been applied to the soil. When the top half of the soil had been supplied with trace metals, plants grew just a little better than when they were mixed with all the soil and an apparent reason was roots growing down the sides of the container to the clean soil below. The volume of clean soil available to the plant...

Effect of soil pH on iron uptake and its specific activity by two cultivars of soybeans differing in ability to accumulate iron and by oleander

Abstract PI54619–5–1 and Hawkeye soybeans (Glycine max L.) were grown in Yolo loam soil with different amendments to alter the soil pH (5, 6, 7.4, and 8.2). High specific activity 59Fe had been equilibrated with the soil before transplanting. The numbers of plants per pot varied to create competition (8 or 2 for each variety plus 4 of each variety together). The PI54619–5–1 soybeans were Fe deficient at pH 7.2 and both Varieties were deficient at pH 8.5. The Hawkeye accumulated the most Fe except at pH 8.5. Iron accumulation and specific activity were both decreased at this pH value. Specific activity otherwise increased with soil pH, but varietal difference was most pronounced at pH 8.5. No stress effects were noted for growing the two soybean varieties together in these same pots. A high level of hydroquinone (10‐3 M) in the nutrient solution increased both Fe level and specific activity of 59 Fe in PI54619–5–1 soybeans. The DTPA (diethylene triamine pentaacetic acid) did not always extract the same spe...

Will high usage of synthetic chelating agents eventually harm soils?

Abstract To test the hypothesis that long‐usage of metal chelates on soils will eventually result in abnormal plant nutrition, bush bean plants (Phaseolus vulgaris L. cv. Improved Tendergreen) were grown in Yolo loam soil which had been equilibrated with high levels of DTPA and EDDHA as Na salts; the levels were 500 and 1000 ng/g for each. Two crops of plants were grown at different points in the leaching stages. Yields were not affected by the treatments. Several trace elements were elevated in leaves after partial leaching and, after apparent complete leaching, Mn was elevated in primary leaves of 3 of 4 chelate treatments but in only one of four treatments in trifoliate leaves. There was a residual effect on Zn and P in primary leaves but not in trifoliate leaves. There was no real indication of adverse effects of the high levels of chelating agents after they had been leached from the soil.

Effect of steam sterilization of soil on plants susceptible to iron deficiency

Abstract When soybeans efficient and inefficient for Fe were grown in sterilized and nonsterilized Yolo loam (pH 6) soil, the inefficient PI54619–5–1 soybean became Fe deficient because increased Mn uptake decreased Fe uptake. In efficient Hawkeye soybean, Fe was not depressed enough for Fe deficiency. The Fe inefficient YSI corn inbred was chlorotic whether or not soil was sterilized and Zn and Cu concentrations were elevated. Increased Mn did not further depress Fe. The efficient WF9 inbred was green for both soil treatments.

Single and multiple trace metal excess effects on three different plant species

Abstract Three crops of plants (corn (Zea mays L. cv. Golden Cross N.C.). barley (Hordeum vulgare L. cv. Atlas), soybeans (Glycine max L. cv. Hawkeye and PI54619–5–1) were grown in succession in flats of Yolo loam soil which had received in μg/g soil 0, 13 Li, 200 Zn, 200 Cu, 75 Co, 100 Ni, and 100 Cd both singly and in various combinations. The three plant species with two cultivars of soybeans reacted differently to the trace metals. Protective (competitive), additive and synergistic effects were all present. The treatments slightly modified soil pH but this did not explain all effects. Barley was most tolerant of the trace metals and yield depression occurred only when all six trace metals were applied simultaneously and this probably because of metal induced P deficiency.

Trace metal placement in soil on metal uptake and phytotoxicity

Abstract Corn plants (Zea mays L. cv. Golden Cross N. C.) were grown for 21 days in Yolo loam soil to which a mixture of trace metals had been blended and applied to the soil in compartments. The treatments were control, all contaminated, top 1/2 control ‐ bottom l/2 contaminated, top contaminated ‐ bottom control, and 1/2 contaminated with 1/2 control uniformly mixed. The trace metals involved were applied as sulfates and in μg/g were 200 Zn, 200 Cu, 75 Co, 100 Ni, 100 Cd, and 13 Li. Treatments having l/2 noncontaminated soil whether top or bottom grew plants without stress. The same quantity of trace metals uniformly mixed with all soil gave some indications of phytotoxicity and the treatment with all contaminated soil (two times more trace metals than the other three treatments receiving trace metals) showed severe toxicity symptoms most of which were probably due to Cd. The Zn, Mn, Co, Ni, Li, and Cd concentrations in leaves were highest for this treatment. When the bottom half of soil was contaminate...