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Carl R. Crozier, Ronnie W. Heiniger, and Michael Bishop

During Summer 1997, soil compaction in agricultural fields was evaluated using a portable electronic cone penetrometer. Rather than requiring the operator to read from an analog scale, this penetrometer stores data in a digital form, which are downloaded to a personal computer for analysis. Soil strength, measured in 1-inch (2.5-cm) increments, can be stored for up to 100 25-inch (64-cm) deep soil profiles. This instrument can be operated by a single person and facilitates collecting large data sets required to characterize highly variable soil environments. Because the penetrometer was designed to measure and formulate predictions about the trafficability of wet soils, it is often incapable of measuring the higher soil resistance occurring in drier agricultural fields. If used soon after rainfall or irrigation, it is useful in detecting hardpans associated with tillage or traffic patterns.

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Juan Carlos Gilsanz, D. C. Sanders, and G. D. Hoyt

Rye plus crimson clover cover crops were followed by spring potato and fall snap bean or sorghum or fallow. The soil samples at 15 cm increments to 90 cm were evaluated for nitrate levels after each crop and cover crop. After the cover crops, soil nitrate levels were reduced relative to the fallow area. After the potato, crop soil nitrate levels increased above initial spring levels due a uniform fertilization due to the amount of N applied and short cycle of the crop. Snap beans and sorghum had increased plant stands and reduced soil impedance after fall cover crops. HOW nitrate levels varied with soil depth and time will be discussed.

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David W. Wolfe, Daniel T. Topoleski, Norman A. Gundersheim, and Betsy A. Ingall

A 3-year field study conducted on an Eel silt loam soil (Aquic Udifluvent) compared cabbage (Brussica oleracea L. capitata group), cucumber (Cucumis sativus L.), snap bean (Phaseolus vulgaris L.), and sweet corn (Zea mays L.) for their growth and yield response to an artificially compacted soil layer beginning at about the 10-cm depth. Slower growing cabbage seedlings in compacted plots were more subject to flea beetle damage than the uncompacted controls. Prolonged flooding after heavy rainfall events in compacted areas had a more adverse effect on cabbage and snap bean than on cucumber or sweet corn. Sweet corn showed almost no growth reduction in one of the three years (1993) when relatively high fertilizer rates were applied and leaf nitrogen deficiencies in compacted plots were prevented. Maturity of cabbage, snap bean, and cucumber was delayed, and the average reduction in total marketable yield in (direct-seeded) compacted plots was 73%, 49%, 41%, and 34% for cabbage, snap bean, cucumber and sweet corn, respectively. Yield reduction in transplanted cabbage (evaluated in 1993 only) was 29%. In a controlled environment greenhouse experiment using the same soil type and similar compaction treatment as the field study, compaction caused a reduction in total biomass production of 30% and 14% in snap bean and cabbage, respectively, while cucumber and sweet corn showed no significant response. The growth reductions of snap bean and cabbage in the greenhouse could not be attributed to compaction effects on soil water status, leaf turgor, nutrient deficiency, or net CO, assimilation rate of individual leaves. Root growth of sweet corn was least restricted by the compacted soil layer. The contrast between our field and greenhouse results indicates that the magnitude of yield response to compaction in the field was often associated with species sensitivity to secondary effects of compaction, such as prolonged flooding after rainfall events, reduced nutrient availability or uptake, and prolonged or more severe pest pressure.

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Jae H. Han, George L. Good*, and Harold M. Van Es

Field experiments were conducted in 1998 and 1999 to determine the effect of soil-incorporated, composted municipal biosolids on the growth and nutrient content of 30.8 cm-38.5 cm Rhododendron × `PJM' grown as containerized plants. Biosolid compost produced in Endicott, N.Y., was incorporated in May 1998 and 1999 at rates of 0, 9.8 Mg/ha and 19.7 megag/ha to a depth of 23 cm. Each treatment was replicated six times in a randomized block design. Plants were planted 10 June 1998 and 8 June 1999. Plants were harvested 10 June, 19 Aug., and 22 Oct. 1998 and 8 June and 22 Sept.1999 after which they were dried, weighed, and analyzed. During 1998, there was little difference in dry weight or nutrient content in plants harvested at the August harvest date, however, dry weight and most nutrient levels increased with increasing rates of compost application in plants harvested at the October harvest date. In 1999, no statistical differences were noted at the September harvest date in plant dry weight or nutrient content. In 1999, measured soil physical properties (water retention, bulk density, water content, and soil strength) did not differ significantly between treatments. Excellent soil structure and drainage, relatively low rates of compost application and a severe drought may have contributed to the lack of any conclusive results noted in 1999 though some positive plant responses to the treatments were evident in 1998.

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Gregory Peck, Ian M. Merwin, Emily Vollmer, and Kristine Averill

Apple growers in New York lack the tools to produce high quality fruit for the organic or IFP marketplace. We are systematically evaluating OFP and IFP systems for pest control efficacy, fruit and soil quality, environmental impacts, and economic sustainability, in an orchard of disease-resistant `Liberty' on M.9 rootstock. The OFP system follows USDA-NOP standards and the IFP system follows newly developed NY IFP standards. In the first year of this study (2004), both systems were equally productive, but variable costs for OFP were twice that of IFP, due to 11 kaolin applications, while returns were comparable. In 2005, OFP yields were 25% greater than IFP yields, but 30% of OFP fruit was unmarketable largely due to insect damage. This loss, plus small fruit size, resulted in OFP returns of $5432 per hectare, about half the IFP returns. With only four kaolin applications in 2005, OFP costs were $2437 per hectare, marginally greater than the $2083 per hectare costs for IFP apples. Harvest maturity indices were similar and peak fruit quality was attained in both systems in early Oct. In 2004, consumer panelists could not detect differences between fruit from the two systems, but in 2005 panelists rated OFP apples as sweeter, more tart, better flavored, and more acceptable overall. Antioxidant activity, total phenolics concentrations, and mineral content of apples were similar between systems in both years. Values for all essential plant nutrients, organic matter content, pH, and CEC were also equivalent in each system both years. Cultivation was likely responsible for lowering the bulk density, soil strength, and aggregate stability of the OFP top soil in 2005. While OFP remains very challenging, IFP can be implemented successfully in New York orchards.

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Glenn R. Wehtje, Joey N. Shaw, Robert H. Walker, and Walker Williams

Various inorganic soil amendments have been promoted as a means of improving the chemical and physical properties of certain soils. To test this hypothesis, a marginally productive soil was supplemented with 20%, 40%, 60%, and 80% (v/v) of either selected inorganic amendments or sand. Amendments consisted of commercially available diatomaceous earth, calcined clay, zeolite, and crystalline SiO2. The soil material was extracted from the argillic horizon of a Cecil sandy loam (fine, kaolinitic, thermic Typic Kanhapludults). Ability of these soil-amendment mixtures to promote `Tifway' bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy] growth was evaluated under greenhouse conditions, and contrasted to that obtained in nonamended soil. Selected chemical and physical properties that are pertinent to plant growth were also evaluated. The experiment, which was conducted 3×, began with a §60-day period in which both water and nutrients were optimum. This was followed by a 30-day drought. During optimum water and nutrients, no soil-amendment treatment(s) consistently resulted in superior bermudagrass growth compared to soil alone. However, <2% of the bermudagrass tissue that was produced during the drought became green and succulent with the resumption of irrigation in nonamended soil. This percentage was exceeded by all treatments that contained either ≥60% diatomaceous earth (Axis), or ≥40% calcined clay (Profile); and by 100% zeolite (Clinolite) and 100% silica (Green's Choice). Drought-sustaining ability of soil-amendment mixtures was significantly (P < 0.05) correlated with water-holding ability, soil strength, bulk density, and oxygen diffusion rate, but not correlated with either pH or cation exchange capacity (CEC). While certain inorganic amendments did improve the drought-sustaining ability of soil, the amount required was generally ≥40%.

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Kevin R. Kosola, Beth Ann A. Workmaster, James S. Busse, and Jeffrey H. Gilman

correlation between root damage and soil moisture. Because soil strength is lower in wetter soil ( Hillel, 1982 ), we hypothesized that the lowest root damage would be found in plots with the wettest soil. The wettest soil was found in the plot of swamp white

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Ted S. Kornecki, Francisco J. Arriaga, and Andrew J. Price

recover. Also, uneven soil surface (i.e., depressions from previous raised beds) and possibly lower soil strength resulting from higher volumetric soil moisture content that averaged ≈15% at rolling time could reduce crimping effectiveness. To avoid late

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Maren J. Mochizuki, Anusuya Rangarajan, Robin R. Bellinder, Thomas Björkman, and Harold M. van Es

, and nitrogen on head weight, yield, and nutrient concentration of spring cabbage J. Amer. Soc. Hort. Sci. 106 540 545 Laboski, C.A.M. Dowdy, R.H. Allmaras, R.R. Lamb, J.A. 1998 Soil strength and

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Ted S. Kornecki and Francisco J. Arriaga

minimize weed populations. Conventional tillage increases soil erosion and nutrient loss, reduces organic carbon, and increases soil strength ( Blough et al., 1990 ; Mahboubi et al., 1993 ). Plastic mulch is expensive and could cause environmental problems