Physical Soil Amendments, Soil Compaction, Irrigation, and Wetting Agents in Turfgrass Management III. Effects on Oxygen Diffusion Rate and Root Growth1
Abstract:The O.D.R. values under tensiometer guided irrigation were found to be high at the time measurements were made. Under the set irrigation program, the O.D.R. were lowest for unamended soil, next lowest for peat amended soil, and highest for soil amended with lignified redwood and calcined clay. Root growth in containers receiving water on a set schedule was associated with the measured O.D.R. A value of about 0.15 µg cm−2min−1 appeared to be the lower limit for root growth. Each amendment promoted the developme… Show more
“…The 3 to 6 em zone changed very little. Compaction in our study was similar to that on recreational turf, which is confined to the surface 2 to 3 em (2,6,12,16).…”
Section: Soil Physical Responsessupporting
confidence: 82%
“…Total root weights decreased under the set irrigation where considerably more water was being applied, which may have resulted in less favorable aeration status for root growth and viability. Decreased rooting with compaction is commonly reported (3,4,5,6,7,12,20) and irrigation treatments may also affect rooting. Watson (24) found the deepest root system for a mixture of cool-season grasses was with no supplemental irrigation but an unacceptable turf quality occurred.…”
Soil compaction and efficient use of irrigation water are important concerns of turfgrass managers. This field study examined effects of soil compaction on growth and water utilization of a cool‐season turfgrass species under different irrigation programs.
A 2‐year‐old stand of Poa pratensis L., ‘Baron,’ on a fine, montmorillonitic mesic Aquic Arguidoll soil, was subjected to four treatments resulting from a factorial design with two levels of compaction (none and 30 passes per week with roller) and two levels of irrigation (set schedule of 3.8 cm water per week plus rainfall and 3.8 cm when tensiometer at 10 cm depth read −0.70 bar).
Soil compaction had no effect on root weight or distribution. Visual quality, shoot density, verdure, and percent total cover were reduced by compaction while total nonstructural carbohydrates (TNC) were unaffected. In the surface 3 cm of soil, compaction increased bulk density and moisture retention but reduced aeration porosity at −0.1 bar from 18.1 to 12.5%. Irrigation treatment had no effect on any of the soil physical properties.
Without affecting turf quality, water use with tensiometer was reduced by 28 and 48% on noncompacted and compacted areas, respectively, compared to set‐schedule irrigated plots. Water use over a 9‐day period in August indicated that the turf grown under the tensiometer scheduled regime was physiologically or anatomically adapted to use less water even when it was available. This adaptation was not due to differences in vegetative or root growth in this study.
Compaction reduced water use by 20% over the 4 month study. During a 9‐day period in August, compaction reduced water use by 3.5 to 11% for the tensiometer and set‐scheduled treatments, respectively. This response appeared to be due primarily to altered moisture retention properties and reduced shoot growth. Thus, compacted and noncompacted sites should be irrigated on separate schedules.
“…The 3 to 6 em zone changed very little. Compaction in our study was similar to that on recreational turf, which is confined to the surface 2 to 3 em (2,6,12,16).…”
Section: Soil Physical Responsessupporting
confidence: 82%
“…Total root weights decreased under the set irrigation where considerably more water was being applied, which may have resulted in less favorable aeration status for root growth and viability. Decreased rooting with compaction is commonly reported (3,4,5,6,7,12,20) and irrigation treatments may also affect rooting. Watson (24) found the deepest root system for a mixture of cool-season grasses was with no supplemental irrigation but an unacceptable turf quality occurred.…”
Soil compaction and efficient use of irrigation water are important concerns of turfgrass managers. This field study examined effects of soil compaction on growth and water utilization of a cool‐season turfgrass species under different irrigation programs.
A 2‐year‐old stand of Poa pratensis L., ‘Baron,’ on a fine, montmorillonitic mesic Aquic Arguidoll soil, was subjected to four treatments resulting from a factorial design with two levels of compaction (none and 30 passes per week with roller) and two levels of irrigation (set schedule of 3.8 cm water per week plus rainfall and 3.8 cm when tensiometer at 10 cm depth read −0.70 bar).
Soil compaction had no effect on root weight or distribution. Visual quality, shoot density, verdure, and percent total cover were reduced by compaction while total nonstructural carbohydrates (TNC) were unaffected. In the surface 3 cm of soil, compaction increased bulk density and moisture retention but reduced aeration porosity at −0.1 bar from 18.1 to 12.5%. Irrigation treatment had no effect on any of the soil physical properties.
Without affecting turf quality, water use with tensiometer was reduced by 28 and 48% on noncompacted and compacted areas, respectively, compared to set‐schedule irrigated plots. Water use over a 9‐day period in August indicated that the turf grown under the tensiometer scheduled regime was physiologically or anatomically adapted to use less water even when it was available. This adaptation was not due to differences in vegetative or root growth in this study.
Compaction reduced water use by 20% over the 4 month study. During a 9‐day period in August, compaction reduced water use by 3.5 to 11% for the tensiometer and set‐scheduled treatments, respectively. This response appeared to be due primarily to altered moisture retention properties and reduced shoot growth. Thus, compacted and noncompacted sites should be irrigated on separate schedules.
“…Peat, reed sedge or sphagnum, are the most common amendments used in putting green construction (Waddington, 1992). The benefits of peat include reduced soil bulk density, improved rootzone aeration, increased soil moisture retention, gradual release of plant‐available water, and improved turfgrass germination (Letey et al, 1966; McCoy, 1992; Juncker and Madison, 1967; Bigelow et al, 1999). Because peat is an organic material and subject to natural decomposition, it may eventually lose its desirable characteristics (Huang and Petrovic, 1995).…”
A trend to replace peat with inorganic amendments such as calcined clay (CC) and diatomaceous earth (DE) is occurring for athletic fields and golf course putting greens. For laboratory experiments, washed rootzone sand was amended at 15% (v/v) with either Canadian sphagnum peat (CSP), CC, or DE. Amendments reduced the bulk density and increased the total porosity of all mixtures. The DE mixture had the lowest Ksat (41.9 cm h−1), which was attributed to the 2% by weight of particles <0.05 mm in diameter. The inorganic mixtures retained 0.021 to 0.084 cm3 cm−3 less water than the CSP mixture at pressures less than −2.5 kPa. The CSP mixture held significantly more water in the entire profile and in the upper 15 cm compared with the inorganic mixtures and straight sand. Approximately 75% of the total water was lost within the first 15 min after drainage initiation for sand alone and the inorganic mixtures; only 65% was lost in the first 15 min for the CSP mixture. After 24 h of free drainage, the CC mixture lost the most water, while the DE mixture lost the least. Differences among the rootzone mixtures were measured in the first 3 min of drainage, with straight sand and the CC mixture having the greatest flow rate compared with DE and CSP mixtures. After 24 h of free drainage, the gravel layer remained saturated. For improved water retention in the rootzone, CSP remains the preferable amendment to sand when mixed at these ratios.
“…Another potential problem associated with the use of RW is surface and groundwater pollution caused by leaching and runoff of RW (Thomas et al, 2006). Soil amendments, such as calcined clay and peat (Letey et al, 1966; Morgan et al, 1966; Valoras et al, 1966) and wetting agents (Karnok and Tucker, 2001), have long been used to improve water movement in turfgrass soils adversely affected by compaction, salinity, and other factors. For example, gypsum has been used to decrease P leaching and runoff (Torbert et al, 2005; Watts and Torbert, 2009) as well as to aid in the reclamation of calcareous saline‐sodic soils (Gharaibeh et al, 2009).…”
Recycled wastewater (RW) is a source of irrigation for golf courses in many parts of the world. The objectives of this study were to determine the effects of gypsum and wetting agent applications on the turfgrass quality, clipping yield, root zone chemical and physical properties, and leachate of a sand‐based putting green irrigated with secondary and tertiary RW. Our results showed that gypsum amendment produced better turfgrass quality under summer heat stress than the wetting agent and the control. Soil water infiltration was impeded by secondary and tertiary RW but was improved by the gypsum treatments. When compared with topdressing with straight sand, the wetting agent application did not improve turfgrass quality or soil properties when irrigated with RW. Monthly applications of a wetting agent resulted in lower water infiltration rates, but the values remained within the U.S. Golf Association recommendations for putting green construction. Golf course superintendents are encouraged to use gypsum when managing sand‐based putting greens with RW as the primary source of irrigation water.
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