Soil Compaction and Moisture Stress Preconditioning in Kentucky Bluegrass. I. Soil Aeration, Water Use, and Root Responses¹

Abstract

Soil compaction and moisture stress are major problems on recreational turfgrass sites. In the greenhouse, we investigated root responses to soil compaction and moisture stress preconditioning, and their effects on water use of Kentucky bluegrass (Poa pratensis L. 'Ram 1'). The compaction treatments included: (i) NC = no compaction, (ii) LT = long-term compaction (equivalent to 720 J energy) over a 99-day period, and (iii) ST = short-term compaction for 9 days. Irrigation regimes were initiated at the same time as LT compaction. They included: (i) well watered = irrigation at -0.045 MPa and (ii) water stressed = irrigation at -0.400 MPa. Ninety-nine days after initiation of preconditioning treatments and after watering each treatment to saturation, a dry-down cycle was started. Compaction treatments reduced ODR to below 0.20 l'g cm-2 min-1 for 143 h compared with 26 h in the uncompacted turf. Long-term compaction increased root weights in the upper 5 em and decreased root weights in the lower 10 to 20 em profile. Short-term compaction decreased root weights only at 15 to 20 em. Root porosity was increased by L T compaction, but the greatest increase was for the combination of LT compaction and water stress resulting in root porosities of 23%. Plants with higher root porosities also exhibited greater water uptake during low soil 0 2 conditions. Soil compaction reduced total water use and moisture extraction in the deeper zones. Moisture stress preconditioning had no effect on root distribution but resulted in greater total water use, primarily from the 0-to Sand 5-to I 0-cm soil zones.----------------

Measurement of plant water use under controlled soil moisture conditions by the negative pressure water circulation technique

“…Previous reports (AGNEW and CARROW 1985;BAR-YOSEF and LAMBERT 1981) have indicated that the influence of soil compaction on water uptake is not consistent. AGNEW and CARROW (1985) found that compaction decreased the total water use but increased the water use efficiency of roots for Kentucky bluegrass grown on a silt loam.…”

Water Competition of Intercropped Pearl Millet with Cowpeaunder Drought and Soil Compaction Stresses

“…The reports on the effects of soil compaction on water-uptake by the plants are inconsistent. The water uptake by Kentucky bluegrass (Agnew and Carrow, 1985), pigeon pea (Kirkegaard et al, 1992), and maize (Amato and Ritchie, 2002) was decreased by soil compaction. On the other hand, Lipiec et al (1988) indicated that water uptake by maize was enhanced by higher soil bulk density.…”

Combined Soil Physical Stress of Soil Drying, Anaerobiosis and Mechanical Impedance to Seedling Root Growth of Four Crop Species

“…Agnew and Carrow, 1985;Engelaar et al, 2000;Trautner and Arvidsson, 2003), few investigators have studied the root growth responses to different levels of combined soil physical stresses. Among them, Eavis (1972) used the pea radicle grown in a sandy loam soil under different levels of soil water potential and soil bulk density, and measured the length and diameter of the radicle as the criteria of the combined stresses under different levels of soil water, air and impedance status.…”