J. Letey

GROWTH AND NUTRIENT UPTAKE OF NEWPORT BLUEGRASS AS AFFECTED BY SOIL OXYGEN

SummaryAn oxygen diffusion rate of 20×10−8 g cm−2 min−1 is required for root growth of Newport bluegrass. The optimum O.D.R. is in a range above 40.During the first growth period, the vegetative growth was not greatly affected by oxygen treatment except during the <1% treatment which did not permit root growth. After clipping, the growth increased with increasing oxygen to a maximum at the 10% treatment and then exhibited a lower growth under the 21% treatment. The plants survived through all oxygen treatments.The concentration of N, P, and K in the leaves generally increased with increased oxygen supply. Na accumulated to a high concentration under the lowest oxygen treatment.

INFLUENCE OF SOIL-OXYGEN DIFFUSION RATES ON SUSCEPTIBILITY OF TOMATO PLANTS TO AIR-BORNE OXIDANTS

Tomato plants established in containers of soil with different oxygen diffusion rates were subjected to airborne oxidants for short periods of time. The supply of oxygen to plant roots, or the oxygen diffusion rate, influenced the susceptibility of plants to airborne oxidants. Plants growing in soils with oxygen diffusion rates of 16 to 24 x 10/sup -8/ g. cm./sup -2/ min./sup -1/ were not damaged by peroxyacetyl nitrate (PAN) or ozone. Plants growing in soils with oxygen diffusion rates of 34 to 90 x 10/sup -8/ g. cm./sup -2/ min./sup -1/ were moderately to severely damaged by both PAN and ozone. Water-use data and plant symptoms were an indication of reduced plant vigor at the lower-oxygen treatments. Soil oxygen diffusion rates taken in field plots show that limited oxygen supply to plants could affect the susceptibility of plants to airborne oxidant damage under field conditions. 9 references, 3 figures, 2 tables.