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Abstract
Injury to woody ornamental plants, caused by unseasonably cold weather in early fall or late spring, is a major problem not only to producers and retailers of woody plants but also to consumers who purchase plants for use in the home landscape.
Abstract
The rabbiteye blueberry, V. ashei, is planted to a limited extent in the Southeast, although it is adapted to an area extending from Virginia to Texas. The difficulty in propagating the species is one factor limiting the planting of improved selections (1). Many factors are known to influence root initiation and development in cuttings of rabbiteve, lowbush, and highbush blueberry species (2,4,5,7,8,9,10), but the effect of extended photoperiods on the rooting of the rabbiteye species is lacking. This study was conducted in 1963 and 1964 to investigate the effect of photoperiod and IBA on the rooting of cuttings of the rabbiteye blueberry, ‘Woodard’.
Abstract
Multiple applications of nitrapyrin (5 ppm/pot/week) increased NO3-N retention significantly over the control, and medium NO3-N was consistantly higher with multiple applications than with a single preplant application of nitrapyrin (50 ppm) when NO3-N was the fertilizer source. Multiple applications of nitrapyrin were less effective in increasing plant growth than a single application with an NH4-N fertilizer source.
Abstract
Internal porosity, availability of internally adsorbed water, and root growth within a pine bark particle were studied. Internal pore spaces comprised about 43% to 44% of the volume of a pine bark particle. Scanning electron microscopy (SEM) of Coleus blumei Benth. and Vaccinium ashei Reade showed roots anchored on the exterior surface and developing within the bark particle. Seedling development (Raphanus sativus L.) in water-saturated pieces indicated that internally adsorbed water was available provided that roots developed within the bark particle. The quantity of available water remains to be determined.
Abstract
Under greenhouse conditions, pecan nuts begin to germinate 1 to 2 months after planting and continue to germinate over a 3 to 4 month period (3). Such irregular germination makes studies that require newly germinated pecan seedlings with a uniform physiological age difficult to conduct. A study was initiated to determine the effect of the shell on time to germinamatetion of the first nut (initial germination), uniformity of germination, and percentage germination of pecan nuts.
Abstract
Potassium concentration was highest in the upper 5 cm of medium after leaching with 10 cm H2O, lowest in the middle of the soil column (10 and 15 cm depths), and intermediate at the bottom of the column. Increasing concentrations of applied K (336, 671, and 1007 kg/ha) increased the K level in each medium tested, except 100% sand, and at each depth in the soil column. After leaching, media containing high percentages of sand (75 and 100%) had a lower K concentration at all applied K rates than media containing high percentages of bark (0 and 25% sand). Cation exchange capacity was greater in bark than sand and is probably the most important factor influencing the movement of K in pine bark and sand media.
Abstract
Bulk density (BD) of potting media increased as the percentage of sand was increased in the medium. Because of the “fitting” together of particles, volume of medium mixtures was always less than the total volume of the separate components. Particle size distribution was determined most accurately on a volume basis and was used to identify the potting mixtures. The percentage of medium components (bark or sand) retained on any given sieve size could be determined from BD data. Percolation rate, and cation exchange capacity (CEC) declined as the percentage of sand was increased in the potting mixture. CEC was most accurately determined on a volume basis. Increasing the percentage of sand in the potting medium raised pH from 4.1 to 5.4.
Abstract
Nitrapyrin at 50 ppm, increased dry weights of tomato (Lycopersicon esculentum Mill.) and total N when pine bark comprised part of the medium and NH4 was part of the N treatment. If the medium consisted only of pine bark, nitrapyrin increased dry weights and total plant N with NO3–N and/or NH4–N treatments. The NO3–N level in the medium was higher with all N treatments when nitrapyrin was incorporated. The increase in plant growth is directly related to the higher NO3–N levels in each medium where nitrapyrin was incorporated. The higher media NO3–N with nitrapyrin are attributed to inhibition of the nitrification process and a subsequent inhibitory effect on NO3–N loss.
Abstract
Soil compaction is considered to be a major factor in the loss of grass in established turf plantings. Associated with the onset of soil compaction is a decrease in soil aeration (1), a reduction in gaseous exchange, and reduced water infiltration rates (2, 6, 7). Attempts to increase turf vigor and putting green resiliency by applying higher rates of fertilizer and by increased irrigation have often accentuated long-standing problems of diseases, poor root development, and low water infiltration rates (3,7). Frequent but light irrigations may also contribute to a buildup of harmful salt concentrations in compacted soils (5, 8).
Abstract
Total fresh weight and crown spread of Juniperus chinensis var. sargentii Henry plants, grown in microplots containing a low fertility medium of 4 soil:l sand:l milled pine bark and amended with 10N-4.4P-8.3K fertilizer at rates of 0, 110, or 220 μg/g, were significantly increased by inoculation with a spore mixture of 3 different vesicular-arbuscular (VA) mycorrhizal fungi. Higher fertilizer concentrations improved crown spread but did not affect plant growth. Root colonization by the endophytes ranged from 24.4 to 39.2% and was unaffected by fertilization rates.