Search Results
Abstract
Soils, and leaf and fruit tissues were collected from 200 peach orchard sites during the 1970 growing season. Results obtained were not markedly different from those obtained in an earlier survey in 1962. Most of the soils were quite acid and the peach leaf N levels were below optimum. Most growers appeared to be overfertilizing with P but applying adequate K. Peach fruit were quite high in K, accounting for a sizeable removal of K from the soil.
Abstract
Mouse ear is an abnormal condition in pecans [Carya illinoensis (Wang.) K. Koch] in which the leaflets of the compound leaf fail to elongate in a normal manner and develop into a “mouse ear” shape. Mouse-ear trees had more Ca, Mn, Fe, Cu, Zn and Mo and less Mg in leaf and stem tissues than normal trees. In both normal and mouse ear pecan, 92–96% of total Ca in leaves and stems was nonextractable in 2% acetic acid solution, being in the form of Ca-oxalate crystals. Crystals of cross-sectional area as large as 2000 μm2 and 6000 μm2 were found in leaves and stems, respectively. Although only 600 to 1200 ppm of Ca was available for physiological functions in leaf tissue other than for precipitation of oxalic acid. There was no significant evidence to show that mouse ear is a Ca-deficiency problem.
Abstract
Increased temperature of the growing bed had no effect on fruit yield, fruit cracking, skin strength, or plant growth of tomato (Lycopersicon esculentum mill.). Yield losses from cracking were 2, 16 and 35% in the fall, spring and summer crops, respectively. The pink-fruited ‘Ohio-Indiana Hybrid O’ and ‘Missouri Hybrid 756’ had greater fruit losses due to cracking than the red-fruited ‘Floradel’ and ‘Rapids’. Large fruit were more susceptible to cracking. Fruit cracking in the fall crop was predominantly concentric in nature whereas cracked fruit in the summer was predominantly radial. Skin puncture resistance was inversely related to fruit cracking.
Abstract
Weekly foliar fertilizer applications of 10 ppm NO3-N [as Ca(NO3)2] or NH4-N [as (NH4)2SO4] significantly reduced dry matter, N accumulation, and yield of ‘Blue Lake 274’ snap bean (Phaseolus vulgaris L.) grown in solution culture. The reduction in dry matter and N accumulation were greatest with the NH4-N vs. the NO3-N foliar treatment. Data obtained in this study indicates that the cultural practice of applying NH4 or NO3 fertilizer through an overhead irrigation system may reduce snap bean yield.
Abstract
Glasshouse microclimate during 3 growth periods in the Southern Piedmont region of the United States was characterized. An increase in density of tomato plants (Lycopersicon esculentum Mill.) by one-third, which doubled radiation interception, was suggested by early observations. Maintenance of clean glass surfaces was found to be particularly important during cloudy weather. There was no significant difference between mean air temperature and mean rooting media temperature in the raised beds used. CO2 concentration was found to be low (240 ppm) when fans were not circulating outside air. CO2 generators, installed to increase greenhouse CO2 levels, were not effective possibly because control was inadequate. The use of CO2 enrichment requires further study under Southeastern conditions. Relative humidity remained below the recommended 90% in the green-house except during cloudy-mild weather. Although inside relative humidity was generally less than outside relative humidity, values ranged from 90 to 100%.
Abstract
Most of the leaf Ca collected from healthy and declining peach trees (Prunus persica L. Batsch. cv. Loring) growing on both limed and unlimed field plots was found to be non-extractable in acetic acid irrespective of leaf age, health status, or lime treatment. The concentration of extractable leaf Ca was less than 100 parts per million. Concentration of total Ca was highest in leaves from declining trees but declining trees had fewer and smaller leaves resulting in less total Ca in decline as compared to healthy trees. Large numbers of Ca-oxalate crystals were observed throughout the leaf and stem tissues. Crystals were primarily concentrated in leaf midveins. Midvein sections of leaves from decline trees contained greater numbers of crystals per unit area than did those from healthy leaves from healthy trees.