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- Author or Editor: H. Christian Wien x
In a two-year field experiment, sweet corn was intercropped with a perennial cover of white clover. The clover was suppressed after corn emergence by rototilling. The nitrogen exchange between the corn, clover, and soil was closely monitored. Soil sampling indicated the rate and amounts of mineralization of nitrogen from soil organic matter and clover. Fertilizer labelled with 15-N was used to assess contributions of nitrogen from the various sources.
Results from 1989 showed little nitrogen benefit to the corn from the clover. Content of 15-N in the corn indicated that non-fertilizer nitrogen uptake was similar in monocropped and intercropped corn treatments. Corn yields were correlated with the amount of nitrogen fertilizer applied.
In a two-year field experiment, sweet corn was intercropped with a perennial cover of white clover. The clover was suppressed after corn emergence by rototilling. The nitrogen exchange between the corn, clover, and soil was closely monitored. Soil sampling indicated the rate and amounts of mineralization of nitrogen from soil organic matter and clover. Fertilizer labelled with 15-N was used to assess contributions of nitrogen from the various sources.
Results from 1989 showed little nitrogen benefit to the corn from the clover. Content of 15-N in the corn indicated that non-fertilizer nitrogen uptake was similar in monocropped and intercropped corn treatments. Corn yields were correlated with the amount of nitrogen fertilizer applied.
When grown in containers, pineapple lily (Eucomis sp.) can produce excessively long foliage and tall scapes, particularly in cultivars with tall pineapple lily (Eucomis comosa) parentage. Height control, through the use of plant growth regulators (PGRs), is necessary to improve crop quality of potted pineapple lily. In year 1 of these trials, bulbs of cultivars Reuben, Tugela Jade, and Tugela Gem were given substrate drenches of flurprimidol or paclobutrazol, each at 2, 4, or 6 mg per 6-inch pot. Drenches were applied at the “visible inflorescence” stage. As concentration increased, scapes were generally shorter in all cultivars for both PGRs, but there was no effect on foliage length or production time. At the rates tested, the reduction in scape length was insufficient to produce marketable plants of the three cultivars. In the second year, substrate drenches were applied at an earlier stage than in year 1, at “leaf whorl emergence,” when shoots were about 7 cm tall. The PGR treatments were notably more effective at controlling plant height in the second year. As concentration increased, scape and foliage length was reduced relative to the controls in all three cultivars for both PGRs. For all cultivars, inflorescence leaning and toppling were sharply reduced at all application rates compared with untreated controls. The reduction in plant height observed in year 2, particularly in plants treated with 4 or 6 mg/pot, resulted in plants with compact scapes and foliage proportional with their 6-inch containers.
The objective of this study was to determine effects of bulb size on production time and factors influencing crop quality in pineapple lily (Eucomis sp.) cultivars developed originally for cut flower production. The percentage of bulbs producing an inflorescence increased as bulb size increased. One hundred percent of bulbs >18 cm circumference flowered in three of the four cultivars whereas ‘Tugela Jade’ exhibited 88% flowering. The number of flowers per inflorescence increased as bulb size increased. Scape length increased as bulb size increased in ‘Reuben’. Inflorescence length increased as bulb size increased in ‘Reuben’, ‘Tugela Jade’, and ‘Tugela Gem’. Days to anthesis from planting decreased as bulb size increased in ‘Reuben’ and ‘Tugela Jade’. For all cultivars, the largest bulbs produced the greatest number of leaves per plant and the highest quality inflorescences, largely attributable to the larger number of flowers produced per inflorescence compared with smaller bulbs.
Abstract
Tomatoes (Lycopersicon esculentum Mill.) were sampled for laboratory analysis of nitrate nitrogen (NO3-N) in one greenhouse and four field experiments. A ratio of about 3:1 (petiole NO3-N to whole leaf NO3-N) was found over a wide range of conditions for the third leaf below the growing tip and leaves further below this point. The ratio was higher for the very youngest leaves. Nitrate-N increased with leaf age and then remained relatively constant. Whole leaves proved just as effective as petioles for reflecting changes in available N.