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- Author or Editor: R. F. Korcak x
- HortScience x
Abstract
Fluidized bed material (FBM), a dry, high-Ca, alkaline waste product from the combustion of coal and limestone, was used as the sole Ca source for ‘York Imperial’ apples (Malus domestica Borkh.) grown in outdoor sand cultures for one season. Leaf Ca tended to increase with increasing rates of FBM and flesh Ca was not significantly increased by FBM application, although incidence of cork spot tended to be reduced. The trees showed no visible symptoms of toxicity or altered nutritional levels from the FBM treatments.
Tomato (Lycopersicon esculentum Mill., cv. Sunny) plants were grown in a sustainable agricultural system of mulches: black plastic, paper, hairy vetch, crimson clover, and hairy vetch + rye. Total yields were highest with hairy vetch (85.8 t ha-1) and lowest with paper mulch (30.0 t ha-1). The low fertilizer input hairy vetch, crimson clover and hairy vetch + rye treatments received one-half the N-P-K fertigation that was applied to other treatments. Immediately before mowing the cover crops, samples were analyzed. Five weeks after transplanting the tomatoes and at the end of 12 weeks, leaf samples were analyzed for macro- and micro-nutrients. Results of the cover crop analyses indicated minimal differences in N, P, K, Ca, Mg, Mn, B, and Fe concentrations. Tomato leaf analyses at 5 weeks after field planting showed that, among the macro-nutrients, only K was significantly higher in the hairy vetch, hairy vetch + rye, crimson clover, and black plastic treatments than in bare soil and paper mulch. End-of-season leaf analyses showed that significantly higher K was found in the vetch + rye treatment compared to all other treatments.
A 3-year experiment was conducted to determine the optimum fertilizer N requirements of fresh-market tomato (Lycopersicon esculentum Mill.) `Sunbeam' grown on a hairy vetch (Vicia villosa Roth.) or black polyethylene mulch. In 1993 and 1994, four rates of fertilizer N (0, 56, 112, and 168 kg·ha-1) as water-soluble NH4NO3 were applied in 14 equal applications through the trickle irrigation system starting 1 week after planting. Four additional rates (224, 280, 336, and 392 kg·ha-1) were applied in 1995 to assess the plant response to supra-optimal levels of N. Hairy vetch produced 3.3–4.5 t·ha-1 of above-ground biomass and a total N content of 126–169 kg·ha-1 in the above-ground biomass. Leaf N content at 7 weeks after transplanting of tomatoes correlated positively with yield from black polyethylene but did not correlate with yield from the hairy vetch plots where leaf N content was optimal at all N rates. Predicted tomato yields were higher for the hairy vetch than for the black polyethylene treatment at all applied N rates in all years. Tomatoes grown in black polyethylene required N at 130 to 144 kg·ha-1 to achieve yields equivalent to those grown following unfertilized hairy vetch. Tomato yield increased in response to applied N in both mulches in all 3 years; optimum N rates of 89 and 190 kg·ha-1 in hairy vetch and black polyethylene, respectively, were predicted by a linear plateau model, and 124 and 295 kg·ha-1 by a quadratic plateau model. The linear plateau model is recommended because it would allow less N to become available for runoff and leaching.
Abstract
Seedlings of highbush blueberry (Vaccinium corymbosum L.) subjected to 3 fungal treatments and 2 soil pH levels (4.2 and limed to 6.0) displayed no significant treatment interaction in respect to growth, mycorrhizal infection intensity, or nutrient uptake. Among the fungal treatments, there were differences in nutrient uptake and infection intensity, but no difference in total linear stem growth or number of shoots. Lower soil pH resulted in significantly greater stem growth and number of shoots; however, intensity of infection was not significantly different compared to the high pH soil.
Abstract
A near-infrared reflectance (NIR) technique was developed that provides a rapid, nondestructive, nonchemical analysis of ground apple (Malus domestica Borkh.) leaf tissue for predicting total N content. Leaf tissue samples of apple with known (chemical) leaf N concentrations ranging from about 1.6% to 2.9% N were used in the calibration of the NIR technique. The NIR technique was highly correlated (r = 0.923) with the chemically determined total leaf N content. Prediction of tissue N values was performed with a standard error of estimate of about ±0.10% N. This value compares favorably with the standard error obtained for duplicate determinations preformed by a tissue analysis facility employing standard chemical (Kjeldahl) digestion methodology.