Supplemental Fe fertilization to improve turfgrass quality has become an increasingly common practice on many turfgrass areas. Field studies were conducted to evaluate the nutrient uptake, growth, and quality of Kentucky bluegrass (Pea pratensis L.) treated with chelated Fe sources. Iron sources were evaluated over 2 years at 1.5,3.0, and 6.0 kg Fe/ha applied in May, July, and September of each year. Turf treated with an iron orthophosphate citrate source (Fe-PC) exhibited more foliar growth than nontreated turf on seven of 11 sampling dates during the study. Iron citrate sources [Fe-C(EI) and Fe-C(T)] and Fe-DTPA applications resulted in similar growth rates, never stimulating growth more than the Fe-PC source and rarely increasing growth compared with nontreated turf. Increasing the Fe rate within source did not typically increase growth. Iron-treated turf exhibited quality superior to nontreated turf throughout the study with all sources performing comparably. Increasing Fe rate did not result in a corresponding increase in quality, due to greater phytotoxicity at higher rates. Although several sources produced notable phytotoxicity at 6.0 kg Fe/ha, repeated application did not decrease turfgrass density. Iron tissue content increased linearly with rate on four of five sampling dates during the study however, no source resulted in tissue Fe content significantly higher than other sources. Application of sources containing supplemental P and/or K did not increase tissue P or K content. Chemical names used: iron citrate (Fe-C); iron diethvlenetriamine pentaacetate (Fe-DTPA); iron orthophosphate citrate (Fe-PC).
, personal observation). Various studies have been completed on the effect of rate of N fertilization on the growth and yield of mature blueberry plants. In a 5-year study on ‘Bluecrop’ blueberry, plants fertilized with a split application of 75 kg·ha −1 of
Abstract
Chrysanthemum plants (Chrysanthemum morifolium Ramat. cv. Bright Golden Anne) were grown for 84 days in plastic pots containing 6 different media treated with inorganic fertilizers or liquid digested sewage sludge at 50, 100, and 200 ml/week. Plants grown in 1 soil: 1 sand: 1 peat, 1 soil: 1 sand, and 1 soil: 1 peat were similar to each other in size, and larger than plants grown in 1 sand:1 peat, all sand, or all peat. Peat-grown plants were smallest. Plant size and flower diameter decreased with increasing rates of sludge application. Plants fertilized with inorganic sources of fertilizer looked the same as those grown with 50 ml/week sludge (6 mm), except the sludge-treated plants were shorter and had a smaller dry weight. Plants treated with 50 ml/week sludge had flowers with a diameter and dry weight equal to those of flowers grown with liquid or pelletized inorganic fertilizer.
We evaluated the effect of fertilization treatments in combination with clippings disposal on perennial ryegrass (Lolium perenne L.) in two adjacent locations. Clippings left on turf during mowing decreased dollar spot (Sclerotinia homoeocarpa F.T. Bennett) in both locations during three summers compared with clippings removed in mower baskets. However, brown patch (Rhizoctonia solani Kuhn) increased during July and Aug. 1995 when clippings were left on turf. Dollar spot was more severe with N (kg·ha–1·year–1) at 120 compared to 240; brown patch was more severe at 240. While clippings disposal had significant effects on disease incidence, implementation may not be practical because of the contrary responses of the observed diseases to this management approach.
During the 1992-93 fruiting season, strawberries were fertigated weekly with 0.28, 0.56, 0.84, 1.12, or 1.40 kg N/ha/day from ammonium nitrate. K was applied uniformly at 0.84 kg/ha/day by fertigation. Irrigation maintained soil moisture tension in the beds between -10 and -15 kPa. Fruit yields responded positively to N fertilization with yields maximized at 0.56 kg N/ha/day. Leaf N and petiole sap nitrate N concentrations increased with N rate with leaf-N for the plants receiving 0.28 kg N/ha/day remaining below 25 g·kg-1 most of the season. Sufficiency ranges for petiole sap nitrate-N quick testing were developed.
The effect of a fish hydrolyzate fertilizer product on growth of Acer rubrum and Pseudotsuga menzeisii was studied. Bare root plants were fertilized at a rate of 90, 180, and 270 kilograms of N/hectare. Soil samples were collected every two weeks throughout the summer and were analyzed for nutrient content. In addition, August leaf samples were collected and analyzed for N, P, and K content. Growth measurements on Acer rubrum indicate that stem caliper was significantly increased by all fertilizer treatments over the control trees. The granular fertilizer produced a significant linear increase in caliper growth with respect to fertilizer rate. Shoot growth was also significantly increased by all fertilizer treatments; however, as with caliper growth, the granular fertilizer treatments resulted in the greatest and most consistent response. The response of Pseudotsuga menzeisii showed significant increases in shoot growth and stem caliper but results were not as consistent as in the case of the maple.
In Michigan boron (B) deficiencies in sour cherry have resulted in routine use of B sprays to enhance fruit set and increase fruit yield. However, field observations indicate that high B levels are associated with premature softening, making fruit unacceptable for processing. Our fertilization studies show that fruit B levels are higher, but B generally has little or no effect on fruit size, maturity, color, or pull force. However, at some locations, B applications increase the number of soft fruit, especially when harvest is delayed well after the optimum maturity date (as indicated by pull force). B-induced yield increases can be achieved without inducing excessive fruit softening by careful monitoring of fruit maturation and prompt harvest. Leaf and fruit B levels will be presented.
When using the closed, insulated pallet system (CIPS), it is desired to apply the fertilizers once at the beginning of planting and last through harvest. When doing so, the electrical conductivity (EC) of the root environment needs to be at a reasonable level. Therefore, the objective of this experiment was to determine the effect of fertilizer conserver placement and increasing rate on the EC of the growth media. When delivering nutrients in such a manner, the fertilizer ions have limited surface area in contact with the root growth media that limits ion diffusion rate. Five fertilization rates, 15, 45, 60, 75, and 105 g per 1.5-L media pouch, were tested in a completely randomized arrangement. In each pouch, two fertilizer conservers were placed in the center of the lower half of media, each containing a different source of fertilizer. Tomato cv. `Pik Red' was used to test the growth response to treatment. At day 100, the ECs of the middle 5 cm stratum of the growth media for the 15–75 g treatments were not significantly different from each other. Their ECs ranged from 2.52 to 4.51 dS/m. However, middle layer in the 105g treatment was 12.97 dS/m, while EC for the layer immediately below it was 1.18 dS/m. Because there were no differences in shoot and fruit weights among all fertilization treatments, compensation nutrient uptake and water uptake specialization may have occurred in the high salinity and lower salinity, respectively. The data illustrate that delivery of nutrients in small conservers is a feasible approach for the CIPS. Only small amounts of fertilizer are required for a 100-day tomato crop grown in CIPS.
Two field experiments were conducted with shallot (Allium cepa var. ascalonicum Baker) on heavy clay soil to evaluate growth and yield response to mulching and nitrogen fertilization under the subhumid tropical climate of eastern Ethiopia during the short and main rainy seasons of 1999 with rainfalls amounting to 240 and 295 mm, respectively. The treatments included wheat straw, clear and black plastic mulches, and an unmulched control, each with nitrogen rates of 0, 75, or 150 kg·ha-1. Straw and black plastic mulches increased soil moisture while clear plastic reduced it considerably. Weed control was best with black and clear plastics in the short season and with black plastic or straw mulch in the main season. Both plastic mulches elevated soil temperature, especially clear plastic, which also caused most leaf tip burn. Yield increased nearly three-fold with the black plastic mulch in the short season and by one fourth in the main season compared to the bare ground. The straw and clear plastic mulches increased yield during the short sea son, but slightly reduced yield in the main season. The growth and yield of shallot were related to the weed control and soil moisture conservation efficiency of the mulches. Mulching did not alter the dry matter and the total soluble solids contents of the bulbs. Nitrogen fertilizer increased leaf numbers, plant height, mean bulb weight, bulb dry matter, and total soluble solids while reducing marketable bulb number, but did not significantly affect yield, leaf tip burn, or weed abundance.
The effects of Ca and N on cut flower production of Alstroemeria were determined in separate greenhouse experiments. Calcium was supplied as Ca(NO3)2 and CaCl2 at 0, 1, 2, 4, 8, and 12 mmol·L-1 added to tap water containing Ca at ≈0.2 mmol·L-1. Nitrogen was supplied as KNO3 and Ca(NO3)2 providing total N at 0, 3.5, 7, 14, 28.5, and 57 mmol·L-1 in tap water containing N <0.2 mmol·L-1. Nutrient solutions were applied at 7- or 10-day intervals to plants growing in a soilless medium in 2.6- or 5.5-L containers. Flowering stems were harvested when the primary florets opened. Total N concentration was measured in leaf tissue from the upper portion of flowering stems. Flower production was not affected by Ca supply, but increased with N supply to a maximum of about four stems per plant on a weekly basis at 28.5 mmol·L-1, then decreased to less than three stems per plant at 57 mmol·L-1. Nitrogen concentration in leaf tissue on a dry mass basis was maintained at 45 ±3 g·kg-1 in plants supplied with N at 28.5 mmol·L-1, 52±5 g·kg-1 at 57 mmol·L-1, but <40 g·kg-1 with N supply of 14 mmol·L-1 or lower. Nitrogen fertilization of Alstroemeria should be managed to maintain leaf tissue N close to 45 g·kg-1.