scholarly journals Effect of Application Date on Absorption of 15Nitrogen by Highbush Blueberry

1997 ◽  
Vol 122 (3) ◽  
pp. 422-426 ◽  
Author(s):  
Philip A. Throop ◽  
Eric J. Hanson

Rates of absorption of 15N-enriched ammonium sulfate by young `Bluecrop' highbush blueberries (Vaccinium corymbosum L.) were compared following applications on six dates between late April and September. Ammonium sulfate solutions containing 2.1 g N (10.2 atom % 15N) were dripped directly into the root zone of single bushes. Soil covers and irrigation were used to maintain similar soil moisture conditions during treatment periods. Treated bushes from each application date were excavated after 2 weeks of exposure and separated into roots, stems, and current season's growth (new shoots, leaves, fruit). Tissues were dried, weighed, and analyzed for 15N and 14N by mass spectrometry. Soils were also analyzed for labeled and nonlabeled N. Bushes treated in late May, June, and July absorbed a greater percentage of applied N (6% to 9%) than bushes treated in April, August, or September (1% to 3%). Absorption of N appeared to be affected more by the demand of the plants than soil N availability. Plants absorbed N most efficiently during active growth between late bloom and fruit maturity.

2000 ◽  
Vol 10 (2) ◽  
pp. 308-314 ◽  
Author(s):  
Sridhar Polavarapu

A common practice in highbush blueberry (Vaccinium corymbosum L.) culture is to use combinations of insecticides and fungicides to reduce the number and cost of pesticide applications. In response to apparent phytotoxicity observed in commercial fields that were treated with combinations of diazinon and captan formulations, phytotoxicity of two formulations of diazinon (Diazinon AG600 and Diazinon 50W) and captan (Captan 80WP and Captec 4L) was investigated on highbush blueberries during 1997 and 1998. Phytotoxicity injury similar to injury observed in commercial fields was reproduced in treatments with diazinon and captan mixtures in all experiments. The Diazinon AG600 and Captec 4L mixture was the most severe and caused significantly more phytotoxic-ity to fruit and leaves than individual treatments of Diazinon AG600, Captec 4L or untreated control. Separation of diazinon and captan applications by 8 h significantly reduced phytotoxicity compared to mixture treatments. Injured fruit and leaves recovered over time and most treatments showed only a mild injury at the time of harvest. Phytotoxicity on fruit and leaves caused by Diazinon AG600 and Captec 4L mixture was significantly affected by application date with the earliest application causing the greatest injury. These data indicate that diazinon and captan mixtures cause phytotoxicity on highbush blueberries and therefore the two should not be applied in combination.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 436c-436
Author(s):  
Philip A. Throop ◽  
Eric J. Hanson

Absorption of “N-enriched fertilizer by young `Bluecrop' bushes was compared following applications on six dates between April and Sept. Ammonium sulfate solutions containing 2.1 g N (10.2 atom % 15N) were dripped directly into the root zone of single bushes. Soil covers and irrigation were used to maintain similar soil moisture conditions during treatment periods. Bushes were excavated after two weeks of exposure, and separated into roots, stems, and current-season growth (shoots, leaves, fruit). Tissues were dried, weighed, and analyzed for 15N and 14N by mass spectrometry. Bushes treated in May, June and July absorbed a greater percentage of applied N (6-8%) than bushes treated in Apr, Aug or Sept (1-3%). Results indicate that fertilization between late May and late July may result in the greatest efficiency of fertilizer use.


2013 ◽  
Vol 30 (1) ◽  
pp. 1-10
Author(s):  
Jana Apse ◽  
Aldis Karklins

Abstract Highbush blueberries are a relatively new crop in Latvia raising interest in farmers who wish to diversify their commercial horticultural activities. It is considered that soil properties are one of the possible shortcomings limiting establishment of high-productive plantations in areas where soil reaction is close to neutral. The research objective was to test the main soil characteristics in a commercial highbush blueberry plantation where initial soil properties were changed as a result of soil modification (deep tillage, peat additions) before planting of bushes and afterwards maintained (mulching with acid peat and sawdust) periodically. The research was carried out in 2011 - in a farm where the blueberry plantation had been established seven years ago. The experimental plots were arranged on a complex slope, by choosing different parts of terrain. Soil - Haplic Cambisol, sandy loam, formed on a low calcareous moraine. Original topsoil’s reaction was pH KCl 5.37. Five experimental plots, each consisting of seven bushes, were set up. Research showed that modification of topsoil significantly changed the physical and agrochemical properties of soil. Soil bulk density reduced, porosity and soil aeration increased. Sphagnum peat (pH KCl 3.0) as a soil modifier allowed efficiently reducing the soil reaction at the soil root zone and provided an optimal environment for blueberries. Soil properties were not the determinant factor that limited establishment of a productive blueberry plantation. Soil properties adjusted accordingly to the requirements of highbush blueberry gave the possibility of establishing plantations also in typical mineral soils that develop on a low calcareous moraine.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 394C-394
Author(s):  
W. Kalt ◽  
C. Lawand ◽  
C.F. Forney

Highbush blueberry (Vaccinium corymbosum) fruit of the cultivars `Bergitta', `Bluegold', and `Nelson' were harvested at six stages of maturity and evaluated for their antioxidant capacity and anthocyanin and phenolic content. Fruit of the four earliest maturities were also stored at 20 °C for up to 8 days. At the time of harvest, fruit of different maturities had substantial differences in their anthocyanin content, and less marked differences in phenolic content and antioxidant capacity. Substantial anthocyanin synthesis occurred in under-ripe fruit during 20 °C storage, and varied depending on fruit maturity at harvest. Total phenolic content changed very little during storage, and there was no change in fruit antioxidant capacity. The results suggest that anthocyanin phenolics are formed on or off the plant, primarily from other pre-existing phenolic components. Whether phenolics are present as anthocyanins or other colorless forms, has relatively little impact on antioxidant capacity.


2001 ◽  
Vol 1 ◽  
pp. 207-215 ◽  
Author(s):  
Kenneth W. Staver

Historically, N availability has limited agricultural production as well as primary production in coastal waters. Prior to the middle of the last century, N available for grain production generally was limited to that supplied by previous legume crops, released from soil organic matter, or returned to the soil in animal wastes. The development of infrastructure to produce relatively low-cost inorganic N fertilizers eliminated the need to focus management of the entire agricultural system on increasing soil N availability. Increased N availability has contributed to dramatic increases in agricultural production but also has led to increased losses of both N and C from agricultural systems. N losses from cropland have been linked to increased algal production in the Chesapeake Bay, with N loss from cropland estimated to be the primary N input to the Bay from Coastal Plain regions of the watershed. The decade-long effort to reduce these losses has focused on reducing agricultural N use, but this strategy has yet to yield apparent reductions in N loadings to Coastal Plain tributaries. Although nitrate leaching losses are often attributed to inefficient use of N inputs, soil nitrate data indicate that both corn and soybeans can utilize nearly all available soil nitrate during periods of active growth. However, both crops tend to stop utilizing nitrate before mineralization has ceased, resulting in a late season buildup of root zone nitrate levels and significant leaching losses even when no N was applied. Reducing nitrate losses due to the inherent N inefficiency of summer annual grain crops will require the addition of winter annual crops to rotations or changes in weed management approaches that result in plant N uptake capacity being more closely matched to soil microbial N processes.


Author(s):  
JÚLIA RIBEIRO SARKIS ◽  
ISABEL CRISTINA TESSARO ◽  
LIGIA DAMASCENO FERREIRA MAECZAK

The objective of this study was to apply a HPLC methodology for qualitative and quantitative analysis of the six anthocyanidins present in fruits and to analyze the anthocyanin and anthocyanidin content of blueberries cultivated in Southern Brazil. The samples used belong to highbush blueberries (Vaccinium corymbosum) cultivars. Total anthocyanin content was determined by the pH differential method and an HPLC gradient elution system with C18 column and UV-Vis detection at 520 nm were used for separation and quantification of the anthocyanidins. Total anthocyanin content was of 128 ± 3 mg per 100 g of fresh pulp. Blueberry pulp presented 55 % of delphinidin, 8 % of cyanidin, 3 % of peonidin and 34 % of malvidin. Pelargonidin was not identified in the sample and petunidin was below the limits of quantification. The results were similar to those reported in studies using North American and European blueberries.


1998 ◽  
Vol 123 (4) ◽  
pp. 706-713 ◽  
Author(s):  
D. Neilsen ◽  
P. Parchomchuk ◽  
G.H. Neilsen ◽  
E.J. Hogue

Direct application of fertilizers in irrigation water (fertigation) is an efficient method of supplying nutrients to fruit trees. Information is needed on the relationship between irrigation and N inputs on N availability in order to target nutrient applications to meet plant demands. Soil solution was collected from permanently installed suction lysimeters and NO3-N concentration was measured over the growing season in three experiments: 1) comparison of sprinkler irrigation + broadcast fertilizer with weekly fertigation + daily drip irrigation; 2) comparison of (NH4)2SO4 or Ca(NO3)2 as N sources under daily fertigation; and 3) comparisons of combinations of irrigation applied at either fixed rates or to meet evaporative demand and fertilizer (Ca(NO3)2) applied daily either at fixed rates or to maintain a given concentration in the fertigation solution in two soil types—loamy sand and silt loam. Trials are located in high density apple plantings of either `Gala' or `Empire' apple (Malus × domestica Borkh.) on M.9 rootstock. Nitrate-N concentration in the soil solution measured at 30 cm deep remained higher, over more of the growing season, for weekly fertigation + daily drip irrigation than for a single broadcast fertilizer application + sprinkler irrigation. With daily Ca(NO3)2 fertigation, soil solution NO3- N concentrations increased and decreased rapidly with the onset and end of fertigation respectively, remained relatively constant during the intervening period and were directly proportional to either the amount of N or the amount of irrigation water added. Daily fertigation with (NH4)2SO4 resulted in less control of NO3-N availability in the root-zone than with Ca(NO3)2, which may be problematic for precise timing of N nutrition. Except for the fixed irrigation rate applied to the loamy sand soil, soil solution NO3-N concentrations at 30 cm beneath the emitter were similar to average concentrations in the fertigating solution, for all methods of irrigation management in both soil types. Elevated NO3-N concentrations in soil solution below the root zone (75 cm deep) were detected in the loamy sand regardless of methods of N application and irrigation although there was some evidence of less leaching to this depth, under scheduled irrigation. In the silt loam soil, considerably lower concentrations of NO3-N were found beneath the root zone than at 30 cm deep for all of irrigation procedures and frequently there was insufficient water moving to 75 cm to provide sample. Tree growth in the loamy sand was less than in the silt loam soil; was limited by low application of irrigation water in 1992 and 1993; was unaffected by NO3-N concentration in the root zone, indicating that N inputs could be minimized by adding N to maintain concentrations of 75 μg·mL-1 or possibly less. Nitrogen inputs may also be reduced if fertilizer N and irrigation water could be retained within the root zone. For coarse-textured soils this will require precise additions of water and possibly soil amendments to improve water holding capacity.


2012 ◽  
Vol 58 (No. 5) ◽  
pp. 236-241 ◽  
Author(s):  
S. Mihaljević ◽  
B. Salopek-Sondi

Auxins and their synthetic analogues are commonly used for rooting of cuttings, but their efficiency depends on experimental set-up and, even more importantly, on species or cultivar, and type of explants investigated. In attempt to improve rooting procedure for highbush blueberries (Vaccinium corymbosum L.), we investigated alanine conjugate of indole-3-butyric acid (IBA-Ala) as potential root-promoting compound and compared with commonly used auxins indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA). The effect of different concentrations of auxins on the rooting of highbush blueberry stem cuttings (var. Bluecrop, Bluetta, Burlington and Jersey) and in vitro-derived microcuttings (var. Jersey) was investigated. Auxin treatments significantly promoted rooting of all four varieties in comparison to control. The most efficient rooting promoter in all varieties appeared IBA-Ala (provided up to 83%, and 93% of the rooted cuttings and microcuttings, respectively). Furthermore, IBA-Ala caused a vigorous, well-branched root system that resulted in better acclimatization and survival of plants. Results suggest the application of IBA-Ala may be beneficial for rooting of difficult-to-root varieties of blueberry and related species and their practical application in the nursery industry.  


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