Soil Heating Studies with Cool Season Turfgrasses. II. Effects of N Fertilization and Protective Covers on Performance and Chlorophyll Content 1

1971 ◽  
Vol 63 (5) ◽  
pp. 680-685
Author(s):  
F. B. Ledeboer ◽  
C. R. Skogley ◽  
C. G. McKiel
Keyword(s):  
Chlorophyll Content ◽  
N Fertilization ◽  
Cool Season ◽  
Soil Heating

scholarly journals Urochloa ruziziensis responses to sources and doses of urea

2016 ◽  
Vol 20 (5) ◽  
pp. 401-407 ◽  
Author(s):  
João E. S. Lima ◽  
Adriano S. Nascente ◽  
Wilson M. Leandro ◽  
Pedro M. da Silveira
Keyword(s):  
Chlorophyll Content ◽  
Dry Matter ◽  
N Fertilization ◽  
N Losses ◽  
Total N ◽  
Rainy Period ◽  
N Sources ◽  
Use Efficiency ◽  
Tiller Density ◽  
Relative Chlorophyll Content

ABSTRACT The use of products that promote reduction of nitrogen (N) losses from the urea fertilizer can contribute to increasing its use efficiency in forage grasses. This study aimed to evaluate the effects of N sources and doses on the growth of Urochloa ruziziensis. The experiment was carried out in the growing season of 2007/2008 in Santo Antônio de Goiás-GO, in a Brazilian Oxisol. A completely randomized block was used, with four replicates in a factorial scheme, corresponding to two N sources (conventional urea and urea with urease inhibitor) and five N doses (0, 50, 100, 200 and 300 kg ha-1), divided into equal applications in five periods (Nov 14 to Dec 13, Dec 14 to Jan 12, Jan 13 to Feb 11 - rainy season, Mar 24 to Apr 22 and Jul 10 to Aug 08 - dry season). The effects of the treatments were evaluated for: shoot dry matter, tiller density, total N content in the leaves and relative chlorophyll content. N fertilizer sources did not affect the evaluated variables; however, N fertilization allowed linear increases in all variables with higher values during the rainy period. The relative chlorophyll content in U. ruziziensis had positive correlation with its dry matter productivity.

scholarly journals The Influence of Nitrogen Fertilization on Waterlogging Stresses in Fagus sylvatica L. and Quercus robur L.

2008 ◽  
Vol 34 (1) ◽  
pp. 29-40
Author(s):  
Glynn Percival ◽  
Ian Keary
Keyword(s):  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Chlorophyll Content ◽  
European Beech ◽  
Dry Weight ◽  
N Fertilization ◽  
N Fertilizers ◽  
Leaf Chlorophyll ◽  
Total Plant ◽  
English Oak

The aims of this study were to determine the influence of nitrogen (N) fertilizers on tree tolerance under prolonged waterlogging conditions and investigate the effect of N fertilization on aiding tree recovery from waterlogging damage using containerized English oak (waterlogging-intermediate) and European beech (waterlogging-sensitive) as test species. English oak proved to be more waterlogging-tolerant than European beech. Tree vitality as measured by chlorophyll fluorescence, photosynthetic rates, leaf chlorophyll content, stomatal conductance, leaf and root protein concentration, and foliar N content was consistently higher in trees in which N fertilizers were added to the waterlogged solutions compared with trees waterlogged with tapwater only for 18 days. Measurement of light absorbance, light trapping, electron transport, and dissipation fluxes per leaf cross-section of photosystem II after the 18-day waterlogging period indicated a beneficial influence of N fertilization on leaf photosynthetic processes at the cessation of the waterlogging period. Addition of N induced greater resource allocation in favor of roots over shoots in both tree species. At the cessation of the 18-day waterlogging period and after a 10-day regeneration period, growth (leaf area, shoot, root, total plant dry weight) was constantly higher in N waterlogged trees compared with non-N waterlogged ones. In a separate study, recovery rates of trees as measured by chlorophyll fluorescence, photosynthetic rates, leaf chlorophyll content, and stomatal conductance over a 6-week period after the cessation of 18 days waterlogging were 30% to 50% higher in N-fertilized trees compared with non-N-fertilized trees irrespective of species. In all cases, nonfertilized trees had the least capacity for recovery. In addition, leaf area, shoot, root, and total plant dry weight were higher in N-fertilized trees compared with nonfertilized ones. Results of this investigation indicate 1) applications of N fertilizers enhance the tolerance of trees under prolonged waterlogged conditions; and 2) applications of N fertilizers after waterlogging stress would be of benefit to improve tree recovery rates and growth. From a practical point of view, N fertilization 14.5 g (0.51 oz) or greater N per liter (0.26 gal) of water is tentatively suggested based on preliminary results of this study.

scholarly journals Optical Sensing of Turfgrass Chlorophyll Content and Tissue Nitrogen

HortScience ◽  
2004 ◽  
Vol 39 (5) ◽  
pp. 1130-1132 ◽  
Author(s):  
G.E. Bell ◽  
B.M. Howell ◽  
G.V. Johnson ◽  
W.R. Raun ◽  
J.B. Solie ◽  
...  
Keyword(s):  
Chlorophyll Content ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Cynodon Dactylon ◽  
Optical Sensing ◽  
Creeping Bentgrass ◽  
N Fertilization ◽  
Agrostis Palustris ◽  
Small Areas ◽  
N Rates

Differences in soil microenvironment affect the availability of N in small areas of large turfgrass stands. Optical sensing may provide a method for assessing plant N needs among these small areas and could help improve turfgrass uniformity. The purpose of this study was to determine if optical sensing was useful for measuring turfgrass responses stimulated by N fertilization. Areas of `U3' bermudagrass [Cynodon dactylon (L.) Pers.], `Midfield' bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis Burtt-Davy], and `SR1020' creeping bentgrass (Agrostis palustris Huds.) were divided into randomized complete blocks and fertilized with different N rates. A spectrometer was used to measure energy reflected from the turfgrass within the experimental units at 350 to1100 nm wavelengths. This spectral information was used to calculate normalized difference vegetation index (NDVI) and green normalized difference vegetation index (GNDVI). These spectral indices were regressed with tissue N and chlorophyll content determined from turfgrass clippings collected immediately following optical sensing. The coefficients of determination for NDVI and GNDVI regressed with tissue N averaged r2 = 0.76 and r2 = 0.81, respectively. The coefficients of determination for NDVI and GNDVI regressed with chlorophyll averaged r2 = 0.70 and r2 = 0.75, respectively. Optical sensing was equally effective for estimating turfgrass responses to N fertilization as more commonly used evaluations such as shoot growth rate (SGR regressed with tissue N; r2 = 0.81) and visual color evaluation (color regressed with chlorophyll; r2 = 0.64).

scholarly journals Seedling Geranium Response to Nitrogen Deprivation and Subsequent Recovery in Hydroponic Culture

HortScience ◽  
2011 ◽  
Vol 46 (12) ◽  
pp. 1615-1618 ◽  
Author(s):  
James C. Locke ◽  
James E. Altland ◽  
Deanna M. Bobak
Keyword(s):  
Chlorophyll Content ◽  
N Fertilization ◽  
Hydroponic Culture ◽  
Nitrogen Deprivation ◽  
N Source ◽  
Bedding Plant ◽  
N Deficiency ◽  
Growth Of Seedlings ◽  
Plant Crop ◽  
Degree Of Recovery

Nitrogen (N) fertilization recommendations to achieve optimum growth are well established for many floriculture crops. Although it has been shown that plant functions can recover from N deficiency in other crops, little research has investigated the threshold beyond which a bedding plant crop is recoverable. The objective of this research was to determine the effect of N deficiency on geranium chlorophyll content and growth and then to document the degree of recovery and recovery time from N deprivation. This was determined in two experiments by monitoring chlorophyll content and growth of seedlings grown in hydroponic culture in which the N source was removed and then restored after differing lengths of time. Summarizing across both experiments, chlorophyll and foliar N levels were shown to rebound quickly after N deprivation; however, growth was reduced after just 4 days compared with plants fed constantly. Geraniums grown without N for 4 to 12 days resulted in smaller, more compact plants with lower shoot–to-root ratios. Although foliar chlorophyll and N concentration recovered from longer periods in N growth solution, geranium growth was reduced and failed to completely recover for any plant receiving more than 2 days of N-free solution.

Response of Landscape-grown Warm- and Cool-season Annuals to Nitrogen Fertilization at Five Rates

2012 ◽  
Vol 22 (3) ◽  
pp. 368-375
Author(s):  
Gitta Shurberg ◽  
Amy L. Shober ◽  
Christine Wiese ◽  
Geoffrey Denny ◽  
Gary W. Knox ◽  
...  
Keyword(s):  
Warm Season ◽  
Maximum Size ◽  
Plant Size ◽  
N Fertilization ◽  
N Fertilizer ◽  
Plant Quality ◽  
Shoot Biomass ◽  
Future Research ◽  
Annual Species ◽  
Cool Season

Current nitrogen (N) fertilizer recommendations for landscape-grown ornamentals are based on limited research. The objective of this research was to evaluate plant response of selected warm- and cool-season annuals to N fertilizer applied at five rates in the landscape. Three warm-season annual species [‘Profusion Cherry’ zinnia (Zinnia elegans ×angustifolia), ‘Cora White’ vinca (Catharanthus roseus), and ‘Golden Globe’ melampodium (Melampodium divaricatum)] and three cool-season annual species [‘Telstar Crimson’ dianthus (Dianthus chinensis), ‘Delta Pure Violet’ pansy (Viola wittrockiana), and ‘Montego Yellow’ snapdragon (Antirrhinum majus)] were transplanted into raised beds containing subsoil fill in U.S. Department of Agriculture (USDA) hardiness zone 9a. Slow-release N fertilizer was applied over an 18-week period at an annual N rate of 0, 2, 4, 6, and 12 lb/1000 ft2. Trials were replicated a second year. Plant size index (SI), tissue chlorophyll (SPAD), and plant quality were determined every 6 weeks. Shoot biomass and tissue total Kjeldahl N (TKN) were determined at 18 weeks. Regression analysis indicated that all species required N inputs at annual rates exceeding 8 lb/1000 ft2 to achieve maximum size, shoot biomass, or SPAD. However, acceptable quality plants were produced at much lower N rates. We suggest application of N fertilizer at a rate of 4 to 6 lb/1000 ft2 per year to landscape-grown annuals to maintain acceptable plant quality and growth. We expect fertilization at lower rates (based on aesthetics) can reduce the amount of fertilizer applied and the potential for nutrient losses in runoff or leachate. Future research should address N fertilization needs in higher fertility soils as well as the response of other plant species.

Effects of Air and Soil Temperatures on Colour of Eggplant Fruits (Solanum melongenaL.)

1978 ◽  
Vol 14 (3) ◽  
pp. 189-195 ◽  
Author(s):  
J. Nothmann ◽  
Irena Rylski ◽  
M. Spigelman
Keyword(s):  
Fruit Growth ◽  
Fruit Colour ◽  
Cool Season ◽  
Seasonal Influence ◽  
Soil Heating ◽  
Varietal Differences ◽  
Final Weight ◽  
Soil Temperatures ◽  
Hot Season ◽  
Colour Development

SUMMARYColour development in fruits of dark purple eggplant cultivars was greatly influenced by temperature conditions. During the cool season, colour development was much slower than during the hot season, corresponding to slower fruit growth and much lower final weight. There were varietal differences in seasonal influence on the distribution of various colour shades, both during fruit growth and at harvest. Soil heating during the cool season improved fruit colour.

scholarly journals Plant growth-promoting endophytic bacteria on maize and sorghum1

2019 ◽  
Vol 49 ◽  
Author(s):  
João Pedro Alves de Aquino ◽  
Francisco Barbosa de Macedo Junior ◽  
Jadson Emanuel Lopes Antunes ◽  
Marcia do Vale Barreto Figueiredo ◽  
Francisco de Alcântara Neto ◽  
...  
Keyword(s):  
Plant Growth ◽  
Chlorophyll Content ◽  
Dry Mass ◽  
N Fertilization ◽  
Stem Diameter ◽  
Plant Growth Promoting Bacteria ◽  
N Accumulation ◽  
Plant Growth Promoting ◽  
Promote Plant Growth ◽  
Growth Promoting

ABSTRACT Plant growth-promoting bacteria (PGPB) are found in plant tissues and promote plant growth by secretion of hormones and enzymes, or by facilitating the nutrient uptake. This study assessed forty PGPB isolates to determine their effects on maize and sorghum growth. These isolates were also compared with uninoculated plants, as negative (-N; without N fertilization) and positive (+N; with N fertilization) controls. Plant height, stem diameter, shoot and root dry mass, leaf N accumulation and chlorophyll content were evaluated. For both the maize and sorghum, the height, stem diameter and shoot dry mass in plants inoculated with PGPB were similar to those of uninoculated plants supplied with N, and the responses for root mass were higher than in plants supplied with N. However, the PGPB isolates did not promote N accumulation and chlorophyll content similar to those of uninoculated plants supplied with N. The IPACC26 and IPACC30 isolates, both identified as Bacillus subtilis, resulted in better responses for plant growth and N accumulation than the other isolates.

scholarly journals Preplant Cultivation Techniques and Planting Date Effects on White Clover Establishment into an Existing Cool-season Turfgrass Sward

HortScience ◽  
2015 ◽  
Vol 50 (4) ◽  
pp. 615-620 ◽  
Author(s):  
Bret Sparks ◽  
Gregg Munshaw ◽  
David Williams ◽  
Michael Barrett ◽  
Jeffrey Beasley ◽  
...  
Keyword(s):  
White Clover ◽  
Festuca Arundinacea ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
N Fertilization ◽  
Planting Date ◽  
Cool Season ◽  
Planting Dates ◽  
Nps Pollution ◽  
Significant Difference

Managed turfgrass species require frequent inputs to maintain an acceptable level of density and appearance. Among these inputs, the N supply is often the most limiting input in terms of growth and development of the turfgrass stand. However, N fertilization has been linked to nonpoint source (NPS) pollution of groundwater and natural water bodies. White clover (WC), which would provide N in mixed turfgrass swards, could help reduce NPS pollution from N fertilization of turf. To test the feasibility of introducing WC into existing turf, a field study was designed to determine the best method of incorporating WC in mature stands of two cool-season grasses. Two varieties of WC, ‘Dutch White’ (DW), and ‘Microclover’ (MC), were sown (24.4 kg·ha−1) into existing stands of kentucky bluegrass (KBG) (Poa pratensis L.) and tall fescue (TF) (Festuca arundinacea Schreb.). Establishment techniques tested included core aeration (CA), scalping (SC), and vertical mowing (VM) compared with direct sowing into the turfgrass stand. Establishment treatments were performed in April, July, and October of 2012–13 to examine for any seasonal timing effect on establishment. No significant difference in plant numbers (individual clover plants per square meter) was found between WC varieties among planting dates and techniques. The SC treatment resulted in the highest individual clover plant numbers. However, turfgrass recovery was significantly slower from the SC treatment than all other treatments. The summer planting date yielded the highest WC plant numbers. Recovery of the turfgrass from all preplanting treatments was also highest at the spring and summer planting dates.

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