SAP NITRATE TESTING FOR IMPROVED NITROGEN MANAGEMENT ON POTATOES

A procedure for rapid determination of nitrate in the fresh petiole sap using an ion specific electrode was developed. A highly significant correlation (R2-0.92) was obtained between the nitrate measured by the sap test and the conventional oven-dried tissue method. The effects of five nitrogen(N) rates ranging from 0 to 268 kg ha-1, and five dates of sampling dates beginning at tuber initiation, on the sap nitrate concentration were investigated. The nitrate level increased in proportion to N fertilizer rate. The nitrate level was generally higher at tuber initiation and decreased as the season progressed. The rate of decrease was related to the N supply in the soil. At N rates of 0 and 67 Kg ha-1, the average weekly decrease in the nitrate level was greater than 100 ppm. Based on yield response, the nitrate levels were partitioned as deficient adequate and excessive, and a critical nutrient range was established. The sap test offers a tactical approach for corrective in-season fertilization and a means to increase the efficiency of both fertilizer and available soil N.

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A Petiole Sap Nitrate Test for Cauliflower

HortScience ◽

10.21273/hortsci.31.6.934 ◽

1996 ◽

Vol 31 (6) ◽

pp. 934-937 ◽

Cited By ~ 16

Author(s):

Aki Kubota ◽

Thomas L. Thompson ◽

Thomas A. Doerge ◽

Ronald E. Godin

Keyword(s):

Application Rate ◽

Nitrate Ion ◽

Growing Seasons ◽

Water Rates ◽

Nitrate Determination ◽

N Rates ◽

The Relationship ◽

Crop Maturity ◽

Petiole Sap ◽

Sap Test

This study was conducted to evaluate the accuracy of sap analysis using a portable nitrate ion meter for cauliflower (Brassica oleracea L. Botrytis Group, cv. Candid Charm) petiole nitrate determination. The relationship between NO3-N concentration in fresh petiole sap and in dried petiole tissue was studied for cauliflower grown in southern Arizona during the 1993–94 and 1994–95 growing seasons. Experiments were factorial combinations of three water rates and four N rates, both ranging from deficient to excessive. Petioles were collected throughout each season and were split for analysis of sap NO3-N and dried petiole NO3-N. Linear correlations between the two methods were similar in both seasons, with no consistent effect due to water application rate or crop maturity. Therefore, a single regression equation was derived: petiole sap NO3-N (mg·liter–1) = 0.047 × dry petiole NO3-N (mg·kg–1) + 218 (r2 = 0.772). This equation can be used to relate sap test measurements to existing guidelines for NO3-N concentrations in cauliflower petioles. These results suggest that the quick sap test, using the portable nitrate ion meter, is a valuable technique for monitoring N status of cauliflower.

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N, P, and S fertilization effects on industrial hemp in Saskatchewan

Canadian Journal of Plant Science ◽

10.4141/cjps09101 ◽

2010 ◽

Vol 90 (2) ◽

pp. 179-184 ◽

Cited By ~ 12

Author(s):

C L Vera ◽

S S Malhi ◽

S M Phelps ◽

W E May ◽

E N Johnson

Keyword(s):

Seed Yield ◽

Cannabis Sativa ◽

Maximum Yield ◽

N Fertilizer ◽

Maximum Height ◽

Fertilizer Rate ◽

P Fertilizer ◽

N Rates ◽

Industrial Hemp ◽

N Fertilizer Rate

Industrial hemp (Cannabis sativa L.) has become a well-known crop in western Canada in recent years, but insufficient information is available on its nutrient requirements for optimum yield. Our objective was to confirm the response of two hemp cultivars to increasing levels of nitrogen (N), phosphorus (P) and sulphur (S) in various sites in the province of Saskatchewan, during 2006-2008. Increasing N rates significantly increased plant height, biomass, and seed yield, when data were averaged across all sites (location-years), reaching maximum values at about 150 kg N ha-1 of applied N fertilizer. The cultivar Crag was taller and produced greater biomass than the cultivar Finola over all levels of N fertilizer rate. The minimum rate of N fertilizer to achieve maximum height/biomass for Crag, relative to Finola, was 5 kg N ha-1 lower for height (Finola: 163 kg N ha-1) but 9 kg N ha-1 higher for biomass (Finola: 180 kg N ha-1). Finola seed yield was more responsive to progressively greater rates of N fertilizer. Consequently, maximum seed yield (plateau) was 27% greater for Finola than for Crag, but 198 kg N ha-1 of fertilizer was required to achieve this maximum yield vs. 175 kg N ha-1 for Crag. There was generally little or no response to P fertilizer, on soils with adequate available P, or to S fertilizer on an S-deficient soil. Results from this study indicate that N fertilizer rate and cultivar choice are important management parameters to consider for industrial hemp production.Key words: Fertilizer, hemp cultivars, nitrogen, phosphorus, sulphur, soil extractable P, soil nitrate-N

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Yield response of forage grasses to N fertilizer as related to spring soil nitrate sorbed on anionic exchange membranes

Canadian Journal of Soil Science ◽

10.4141/s99-048 ◽

2000 ◽

Vol 80 (1) ◽

pp. 203-212 ◽

Cited By ~ 17

Author(s):

N. Ziadi ◽

R. R. Simard ◽

G. Allard ◽

G. Parent

Keyword(s):

N Uptake ◽

N Fertilizer ◽

Forage Yield ◽

Yield Response ◽

Soil Nitrate ◽

Forage Grasses ◽

Fertilizer N ◽

Fertilizer Rate ◽

Anionic Exchange ◽

N Fertilizer Rate

Soil N availability is an important factor in forage grass production. Maximising N fertilizer efficiency is essential to improve profitability and to reduce the environmental risk associated with residual excess soil N. The objectives of this study were (i): to determine the effects of N fertilizer on yield, N uptake and NO3–N concentration of forage grasses produced in Western Quebec; and (ii) to compare spring soil NO3−measured by anionic exchange membranes (NO3AEMs) and by water extraction (NO3w) as a criterion to predict fertilizer N requirements of forage grasses. The yield response of grasses, especially timothy (Phleum pratense L.), to different rates of NH4NO3 (0 to 240 kg N ha−1) on heavy clay soils (Humic Gleysols) was studied from 1994 to 1996 at four sites in the Abitibi-Temiscamingue area, Quebec (Canada). Nitrogen significantly (P < 0.001) increased forage yield, N uptake, and NO3–N concentration. The economically optimum N fertilizer rate (Nop) for forage yield varied from 25 to 240 kg N ha−1 depending on sites and years, and averaged 125 kg N ha−1. The Nop can be predicted more adequately by NO3AEMs (R2 = 0.45) than by NO3w (R2 = 0.09). Based only on the relationship between the relative yield and spring soil nitrate, NO3AEMs could be used as a criterion for fertilizer N recommendation of forage grasses in this cool continental climate. Key words: N fertilizer, nitrate, grass, economically optimum N fertilizer rate

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Rotational Cropping Sequence Affects Nitrogen Fertilizer Requirements in Processing Pumpkins (Cucurbita moschata)

HortScience ◽

10.21273/hortsci.39.1.75 ◽

2004 ◽

Vol 39 (1) ◽

pp. 75-79

Author(s):

John M. Swiader ◽

William H. Shoemaker

Keyword(s):

Field Experiments ◽

Cropping Systems ◽

N Fertilization ◽

Fruit Weight ◽

N Fertilizer ◽

Yield Response ◽

Cucurbita Moschata ◽

Ripe Fruit ◽

Fertilizer Rate ◽

N Fertilizer Rate

Field experiments were conducted over a 5-year period (1994-98) to determine the effect of various cropping systems (rotations) on fertilizer N requirements in processing pumpkins [Cucurbita moschata (Duchesne ex Lam.) Duchesne ex Poir.] on medium- to fine-textured soil. Treatments consisted of a factorial combination of five N fertilization rates (0, 56, 112, 168, 224 kg·ha-1 N) and four pumpkin cropping systems: 1) pumpkins following corn (Zea mays L.); 2) pumpkins following soybeans [Glycine max (L.) Merrill]; 3) pumpkins following 2-years corn; and 4) pumpkins following fallow ground. Cropping systems were chronologically and spatially arranged in two complete cycles, with pumpkin studies taking place in 1996 and 1998. Averaged over the two studies, the optimal N fertilization rate for highest total weight of ripe fruit following soybeans was estimated at 109 kg·ha-1 N, compared to 128 kg·ha-1 N following fallow ground, even though yields were similar, suggesting a soybean N-credit of 19 kg·ha-1 N. Concurrently, the N fertilizer rate for highest total ripe fruit weight following corn was estimated at 151 kg·ha-1 N, and 178 kg·ha-1 following 2-years corn, indicating a negative rotation effect on pumpkin N requirements of 23 and 50 kg·ha-1 N, respectively. Minimum N fertilizer requirements, the N fertilizer rate associated with a ripe fruit yield of 50 t·ha-1, were calculated at 45, 37, 69, and 47 kg·ha-1 N in the respective cropping systems. Negative effects from excessive N fertilization were greater in pumpkins following soybeans than in pumpkins following corn or 2-years corn, with reductions in total ripe fruit weight of 21%, 9%, and 3%, respectively, at the highest N rate. A critical level for preplant soil NO 3-N of 17.6 mg·kg-1 was identified above which there was little or no pumpkin yield response to N fertilization.

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Agronomic practices to reduce leaf spotting and Fusarium kernel infections in durum wheat on the Canadian prairies

Canadian Journal of Plant Science ◽

10.4141/cjps2012-304 ◽

2014 ◽

Vol 94 (1) ◽

pp. 141-152 ◽

Cited By ~ 12

Author(s):

W. E. May ◽

M. R. Fernandez ◽

F. Selles ◽

G. P. Lafond

Keyword(s):

Grain Yield ◽

Durum Wheat ◽

Flag Leaf ◽

N Fertilizer ◽

Seeding Rate ◽

Fertilizer Rate ◽

Canadian Prairies ◽

Agronomic Practices ◽

N Rates ◽

N Fertilizer Rate

May, W. E., Fernandez, M. R., Selles, F. and Lafond G. P. 2014. Agronomic practices to reduce leaf spotting and Fusarium kernel infections in durum wheat on the Canadian prairies. Can. J. Plant Sci. 94: 141–152. Fusarium head blight (FHB) has become an important disease of durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn] in the humid and sub-humid regions of the prairies along with leaf spots, black point and red smudge. Together, they contribute to lower grain yields and grain quality. The study objective was to determine the effect of seeding rate, nitrogen (N) fertilizer rate, fungicidal treatment, and cultivar on disease severity, crop development, grain yield and quality in durum. A four-way factorial design was used with two seeding rates (150 and 300 viable seeds m−2), two N rates (75 and 100% of recommended rate), three cultivars (AC Avonlea, AC Morse and AC Navigator), four fungicide treatments (no application, propiconazole at flag leaf, tebuconazole at anthesis, and propiconazole at flag leaf followed by tebuconazole at anthesis) and three locations (two in Saskatchewan and one in Manitoba) from 2001 to 2003. There were no interactions among fungicide, seeding rate, N fertilizer and cultivar for all measured variables. Foliar fungicide treatments resulted in greater kernel weight, grain yield and test weight than the no-fungicide treatment. The application of tebuconazole at anthesis did not reduce the amount of FDK in the harvested grain. The application of a fungicide increased the percentage of kernels infected by black point from 0.38% to over 0.50% and red smudge from 0.54 to 0.61%. Two fungicide applications increased red smudge to 0.85%. Grain yield increased by 2.4% when the seeding rate was increased from 150 to 300 plants m−2. Increasing N fertilizer rate increased grain yield by 5.2%, protein concentration by 5.4% and hard vitreous kernels (HVK) by 2.6%, but decreased test weight by 0.5%. Cultivar selection had the largest effect on FDK. In conclusion, effects of a fungicide application on durum wheat did not interact with selection of seeding rates, cultivars or N rates used in this study.

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Rapid Determination of Nitrogen Status in Annual Vinca

Journal of Environmental Horticulture ◽

10.24266/0738-2898-20.3.189 ◽

2002 ◽

Vol 20 (3) ◽

pp. 189-194 ◽

Cited By ~ 2

Author(s):

James E. Altland ◽

Charles H. Gilliam ◽

James H. Edwards ◽

Gary J. Keever ◽

Donna C. Fare ◽

...

Keyword(s):

Rapid Determination ◽

Correlation Coefficients ◽

Growth Index ◽

Dry Weight ◽

Total N ◽

The Relationship ◽

Petiole Sap ◽

Spad Readings ◽

N Status

Abstract Three experiments were conducted to develop a method for rapid determination of nitrogen (N) status in ‘Pacifica White’ vinca (Catharanthus roseus (L.) G. Don). In experiment 1, N was applied to potted vinca at 40, 80, 120, or 160 ppm N to produce plants ranging from N deficient to N sufficient. Data were collected 14, 28, and 42 days after treatment (DAT) and included flower number, growth index [(height + width + width) ÷ 3], and from recently matured foliage the following parameters: SPAD-502 readings, petiole sap nitrate (SN) concentration, and total-N (percent of dry weight) (FN). Experiment 2 was similar with the exception that N rates applied were 30, 60, 90, 120, 150, or 180 ppm N, and data were collected 14, 29, and 42 DAT. In experiment 3, N was applied at 0, 90, or 180 ppm N and data were collected 0, 4, 7, 10, and 14 DAT. In experiments 1 and 2, SPAD readings were poorly correlated to FN (correlation coefficients ranged from 0.35 to 0.88) and the relationship between FN and SPAD readings changed at different collection dates. Petiole sap nitrate concentration determined by a Cardy nitrate meter was highly correlated throughout the three experiments. Above 380 ppm SN, the relationship between FN and SN was determined to be: SN/1000 = 2.3 × FN-4.8 (r2 = 0.73, n = 104). In experiment 3, FN and SN readings were able to detect N deficiency in vinca by 4 DAT, despite lack of visual symptoms until 14 DAT. SPAD readings were not suitable for predicting FN and plant N status. SN was a reliable predictor of FN and thus could be used to rapidly determine plant N status.

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Weak Beam Imaging and Diffraction Studies of Stacking Faults in Silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092918 ◽

1976 ◽

Vol 34 ◽

pp. 590-591

Author(s):

T. Y. Tan ◽

W. K. Tice

Keyword(s):

Fast Neutron ◽

Rapid Determination ◽

Stacking Faults ◽

Imaging Method ◽

Large Reduction ◽

Dislocation Loops ◽

Fringe Spacing ◽

Weak Beam ◽

Kinematical Theory

In studying ion implanted semiconductors and fast neutron irradiated metals, the need for characterizing small dislocation loops having diameters of a few hundred angstrom units usually arises. The weak beam imaging method is a powerful technique for analyzing these loops. Because of the large reduction in stacking fault (SF) fringe spacing at large sg, this method allows for a rapid determination of whether the loop is faulted, and, hence, whether it is a perfect or a Frank partial loop. This method was first used by Bicknell to image small faulted loops in boron implanted silicon. He explained the fringe spacing by kinematical theory, i.e., ≃l/(Sg) in the fault fringe in depth oscillation. The fault image contrast formation mechanism is, however, really more complicated.

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