Diagnostic nitrogen concentrations for cabbages grown in sand culture

1989 ◽  
Vol 29 (6) ◽  
pp. 883 ◽  
Author(s):  
DO Huett ◽  
G Rose
Keyword(s):  
Growth Rate ◽  
Growth Period ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Sand Culture ◽  
Total N ◽  
Rate Range ◽  
Nitrate N ◽  
N Concentration ◽  
Petiole Sap

The cabbage cv. Rampo was grown in sand culture with 5 nitrogen (N) levels, between 2 and 43 mmol/L, applied as nitrate each day in a complete nutrient solution. The youngest fully opened leaf (YFOL), which became the wrapper leaf at heading, the youngest fully expanded leaf (YFEL) and the oldest green leaf (OL) were harvested at a minimum of 2-week intervals over a 12-week growth period. Standard laboratory leaf total N and nitrate-N determinations and rapid petiole sap nitrate-N determinations were conducted on YFOL, YFEL and OL. Total N was also determined in bulked leaves. The relationship between growth rate relative to the maximum at each sampling time and leaf N concentration was used to derive diagnostic petiole sap nitrate-N, leaf nitrate-N and total N in YFOL, YFEL and OL and bulked leaf total N concentrations. Critical concentration corresponded to 90% maximum growth rate and adequate concentration corresponded to 9 1-1 00% maximum growth rate. Petiole sap nitrate-N concentration, which can be measured rapidly in the field, and leaf nitrate-N concentration were very responsive to N application where positive growth responses were recorded. Critical N concentrations are presented for all leaves at most sampling times throughout the growth period. Critical total N concentrations in YFOL, YFEL and bulked leaves were higher during the pre-heading growth stage (weeks 2-6) than the post-heading growth stage (weeks 8-12). Critical N concentrations were inconsistent over the growth period and it was not possible to present single values to represent the full growth period, with 2 exceptions. A critical petiole sap nitrate-N concentration for OL of 3.0 g/L can be recommended for the full growth period because it represents a percentage of maximum growth rate range of 88-95%. Similarly, for YFEL, a critical total N concentration of 4.10% pre-heading (range 4.10-4.38%) represents a percentage maximum growth rate range of 62-90% and a post-heading critical total N concentration of 3.10% (range 3.10-3.50%) represents a percentage maximum growth rate range of 76-90%. The concentrations of potassium, phosphorus, calcium, magnesium and sulfur in YFOL, YFEL, OL and bulked leaf corresponding to N treatments producing maximum growth rates are also presented.

Determination of critical nitrogen concentrations of zucchini squash (Cucurbita pepo L.) cv. Blackjack grown in sand culture

1991 ◽  
Vol 31 (6) ◽  
pp. 835 ◽  
Author(s):  
DO Huett ◽  
E White
Keyword(s):  
Growth Rate ◽  
Growth Period ◽  
Sand Culture ◽  
Total N ◽  
N Supply ◽  
Nitrate N ◽  
Fruit Harvest ◽  
Petiole Sap ◽  
Leaf Nitrate

A gamma x quadratic response surface model was used to predict the growth rate over the 14-week growth period of zucchini squash (Cucurbita pepo L.) cv. Blackjack in sand culture with nitrogen (N) levels of 2, 7, 14, 29 and 43 mmol/L. Growth rate relative to maximum was plotted against tissue N concentration every 2 weeks, to derive diagnostic petiole sap; leaf nitrate-N and leaf total-N in youngest fully opened leaf, youngest fully expanded leaf and oldest green leaf; and total N in bulked leaf samples. Critical concentrations corresponding to 90% maximum growth rate for deficiency and toxicity are presented. Petiole sap and leaf nitrate-N were much more responsive than leaf total N concentrations over the 2-14 mmol N/L range where positive growth responses were recorded. At 2 mmol N/L, plants were severely N-deficient and growth rate was low (1.6 g/plant.week at fruit set). Tissue nitrate concentrations were negligible, while leaf total N concentrations exceeded 2.6%. Salt toxicity occurred at 29 and 43 mmol N/L, and at the highest N level, tissue N concentrations were sometimes reduced so that concentration ranges for adequacy and toxicity overlapped. Critical tissue N concentrations always exceeded (P<0.05) levels recorded in plants receiving a marginally deficient N level (7 mmol/L). Critical petiole sap and leaf nitrate-N concentrations were much more variable between sampling periods than leaf total N concentrations. Adequate concentration ranges (values between critical concentrations for deficiency and toxicity) were determined for the pre-fruit harvest (weeks 2-6) and fruit harvest (weeks 8-14) growth stages where values were common for consecutive weeks within each sampling period. It was only possible to determine adequate concentrations over the entire growth period for bulked leaf total N (4.30440% prefruit harvest and 4.15-4.45% fruit harvest). Concentrations of potassium (K), phosphorus and sulfur were affected (P<0.05) by N application level, with the largest effect being recorded for K. This confirms the importance of optimising N supply when determining critical levels of these nutrients for zucchini squash. Determination of petiole sap nitrate-N concentrations in the field can be used to distinguish between a deficient and an adequate N supply, but the large variation in values between sampling periods renders this technique less reliable than leaf total N. Tissue N concentrations which exceed critical deficient levels can be interpreted as such because they were recorded when growth was depressed at high N levels. This will rarely occur under field conditions.

Determination of critical nitrogen concentrations of lettuce (Lactuca sativa L. cv. Montello) grown in sand culture

1992 ◽  
Vol 32 (6) ◽  
pp. 759 ◽  
Author(s):  
DO Huett ◽  
E White
Keyword(s):  
Dry Matter ◽  
Growth Period ◽  
Sand Culture ◽  
N Application ◽  
Total N ◽  
N Supply ◽  
Nitrate N ◽  
N Concentration ◽  
Nitrate Concentrations ◽  
Petiole Sap

A gamma x cubic response surface model was used to predict the dry matter yield of lettuce cv. Montello over the 8-week growth period in sand culture with nitrogen (N) levels of 2, 5, 11, 18 and 36 mmol/L. At 1, 2, 3, 5, 7 and 8 weeks after transplanting, dry matter yield relative to maximum was plotted against tissue N concentration to derive diagnostic concentrations of petiole sap nitrate-N and leaf total N in youngest fully opened leaf (YFOL), youngest fully expanded leaf (YFEL) and oldest green leaf (OL), and total N in bulked leaf samples. Critical concentrations corresponding to 90% maximum yield are presented. Growth was consistently depressed at 2 mmol N/L due to N deficiency, and at 36 mmol N/L due to salt toxicity. Petiole sap nitrate concentrations were more responsive than leaf total N concentrations to N application levels. Leaf N concentrations at N application levels of 18 and 36 mmol/L were often similar. Critical leaf total N concentrations in YFOL and YFEL decreased from 2 weeks after transplanting to maturity, whereas the opposite trend occurred for petiole sap nitrate concentrations. Critical total N concentration ranges in YFEL were 0.30-0.95 g/L for petiole sap nitrate-N, and 4.00-5.30% for leaf total N concentration. Critical leaf total N and petiole sap nitrate concentrations clearly differentiated between inadequate and adequate N application rates. Critical values in most cases, differentiated toxic concentrations. Nitrogen application levels of 2 and 36 mmol N/L reduced (P<0.05) potassium, calcium and magnesium concentrations in all leaves. This confirms the importance of optimising N supply when determining critical levels of these nutrients for lettuce. Petiole sap nitrate-N concentrations, which can be determined rapidly in the field, can be used to distinguish between a deficient and an adequate N supply. The marked increase in critical concentration over the growth period requires consecutive determinations to verify the N status of lettuce.

Diagnostic nitrogen concentrations for tomatoes grown in sand culture

1988 ◽  
Vol 28 (3) ◽  
pp. 401 ◽  
Author(s):  
DO Huett ◽  
G Rose
Keyword(s):  
Critical Values ◽  
Sand Culture ◽  
Nutrient Concentrations ◽  
Total N ◽  
Nitrate N ◽  
N Concentration ◽  
Leaf N Concentration ◽  
Petiole Sap ◽  
N Status ◽  
Leaf N

The tomato cv. Flora-Dade was grown in sand culture with 4 nitrogen (N) levels of 1.07-32.14 mmol L-1 applied as nitrate each day in a complete nutrient solution. The youngest fully opened leaf (YFOL) and remaining (bulked) leaves were harvested at regular intervals over the 16-week growth period. Standard laboratory leaf total and nitrate N determinations were conducted in addition to rapid nitrate determinations on YFOL petiole sap. The relationships between plant growth and leaf N concentration, which were significantly affected by N application level, were used to derive diagnostic leaf N concentrations. Critical and adequate concentrations in petiole sap of nitrate-N, leaf nitrate-N and total N for the YFOL and bulked leaf N were determined from the relationship between growth rate relative to maximum at each sampling time and leaf N concentration. YFOL petiole sap nitrate-N concentration, which can be measured rapidly in the field by using commercial test strips, gave the most sensitive guide to plant N status. Critical values of 770-1 120 mg L-I were determined over the 10-week period after transplanting (first mature fruit). YFOL (leaf + petiole) total N concentration was the most consistent indicator of plant N status where critical values of4.45-4.90% were recorded over the 4- 12 week period after transplanting (early harvests at 12 weeks). This test was less sensitive but more precise than the petiole sap nitrate test. The concentrations of N, potassium, phosphorus, calcium and magnesium in YFOL and bulked leaf corresponding to the N treatments producing maximum growth rates are presented, because nutrient supply was close to optimum and the leaf nutrient concentrations can be considered as adequate levels.

Determination of critical nitrogen concentrations of potato (Solanum tuberosum L. cv. Sebago) grown in sand culture

1992 ◽  
Vol 32 (6) ◽  
pp. 765 ◽  
Author(s):  
DO Huett ◽  
E White
Keyword(s):  
Dry Matter ◽  
Maximum Yield ◽  
Growth Period ◽  
Sand Culture ◽  
N Application ◽  
Total N ◽  
Nitrate N ◽  
Nitrate Concentrations ◽  
Petiole Sap ◽  
Leaf Nitrate

A gamma x cubic response surface model was used to predict the dry matter yield of potato cv. Sebago over the 12-week growth period in sand culture with nitrogen (N) levels of 2, 7, 14, 29 and 43 mmol N/L. At each 2-week sampling period after emergence, dry matter yield relative to maximum was plotted against tissue N concentration to derive diagnostic petiole, petiole sap, leaf nitrate-N and leaf total N in youngest fully opened leaf (YFOL), youngest fully expanded leaf (YFEL) and oldest green leaf (OL) and for total N in bulked leaves. Critical concentrations corresponding to 90% maximum yield are presented. Tissue nitrate was much more responsive than leaf total N to applied N over the 2-14 mmol/L range where positive growth responses to N were recorded. Plants grown with 2 mmol N/L were severely N deficient and growth was depressed. Tissue nitrate concentrations in these plants from 4 weeks after emergence onwards were negligible, while leaf total N concentrations exceeded 2.36%. Salt toxicity occurred at 29 and 43 mmol NIL, and it sometimes reduced tissue N concentrations so that adequacy and toxicity concentrations overlapped. Critical tissue N concentrations declined over the growth period, the largest decline occurring for nitrate. Critical tissue N concentrations for YFEL, from 2 weeks after emergence to final harvest were: petiole sap nitrate-N, 1.2-0.2 g/L; petiole nitrate-N, 2.1-0.1%; leaf nitrate-N, 0.44-0.08%. Critical tissue nitrate concentrations clearly differentiated between inadequate and adequate N application levels. Critical leaf total N concentrations only differentiated between inadequate and marginal N application rates, except for OL when inadequate and marginally adequate (80-90% maximum yield) concentrations were not different (P>0.05). Nitrogen application level affected (P<0.05) leaf potassium, phosphorus, calcium (Ca), magnesium (Mg) and sulfur concentrations. The largest effects were recorded for Ca and Mg where increasing N application level reduced leaf nutrient concentration. Petiole sap nitrate concentrations can be used as a rapid field test for distinguishing between a deficient and an adequate N supply. Where concentrations exceed critical values, they can be interpreted as such because N fertiliser toxicity rarely occurs under field conditions.

Phenological and growth response of legume cover crops to shading

2013 ◽  
Vol 152 (6) ◽  
pp. 917-931 ◽  
Author(s):  
R. P. MAURO ◽  
O. SORTINO ◽  
M. DIPASQUALE ◽  
G. MAUROMICALE
Keyword(s):  
Growth Rate ◽  
Cover Crops ◽  
Seedling Emergence ◽  
Growth Period ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Cycle Duration ◽  
Cover Cropping ◽  
Future Attempt ◽  
Annual Medics

SUMMARYAnnual medics and clovers have distinct properties in terms of usage as cover crops in Mediterranean orchards, but little is known of their capacity to adapt to the level of shading encountered on an orchard floor. A 2-year field experiment was conducted in South–Eastern Sicily to investigate the effects of withholding 0·50 of sunlight on the phenology and growth pattern of four medic and five clover accessions, focusing on traits known to be important for cover cropping. Shading delayed both seedling emergence and the onset of flowering (by up to 5 and 9 days, respectively), while it extended both the growth period and the overall life-cycle duration (by up to 5 and 11 days, respectively). It also induced an increase in cover crop height (from 34 to 38 cm) and crop light use (from 0·60 to 0·94 g DW/m2/MJ), but a reduction in soil coverage, above-ground dry biomass, maximum growth rate and maximum relative growth rate (by up to 13, 18, 21 and 7%, respectively), so compromising the competitiveness of cover crops against weeds. The responses to shading varied between genotypes. Medicago polymorpha ecotype S. Rosalia, Medicago rugosa ecotype Piano Lauro and ecotype Zappulla were the strongest competitors against weeds, whereas Trifolium tomentosum ecotype Bucampello was interesting in terms of its biomass yield and crop light use. The performance was unstable over seasons, so any future attempt to improve the species’ performances under shade by breeding will need to focus on reseeding capacity.

The assessment of seasonal yield using some Stylosanthes guyanensis accessions in humid tropical and sub-tropical environments

1977 ◽  
Vol 17 (86) ◽  
pp. 425 ◽  
Author(s):  
LA Edye ◽  
WT Williams ◽  
RL Burt ◽  
B Grof ◽  
SL Stillman ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Growth ◽  
Growth Period ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Growth Patterns ◽  
Seasonal Growth ◽  
Seasonally Dry ◽  
Tropical Environments ◽  
Dry Tropics

The seasonal growth patterns of some S. guyanensis accessions were compared in three humid environments at South Johnstone (extended rainfall tropics), 'Heathlands' (seasonally dry tropics) and Cooroy (humid sub-tropics). The accessions were selected mainly for their productivity in previously described small mown sward experiments over three years at each site. Previous methods of presenting seasonal growth patterns are reviewed, and a new, simpler method of presentation is defined. Growth was highly seasonal at all sites. There was no growth during July to November at 'Heathlands' and Cooroy due to moisture and temperature limitations respectively. At South Johnstone growth was continuous but depressed in August and December with limitations due to both soil moisture and temperature: the maximum growth rate was 22 times the minimum growth rate. The accessions differed markedly in their growth patterns at each site. In general, the yield differences between accessions were greater at the beginning and end of the growing season than during the peak growth period. The highest yielding accessions at each site had high growth rates spread over a long period. The yield distribution and persistence of Q8231 and 46589C seemed superior to existing cultivars in tropical and sub-tropical environments respectively

Influence of phosphorus on growth and biomass distribution of Alaskan taiga tree seedlings

1983 ◽  
Vol 13 (6) ◽  
pp. 1092-1098 ◽  
Author(s):  
F. Stuart Chapin III ◽  
Peter R. Tryon ◽  
Keith Van Cleve
Keyword(s):  
Growth Rate ◽  
Black Spruce ◽  
White Spruce ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Sand Culture ◽  
Tree Seedlings ◽  
Slow Growth Rate ◽  
Phosphate Supply ◽  
High Phosphate

Seedlings of six Alaskan taiga tree species and one tall shrub were grown in sand at three phosphate levels. There was a positive correlation between the growth rate of a species at the high-phosphate level in sand culture and its productivity in the natural environment. Poplar (Populusbalsamifera L.), which had highest growth rate under high phosphate, was most sensitive to reduction in phosphate supply, followed by birch (Betulapapyrifera (Reg.) Fern, and Raup) and aspen (Populustremuloides Michx.), whereas growth of conifers (larch (Larixlaricina (Du Roi) K. Koch), white spruce (Piceaglauca (Moench) Voss), and black spruce (P. mariana (Mill.) B.S.P.)) from late successional sites was slow and unaffected by phosphate supply. Similarly, when birch and white spruce seedlings were transplanted into natural forest stands, the maximum growth rate of birch was greater than that of white spruce, but birch growth was curtailed more by unfavorable conditions than was that of white spruce. We conclude that a slow growth rate reduces nutrient requirement and therefore minimizes nutrient stress on infertile sites, whereas a rapid growth enables nutrient-demanding species to dominate fertile sites.

A note on growth curves of rabbit lines selected on growth rate or litter size

1993 ◽  
Vol 57 (2) ◽  
pp. 332-334 ◽  
Author(s):  
A. Blasco ◽  
E. Gómez
Keyword(s):  
Growth Rate ◽  
Litter Size ◽  
Growth Curves ◽  
Live Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Standard Errors ◽  
Adult Weight ◽  
Weight Growth ◽  
Using Data

Two synthetic lines of rabbits were used in the experiment. Line V, selected on litter size, and line R, selected on growth rate. Ninety-six animals were randomly collected from 48 litters, taking a male and a female each time. Richards and Gompertz growth curves were fitted. Sexual dimorphism appeared in the line V but not in the R. Values for b and k were similar in all curves. Maximum growth rate took place in weeks 7 to 8. A break due to weaning could be observed in weeks 4 to 5. Although there is a remarkable similarity of the values of all the parameters using data from the first 20 weeks only, the higher standard errors on adult weight would make 30 weeks the preferable time to take data for live-weight growth curves.

Reassessment of Maximum Growth Rates for C3 and C4 Crops

1978 ◽  
Vol 14 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. L. Monteith
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growing Season ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Crop Growth ◽  
Close Inspection ◽  
Similar Difference ◽  
Photosynthetic Efficiencies

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.

Interpretation of Experimental Data with Regard to the Activated Sludge Model No.1 and Calibration of the Model for Municipal Wastewater Treatment Plants

1992 ◽  
Vol 25 (6) ◽  
pp. 167-183 ◽  
Author(s):  
H. Siegrist ◽  
M. Tschui
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Municipal Wastewater Treatment ◽  
Activated Sludge Model

The wastewater of the municipal treatment plants Zürich-Werdhölzli (350000 population equivalents), Zürich-Glatt (110000), and Wattwil (20000) have been characterized with regard to the activated sludge model Nr.1 of the IAWPRC task group. Zürich-Glatt and Wattwil are partly nitrifying treatment plants and Zürich-Werdhölzli is fully nitrifying. The mixing characteristics of the aeration tanks at Werdhölzli and Glatt were determined with sodium bromide as a tracer. The experimental data were used to calibrate hydrolysis, heterotrophic growth and nitrification. Problems arising by calibrating hydrolysis of the paniculate material and by measuring oxygen consumption of heterotrophic and nitrifying microorganisms are discussed. For hydrolysis the experimental data indicate first-order kinetics. For nitrification a maximum growth rate of 0.40±0.07 d−1, corresponding to an observed growth rate of 0.26±0.04 d−1 was calculated at 10°C. The half velocity constant found for 12 and 20°C was 2 mg NH4-N/l. The calibrated model was verified with experimental dam of me Zürich-Werdhölzli treatment plant during ammonia shock load.

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