View Full Table | Close Full ViewTable 1.

Soil characteristics for the study area at Legnaro, northeastern Italy, to a depth of 20 cm from samples collected before seeding alfalfa in March 2005.

 
Parameter Method of determination Value
Sand, % (0,05–2 mm) gravimetric 18.0
Silt, % (0002–0,05 mm) gravimetric 65.9
Clay, % (<0002 mm) gravimetric 16.0
Organic matter, % Walkley and Black 2.28
pH electrode (1:2) 8.1
Total N, g kg–1 Kjeldahl 0.125
Total P, ‰ P2O5 mineralization via HNO3 and H2SO4 1.9
Available P, mg kg–1 Olsen 38.2
Exchangeable K, mg kg–1 buffered BaCl2 178.0
C/N ratio Organic C ÷ Organic N 10.7



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Standard error of cross-validation in modified partial least square regression (SECV) and coefficient of determination (r2) for calibration of near infrared reflectance spectroscopy analysis of forage nutritive values for alfalfa harvested at early bud during 3 yr at Legnaro, northeastern Italy.

 
Constituent SECV r2
Crude protein 0.97 0.89
Ether extract 0.31 0.57
Neutral detergent fiber 1.90 0.88
Acid detergent fiber 1.96 0.86
Acid detergent lignin 1.01 0.66
Ash 0.41 0.91



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Analysis of variance for forage yield, canopy height, stem density, and forage nutritive values (crude protein [CP], ether extract [EE], neutral detergent fiber [NDF], acid detergent fiber [ADF], and acid detergent lignin [ADL], ash, P, and K), of alfalfa subjected to three fertilization rates of P and three of K from 2005 to 2007 at Legnaro, northeastern Italy.

 
Canopy height Stem density Forage nutritive values
Source Yield CP EE NDF ADF ADL Ash P K
P ns† ns ns ns ns ns ns ns ns ns ns
K ** *** ns * ns ns ns ns *** ** ***
P × K ns ns ns ns ns ns ns ns ns ns *
Yr ** *** *** *** *** *** *** *** *** *** **
P × yr ns ns ns ns *** ns ns ns ns ns *
K × yr *** *** ns *** ns ns ns ns *** ns **
P × K × yr ns ns ns ** ns ns ns ns ns ns ns
*Significant at the 0.05 level.
**Significant at the 0.01 level.
***Significant at the 0.001 level.
Not significant at the 0.05 probability level.



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Dry matter yield, canopy height, ash, and K content of alfalfa under the influence of three K fertilization rates at Legnaro, Italy, from 2005 to 2007. The data were averaged over three P fertilization rates and three replicates.

 
K2O 2005 2006 2007 Average
kg ha–1 yr–1
Dry matter yield, Mg ha–1
0 14.9a† 22.9b 18.3c 18.7b
300 15.0a 23.9a 20.3b 19.7a
600 14.9a 24.1a 21.3a 20.1a
Canopy height, cm
0 66.3a 71.0b 60.0c 65.8c
300 66.9a 72.6ab 65.0a 68.1b
600 67.7a 72.9a 67.7a 69.4a
Ash, g kg–1 dry wt.
0 101a 96c 98c 99c
300 102a 101b 104b 102b
600 101a 105a 110a 105a
K, g kg–1 dry wt.
0 22.6c 22.0c 20.8c 21.8c
300 23.3b 24.5b 24.1b 24.0b
600 24.5a 25.9a 26.9a 25.8a
Within a column and measurement parameter, values followed by the same letter are not significantly different at 0.05 level of probability (Fisher’s protected LSD).



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Crude protein of alfalfa forage as affected by various combinations of P and K fertilization rates during three growing seasons (2005– 2007) in Legnaro, northeastern Italy. Data are the means of three replicates.

 
P2O5 K2O 2005 2006 2007
kg ha–1 yr–1 g kg–1 dry wt.
0 0 186a† 194a 195a
0 300 185a 188c 194a
0 600 186a 188c 196a
100 0 185a 192abc 199a
100 300 183a 193ab 197a
100 600 187a 189bc 185b
200 0 178b 191abc 196a
200 300 185a 193ab 195a
200 600 184a 188c 187b
Within a column, values followed by the same letter are not significantly different at 0.05 level of probability (Fisher’s protected LSD).



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Forage concentration of K as affected by three P fertilization rates in combination with three K fertilization rates and during 3 yr (2005–2007) at Legnaro, northeastern Italy. Potassium rate data are the means of 3 yr and three replicates; and annual data are the means of three K fertilization rates and three replicates.

 
K2O, kg ha–1 yr–1
P2O5 0 300 600 2005 2006 2007
kg ha–1 yr–1 mg kg–1 dry wt.
0 226a† 246a 257a 235a 248a 244a
100 219ab 237a 256a 238a 236b 240a
200 211b 237a 263a 232a 241ab 237a
Within a column, values followed by the same letter are not significantly different at 0.05 level of probability (Fisher’s protected LSD).



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Analysis of variance for soil P and K at various soil depths (0–5, 5–10, and 10–20 cm) and soil balances for P and K after 3 yr of alfalfa subjected to three rates of P fertilization in combination to three K fertilization at Legnaro, northeastern Italy.

 
Soil P
Soil K
Soil balance
Source 0–20 cm 0–20 cm P K
P *** ** ns ns *** ns
K ns† ns *** *** *** **
P × K ns ns ns ns ns ns
Depth (D) *** ***
P × D *** ns
K × D ns ***
P × K × D ns ns
**Significant at the 0.01 probability level.
***Significant at the 0.001 probability level.
Not significant at the 0.05 probability level.



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Concentration of P and K in 0 to 20 cm of soil (weighted mean of 0–5-, 5–10-, and 10–20-cm depths), and soil balance of K and P after 3 yr of alfalfa subjected to three rates of P fertilization in combination to three K fertilization at Legnaro, northeastern Italy. Data are the means of three replicates.

 
Soil balance†
Fertilization treatment Soil P Soil K P K
kg ha–1
P2O5, kg ha–1
 0 32.1c§ –142c
 100 43.7b –9b
 200 53.7a 122a
K2O, kg ha–1
 0 139b –2a –1013c
 300 168b –13b –482b
 600 246a –19c 862a
Calculated as: Crop exportation – (Initial soil content + Fertilization supplies).
Results of soil analyses are reported assuming a soil bulk density of 1.3 g cm–3.
§Within a column and measurement parameter, values followed by the same letters are not significantly different at 0.05 level of probability (Fisher’s protected LSD).