View Full Table | Close Full ViewTable 1.

Properties of the 0- to 20-cm layer of the Red Latosol of the experimental area.

 
pH (CaCl2; 0.0125 mol L−1) OC† P‡ K Ca Mg H+Al§ CEC¶ Soil texture#
Clay Silt Sand
g dm−3 mg dm−3 mmolc dm−3 g kg−1
5.6 12 8 2.7 22 12 19 55.9 410 175 415
Organic carbon (oxi-reduction).
Phosphorus, K, Ca, and Mg were extracted with ion exchange resin.
§Buffer solution (pH 7.0).
Cation exchange capacity.
#Soil texture determined by the densimeter method.



View Full Table | Close Full ViewTable 2.

Cumulative nitrous oxide emissions for 217 d from urea, incorporated in the Red Latosol, with or without nitrification inhibitors (dicyandiamide and 3,4-dimethylpyrazole phosphate) or polymer and sulfur–coated urea applied to ratoon cane, 2011/2012.

 
Treatments† Cumulative N2O–N emissions Differences from urea¶
g ha−1 % of N applied§ %
No N (control) 1098b
UR 1924a 0.69
UR+DCD 1142b 0.04 −95
UR+DMPP 1112b 0.01 −98
PSCU 2213a 0.93 +35
DCD, dicyandiamide; DMPP, 3,4-dimethylpyrazole phosphate; PSCU, polymer and sulfur–coated urea; UR, urea.
Values followed by the same lowercase letter are not significantly different at P ≤ 0.05 using the Tukey test.
§Results from treatment without N were subtracted for this calculation.
(−) reduction, (+) increase; coefficient of variation: 15%.



View Full Table | Close Full ViewTable 3.

Cumulative nitrous oxide emissions for 382 d from urea, incorporated in the Red Latosol, with or without nitrification inhibitors (dicyandiamide and 3,4-dimethylpyrazole phosphate) or polymer sulfur coated–urea applied to ratoon cane 2012/2013.

 
Treatments† Cumulative N2O–N emissions Differences from urea¶
g ha−1 % of N applied§ %
No N (control) 587c
UR 1484b 0.75
UR+DCD-R 674c 0.07 −90
UR+DMPP-R 643c 0.05 −94
UR+DCD 759c 0.14 −81
UR+DMPP 584c 0.00 −100
PSCU 1901a 1.09 +46
DCD, dicyandiamide; DMPP, 3,4-dimethylpyrazole phosphate; PSCU, polymer and sulfur–coated urea; R, inhibitor reapplied in same plot of previous cycle; UR, urea.
Values followed by the same lowercase letter are not significantly different at P ≤ 0.05 using the Tukey test.
§Results from treatment without N were subtracted for this calculation.
(−) reduction, (+) increase; coefficient of variation: 17%.