Table 1: Cowpea nodules number (nodules/plant) and efficiency as affected by cropping system and cowpea variety at flower buds stage at Cinzana Agronomic Research Station, 2007 and 2008.

TreatmentsFlower buds stage
Nodules number (nodules/plant)Efficient nodules (%)

Years
 Year 1: 200741a77
 Year 2: 200830b76

Cropping systems
 Millet/cowpea intercropping (1 row/1 row)47a78ab
 Millet/cowpea intercropping (2 hills/1 hill)19c69b
 Cowpea sole crop40b81a

Cowpea varieties
 V1: IT89KD-3743686a
 V2: CZ1-94-23-13262b
 V3: CZ11-94-5C3780a

Effect values values
 Year (Y)<0.01
 Cropping system (S)<0.010.03
 Year × cropping system (Y × S)0.07
 Cowpea variety (V)0.06<0.01
 Year × variety (Y × V)<0.010.30
 Cropping system × cowpea variety (S × V)
 Year × cropping system × variety (Y × S × V)0.13
 Coefficient of variation (%)22.7821.21

Means followed by the same letters in the same column for each parameter are not significantly different ( ), according to Duncan test.