Table 2.
Physico-chemical properties of soil prior to rice harvesting stage
| Soil properties | Continuous irrigation | Intermittent irrigation | LSD0.05 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Urea alone | Urea + calcium carbide | Urea + calcium silicate | Urea + PG | Urea + biochar | Urea alone | Urea + calcium carbide | Urea + calcium silicate | Urea + PG | Urea + biochar | ||
| Soil porosity | 0.52 | 0.54 | 0.56 | 0.55 | 0.56 | 0.53 | 0.55 | 0.57 | 0.56 | 0.59 | 0.01 |
| Soil pH (1:5 with H2O) | 6.6 | 6.8 | 7.1 | 6.8 | 6.9 | 6.5 | 6.6 | 6.9 | 6.7 | 6.8 | 0.03 |
| Soil Eh | −95.0 | −73.0 | −61.0 | −65.0 | −68.9 | −71.0 | −60.0 | −43.0 | −37.0 | −40.0 | 5.9 |
| Organic matter (g kg−1) | 24.5 | 25.9 | 28.5 | 26.9 | 31.6 | 24.1 | 25.1 | 27.9 | 26.6 | 29.5 | 4.5 |
| Available P2O5 (mg kg−1) | 63.5 | 71.5 | 105.0 | 98.0 | 97.0 | 59.5 | 67.5 | 73.5 | 91.5 | 89.0 | 12.0 |
| Available SiO2 (mg kg−1) | 59.0 | 79.5 | 117.0 | 108.0 | 93.0 | 57.5 | 67.0 | 97.9 | 93.0 | 85.0 | 15.0 |
| Ex. cations (cmol+ kg−1) | |||||||||||
| Ca | 3.9 | 4.1 | 5.6 | 6.9 | 6.3 | 3.6 | 3.6 | 5.7 | 6.3 | 5.5 | 0.35 |
| Mg | 1.1 | 1.3 | 1.6 | 1.5 | 1.5 | 1.1 | 1.2 | 1.4 | 1.30 | 1.4 | 0.11 |
| K | 0.21 | 0.29 | 0.35 | 0.38 | 0.39 | 0.22 | 0.34 | 0.41 | 0.43 | 0.47 | 0.03 |
| Active iron (g Fe kg−1)a | 6.50 | 7.80 | 11.50 | 10.20 | 9.50 | 6.70 | 9.20 | 12.50 | 11.50 | 10.30 | 7.16 |
| Ferrous iron (mg Fe2+ kg−1)b | 81.5 | 123.0 | 149.0 | 173.0 | 143.0 | 73.5 | 101.0 | 117.5 | 159.0 | 103.0 | 29.6 |
| NH4+-N (mg kg−1) | 37.5 | 49.5 | 39.5 | 37.9 | 35.5 | 30.7 | 37.9 | 28.5 | 31.5 | 29.8 | 4.6 |
| NO3−-N (mg kg−1) | 0.69 | 0.83 | 0.95 | 0.97 | 0.93 | 1.13 | 0.95 | 1.07 | 1.29 | 1.21 | 0.31 |
| SO42− (mg kg−1) | 33.5 | 57.5 | 95.0 | 139.5 | 121.5 | 39.5 | 47.0 | 129.5 | 148.5 | 119.0 | 23.5 |