Research Article

Evolution of Soil Biochemical Parameters in Rainfed Crops: Effect of Organic and Mineral Fertilization

Table 5

Evolution of the soil biological parameters (SOM1, SOMM2, SMBC3, CO2 to ATP ratio, NO3-N) according to the fertilization treatments over the field experiment.

Soil parameterTreatmentSept-00Dec-00May-01Sept-01Dec-01Feb-02May-02Sept-02Dec-02Feb-03May-03Average

SOM1 (g 100 g−1)Chemical1.23 a1.23 a0.99 a1.23 a1.31 a1.43 a1.43 a1.40 a1.25 a1.29 a1.31 a1.28 a
Organic1.17 a1.21 a1.01 a1.17 a1.28 a1.14 b1.17 b1.26 a1.35 a1.21 a1.12 a1.19 b
No fertilization1.15 a1.12 a1.10 a1.14 a1.15 a1.27 ab1.23 b1.27 a1.28 a1.16 a1.31 a1.20 b
Average1.18 AB1.19 AB1.03 B1.18 AB1.25 A1.28 A1.28 A1.31 A1.29 A1.22 A1.25 A1.22

SOMM2 (μg OM g−1 15 d−1)Chemical739 a280 a260 a200 a253 a260 a334 a304 a380 a412 a520 a358 a
Organic793 a259 a281 a174 a257 a241 a282 ab362 a340 a324 a495 a346 a
No fertilization631 a315 a337 a178 a224 a270 a258 b255 a367 a430 a447 a337 a
Average721 A284 DE293 DE184 E245 DE257 DE291 DE307 CDE362 CD388 C487 B347

SMBC3 (ATP, ng g−1)Chemical970 a561 a823 a224 a252 a299 a330 b205 a353 a462 a448 a
Organic757 b381 b790 a243 a197 a222 a569 a215 a214 a453 a404 a
No fertilization856 ab409 b835 a248 a265 a265 a391 ab239 a390 a531 a443 a
Average861 A450 B816 A238 C238 C262 C430 B219 C319 C482 B432

CO2 to ATP ratio (μg CO2  μg−1 ATP)Chemical4.85 a2.61 a1.81 a7.79 a7.41 a7.97 a6.81 a13.84 a7.82 a7.77 a6.87 a
Organic6.07 a3.73 a2.10 a7.03 a8.25 a8.22 a4.42 a10.36 a11.61 a7.33 a6.91 a
No fertilization4.60 a3.65 a2.28 a6.05 a7.21 a6.53 a4.86a a9.29 a8.84 a5.86 a5.92 a
Average5.17 DE3.33 EF2.07 F6.95 CD7.62 BC7.57 BC5.36 D11.16 A9.42 AB6.98 CD6.57

NO3-N (ppm)Chemical6.2 a9.4 a8.3 a35.8 a25.3 a23.6 a17.4 a15.5 a14.6 a14.6 a19.3 a17.3 a
Organic4.6 a9.2 a7.6 a32.2 a22.0 a15.8 a12.3 b12.0 a12.2 a11.5 a15.5 a14.1 b
No fertilization4.7 a10.4 a7.7 a36.5 a17.6 a16.8 a12.3 b15.7 a13.3 a13.1 a17.2 a15.0 b
Average5.2 G9.7 F7.8 FG34.8 A21.6 B18.7 BC14.0 DE14.4 DE13.4 E13.1 E17.3 CD15.5

1SOM: soil organic matter. 2SOMM: soil organic matter mineralization. 3SMBC: soil microbial biomass carbon.
Different small letters in the same column for each variable indicate significant differences at . Different capital letters in the same row indicate significant differences at .