impact of farmers' organic farming practices on soil properties in ...

In kharif jowar based cropping system (Table 19), the average <strong>of</strong> two soils indicated
an increase in iron content due to <strong>organic</strong> <strong>farming</strong> from 4.42 to 5.93 ppm and 2.81 to 4.17
ppm in surface and subsurface soils, respectively, accounting for an increase <strong>of</strong> 34.20 per
cent in surface soil and 48.40 per cent in subsurface soils. The highest increase in iron
content was observed in soils <strong>of</strong> K 1 farmer (43.75%) than K 2 farmer (38.00%).
In rabi jowar based cropping system (Table 19) also there was an increase in
average iron content <strong>of</strong> soils from 4.38 ppm in conventional farm to 5.91 ppm in <strong>organic</strong> farm
in the surface soils and from 3.19 to 4.57 ppm in the subsurface soil. Among three <strong>organic</strong>
farms, the highest increase in iron content <strong>of</strong> <strong>organic</strong> farm, over conventional farms was
observed in soils <strong>of</strong> R1 farmer (44.05%) and lowest increase was in soils <strong>of</strong> R3 farmer
(35.90%).
All the four soils under sugarcane based cropping system (Table 20) showed an
increase in iron content due to <strong>organic</strong> <strong>farming</strong> practice. The DTPA-Fe content in soils <strong>of</strong>
<strong>organic</strong> farms varied narrowly (5.56 to 5.89 ppm). The overall average increase in iron
content due to <strong>organic</strong> <strong>farming</strong> over conventional <strong>farming</strong> was 35.50 per cent and 39.94 per
cent in surface and subsurface soils, respectively. The highest increase in iron contents was
noticed in soils <strong>of</strong> S 3 farmer (41.30%) and lowest was in soils <strong>of</strong> S 1 farmer (34.20%),
The iron content <strong>of</strong> three soils under vineyards (Table 21), increased due to <strong>organic</strong>
<strong>farming</strong> to the extent <strong>of</strong> 6.14 and 4.96 ppm in surface and subsurface soils, respectively from
4.72 and 3.65 ppm in conventional farms. The average increase in iron in surface soil was
30.08 per cent and it was 35.89 per cent in subsurface soil. The soil from V 3 farmer recorded
highest increase in iron content (36.03%), while the lowest increase was in soils <strong>of</strong> V2 farmer
(27.68%).
4.4.5.3 Manganese
The results on DTPA-extractable manganese (DTPA-Mn) content <strong>of</strong> soils are
presented in Table 22, 23, 24 and 25. All the soils, irrespective <strong>of</strong> type <strong>of</strong> <strong>farming</strong> and
cropping system, contained DTPA-Mn content above the critical concentration.
In cotton based cropping system (Table 22), the mean DTPA-Mn content in soils <strong>of</strong>
<strong>organic</strong> farms ranged from 7.25 ppm (C 4) to 8.25 ppm (C 1) as against 5.50 to 6.37 ppm in
conventional farms. On an average, manganese content increased from 6.80 to 8.71 ppm and
5.06 to 6.63 ppm in surface and subsurface soils, respectively under the influence <strong>of</strong> <strong>organic</strong>
<strong>farming</strong>. Among the soils <strong>of</strong> four <strong>organic</strong> farms, the highest increase in manganese content
was observed in soils <strong>of</strong> C 4 farmer (31.20%) followed by C 3 farmer (30.35%) and lowest
increase was observed in soils <strong>of</strong> C1 farmer (27.50%).
In kharif jowar based cropping system (Table 23), the average <strong>of</strong> two soils indicated
an increase <strong>of</strong> manganese from 7.83 ppm in conventional farm to 9.76 ppm in <strong>organic</strong> farm in
surface soil and from 5.85 to 7.72 ppm in subsurface soil. The overall increase in available
manganese due to <strong>organic</strong> <strong>farming</strong> was 27.77 per cent. The highest increase was observed in
soils <strong>of</strong> K1 farmer (30.90%) than K2 farmer (24.80%).
The soils under rabi jowar based cropping system (Table 23) also showed an
increase in available manganese due to <strong>organic</strong> <strong>farming</strong> (7.77 to 9.50 ppm and 6.16 to 7.76
ppm in surface and surface soils, respectively). Among the three soils, the highest increase in
available manganese was observed in soils <strong>of</strong> R2 farmer (29.50%) and lowest was in soils <strong>of</strong>
R1 farmer (20.60%).
The average increase in available manganese content <strong>of</strong> soil due to <strong>organic</strong> <strong>farming</strong>
in sugarcane based cropping system (Table 24) was 23.04 (8.47 to 10.36 ppm) and 29.61
per cent (6.28 to 8.14 ppm) in surface and subsurface soils, respectively. The Mn content
soils <strong>of</strong> S3 farmer accounted for highest increase (32.45%), while soils <strong>of</strong> S1 farmer
accounted for lowest increase (20.90%).
In vine yard system (Table 25), the average <strong>of</strong> three soils indicated that available
manganese content increased due to <strong>organic</strong> <strong>farming</strong> from 8.45 to 10.51 ppm and 6.31 to
7.73 ppm in surface and subsurface soils, respectively. The highest and lowest increase in
manganese content due to <strong>organic</strong> <strong>farming</strong> were recorded in soils <strong>of</strong> V 3 farmer (25.88%) and
V2 farmer (20.32%), respectively.