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

IV. EXPERIMENTAL RESULTS
The results <strong>of</strong> the study on changes in soil properties as influenced by <strong>organic</strong>
<strong>farming</strong> in some selected <strong>organic</strong> farms in Northern dry zone <strong>of</strong> Karnataka (Zone-3) are
presented in this chapter under the following heads.
4.1 Organic manures as a source <strong>of</strong> plant nutrients
4.2 Effect <strong>of</strong> <strong>organic</strong> <strong>farming</strong> on soil physical properties
4.3 Effect <strong>of</strong> <strong>organic</strong> <strong>farming</strong> on soil chemical properties
4.4 Effect <strong>of</strong> <strong>organic</strong> <strong>farming</strong> on availability <strong>of</strong> plant nutrients
4.5 Effect <strong>of</strong> <strong>organic</strong> <strong>farming</strong> on soil biological properties
4.1 ORGANIC MANURES AS A SOURCE OF PLANT
NUTRIENTS
4.1.1 Analysis <strong>of</strong> <strong>organic</strong> manures used by <strong>organic</strong> farmers
The analytical results <strong>of</strong> the representative samples <strong>of</strong> <strong>organic</strong> manures used by
farmers are presented in Table 2.
Among different vermicompost samples used in <strong>organic</strong> <strong>farming</strong>, vermicomposts
used by C1 and R3 farmer recorded highest <strong>organic</strong> carbon (42.46%) and lowest was
recorded in the sample <strong>of</strong> K1 farm (32.68%). Farmyard manure (FYM) sample collected from
K 2 farmer recorded highest <strong>organic</strong> carbon (30.15%) and the lowest was noticed in the
sample <strong>of</strong> V1 farm (24.60%).
The total N content in vermicompost samples varied from a low 2.04 per cent (C2) to
a high <strong>of</strong> 3.10 per cent (C3). In FYM samples the total N content was lower than its content in
vermicomposts. It ranged from 0.68 per cent in the sample <strong>of</strong> K 1 farmer to 1.20 per cent in the
sample <strong>of</strong> K2 farmer.
The total P content in vermicompost was highest in the sample <strong>of</strong> K1 farm (0.78%)
and was lowest (0.52%) in the sample <strong>of</strong> C1 farm. The total P content in FYM samples varied
from a high <strong>of</strong> 0.54 per cent (V 2) to a low <strong>of</strong> 0.30 per cent (C 1).
The total K content in vermicompost samples was around 1.0 per cent in most <strong>of</strong> the
samples, the highest (1.17%) being in the sample used by C3 farmer and lowest (0.98%) in
sample <strong>of</strong> V1 farmer. In FYM, total K content varied from 0.64 (S2) to 1.02 (K2) per cent.
The C:N ratio was narrow in vermicompost samples (13:1 in C 3 to 20:1 in C 1 sample)
compared to FYM samples (25:1 in K2 to 38:1 in C1 sample).
4.1.2 Quantity <strong>of</strong> nutrients added to soil through <strong>organic</strong>s under different
cropping systems
The Table 3 shows the total quantity <strong>of</strong> nutrients added to the soil through <strong>organic</strong>s
under different cropping systems. The addition <strong>of</strong> nitrogen through <strong>organic</strong>s in cotton based
cropping system varied from 95.56 (C1) to 162.60 (C4) kg per ha per year, phosphorus from
36.24 (C1) to 79.90 (C4) kg per ha per year and potassium from 99.15 (C2) to 144.60 (C4) kg
per ha per year.
In case <strong>of</strong> kharif jowar based cropping system, nitrogen content added through
<strong>organic</strong>s ranged from 89.30 to 118.70 kg per ha per year, phosphorus content from 47.20 to
55.80 kg per ha per year and potassium content from 93.40 to 94.00 kg per ha per year.
Under rabi jowar based cropping system, nitrogen content added through <strong>organic</strong>s ranged
from 95.60 (R 3) to 123.90 (R 1) kg per ha per year, phosphorus content from 41.20 (R 3) to
58.80 (R1) kg per ha per year and potassium content from 96.20 (R3) to 109.50 (R1) kg per ha
per year.