Parewa et al.

Soil Chemical Properties

nutrients following application of 75% and 100% NPK

A perusal of data on pH and EC as affected by various

were at par during both the years. These observations are

treatments under study indicated that application of

in close conformity to those obtained by Abraham and

fertilizer levels, FYM and bioinoculants have no

Lal (2004) and Thakur et al., (2011).

significant effect on EC and pH during both the years.

Addition of FYM @ 10 t ha -1 significantly increased the

However soil pH maintained or slight decreased to the

available N, P and K in soil as compared to no FYM

initial value (Table 1) might be due to the formation

application during both the years. The increase was

of organic acids during the decomposition of organic

might be due to the direct addition of nutrients through

manure and crop residues (Sharma et al., 2013).

decomposition of the FYM added to the soil and could

Organic carbon and cation exchange capacity (CEC)

convert organically bound N to inorganic form and

differed significantly under various treatments over

retardation of soil P fixation by organic anions formed

control in soil after harvest of the wheat. The significant

during FYM decomposition, moreover minimizing the

higher values of organic carbon and CEC under 100%

losses due to fixation as well as solubilization of K through

NPK level compared to control (Table 1) clearly

the action of organic acids librated during decomposition.

indicate the effect of fertilizer in an improvement of

These results were in the same line with those obtained

soil condition. The use of fertilizer helps in increasing

by Patidar and Mali (2004) and Singh et al., (2012).

organic carbon content and CEC of soil due to higher

Bioinoculants did not show any significant variation in

biomass which might be due to the differential rate of

available N and K status estimated under soil. Moreover,

oxidation of organic matter by microbes (Trehan, 1997).

combined inoculation of PGPR+VAM increased the

The highest values of organic carbon (0.50 and 0.52%)

available P content of soil after the harvest of crop during

and CEC [22.14 and 22.43 C mol (P+) kg -1 soil] due to

both the years. The increase availability of P might be

incorporation of FYM @ 10 t ha -1 were recorded during

due to greater multiplication of soil microbes causing

both the years. These values higher due to direct addition

greater mineralization and production of organic acids,

of FYM and release of cations with the decomposition of

which reduce the fixation of phosphate by providing

organic matter. The result of the present investigation is

protective cover on sesquioxides and thus reduce the

harmony with the findings of Bhardwaj et al., (2010) and

phosphate fixing capacity and increase the available P in

Datt, et al., (2013). Use of bioinoculants did not show

soil (Bharadwaj and Omanwar, 1994).

any significant variation in organic carbon content in soil

after harvest of the wheat during both the years.

Biological properties

Available N, P and K content in control treatment

The activity of dehydrogenase and phosphatase enzyme

decreased from its initial value (207.87, 17.9 and 227.0

differed significantly amongst all the treatments (Table 4).

kg ha -1 respectively) whereas the availability of these

The minimum activities of these enzymes were recorded

nutrients in rest of the treatments increased from its initial

in control and maximum was found at each highest levels

levels. Higher values of available N (227.48 and 228.76

of the treatment during both the years. The increased

kg ha -1 ), P (18.25 and 18.31 kg ha -1 ) and K (233.40

activity by increasing levels of fertilizer application

and 235.78 kg ha -1 ) were obtained due to combined

might be attributed to the fact that inorganic source of

application of 100% NPK fertilizer, FYM @ 10 t ha -1 and

nutrient stimulated the activity of microorganisms to

bioinoculants during both the years ascribed due to direct

utilize the native pool of organic carbon as a source of

application of fertilizer in the soil. The lower values of

carbon, which acts as substrate for these enzyme. Masto

these nutrients in control during both the years might

et al., (2006) reported that dehydrogenase activity was

be due to more absorption of nutrients by component

dependent on addition of number and amount of nutrient.

wheat crop. It is clear from the Table 2 that available

Addition of FYM @ 10 t ha -1 significantly increased the

N, P and K content in soil increased significantly with

enzyme activity in the soil. This increased might be due

increasing levels of fertilizer application but these

to manure promote biological and microbial activities

520