Decision Support System for

Soil Health Assessment

Division of Soil Science and Agricultural Chemistry

Indian Agricultural Research Institute

New Delhi

 

 

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Ratings of Soil Health Parameters

 Sr.no. Parameter Unit Low Medium  High
 Chemical indicator
1  pH (1:2::soil:water::w:v) unit less <6.5 6.5-8.5 >8.5
2  Electrical conductivity (1:2::soil:water::w:v) dS m-1 <0.2 0.2-1.6 >1.6
3  Soil organic carbon  (g kg-1) <4.5 4.5-7.5 >7.5
4  KMnO4 oxidisable carbon  (mg kg-1) <150 150-300 >300
5  Available phosphorus (Bray-P1) (mg kg-1) <13 13-20 >20.0
6  Available potassium (NH4OAC, pH 7.0) (mg kg-1) <55 55-125 >125
7  Available iron (DTPA, pH 7.3) (mg kg-1) <4.8 4.8-8.0 >8.0
8  Available manganese (DTPA, pH 7.3) (mg kg-1) <2.0 2.0-4.0 >4.0
9  Available zinc (DTPA, pH 7.3) (mg kg-1) <0.6 0.6-1.2 >1.2
10  Available copper (DTPA, pH 7.3) (mg kg-1) <0.2 0.2-0.4 >0.4
 Physical indicator
11  Bulk density (Core method) (Mg m-3) <1.0 1.0-1.4 >1.4
12  Maximum water holding capacity
(Keen Box method)
(%) <30 30-40 >40
 Biological indicator  
13  Microbial biomass carbon (MBC)
(Substrate induced respiration method)
(mg kg-1) <200 200-500 >500
14  Dehydrogenase activity
(24 h incubation at 28 oC)
(g TPF g-1 24h-1) <50 50-150 >150
15  Potentially mineralisable nitrogen
(21 day incubation at 28 oC)
(mg kg-1) <20 20-60 >60
16  Carbon mineralization (Cmin)
(30 day incubation at 37 oC)
(g CO2-C g-1 h-1 ) <0.5 0.5-1.0 >1.0
17  Microbial metabolic quotient
(Cmin last week/MBC)
(g CO2-C h-1 kg-1 MBC) <0.35 0.35-0.65 >0.65

 

  Soil Quality Index (unit less):     > 0.90      (Excellent);      0.75-0.90 (Very good);  0.50-0.75  (Good)

                                                            0.25-0.50  (Poor);       <0.25        (Very poor)