A raw data article on the physico-chemical properties of soil from six firkas in Dharmapuri district, Tamil Nadu, India

The present study was aimed to assess the physical and chemical characteristics of soil belonging to six firkas covering three blocks of Dharmapuri district. A total of 125 samples were collected by means of Global Positioning System (GPS). The processed soil samples were analyzed for pH, Electrical conductivity (EC), soil separates, Bulk density (BD), Water holding capacity (WHC), organic carbon (OC), calcium carbonate (CaCO3), available nitrogen (AVN), available phosphorus (AVP), and available potassium (AVK). Extreme value in the data set was removed by outlier removal algorithm. Spatial variability maps were prepared using the kriging method using ArcGIS 10.4 . The best fitted semi variance model for pH, EC, AVK and CaCO3 was spherical; BD, sand, silt, and OC was circular; a Gaussian model was best fitted for WHC and AVN, while clay and AVP were exponential. The data presented in this study will help farmers, land managers, and policymakers to mitigate land degradation, and other environmental issues, thereby helping to increase land productivity.


Specification
The study area boundary was extracted using SOI Toposheet (57H/14, 57H/15, 57L/3, and 57L/4) from GSI, a cadastral map, and Block boundary map from local authorities. The soil sample's location was determined by the regular point sampling method. The soil samples were collected during fallow period (February and April, 2021). The soil sample's location was recorded using GARMIN 76 CS x GPS device. Data format Raw and Analyzed data Description of data collection The soil sample's location was predetermined by regular point generation technique and recorded using a GPS device. The surface litters and grass were removed and 'v' shaped pit was dug at the depth of 15 cm. After cleaning the pit, one-inch thickness soil was collected from each side. Using a wooden mallet, the air-dried soil samples were ground into powder. The samples were mixed and reduced in volume to roughly 500 g by quartering method. The samples were stored in air tight container and analyzed for pH, EC, particle size analysis, BD, WHC, OC, CaCO 3 and available NPK by following the standard procedures. These data were converted into vector layers and kriging was applied to create a spatial variable map for each soil parameters.

Data source location
The study area is the part of Dharmapuri district, Tamilnadu

Value of the Data
• This data set will be used to determine the agricultural land suitability and crop suitability of the study area. • This data will help the land manager and policymakers to suggest an action plan for sustainable crop production. • Furthermore, this data will aid other science and engineering fields in better understanding the soil in the study region, and it can be used for educational and research purposes.

Data Description
The data represents the physico-chemical properties of soil located in six firkas of Dharmapuri district. Tables 1-6 presents the physical and chemical properties of the soil in the study area. Table 7 presents the descriptive statistics of the soil properties. Fig. 1 shows the study area map and sample's location.  Table 1 The Physico-chemical properties of the Marandahalli firka soil samples from the Dharmapuri district in Tamil Nadu, India.

Table 2
The Physico-chemical properties of the Vellichandai firka soil samples from the Dharmapuri district in Tamil Nadu, India.      Table 6 The Physico-chemical properties of the Periyanahalli firka soil samples from the Dharmapuri district in Tamil where the number of pairs parted by distance is indicated by N(h), and Z(xi) and Z(xj) represent Z in the x i and x j positions, respectively.
The soil physico-chemical data were converted into shape file and kriged to identify soil characteristic of unknown location. The spatial variability maps are presented in Figs. 2 , 3 and 4 .

Ethics Statement
All the authors declare that there is no ethical statement or clearance required for the presented data.
CRediT Author Statement S. Sathiyamurthi: Conceptualization, Methodology, Data analysis and manuscript reviewing and editing; M. Ramya: Lab analysis, data curation, and manuscript writing.

Declaration of competing Interest
On behalf of all authors, there is no conflict of interest.

Data Availability
raw data article on the physico-chemical properties of soil from six firkas in Dharmapuri district, Tamil Nadu, India (Original data) (Mendeley Data).