[Retracted] Application of Regression Analysis to Identify the Soil and Other Factors Affecting the Wheat Yield

Table 1

Apparatus for measuring the soil characteristics

Sr. No	Variable	Apparatus
1	Saturation percentage	1. Polythene sheets
		2. Spade
		3. Soil auger
		4. Moisture boxes/cans
		5. Balance
		6. Oven
		7. Ring stand
		8. Funnel (glass or plastic)
		9. Tubing (to attach to bottom of funnel)
		10. Clamp (to secure tubing)
		11. Filter paper (to line funnel)
		12. Beakers (250 mL)
		13. Graduated cylinder
		14. Stirring rod (long)
2	Electrical conductivity	1. Conductivity bridge
		2. Vacuum filtration system
3	Power of hydrogen	1. pH meter with combined electrode
		2. Beakers: Preferably use polyethylene or TFE beakers
		3. Mechanical stirrer, with inert plastic coating
		4. Wash bottle, plastic
4	Organic matter	1. Magnetic stirrer and teflon-coated magnetic stirring bar
		2. Glassware and pipettes for dispensing and preparing reagents
		3. Titration apparatus (burette)
5	Phosphorus	1. Spectrophotometer or colorimeter
		2. Standard laboratory glassware: beakers, volumetric flasks, pipettes, and funnels
6	Potassium	1. Flame photometer with accessories
		2. Beakers
		3. Pipettes and volumetric flasks, as required for dilution and tests of interference effects
7	Calcium carbonate	1. Hot plate
		2. Burette
		3. Erlenmeyer flask
		4. Volumetric pipette
8	Zinc	1. Atomic absorption spectrophotometer
		2. Mechanical shaker, reciprocal
9	Copper	1. Atomic absorption spectrophotometer
		2. Mechanical shaker, reciprocal
10	Iron	1. Atomic absorption spectrophotometer
		2. Mechanical shaker, reciprocal
11	Manganese	1. Atomic absorption spectrophotometer
		2. Mechanical shaker, reciprocal
12	Boron	1. Porcelain crucibles
		2. Spectrophotometer
		3. Polypropylene test tubes