. 2019 Feb;81:100–110. doi: 10.1016/j.landusepol.2018.10.046

Table 2.

Multiple Regression Coefficients for Determinants of Soil Quality Parameters.

	OC		RC		pH		P
	MODEL-I	MODEL-II	MODEL-III	MODEL-IV	MODEL-V	MODEL-VI	MODEL-VII	MODEL-VIII
Size of Maize Plot (Ha)	−0.200	−0.12	0.002	0.001	−0.08	−0.02	−0.74	−3.15
Duration Plot used (Yrs)	0.0005	0.001	−1.2E-05	−0.00002	0.005	0.001	−0.01	−0.01
Proportion of land left fallow	0.057^*	0.05^*	0.0005	0.0005	0.002	0.02	−0.92	−0.51
Terraces Implemented (Yes=1)	0.065	0.06	−0.001	−0.001	−0.07	−0.02	3.21	3.13^*
Mechanized Land preparation (Yes=1)	−0.969^***	−0.68^***	−0.011^***	−0.008^*	0.38^*	0.26	8.45^*	−1.29
Use of Crop residues (Yes=1)	0.054	0.01	0.001	−0.0002	−0.10	−0.05	1.19	0.92
Quantity of Manure used (Kg/Ha)	0.045^***	0.03^*	0.00015	0.0003	3E-05^***	0.00002^**	−0.69	0.72^**
Quantity of Nitrogen (Kg/Ha)	−0.002^**	−0.001	7.4E-06	0.00,001	0.003	0.0001	0.04^**	0.03
Quantity of Phosphorous (Kg/Ha)	0.002	0.001	3.7E-07	−0.000001	0.002	−0.0002	−0.04	−0.03
Clay content in the soil (%)	0.008^**	0.01^**	0.0002^*	0.000055	−0.02^***	−0.01^***	−0.05	0.18^**
Soil pH	−0.082	−0.04	0.005^***	0.007^***	–	–	8.60^***	8.12^***
Farm has Cashcrop (Yes=1)	−0.188^**	−0.18^**	0.015^***	−0.00005	0.14	0.13	−1.83	2.53
Total Organic Carbon (%)			0.003^***	0.015^***
County Dummy (Machakos=1)		−0.03		−0.009^*		−0.04		10.81^**
Population Density (Persons/Km²)		0.01^**		−0.001^***		0.01^**		0.94^***
Population Density Squared (Persons/Km²)		−1.2E-05^**		4.2E-07^***		−0.00001^**		−0.0006^***
Proportion of land under crops		0.36^**		0.003		−0.08		−1.34
Distance to Cereals Board (Km)		0.01^**		−0.00009		0.01		−0.16
Cost of Transporting Fertilizer (Ksh/50 Kg bag/km)		0.0004^*		−0.00001		−0.0001		0.00
Village Wage rate (KSh/Manday)		−0.002		−0.00002		0.004		0.20^***
Distance to nearest extension services (kms)		−0.01		−0.00016		−0.02^**		0.00
Price of DAP Fertilizer (KSh/Kg)		0.02		−0.00021^**		0.01^*		−0.16
Land Tenure (Secure=1)		0.03		−0.003^*		0.06		−1.12
Number of Adults in the Household		0.04		0.00004		0.01		−0.98
Education level of the household head (Years)		0.01^*		0.00005		−0.01^*		0.24^**
Age of the Household Head(Years)		−0.002		0.00002		0.003		0.06
Distance to nearest town (Km)		−0.01		0.00,030^*		−0.02^*		0.01
INTERCEPT	2.189	−4.24^***	0.013	0.195^***	6.28^***	0.94^***	−32.19^***	−398.48^***
R²	0.13	0.34	0.41	0.48	0.08	0.20	0.18	0.44
F	3.42	5.09	14.78	9.22	1.70	2.28	5.05	8.13
Number of Observations (N)	290	290	290	290	290	290	290	290

*,**,*** parameters are significant at the 0.1, 0.05 and 0.01 levels respective. OC = Organic Carbon, RC = Reactive Carbon P = Plant available Phosphorous.