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Table 6 Determinants of nitrogen pollution costs ratio: within-between model estimates

From: Environmental Efficiency and Pollution Costs of Nitrogen Surplus in Dairy Farms: A Parametric Hyperbolic Technology Distance Function Approach

Variables Northern Ireland Republic of Ireland
Estimates SE Estimates SE
Within (time) effect
Intercept 0.6893*** 0.1705 1.5522*** 0.2159
Farm size (ha) − 0.0008 0.0009 0.0006 0.0009
Age (years) − 0.0012 0.0013 − 0.0035*** 0.0011
Stocking density (LU/ha) 0.0882** 0.0412 − 0.0504 0.0356
Grass grazed (kg/ha) − 0.0003*** 0.0000 − 0.0001 0.0000
Off-farm income (dummy) − 0.0055 0.0534   
Invest. per cow (€/cow)    − 0.0002*** 0.0001
Milk recording (dummy)    − 0.0704*** 0.0181
Discussion group (dummy)    − 0.0087 0.0179
Advisory contact (dummy)    − 0.0217* 0.0129
Between (individual) effect
Farm size (ha) − 0.0012* 0.0006 − 0.0008 0.0011
Age (years) − 0.0042* 0.0022 − 0.0057** 0.0025
Stocking density (LU/ha) 0.1418** 0.0642 − 0.1379 0.1187
Grass grazed (kg/ha) − 0.0005* 0.0000 − 0.0001 0.0000
Off-farm income (dummy) 0.0647 0.0612   
Invest. per cow (€/cow)    − 0.0003** 0.0002
Milk recording (dummy)    − 0.0241 0.0924
Discussion group (dummy)    0.0178 0.1025
Advisory contact (dummy)    − 0.0049 0.1028
  1. LU Livestock units
  2. Single, double, and triple asterisks (*, **, ***) indicate significance at the 10%, 5%, and 1% level, respectively