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Table 5 Parameters of the exponential model (Y t  = Y e  + (Y 0  − Y e ) × exp -rt) fitted to the measurements of changes in nutrient content in 100 kg DM of manure during storage (cf. Fig. 5). Time (t) is expressed in days and r in day−1, Y 0 and Y e represent the initial and final amounts of nutrients per storage unit

From: Carbon and nutrient losses during manure storage under traditional and improved practices in smallholder crop-livestock systems—evidence from Kenya

  Y0 Ye r Ye/Y0 RMSE*
Nitrogen (kg SU−1)
 Pit open air 1.45 0.35 0.057 0.24 0.24
 Heap open air 1.44 0.35 0.014 0.25 0.11
 Heap under roof 1.27 0.48 0.025 0.38 0.06
Mineral N (g SU−1)
 Pit open air 73.8 9.1 0.038 0.12 5.9
 Heap open air 76.3 10.3 0.055 0.14 15.6
 Heap under roof 70.0 8.3 0.011 0.12 8.2
Phosphorus (kg SU−1)
 Pit open air 0.49 0.19 0.015 0.38 0.05
 Heap open air 0.50 0.18 0.013 0.35 0.03
 Heap under roof 0.44 0.15 0.016 0.34 0.02
Potassium (kg SU−1)
 Pit open air 0.97 0.19 0.080 0.20 0.69
 Heap open air 0.99 0.18 0.052 0.18 0.02
 Heap under roof 0.90 0.31 0.031 0.34 0.01
  1. SU Storage unit; RMSE root mean squared error of the differences
  2. *All regressions were significant at P < 0.01 except for potassium, at P < 0.001