180
(1–BD ∗ PD
−1
)
−1
, where BD = bulk density and PD = particle density, where the
particle density (PD) was assumed to be 2.65 g cm
−3
(Brady and Weil 2014).
2.4 Field Experimental Design and Treatments
A field experiment was conducted over two consecutive growing seasons, 2015/16
and 2016/17. The agronomic and economic performance of cotton was tested under
a range of fertilisation and pest control strategies for both conventional and organic
farming. As described in Tables 2 and 3, the current low-input conventional and
organic cotton farming practices were tested against higher application rates and
innovative practices, as well as against control treatments without fertilisers or pesticides. For conventional fertilisation management practices, two application rates
of nitrogen (N) from the inorganic fertilisers diammonium phosphate (DAP) and
urea and an innovative practice of combining inorganic fertilisers and organic
manure were tested. For organic farming, the fertility management practices include
two different levels of organic manure and an innovative practice of intercropping
cotton and green gram.
Table 2 Soil fertility management treatments
Management Treatments
Description
At planting
Later in the season
Conventional CF-0 – No fertilisers
No fertilisation
No fertilisation
CF-30 – Currently practised
fertilisation: 30 kg N ha
−1
75 kg ha
−1 DAP
(13.5 kg N ha
−1
, 15 kg P
ha
−1
)
At squire formation,
top-dress with
35.9 kg ha
−1 urea
(16.5 kg N ha
−1 )
CF-60 – Higher fertilisation
rate: 60 kg N ha
−1
100 kg ha
−1 DAP
(18 kg N ha
−1 + 20 kg P
ha
−1 )
At squire formation,
top-dress with
91.4 kg ha
−1 urea
(42 kg N ha
−1 )
CF-30 + M – Innovative
fertilisation: 3 Mg ha
−1
FYM + 30 kg N ha
−1
3 Mg ha
−1 FYM
At squire formation,
top-dress with
65.2 kg ha
−1 urea
(30 kg N ha
−1 )
Organic
OF-0 – No fertilisers
No fertilisation
No fertilisation
OF-3 – Currently practised
fertilisation: 3 Mg ha
−1 FYM
3 Mg ha
−1 FYM
No fertilisation
OF-5 – Higher fertilisation
rate: 5 Mg ha
−1 FYM
5 Mg ha
−1 FYM
No fertilisation
OF-3 + L – Innovative
fertilisation: 3 Mg ha
−1
FYM + intercropping with
green gram
3 Mg ha
−1 FYM
At 2–4 weeks after
planting cotton, plant
green gram (Vigna
radiata) between cotton
rows
T. N. Bwana et al.
(1–BD ∗ PD
−1
)
−1
, where BD = bulk density and PD = particle density, where the
particle density (PD) was assumed to be 2.65 g cm
−3
(Brady and Weil 2014).
2.4 Field Experimental Design and Treatments
A field experiment was conducted over two consecutive growing seasons, 2015/16
and 2016/17. The agronomic and economic performance of cotton was tested under
a range of fertilisation and pest control strategies for both conventional and organic
farming. As described in Tables 2 and 3, the current low-input conventional and
organic cotton farming practices were tested against higher application rates and
innovative practices, as well as against control treatments without fertilisers or pesticides. For conventional fertilisation management practices, two application rates
of nitrogen (N) from the inorganic fertilisers diammonium phosphate (DAP) and
urea and an innovative practice of combining inorganic fertilisers and organic
manure were tested. For organic farming, the fertility management practices include
two different levels of organic manure and an innovative practice of intercropping
cotton and green gram.
Table 2 Soil fertility management treatments
Management Treatments
Description
At planting
Later in the season
Conventional CF-0 – No fertilisers
No fertilisation
No fertilisation
CF-30 – Currently practised
fertilisation: 30 kg N ha
−1
75 kg ha
−1 DAP
(13.5 kg N ha
−1
, 15 kg P
ha
−1
)
At squire formation,
top-dress with
35.9 kg ha
−1 urea
(16.5 kg N ha
−1 )
CF-60 – Higher fertilisation
rate: 60 kg N ha
−1
100 kg ha
−1 DAP
(18 kg N ha
−1 + 20 kg P
ha
−1 )
At squire formation,
top-dress with
91.4 kg ha
−1 urea
(42 kg N ha
−1 )
CF-30 + M – Innovative
fertilisation: 3 Mg ha
−1
FYM + 30 kg N ha
−1
3 Mg ha
−1 FYM
At squire formation,
top-dress with
65.2 kg ha
−1 urea
(30 kg N ha
−1 )
Organic
OF-0 – No fertilisers
No fertilisation
No fertilisation
OF-3 – Currently practised
fertilisation: 3 Mg ha
−1 FYM
3 Mg ha
−1 FYM
No fertilisation
OF-5 – Higher fertilisation
rate: 5 Mg ha
−1 FYM
5 Mg ha
−1 FYM
No fertilisation
OF-3 + L – Innovative
fertilisation: 3 Mg ha
−1
FYM + intercropping with
green gram
3 Mg ha
−1 FYM
At 2–4 weeks after
planting cotton, plant
green gram (Vigna
radiata) between cotton
rows
T. N. Bwana et al.