560
Integrating inorganic and organic fertilizer can generate multiple benefits for the
production of maize, and has the potential to increase NUE (Holden 2018). The
chapter discusses evidence of the impact of integrating inorganic and organic fertilizer on maize productivity using on-farm and household survey studies. On-farm
studies have compared maize yield on control plots where neither organic nor inorganic fertilizer was used with plots where only inorganic or organic fertilizer was
used and plots where organic and inorganic fertilizers were combined.
Compared with control plots, Vanlauwe et al. (2001b) reported that maize yield
was 750, 1000, and 2000 kg/ha higher in plots with inorganic fertilizer, organic
fertilizer and combined inorganic and organic fertilizer, respectively. These findings
were consistent with Sakala et al. (2003) who reported highest maize productivity
impact on plots where green manure was integrated with inorganic fertilizer, compared with plots with only green manure or with continuous cropping. Fandika et al.
(2007) reported similar findings where optimum maize yield was found in fields
where inorganic nitrogen fertilizer (urea) was mixed with either compost manure or
farmyard manure, unlike fields with sole application of inorganic nitrogen fertilizer
or manure. A review by Munthali (2007) showed that sole application of inorganic
fertilizer and organic fertilizer yielded 6.5 Mg/ha and 6.9 Mg/ha, respectively. On
the other hand, integration of organic and inorganic fertilizer yielded a maximum of
7.5 Mg/ha.
Using household survey data, Tchale and Sauer (2007) found that use of ISFM
where organic and inorganic fertilizer were combined had higher levels of technical
efficiency (91%) than when inorganic fertilizer was used in isolation (79%). There
was a loss of yield of 143 kg/ha in plots with chemical fertilizer only due to technical inefficiency, while there was only 58 kg/ha yield loss for households that used
ISFM. In a related on-farm study, Vanlauwe et al. (2011) reported nitrogen agronomic use efficiency of maize between 17 and 26 kg/kgN depending on maize variety. When fertilizer was mixed with organic manure or compost, the result of NUE
was 36 kg/kgN.
A meta-analysis by Chivenge et al. (2011) showed that application of organic
resources, inorganic nitrogen fertilizer, and integration of organic and inorganic fertilizer increased maize yield by 60%, 84%, and 114%, respectively. The combined
effect was due to extra nitrogen available from inorganic fertilizer with organic
resources inducing nitrogen use efficiency and water retention (Vanlauwe et al.
2001a). In contrast, an on-farm study by Ngwira et al. (2013b) showed that maize
yield was higher with sole fertilizer application followed by compost plus fertilizer
and compost only relative to no fertilizer no compost. However, the impact was
highest in areas with a long history of compost use, good rainfall, and good soils.
This is because good soils mean that all essential nutrients are available, including
soil organic matter that increases nitrogen use efficiency. With poor soils and low
rainfall, the soils require compost manure to increase nitrogen use efficiency,
thereby increasing maize yield. In a related study, Kaczan et al. (2013) observed that
application of crop residues increased maize yield response to inorganic fertilizer
by 86–216%.
S. P. Katengeza
Integrating inorganic and organic fertilizer can generate multiple benefits for the
production of maize, and has the potential to increase NUE (Holden 2018). The
chapter discusses evidence of the impact of integrating inorganic and organic fertilizer on maize productivity using on-farm and household survey studies. On-farm
studies have compared maize yield on control plots where neither organic nor inorganic fertilizer was used with plots where only inorganic or organic fertilizer was
used and plots where organic and inorganic fertilizers were combined.
Compared with control plots, Vanlauwe et al. (2001b) reported that maize yield
was 750, 1000, and 2000 kg/ha higher in plots with inorganic fertilizer, organic
fertilizer and combined inorganic and organic fertilizer, respectively. These findings
were consistent with Sakala et al. (2003) who reported highest maize productivity
impact on plots where green manure was integrated with inorganic fertilizer, compared with plots with only green manure or with continuous cropping. Fandika et al.
(2007) reported similar findings where optimum maize yield was found in fields
where inorganic nitrogen fertilizer (urea) was mixed with either compost manure or
farmyard manure, unlike fields with sole application of inorganic nitrogen fertilizer
or manure. A review by Munthali (2007) showed that sole application of inorganic
fertilizer and organic fertilizer yielded 6.5 Mg/ha and 6.9 Mg/ha, respectively. On
the other hand, integration of organic and inorganic fertilizer yielded a maximum of
7.5 Mg/ha.
Using household survey data, Tchale and Sauer (2007) found that use of ISFM
where organic and inorganic fertilizer were combined had higher levels of technical
efficiency (91%) than when inorganic fertilizer was used in isolation (79%). There
was a loss of yield of 143 kg/ha in plots with chemical fertilizer only due to technical inefficiency, while there was only 58 kg/ha yield loss for households that used
ISFM. In a related on-farm study, Vanlauwe et al. (2011) reported nitrogen agronomic use efficiency of maize between 17 and 26 kg/kgN depending on maize variety. When fertilizer was mixed with organic manure or compost, the result of NUE
was 36 kg/kgN.
A meta-analysis by Chivenge et al. (2011) showed that application of organic
resources, inorganic nitrogen fertilizer, and integration of organic and inorganic fertilizer increased maize yield by 60%, 84%, and 114%, respectively. The combined
effect was due to extra nitrogen available from inorganic fertilizer with organic
resources inducing nitrogen use efficiency and water retention (Vanlauwe et al.
2001a). In contrast, an on-farm study by Ngwira et al. (2013b) showed that maize
yield was higher with sole fertilizer application followed by compost plus fertilizer
and compost only relative to no fertilizer no compost. However, the impact was
highest in areas with a long history of compost use, good rainfall, and good soils.
This is because good soils mean that all essential nutrients are available, including
soil organic matter that increases nitrogen use efficiency. With poor soils and low
rainfall, the soils require compost manure to increase nitrogen use efficiency,
thereby increasing maize yield. In a related study, Kaczan et al. (2013) observed that
application of crop residues increased maize yield response to inorganic fertilizer
by 86–216%.
S. P. Katengeza