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combine use of N and P improved the maize grain yield by 14.1 % than the use of
N alone. Application of NPK was most beneficial which enhanced the maize grain
yield by 15.7 % than the use of N alone, while use of NPK than NP provided yield
improvement of 1.9 % (Table 5 ).
3.7 Use of Slow Release Fertilizers and Nitrification Inhibitors
Use of slow release fertilizers and nitrification inhibitors in drylands regions might
be useful to enhance the fertilizer use efficiency and reduce the nutrient losses. Slow
release fertilizers (isobutylidene diurea, N-lignin, sulphur coated urea, shellac
coated urea, urea briquettes, and urea super granules) and nitrification inhibitors
[N-serve (2-chloro-6 (trichloromethyl pyridine), AM (2-amino, 4-chloro, 6 methyl
pyridine), ST (2-sulphanileamide-thiazole) and dicyandiamide has widely tested in
agriculture and offer pragmatic option to improve fertilizer use efficiency and
reduce the nutrient losses in dryland agriculture. In dryland agriculture, losses of N
due to nitrification are high which can be minimized by using the nitrification
Table 4 Improvement in wheat yield (%) due to combine use of nitrogen and phosphorus at
variable rates on a dryland soil deficienta in phosphorus supply
Nitrogen (kg ha−^1 )Phosphorus (P 2 O 5 , kg ha−^1 )
0 17 34 68 102
0 – 27.4 38.4 40.3 40.6
34 7.7 31.0 45.2 47.3 52.7
68 3.9 33.0 46.1 63.0 64.9
102 4.4 43.9 54.1 62.3 65.1
136 23.2 41.1 56.3 63.5 65.2
Source: Li ( 2002 )
P phosphorous
aOlsen-P = 5.7 mg kg− (^1) soil
Table 5 Influence of integrated use of nitrogen (N), phosphorus (P) and potash (K) on percent
increase in maize yield under various precipitation years on a dryland soil
Precipitation
Increase in yield due
to NP than N (%)
Increase in yield due
to NPK than N (%)
Increase in yield due to
NPK than NP (%)
Drought
(<400 mm)
14.1 15.7 1.9
Normal (400–550) 10.7 19.6 10.0
High
(550–650 mm)
12.5 24.1 13.2
Waterlogging
(>650 mm)
34.7 44.0 14.2
Source: Ma et al. ( 2010 )
N, P and K were applied at 150 kg N ha−^1 , 17.9–25 kg P ha−^1 , and 60 kg K ha−^1
A. Nawaz and M. Farooq