Abstract
Considerable nitrogen (N) losses lead to lower N use-efficiency (NUE) in salt-affected soils due to leaching and
volatilization. A lysimeter experiment was conducted to determine NUE in two salt-affected soils of different texture (clay
loam and sandy clay loam), using various rates of N fertilizer. The experiment used a three replicate completely randomized
design. The treatments included five N rates, three higher (15, 30 and 45%) and two lower (15 and 30%) than recommended
rate of 125 kg ha-1. Additionally, gypsum was added at 50 and 100% of soil gypsum requirement (SGR) in both salt-affected
soils. Maximum paddy and straw yields were recorded for sandy clay loam saline-sodic soil collected from Village 132,
Faisalabad (132S), using 45% higher N + gypsum at 100% SGR. Whereas clay loam saline-sodic soil, from Village 84,
Faisalabad (84S) at 30% higher N rate with gypsum at 50% SGR gave the highest paddy and straw yields. In general, the clay
loam soil produced more paddy yield than the sandy clay loam soil at similar N fertilization. In the sandy clay loam soil,
gypsum at 100% SGR along with a 30% higher N rate increased the grain and straw yields of wheat significantly (p < 0.05)
compared to application of gypsum at only 50% SGR. Nitrogen use efficiency was the highest with 45% higher N (N145) with
gypsum applied @ 100% SGR compared to 50% SGR in severe salt-affected (sandy clay loam) soil during rice crop. From
marginal clay loam saline-sodic soil, NUE remained higher with N130 along with gypsum @ 100% SGR which was
statistically on par with gypsum @ 50% SGR. It was concluded that NUE remained highest with N130 and N145 with gypsum
applied @ 100% SGR during rice crop from clay loam and sandy clay loam soils, respectively. Moreover, NUE was higher at
recommended N fertilization when gypsum was applied at 100% SGR during wheat crop which was also attributed to
improved soil chemical properties, i.e. pHs
, ECe
and SAR.
