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Effect of nitrogen on yield, nitrogen uptake and water use efficiency of wheat in rotation systems under semiarid conditions of Morocco
Abstract
A field experiment was conducted during three years at two locations in semiarid regions of Morocco, to determine the effect of fertilizer N on wheat (Triticum aestivum L.) yield, N uptake, water use and water use efficiency. Cropping systems included clean fallow, winter chickpea (Cicer arietinum L.) and wheat with four rates of fertilizer nitrogen. Isotopic N was used to determine N recovery and biological N fixation. Rotation and applied N increased wheat yield, N uptake and water use efficiency. Fallow resulted in more soil nitrate and soil water compared to chickpea or wheat, which resulted in greater yield increase for wheat following fallow than wheat after wheat or wheat after chickpea even with applied N. Grain yield increase ranged from 82 to 92% in a normal year and 189 to 389% in a dry year. Wheat yield after chickpea was higher than yield from continuous wheat despite similarities in soil water and nitrate-N. The percent of N biologically fixed by chickpea ranged from 61 to 74%. Since the whole chickpea plant is taken from the field in Morocco, chickpea took 18 kg N/ha from the soil during a normal year and 5 kg/ha during a dry year. Applied N slightly increased water use but water use efficiency was increased through the increase in yield due to applied N and rotation treatments. Winter chickpea used as much water as wheat but was less efficient at producing dry matter and grain yield because of its slow growth during winter. Although the percent of real N recovery ranged only from 25 to 32%, soil residual N increased only when 120 kg N/ha was applied on wheat after wheat. Wheat yield in unfertilized plots increased with soil nitrate-N levels. The limited data however, did not make it possible to determine critical levels of soil nitrate, but they indicated that soil nitrate level for wheat after fallow is higher than the other studied rotations.
Subject Area
Agronomy
Recommended Citation
El Mejahed, Khalil, "Effect of nitrogen on yield, nitrogen uptake and water use efficiency of wheat in rotation systems under semiarid conditions of Morocco" (1993). ETD collection for University of Nebraska-Lincoln. AAI9415960.
https://digitalcommons.unl.edu/dissertations/AAI9415960