Seedling vigor and nitrogen use efficiency of Moroccan wheat as influenced by level of soil nitrogen

Abstract

One of the characteristics that can help wheat (Triticum aestivum L.) plants escape late season drought in the semiarid areas of Morocco is early stand establishment and adequate vigor. Little is known about the effect of nitrogen (N) on early seedling vigor in wheat. The objective of this study was to determine how N supply affects early root and shoot growth, N partitioning between the two parts and N use efficiency of seedlings. To reach this objective, three spring wheat cultivars were grown in pots in a growth chamber under N conditions which were low, adequate and high. Data showed that optimum N rates increased shoot and root growth but high N concentrations reduced their dry matter accumulation and inhibited root elongation. The cultivars tested behaved differently. ‘Nesma’, an older cultivar, produced 60% more dry matter and accumulated 93% more N in the shoot and root than the newer cultivars ‘Merchouch 8’ and ‘Saada’. Because of its high N uptake, ‘Nesma’ probably reduced soil N concentration at the root zone and avoided the negative effect of high N concentration on root growth. Although, ‘Nesma’ performed better and produced more dry matter, it used N less efficiently than the other two cultivars.

From this study, we can conclude that use of optimum N rates at time of seeing will result in quicker establishment and higher vigor of wheat seedlings. However, excessive N supply may retard seedling growth. The cultivars that produce more seedling dry matter with greater N accumulation are not necessarily the ones that use N more efficiently.

Notes

Published as Paper No. 10150 from the Nebraska Agricultural Experiment Station Work supported in part by USAID MAC/Morocco Project Grant No. ANE‐0136‐C‐00–8019–00.

Agronomist, Adridoculture Center, INRA, Settat, BP 290, Settat, Morocco.

Professor, Department of Agronomy, University of Nebraska, Lincoln, NE.