*Article* **Spelt Wheat: An Alternative for Sustainable Plant Production at Low N-Levels**

### **Eszter Sugár, Nándor Fodor \*, Renáta Sándor, Péter Bónis, Gyula Vida and Tamás Árendás**

Agricultural Institute, Centre for Agricultural Research, Brunszvik u. 2, 2462 Martonvásár, Hungary; sugar.eszter@agrar.mta.hu (E.S.); sandor.renata@agrar.mta.hu (R.S.); bonis.peter@agrar.mta.hu (P.B.); vida.gyula@agrar.mta.hu (G.V.); arendas.tamas@agrar.mta.hu (T.A.)

**\*** Correspondence: fodor.nandor@agrar.mta.hu; Tel.: +36-22-569-554

Received: 31 October 2019; Accepted: 21 November 2019; Published: 27 November 2019

**Abstract:** Sustainable agriculture strives for maintaining or even increasing productivity, quality and economic viability while leaving a minimal foot print on the environment. To promote sustainability and biodiversity conservation, there is a growing interest in some old wheat species that can achieve better grain yields than the new varieties in marginal soil and/or managemen<sup>t</sup> conditions. Generally, common wheat is intensively studied but there is still a lack of knowledge of the competitiveness of alternative species such as spelt wheat. The aim is to provide detailed analysis of vegetative, generative and spectral properties of spelt and common wheat grown under different nitrogen fertiliser levels. Our results complement the previous findings and highlight the fact that despite the lodging risk increasing together with the N fertiliser level, spelt wheat is a real alternative to common wheat for low N input production both for low quality and fertile soils. Vitality indices such as flag leaf chlorophyll content and normalized difference vegetation index were found to be good precursors of the final yield and the proposed estimation equations may improve the yield forecasting applications. The reliability of the predictions can be enhanced by including crop-specific parameters which are already available around flowering, beside soil and/or weather parameters.

**Keywords:** wheat; spelt; sustainable plant production; N-fertilisation; grain yield; vitality indices
