Assessing light and quality indicators of fodder at different levels of nitrogen fertilizer based on additive intercropping of barley (Hordeum vulgare) and vetch (Vicilia ervilia) under dryland farming

Abstract

The intercropping system leads to increasing radiation use efficiency and quality indicators and improving the stability in the production of fodder plants. Intercropping and reducing the use of chemical fertilizers are the most effective methods to achieve sustainable agriculture goals. To investigate light and quality indicators of fodder obtained from barley and vetch additive intercropping at different levels of nitrogen fertilizer, a split plot experiment was performed with a randomized complete block design (RCBD) and 4 replications in two experimental fields in Sisab and Shirvan, North Khorasan Province, Iran, during 2017–2018. The factor included nitrogen fertilizer at three levels (zero, 50 and 100 Kg.ha−1 (N0, N1 and N2)) and the subfactor included the combination of crops at four levels (barley pure cropping (I1), 15% vetch +100% barley (I2), 30% vetch +100% barley (I3) and 45% vetch + 100% barley (I4) additive intercropping). The results showed the highest fodder dry weight, absorbed radiation, radiation use efficiency, light extinction coefficient, ground cover percentage and leaf area index (LAI) in I3 and N2 in Sisab, and the lowest in I1 and N0 in Shirvan. Also, the highest crude protein (CP) was obtained from I4 and N2 in Shirvan, and the lowest crude protein was obtained from I1 and N0 in Sisab, which was inconsistent with neutral detergent fiber (NDF). The study results showed that increasing the percentage of vetch by 30% in intercropping and using nitrogen fertilizer led to increases in the indicators measured in the experiment.