Mixed Intercropping of Wheat and White Clover to Enhance the Sustainability of the Conventional Cropping System: Effects on Biomass Production and Leaching of Mineral Nitrogen

The main goal of our research was to compare the mixed intercropping (MC) of winter wheat ( Triticum aestivum ) and white clover ( Trifolium repens ) with the sole cropping of Triticum aestivum , during two growing seasons (2012–2014), in a lysimetric experiment. We aimed to investigate the effect of the above growing system on total biomass production, grain yield and leaching of mineral nitrogen (N min ). Four variants of intercropping (0 kg N/ha; 112 kg N/ha; 112 kg N/ha + 1.25 L of humic acids/ha; 70 kg N + 0.65 L of humic acids/ha) and two variants of sole cropping (0 kg N/ha; 140 kg N/ha) were used. Research results showed a good potential for growing wheat in the mixed cropping system without any negative effect on grain and total biomass production. No significant differences were found between the variants where winter wheat was grown with white clover (70 and 112 kg N/ha), and variants with sole wheat (140 kg N/ha), in both years of the experiment. The loss of N min from the soil was affected by the application of N fertilizer and mixed intercropping system. During the experiment, the loss of N min was higher by 20% in the variant using the sole winter wheat (140 kg N/ha), than in the MC variants.