Synchrony of nitrogen supply and crop demand are driven via high maize density in maize/pea strip intercropping

Abstract

Cereal density may influence the balance between nitrogen (N) supply and crop N demand in cereal/legume intercrop systems. The effect of maize (Zea mays L.) plant density on N utilization and N fertilizer supply in maize/pea (Pisum sativum L.) strip intercropping was evaluated in a field study with sole maize, sole pea, and intercropped maize/pea with three maize densities (D1, 45,000 plants ha−1; D2, 52,500 plants ha−1; D3, 60,000 plants ha−1) and two N treatments (N0, 0 kg N ha−1; N1, 450 kg N ha−1 for maize and 225 kg N ha−1 for pea). Soil mineral N in intercropped strips decreased with increased maize density. Increased maize density decreased N accumulation for intercropped pea but increased it for maize and the sum of both intercrops. The land equivalent ratio for grain yield (LER grain) showed a 24–30% advantage for intercrops than corresponding sole crops, and was greater with D3 than D1 and D2. Maize/pea intercropping had 4–113% greater nitrogen use efficiency (NUE) than sole maize, which was enhanced with increased maize density. Increasing maize density improved the synchrony of N supply and crop demand in maize/pea strip intercropping.