Contribution of legumes to wheat productivity in Mediterranean environments of central Chile

摘要: Abstract The potential benefits of using a legumes have not been evaluated in the rainfed, cropping systems central Chile where wheat (Triticum aestivum) is typically grown rotation with oats (Avena sativa) high rates nitrogen (N) fertilizer. Two experiments were initiated to compare unfertilized legume-wheat sequences current oat–wheat system without and applications N fertilizer (160 or 207 kg N ha−1). One experiment was located interior dryland (average annual rainfall 650 mm), other Andean foothills 1200 mm). Treatments established different areas same two experimental sites consecutive years (2008 2009) resulting four separate trials evaluating legume effects on yield (2009 2010). Estimates N2 fixation determined 15N natural abundance technique indicated that around 21 kg shoot fixed for every tonne (t) dry matter accumulated by either narrow-leaf lupin (Lupinus angustifolius), field peas (Pisum sativum), yellow luteus), white albus) grain, vetch (Vicia atroporpurea) association green manure. When amounts adjusted account nodulated roots, calculated returned lowest average net inputs following grain harvest (26 kg N ha−1) pea highest (192 kg N ha−1). By comparison manure treatments all above-ground biomass incorporated into soil 67 kg fixed N ha−1. Depending upon location year, growing increased subsequent uptake up 60 kg N ha−1 35 kg N ha−1) vetch + oats 103 kg N ha−1 50 kg N ha−1). Wheat yields after ranged from 2.4 3.0 t ha−1 5.4–6.4 t ha−1 which respectively 72–110% (90% average) 69–83% (75% achieved fertilized wheat. 1.8 7.9 t ha−1 representing 60% 102% In absence half It concluded legume-based manures provide opportunities greatly reduce reliance production