Fertilització orgànica i mineral en una rotació farratgera de doble cultiu anual en clima mediterrani humit

Abstract

Fertilization of field crops with organic materials is a common practice in areas with high livestock activity and availability of these fertilizers (manures and sludges). This practice is even more widespread in the fertilization of crops for fodder use, due to their links to livestock farms. In 2007 an experimental field was set up in La Garrotxa Volcanic Zone Natural Park (NE Spain), where the forage rotations of double-annual crop avena-sorghum and ryegrass-maize were alternated. Different fertilization strategies (10 treatments) based on the application of cattle manure and also in some cases with applications of N mineral fertilizers were evaluated, using an experimental design of randomized blocks in 3 replicates. In order to evaluate these fertilization strategies, different parameters were determined at frequent intervals in the soil-water-crop system. In the context and in the productive system assessed, the manure rate of 170 kg N ha-1 year-1 with a mineral complement allows obtaining maximum yields while minimizing the environmental impacts for accumulation of nutrients in the soil and for loss of N. With the rate of 250 kg N ha-1 year-1, in addition to obtaining high yields and minimizing environmental impacts in the medium term (6 years), there is a greater recirculation of nutrients in the same agrarian system, although in this case the tendency to accumulate P in the soil could be limiting in the longer term.