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Advisor(s)
Abstract(s)
Current environmental concerns, the rising economic and environmental costs of mineral fertilizers and the need
to respond to the limitations of N fertilization in organic farming motivate the search for alternative sources of N
in maize cropping. Forage legumes used as winter cover crops may improve soil N fertility and offer benefits to
the environment. The aim of this study was to examine the effects, in a factorial field experiment, of two sowing
dates (SD) and nine different cover crop treatments (balansa clover, crimson clover, gland clover, arrowleaf
clover, French serradella, yellow lupin, Italian ryegrass, a cover mixture and a weedy fallow) as a potential
alternative N source in an organically managed maize crop. The experiment was conducted at Viseu (Portugal)
for three years (2007/2008, 2008/2009 and 2011/12), in the same field. Results showed that maize grain yield
was not influenced by cover crop species but was affected by SD and the higher dry matter (DM) aboveground
biomass production was observed in early SD (6.1 t ha 1). The cover crops revealed their importance in maize N
uptake: yellow lupin of earlier SD had the highest N uptake (83.6 kg N ha 1), but this was not significantly
different from balansa clover (83.2 kg N ha 1). Ryegrass was the most efficient in depleting soil mineral N but
values were just significantly lower than yellow lupin.
Lupin was the least efficient, leaving more mineral N in the soil than the others cover crops, immediately
before the period when the risk of leaching is high. It was concluded that, under the edaphoclimatic conditions
tested, most of the tested cover crops were efficient in supplying N to maize, and balansa clover had the best
performance.
Description
Keywords
Balansa clover Maize yield Yellow lupin Sowing date Green manures
Citation
Adelaide Perdigão, José L.S. Pereira, Nuno Moreira, Henrique Trindade, João Coutinho, A 3-year field study to assess winter cover crops as nitrogen sources for an organic maize crop in Mediterranean Portugal, European Journal of Agronomy, Volume 128, 2021, 126302,
Publisher
European Journal of Agronomy