Decomposition of lupine seeds and seedlings as N fertilizer in organic vegetable production

作者：Katroschan Kai Uwe^*; Teixeira Goncalo; Kahlen Katrin; Stuetzel Hartmut

来源：Plant and Soil, 2012, 357(1-2): 59-71.

DOI：10.1007/s11104-012-1144-4

• Lupinus angustifolius
• Seed germination
• C:N ratio
• Net N mineralization
• Priming effect
• Organic fertilizer

Nitrogen mineralization of lupine seeds and seedlings to be used as flexible leguminous N source in organic vegetable production was investigated. It was hypothesized that changes in seed chemical composition during germination are associated with increased fertilizer efficiency of seed N.
Net N mineralization of seed meal and seedlings varying in age was determined in pot and field experiments. The temporal mineralization pattern was quantified by fitting first-order kinetics.
In the pot experiment, seedling C:N ratio declined within 2 weeks from initially 8.8 to a minimum of 6.2 prior to a re-increase. Maximum net N mineralization increased strongly with decreasing C:N ratio being up to 44% higher for seedlings compared to seed meal. Time course of net N mineralization in the field showed initial peaks partly exceeding the amount of applied lupine seed N. Ignoring mineralization peaks, the relationship between maximum net N mineralization and C:N ratio was in close agreement with pot experimental data. The critical C:N ratio of the pooled data was 13.
Nitrogen mineralization of field-sown lupine seeds can be manipulated by varying seedling growing time until incorporation. High fertilizer efficiency provided by high net N mineralization is associated with early seedling incorporation and high germination rates.

• 出版日期2012-8