Nitrogen contribution of green pea residues to a succeeding spinach crop
The objectives of this study were to quantify how much nitrogen (N) from harvest residues of pea (Pisum sativum L.) is mineralized during a succeeding spinach (Spinacea oleracea L.) crop, and whether the mineral fertilization of spinach could be reduced by this amount, thereby reducing soil mineral N at harvest and nitrate in the produce without losses in spinach yield.
In 1995 and 1996, two field experiments were conducted at the research station in Großbeeren, Germany, on a sandy soil. In 1995, spinach was grown in a one-factor experiment with and without a preceding pea crop. The results suggested that the recommended standard mineral N fertilization (FINK and SCHARPF 1993) could be reduced by 30 kg N ha-1 with a preceding pea crop. This hypothesis was tested in 1996 in a two-factor experiment.
In 1996, the N balance at harvest date of the spinach crop showed that apparent net N mineralization due to pea residues was 25 and 44 kg N ha-1 in soil layers of 0-30 and 0-90 cm, respectively. The treatments had no effect on the spinach nitrate content. Total fresh matter yield was not significantly affected, comparing the treatments ‚reduced mineral fertilization with pea residues‘ and ’standard mineral fertilization without pea residues‘. It is concluded that mineral fertilization recommended by FINK and SCHARPF (1993) can be reduced by 30 kg N ha-1 if spinach is grown after incorporating pea residues.
Fink, M. (2000) Nitrogen contribution of green pea residues to a succeeding spinach crop Gartenbauwissenschaft 65 (1), 79-82.