Abstract
To estimate the nitrogen competition between crops and living mulch plants, we compared the nitrogen flow in the sweet corn (Zea mays L.) - white clover (Trifolium repens L.) living mulch system (LM) with that in the conventional cultivation (CV). The field experiments were conducted in 2000 - 2002. Yield and total nitrogen content of sweet corn in LM were the same as that in CV. During the sweet corn growing period, the amount of nitrogen supplied from white clover residue to soil was estimated to be 11.72 gm-2. On the other hand, nitrogen taken up by white clover was 7.11 gm-2, and 1.55 gm-2 of which was from soil and fertilizer. The amount of nitrate leached out in LM was about 2.0 gm-2, which was lower than that in CV. The experiment using 15N showed that 27.3 % (2.48 gm-2) of nitrogen taken up by sweet corn was from the white clover residue and 6.62 gm-2 was from soil and fertilizer. The estimation of nitrogen flow showed that the nitrogen removal from soil in LM was about 2 gm-2 less than that in CV. These results suggest that nitrogen competition between sweet corn and white clover would be small. We consider that the rate of nitrogen fertilizer application could be reduced by using this living mulch system.
