The border effect and utilization rate of N fertilizer as base under wheat intercropped with spinach

The experiment was conducted under pool culture with a 65cm width un-cropped strip and 6 rows wheat of 23.5 cm row spacing were planted in both side of the strip. Label 15N fertilizer was applied on the strip as base and urea was supplied in the area where wheat was planted. Two treatments were set up, one was sowing 2 rows spinach on the strip with a row spacing of 25cm, the other one was no crop in the strip (CK). The results showed that there was a significant border effect in CK pattern, but the border effect was sharply decreased in wheat intercropped with spinach, compared with CK. There was a close relationship between border effect and N absorption of border row. There was serious competition for N nutrient under the system of wheat intercropped with spinach, the N uptake of the border row of wheat was decreased because spinach absorbed more N during the growing stage of both crops. After the spinach was harvested, the border row of wheat absorbed more N nutrient and showed higher content than inner row. The intercropping system had higher utilization efficiency, lower content left in the soil and lower loss in anyway of base 15N fertilizer than those of CK.