Intercropping Tomato and Potato Onion

Tomato (cv. Dongnong 708) seeds were obtained from Tomato Breeding Center, Northeast Agriculture University, Harbin, China. The bulbs of potato onion cultivars Suihua (S-potato onion) and Ningan Hongcheng (N-potato onion) were obtained from the Laboratory of Vegetables Physiological Ecology of the Northeast Agricultural University. The soil used was sandy loam soil collected from the soil upper layer (0-15 cm) of an open field in Horticulture Experimental Station, Northeast Agricultural University. The soil physicochemical properties were: organic matter, 22.32 mg kg^-1; inorganic nitrogen, 86.95 mg kg^-1; available phosphorous, 37.23 mg kg^-1; available potassium, 102.42 mg kg^-1; electrical conductivity (1:2.5, w/v), 163.38 µS cm^-1; and pH (1:2.5, w/v), 6.68.