Table 1.
Physical and chemical properties of the experimental soil.
Table 2.
Detailed planting pattern of every treatment in the two experiments.
Fig 1.
Schematic diagram of different treatments.
(1) Monoculture of maize, (2) Monoculture of soybean, (3) 2M:6S (two maize rows intercropping with six soybean rows), (4) 4M:6S (four maize rows intercropping with six soybean rows), and (5) 6M:6S (six maize rows intercropping with six soybean rows).
Table 3.
Crop yield, economic benefit, soil nitrate-N accumulation at 0–200 cm soil depth (NA) and land equivalent ratio (LER) in different crop systems at harvest in the summer of 2010 (Experiment 1).
Table 4.
Residual effect of different summer cropping systems on yield of winter wheat and soil nitrate-N accumulation after harvest of wheat in Experiment 1.
Table 5.
Total N accumulation in crop (Nacc), crop yield, economy, soil nitrate-N accumulation at 0–40 cm soil depth (NA) and land equivalent ratio (LER) in different cropping systems at harvest in the summer of 2011 (Experiment 2).
Table 6.
Net photosynthetic rate (Pn) and transpiration rate (Tg) of maize at tasseling and filling stages under different cropping systems.
Table 7.
Concentration (g kg-1) of N in maize and soybean at each growth stage under different cropping systems.
Table 8.
Crop biomass (g plant-1) at each growth stage under different cropping systems.
Fig 2.
Spatial distribution of nitrate-N concentration (mg kg-1) of each cropping system at different soil depths and maize growth stages.
(a) a soil depth of 0–20 cm: (a-1) pre-jointing stage, (a-2) tasseling stage, (a-3) filling stage and (a-4) ripening stage, and (b) a soil depth of 20–40 cm: (b-1) pre-jointing stage, (b-2) tasseling stage, (b-3) filling stage and (b-4) ripening stage. A row number is defined as in Fig 1. Each data point presents mean of three replicates and an error bar indicated standard deviation.
Table 9.
Residual effect of different summer cropping systems on yield of winter wheat and soil nitrate-N accumulation (0–100 cm) after harvest of wheat in Experiment 2.