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AbstractDominant species in intercropping experience less resource competition compared with its monoculture. This reduced competition for resources may allow cultivating the dominant species at an increased density in intercropping to obtain greater yield. However, experimental results are inconclusive when the optimal within row density in the sole crop is not well established. Here, we conducted a two‐year experiment to test the hypothesis that optimal within row plant density of dominant species in intercropping would be higher in the intercrop than in the sole crop. We tested three maize densities (3, 4.5, and 6 plants m−1) in both sole maize and two replacement designed intercrops. The row configurations of two intercrops are two rows maize intercropped with four rows peanut (M2P4) and four rows maize intercropped with four rows peanut (M4P4). Peanut was grown at the same plant density of 12 plants m−1 row in both sole crop and intercrops. The results indicated that increasing maize density from the optimal density in monoculture is not worthy of promotion to improve yield in intercropping, which denied our hypothesis. The land equivalent ratios (LER) in the dry year (2017) were higher than the wet year (2016). Maize yields per unit area of the whole intercropping system were highest with densities of 4.5 and 6 plants m−1 row, with no significant difference between these two densities. Maximum maize yields in sole cropping were obtained with maize densities of 6 plants m−1 row. Intercropping provided higher yields at low and intermediate sole crop maize densities, but not at high sole crop maize density. Average land equivalent ratios at 3, 4.5, and 6 plants m−1 of maize were 1.09, 1.04, and 0.95 in 2016, and 1.07, 1.10, and 1.02 in 2017. Our results suggest that intercropping performs better at conditions with less resources than adequate resources.

AbstractChinese agriculture needs to become less dependent on fertilizer inputs to enhance sustainability. Cereal/legume intercropping is a potential pathway to lower fertilizer inputs, but there is insufficient knowledge on the nitrogen (N) response in species mixtures. Here, we investigated N response in maize/peanut intercropping. Maize showed a stronger yield response to N input than peanut both in sole cropping and in intercropping, and so did sole crops relative to intercrops. Maize yield was the highest at the maximum level tested: 360 kg N/ha. Agronomic efficiency (AE) of sole maize was 7.8 kg/kg N input, averaged across five N levels (0, 90, 180, 270, and 360 kg/ha). Partial land equivalent ratios (pLERs) for maize decreased with N input, from 0.70 at zero to 0.64 at 360 kg/ha. Sole peanut showed an optimum yield response to N input, with the highest yield at 270 kg/ha and lower yield at 360 kg/ha. The average AE of sole peanut was 1.3 kg/kg. The pLER of peanut declined from 0.43 at zero to 0.32 at 360 kg/ha while the overall LER decreased from 1.13 to 0.96, indicating relative better performance of intercropping at low than at high N input. Apparent recovery (RE) for N was 27.2% for sole maize, 12.4% for sole peanut, and 7.2% for intercrops. Mean N uptake was 179 kg/ha in sole maize, 199 kg/ha in intercropping, and 264 kg/ha in sole peanut. Partial economic budgeting indicated that with the current low Chinese N fertilizer prices, gross margin is maximized with high N input in sole crops; however, for intercropping, the highest gross margin was attained at intermediate N inputs of 180 or 270 kg/ha. Fertilizer price incentives may facilitate a transition to intercropping at moderate N input in China.