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Yang F.,Sichuan Agricultural University | Wang X.,Sichuan Agricultural University | Liao D.,Sichuan Agricultural University | Lu F.,Sichuan Agricultural University | And 7 more authors.
Agronomy Journal | Year: 2015

Planting geometries directly affect crop yields in intercropping systems. Two different field experiments were conducted in 2012-2013 to analyze how different planting geometries in maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] relay strip intercropping systems at 2:2 maize-to-soybean affect yields. Maize plants were planted in narrow-row planting patterns, whereas soybean was planted in wide rows. The effects of bandwidth, row spacing, plant spacing, and the distance between maize and soybean rows on crop yields were studied. Total intercrop yields were higher than those of sole crop maize and soybean, and the land equivalent ratios of the intercropping systems were above 1.3. The yield of the intercropped maize increased with bandwidth reduction at the same plant density, and similar results were found with increased maize narrow-row spacing at the same bandwidth. Plant spacing had a dominant function when the bandwidth of the intercropped soybean was >200 cm. By contrast, the distance between maize and soybean rows had a dominant function when bandwidth was <200 cm. The optimum bandwidth and maize narrow-row spacing in maize-soybean relay intercropping systems were 200 and 40 cm, respectively. These results suggest that the appropriate reduction in the spacing of the narrow maize rows and increase in the distance between maize and soybean rows could be used to achieve high yields in maize-soybean intercropping. © 2015 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. Source

Liu J.,Key Laboratory of Crop Ecophysiology and Farming System in Southwest | Liu J.,Sichuan Agricultural University | Yang C.-Q.,Key Laboratory of Crop Ecophysiology and Farming System in Southwest | Zhang Q.,Key Laboratory of Crop Ecophysiology and Farming System in Southwest | And 6 more authors.
Food Chemistry | Year: 2016

The profiles of isoflavone and fatty acids constitute important quality traits in soybean seeds, for making soy-based functional food products, due to their important contributions to the flavor and nutritional value of these products. In general, the composition of these constituents in raw soybeans is affected by cultivation factors, such as sunlight; however, the relationship of the isoflavone and fatty acid profiles with cultivation factors is not well understood. This study evaluated the isoflavone and fatty acid profiles in soybeans grown under a maize-soybean relay strip intercropping system with different row spacings, and with changes in the photosynthetic active radiation (PAR) transmittance. The effects of PAR on the isoflavone and fatty acid contents were found to be quadratic. Appropriate intercropping shading may reduce the bitterness of soybeans caused by soy aglycone and could improve their fatty acid composition. © 2016 Elsevier Ltd. All rights reserved. Source

Yang F.,Sichuan Agricultural University | Yang F.,Key Laboratory of Crop Ecophysiology and Farming System in Southwest | Huang S.,Sichuan Agricultural University | Gao R.,Sichuan Agricultural University | And 6 more authors.
Field Crops Research | Year: 2014

Maize-soybean intercropping is a common system in several countries. However, different spatial patterns of maize and soybean can directly affect the light environment of soybean growth under this system through the combined effects of the altered light quality and the reduced light quanta. This work aimed to investigate the differences in the light environment of the soybean canopy in terms of the red:far-red (R/FR) ratio and the photosynthetically active radiation (PAR) as well as the different rates of soybean seedling growth under maize-soybean relay strip intercropping and soybean sole planting, to analyze the relationship between the morphological characteristics and the light environment, and to assess the relative contributions of the R/FR ratio and PAR transmittance to soybean seedling growth in intercropping conditions.Field experiments were performed in 2011-2013. The intercropping patterns involved the wide-narrow row planting of alternating maize and soybean. The light environment of the soybean canopy and the morphology of the soybean seedlings were estimated in the relay strip intercropping system by changing the distances of the maize and soybean rows as well as the number of maize vs. soybean rows per strip. These parameters of the intercropping system were compared with those of the soybean monocultures. Furthermore, the relationship between the light environment of the soybean canopy and its morphological parameters were analyzed using correlation analysis.Incident light in maize-soybean relay strip intercropping systems was partly reflected and absorbed by maize leaves. Thus, the spectral irradiance, R/FR ratio, and PAR of the soybean canopy were decreased with maize-soybean intercropping as compared to soybean monocropping. Simultaneously, the stem diameter, root length, aboveground biomass, total root biomass, and root-shoot ratio of relay intercropped soybean were reduced significantly, while its seedling height was increased. The correlation relationship between morphological parameters of soybean and the light environment (R/FR ratio and PAR transmittance) in different planting pattern were significant ( P<. 0.05). Compared to PAR transmittance, the R/FR ratio of the relay intercropped soybean canopy was strongly correlated with morphological parameters of soybean seedling ( P<. 0.01), and the correlation coefficients were higher than 0.88. The response of soybean seedlings to shading by maize was not solely influenced by the PAR or the R/FR ratio. It may be the summed effects of both parameters under relay strip intercropping systems. Therefore, the results reveal the physiological response mechanisms of soybean seedlings to changes in the quality and amount of light, which may support the building three-dimensional growth model of the responses of plant to light quantity and quality, and guide the identification of suitable population planting patterns in the intercropping system in the future. © 2013 Elsevier B.V. Source

Yong T.,Sichuan Agricultural University | Yong T.,Key Laboratory of Crop Ecophysiology and Farming System in Southwest | Liu X.,Sichuan Agricultural University | Yang F.,Sichuan Agricultural University | And 10 more authors.
Plant Production Science | Year: 2015

Intercropping and relay intercropping systems, which significantly improve land use efficiency, are used worldwide to increase crops yield. The wheat-maize-soybean relay intercropping system has been widely employed by famers in Southwestern China for years, but the detailed mechanisms through which the nitrogen fertilizer use efficiency reach the high level in this system remain unclear. In the present study, two separate pot experiments were performed by 15N isotope dilution (ID) labeling and direct 15N foliar feeding (FF) assays, and a solid barrier was employed to prevent the roots intergrowth and N movement among crops in the first experiment, using no barrier as the control. The results showed that, under the no-barrier condition, the grain yields, 15N uptake and 15N recovery efficiency of wheat and maize were significantly increased, but those measures in soybean were decreased compared to the solid barrier condition. Furthermore, bi-directional N transfer was detected during the co-growing stage of crops, the amount (Ntransfer) and percentage (%NT) of 15N transferred varied significantly with the fertilizer-N rate, and the maximum reached at 150 – 300 kg N ha–1 level. The Ntransfer from maize to wheat was 16.1% – 163.0% higher than that from wheat to maize; the Ntransfer from soybean to maize was 1.7 – 6.0 times higher than those from maize to soybean, while the %NT from soybean to maize were 6.7 – 22.2 times higher than those from maize to soybean. Conclusively, this study revealed that the interaction of the roots among crops significantly increased the uptake efficiency and recovery efficiency, and further, the positive N competition and bi-directional N transfer of each crops were the main contributors to improve the N use efficiency in the wheat-maize-soybean relay intercropping system. © 2015, Crop Science Society of Japan. All rights reserved. Source

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