Abstract:

Intercropping is popular cropping system in high-yielding production of food and feed in the world, which is more productive than monocropping because of the intensive utilization of natural resources, such as light, heat, water and fertilizer. Maize-peanut intercropping as an importance cultivated pattern is extended rapidly. Although many researches on intercropping pattern, field microclimate, yield benefit and amelioration of peanut iron nutrition in maize-peanut intercropping system have been conducted. There are a few researches on the use efficiency of light in the photosynthesis characteristic of compound population. The experiment was carried out to investigate the diurnal changes of photosynthetic rate, actual photochemical efficiency of photosystemⅡ(Φ_PSⅡ), maximum photochemical efficiency of photosystemⅡ(F_v/F_m) and chlorophyll content in the intercropping system of maize-peanut. The results showed that the chlorophyll content was enhanced by intercropping and the diurnal change of photosynthetic rate in intercropped maize-peanut was in a single-peak curve, which reached the maximum value at noon. The photosynthetic rate of intercropped maize (the east leaf by spike in the east row) was higher (the east leaf of spike in a row) in the morning and lower in the afternoon than that of sole cropped maize (Fig.1, Fig.3). In sunshine and cloudy days, the photosynthetic rate was obviously enhanced in maize, but decreased in peanut by intercropping. In sunshine days, the diurnal changes of F_v/F_m and Φ_PSⅡ of intercropped maize-peanut were like a converse parabola, the F_v/F_m and Φ_PSⅡ of intercropped maize were much higher than those of sole cropped maize in the morning and on the contrary in the afternoon.(Fig.4, Fig.7), the F_v/F_m of peanut was markedly enhanced by intercropping(Fig.5), the Φ_PSⅡ of intercropped peanut was higher than that of sole cropped peanut in a whole day except at noon(Fig.8). In cloudy days, the F_v/F_m, Φ_PSⅡ of maize were much lower in intercropping than in sole cropping in a whole day except at noon, but the F_v/F_m, Φ_PSⅡ of intercropped peanut were much higher than those of sole cropped peanut(Fig.6, Fig.9). The results suggested that the absorption and utilization weak light in peanut is improved by maize-peanut intercropping.

Key words: Maize, Peanut, Intercrop, Chlorophyll content, Photosynthetic characteristic