豆科–燕麦间作对作物光合特性及籽粒产量的影响

为进一步揭示豆科燕麦间作体系中作物产量优势的光合机制,设置燕麦单作、大豆单作、花生单作、大豆燕麦间作和花生燕麦间作试验,在不施氮肥的条件下,调查大豆、花生同燕麦的产量、功能叶片相对叶绿素含量(SPAD)及光合特性。结果表明,与单作相比,大豆–燕麦和花生–燕麦间作优势明显,土地当量比(LER)分别为1.41~1.63和1.31~1.52。同大豆间作的燕麦除单株粒重及千粒重外,其他各产量构成因子均增加;同花生间作的燕麦各产量构成因子均高于单作燕麦,其中小穗数、穗粒数、单株粒重与单作相比差异显著;间作提高了大豆各产量构成因子,但降低了花生的结荚数及单株粒重。间作提高了燕麦的叶绿素含量和净光合速率,改变了叶绿素构成,使燕麦衰老延缓;间作对大豆的相对叶绿素含量及净光合速率均无显著影响;在燕麦孕穗后期至抽穗期,间作花生净光合速率显著高于单作。在不施氮肥的条件下,间作体系均明显优于单作,其中燕麦花生间作体系显著促进了燕麦的生长发育,大豆燕麦间作体系对燕麦、大豆均有一定促进作用。

Effects of Legumes Intercropping with Oat on Photosynthesis Characteristics of and Grain Yield

Intercropping, a commonly used agronomic management by farmers in China for centuries can improve light, heat, water and nitrogen utilization efficiencies and significantly enhance crop yield. To reveal the mechanism of photosynthesis in soybean-oat and peanut-oat intercropping systems, we conducted a two-year (2011, 2012) field experiment in Baicheng, Jilin province. Under the nitrogen-free condition, crop yield, yield components and photosynthesis and relative chlorophyll content (SPAD) of functional leaves in crops were investigated during growth stage. The results showed that land equivalent ratio (LER) was from 1.41 to 1.63 and from 1.31 to 1.52 for soybean-oat and peanut-oat intercropping, respectively. Also, most yield components from oat (plant height, spike length and spikelet, grain number per spike) under intercropping with soybean were higher than those from mono-cropping oat, except for grain weight per plant and thousand seed weight. Under intercropping with peanut, all yield components of oat increased in comparison with those under mono-cropping oat and spikelet, grain number per spike and grain weight per plant showed significant difference. Moreover, all yield components of soybean intercropping with oat improved, whereas decreased peanut pod number and grain weight per plant. As for photosynthesis, intercropping enhanced chlorophyll content and net photosynthetic rate of oat and altered chlorophyll composition which contributed to the slower process of oat aging. With regard to peanut, chlorophyll content slightly increased when intercropped with oat and net photosynthetic rate significantly improved during the late booting stage to heading stage of oat. In conclusion, under the condition of nitrogen-free, intercropping is demonstrably superior to monoculture. The peanut-oat intercropping system notably promotes the growth of oat, while the oat and soybean are both benefit from the soybean-oat intercropping system.