薯-豆套作模式下作物对种间竞争与补偿作用的响应

以马铃薯-大豆套作模式为研究对象,通过2年的大田试验,分析不同熟期大豆品种与马铃薯组合后系统内作物干物质和养分积累的特性与种间竞争补偿的相互关系,阐明间套作系统种间竞争力弱化和恢复补偿能力提高的作用机理,为实现间套作可持续发展提供科学依据。结果表明:套作马铃薯干物质及养分积累无显著变化,而套作大豆变化显著。出苗60 d内套作大豆干物质积累量是同期单作的43.74%,出苗后80～100 d,晚熟品种干物质积累量相对于中熟和早熟提高的幅度分别为35.54%～59.22%和65.56%～70.81%,大豆收获时,晚熟品种干物质积累接近单作,两者间差异不显著。共生期,套作大豆N、P、K积累量较同期单作降低的幅度分别为31.43%～41.44%、21.17%～25.36%和23.23%～35.6%,晚熟品种与中熟、早熟品种间差异达到显著水平。共生期结束后,套作大豆养分吸收量较单作显著增加,收获时,晚熟品种N、P、K养分积累量接近单作,两者间差异不显著。综上,在该群体中,马铃薯是核心作物,共生期处于竞争优势(A_PS>0、CR_PS>0),而大豆处于竞争弱势(A_PS<0、CR_PS<0),选择晚熟大豆品种与马铃薯组合可弱化种间竞争力和营养竞争比率,还有利于马铃薯收获后恢复补偿能力的发挥。

Interspecies Competition and Compensation Response in Potato-Soybean Relay-Cropping System Under Different Soybean Varieties

Taking the potato and soybean relay-cropping system as study object, two years experiment was carried out in Gansu irrigation districts. The study was aiming at investigating the characteristics of crop growth and nutrient absorption, determining dry matter accumulation, nutrient accumulation characteristics, interspecific competition dynamics and niche differentiation characteristics, clarifying the resources saving mechanism of intercropping. The results showed that there was no significant difference of dry matter and nutrient accumulation between intercropped potato and sole potato, but there was significant difference between intercropped soybean and sole soybean. Dry matter accumulation of inter-soybean relative to sole soybean was decreased by 43.74% at 60 d after soybean sowing, but there was no significant difference between different soybean varieties. Dry matter accumulation of late maturing variety was 35.54%-59.22% and 65.56%-70.81% higher than those under medium maturing and early maturing varieties at 80-100 d after soybean sowing, respectively. When the potato had been harvested, the dry matter accumulation of soybean in all intercropping systems increased, especially late maturing varieties, which became much closer to sole cropping, and there was significant difference between different soybean varieties. During the co-growth period, there was significant difference of Nutrient N, P and K accumulation between late maturing variety and medium and early maturing variety. Nutrient N, P and K accumulation of inter-soybean relative to sole soybean was decreased by 31.43%-41.44%,21.17%-25.36% and 23.23%-35.6%, respectively. After potato harvest, Nutrient N, P and K accumulation of soybean in all intercropping systems increased, especially late maturing varieties, which became much closer to sole cropping, and there was significant difference between different soybean varieties. Therefore, in potato-soybean relay-cropping system, the values of A and CR indicated that the potato was more competitive than soybean, late maturing variety was better than early maturing and medium maturing varieties to intercrop with potato, the interspecific competition in using resources was been weaken during the co-growth period, and it was beneficial to the compensation effect of soybean during the period after potato harvest.