套作条件下种植密度对紫色甘薯干物质生产的影响

为了研究川中丘陵区旱地套作条件下种植密度对紫色甘薯干物质生产的影响，在与玉米套作条件下，以鲜食型紫色甘薯品种‘南紫薯008’为材料，设置5个种植密度，测定紫色甘薯叶面积指数、群体生长率、群体光合势、干物质积累、产量等指标。结果表明：在套作条件下，随着种植密度的增加，‘南紫薯008’群体叶面积指数有升高的趋势，群体生长率、群体光合势、商品薯率、干物质率、鲜薯产量、淀粉产量均呈先升后降的趋势，而单株结薯数、单株薯鲜重则下降，群体干物质积累量和T/R则随生育期的推进不同密度间表现有所差异。公顷种植密度在3.5×10⁴~4.0×10⁴株时，群体干物质积累量、鲜薯产量、淀粉产量和商品薯率均较高。套作条件下‘南紫薯008’最高鲜薯产量为11816.9 kg/hm²，约为其净作产量的42.6%~53.1%。川中丘陵区旱地套作条件下紫色甘薯适宜的种植密度为3.5×10⁴~4.0×10⁴株/hm²。

Effects of Planting Density on Dry Matter Production of Purple SweetpotatoUnder Intercropping Pattern of Maize and Sweetpotato

In order to study the effects of planting density on dry matter production of purple sweetpotato under intercropping pattern of maize and sweetpotato in hilly area of Sichuan province, purple sweet potato variety ‘Nanzishu 008’ was used as test material, five transplanting densities were set to examine the leaf area index, crop growth rate, leaf area duration, dry matter accumulation, yield, yield composition and other index of purple sweet potato. The results showed that: under the condition of intercropping pattern of maize and sweetpotato, in the range of 30000-50000 plant/hm², the leaf area index increase with the increase of transplanting density while the population growth rate, population photosynthesis potential, commodity rate, dry matter ratio, fresh root yield, root starch yield of purple sweet potato all increased firstly, then decreased. Meanwhile, with the increase of transplanting density, the root number per plant, root fresh weight per plant of purple sweet potato decreased. The accumulation of population dry matter and T/R were different among transplanting densities. When the planting density was from 3.5×10⁴ plant/hm² to 4.0×10⁴ plant/hm², the dry matter accumulation, fresh root yield, starch yield and commodity rate were higher. The highest fresh root yield was 11816.9 kg/hm², which was 42.6%-53.1% of the fresh root yield under the condition of sole cropping. Therefore, under the condition of intercropping pattern of maize and sweetpotato, the suitable transplanting density of purple sweet potato variety ‘Nanzishu 008’ was from 3.5×10⁴ plant/hm² to 4.0×10⁴ plant/hm² in hilly area of central Sichuan Basin.