不同品种甘薯的生物量累积、养分吸收和分配规律

Biomass accumulation and nutrients uptake and distribution in sweet potato cultivars

为研究不同品种甘薯的养分吸收和分配规律,选用广薯87、苏薯16、南薯88、宁紫薯1号和宁紫薯2号5个甘薯品种移栽于江苏省农业科学院六合基地,在不同生育期取样并测定各品种甘薯的氮、磷、钾养分吸收及干物质分配情况。结果表明,淀粉型甘薯南薯88干物质累积速率最快,相同条件下更容易获得高产。食用型甘薯广薯87和苏薯16收获期蔓薯比最低,分别为0.20和0.21,表明光合产物向地下部转移比例更高。地上部旺长期,甘薯氮、磷、钾吸收速率分别为1株21.21 mg/d、8.19 mg/d和25.68 mg/d;薯块膨大期,甘薯氮、磷、钾养分吸收速率分别为1株7.40 mg/d、2.83 mg/d和11.17 mg/d。不同品种甘薯每形成1 000 kg鲜薯所需要的养分不同,其中宁紫薯2号和南薯88所需养分总量最高,分别为10.29 kg和8.98 kg。供试品种中紫甘薯对磷的需求量较其他品种高,食用型甘薯对氮的需求量较其他品种高,南薯88和宁紫薯2号对钾的需求量较其他品种高,但总体来说甘薯养分吸收量大小顺序是钾>氮>磷。

Five sweet potato cultivars, Guangshu 87, Sushu 16, Nanshu 88, Ningzishu 1 and Ningzishu 2 were se-lected to study the nutrient transportation without fertilization. Sweet potato with high starch content, Nan 88, showed the fastest dry matter accumulation which made it easier to achieve high yield under the same condition. The shoot ratio of Guangshu 87 and Sushu16, lower than other cultivars, were 0？20 and 0？21 respectively, indicating that more products of photosynthesis were transferred to root. The average daily uptake of nitrogen, phosphorus and potassium by sweet potato in the vigorous growth period of shoots were 21？21 mg, 8？19 mg, 25？68 mg per plant respectively, which in the enlargement period of tuber were 7？40 mg, 2？83 mg and 11？17 mg per plant respectively. The amount of nutrients needed for the yield of 1 000 kg fresh tubers varied with sweet potato cultivars. The total nutrient demands of Ningzishu 2 and Nanshu 88, were 10？29 kg and 8？98 kg, more than other cultivars. Purple sweet potato needed more phosphorus than other cultivars, edible sweet potato demanded more nitrogen, and Nanshu 88 needed＆nbsp;more potassium. In general, the amount of nutrients uptaken by sweet potato was K〉N〉P.