甘薯的氮磷钾养分吸收及分配特性

Uptake and distribution of nitrogen,phosphorus and potassium in sweetpotato(Ipomoea batatas L.)

探明宁紫1号甘薯的氮磷钾养分吸收和分配特性,为合理施肥提供依据。该研究在田间进行,设5个处理3次重复,从甘薯栽插成活到成熟收获期间,每隔15 d取1次植株样,茎叶和根分别称重、烘干,分析氮磷钾养分含量。结果表明:每生产1 000 kg鲜薯需要吸收的氮磷钾总量为11.24 kg,氮磷钾比例为1.00∶0.69∶2.32;不同生长阶段甘薯的氮磷钾养分累积特征明显不同,氮的吸收主要集中在甘薯生长中前期(移栽后60 d内),生长后期由于落叶使累积量反而下降,磷钾的吸收90%以上发生在甘薯生长的中后期(移栽后30 d至成熟);累积在甘薯茎叶和块根中氮磷钾总量相近,但累积在茎叶中的氮和块根中的磷钾偏多,累积在茎叶中氮磷钾的比例为1.00∶0.60∶2.03,块根中为1.00∶0.82∶2.69;移栽后60～75 d是宁紫1号甘薯"源-库"关系的过渡期。

Field experiment was carried out to study the uptake and distribution of nitrogen,phosphorus and potassium in sweetpotato（Ningzi 1）.The whole plants were sampled every fifteen days from transplanting to harvest to weigh the leaves,stems and roots.The results were showed as follows.A total of 11.24 kg of nitrogen,phosphorus and potassium fertilizers was absorbed by sweetpotato for every 1 000 kg fresh tubers,with a ratio of N∶P2O5∶K2O at 1.00∶0.69∶2.32.The accumulations of N,P2O5,and K2O varied in different growth stages.The uptake of nitrogen mainly occured at the early and middle stage（within 60 d from transplanting）,followed by a reduction in late period as the result of leaves falling.However,above 90% of the phosphorus and potassium were absorbed in the middle and late stage（from one month since transplanting to maturation）.A minor difference in total uptakes of N,P,and K appeared between shoots and tuberous roots.The majority of nitrogen was accumulated by shoots,while tubers absorbed majority of phosphorus and potassium.The ratio of N∶P2O5 ∶K2O was 1.00∶0.60∶2.03 in shoots,and 1.00∶0.82∶2.69 in roots.The time period from 60-75 d after transplanting was the transition stage of source to sink.