磷对淀粉型甘薯产量及养分吸收利用的影响

【目的】研究不同磷肥用量对甘薯养分吸收、分配及产量的影响,探究淀粉型甘薯磷肥营养效应,为甘薯高产科学合理施用磷肥提供理论依据。【方法】以淀粉型甘薯渝薯17(淀粉含量24.06%)为材料,设置7个磷肥处理(P2O50、0、37.5、75、112.5、150、300 kg/hm2),田间随机区组排列。其P2O50处理不施任何肥料,其他处理均底施纯氮(N)90 kg/hm2和K2O 150 kg/hm2。甘薯苗移栽后每隔30 d,共计取样5次,对全株样品分叶片、茎蔓和块根测定其鲜重、干重及全氮、磷、钾的含量。收获期测定小区鲜薯产量、茎蔓产量并计算收获指数(HI)及其磷肥农学效率(PAE)、磷肥表观利用率(PAUE)、磷收获指数(PHI)、磷肥生理利用率(PPUE)、磷肥偏生产力(PFPP)和磷肥增产率(PIR);同时计算收获期各器官N、P、K的吸收量,对N、P、K吸收量之间及其与产量之间关系进行相关性分析。【结果】1)适当增施磷肥有利于提高甘薯的经济产量、生物产量和收获指数,且以施P2O5112.5 kg/hm2和150kg/hm2时最优,经济产量增产率分别为19.4%和21.06%。2)不同器官N、P、K最高含量分别出现在栽后60、90、150 d,各处理氮素和磷素含量均为叶片茎蔓块根,而钾素含量为茎蔓叶片块根。栽后60 d后,叶片∶茎蔓∶块根含氮量为4.08∶1.62∶1,栽后90 d后,叶片∶茎蔓∶块根磷含量为2∶1.35∶1,栽后150 d后,茎蔓∶叶片∶块根含钾量为2∶1.8∶1。3)施磷可提高甘薯块根、茎蔓和叶片对N、P、K的吸收,养分总吸收量为钾氮磷;施磷处理中N、P、K的吸收量增幅分别为23.9%66.6%、29.6%58.5%、41.3%73.7%。磷钾吸收量均表现为块根茎蔓叶片,吸氮量表现为块根叶片茎蔓。4)在不同施磷条件下,形成500 kg所吸收的N、P2O5、K2O分别为4.24 6.61 g,1.93 2.84 g和6.94 11.48 g。施P2O5112.5 kg/hm2时,形成500 kg鲜薯吸收的养分最多,N、P2O5、K2O吸收量分别为6.61、2.84和11.08 g。5)磷肥表观利用率、偏生产力在施P2O537.5 kg/hm2时最高,分别为16.6%和343.0 kg/kg P2O5,磷肥农学效率、磷肥生理利用率和磷收获指数在施P2O5112.5 kg/hm2时最高,分别为136.7 kg/kg、777.9 kg/kg和65.9%。6)收获期各器官N、P、K吸收量之间及其与产量之间均呈显著或极显著正相关。【结论】增施磷肥能提高甘薯产量,但其利用效率有下降趋势。本试验中,从甘薯高产高效生产的磷肥管理角度分析,N和K2O施用量分别为90 kg/hm2和150 kg/hm2时,以施P2O5为112.5 kg/hm2为最佳。

Effect of phosphorus on yield and nutrient absorption and utilization in starch-type sweet potato

【Objectives】 In order to provide theoretical basis for scientific and rational application of phosphate fertilizer in high yield sweet potato, different phosphor application amounts on the nutrient uptake, distribution and yield, and the phosphorus nutrition effect of starch-type sweet potato were studied. 【Methods】 A starch-type sweet potato,Yushu 17 with starch content of 24.06 %, was used as material. A field experiment with randomized block design was conducted with seven treatments(application amounts of P2O5 0, 0, 37.5, 75, 112.5, 150, 300 kg/hm2, respectively). For the treatment of P2O5 0, no N and K2O was applied neither. For the others, N 90 kg/hm2 and K2O 150 kg/hm2 were basal applied. The fresh weight, dry weight and total N, P and K contents in the leaves, vines and roots were measured every 30 d, and a total of five samplings were taken since transplanting. The fresh yield, vines yield were weighed, the harvest index(HI), P agronomic efficiency(PAE), P apparent utilization efficiency(PAUE), P harvest index(PHI), P physiological utilization efficiency(PPUE), P partial factor productivity of applied(PFPP)and P increase rate(PIR)were calculated at harvest. The absorption of N, P and K were evaluated at harvest. 【Results】 1)Proper P2O5 application amount are capable of improve the biomass and yield, and thus a high agronomic efficiency. Treatments of P2O5 112.5 and 150 kg/hm2 led to the economic yield increase of 19.4% and 21.06%. 2)The contents of N and P in different parts were all in order of leaves vines roots, and that for K content in order of vines leaves roots at the 60, 90 and 150 days after transplanting. The content ratio of N in leaves: vines: roots was 4.08∶1.62∶1 on the 60 day, the P content ratio was 2∶1.35∶1 on the 90 day, and that of K was 2∶1.8∶1 on the 150 day after transplanting. 3)Application of P increase the absorption of N, P and K in the leaves, vines and roots, and the absorptive amount was in order of KNP. The increasing rate of the absorptive amounts of N, P and K were 23.9% to 66.6%, 29.6% to 58.5% and 41.3% to 73.7% with application of P. The absorptive amounts of P and K were in order of rootsvinesleaves, while that of N was rootsleavesvines. 4)Under different P application amounts, the K2O requirement was from 6.94 g to 11.48 g, N from 4.24 g to 6.61 g and P2O5 from 1.93 g to 2.84 g for every 500 kg fresh tubers. The highest nutrient requirement for every 500 kg fresh tubers was in the treatment of P2O5 112.5 kg/hm2, with requirement of N 6.61 g, P2O5 2.84 g and K2O 11.08 g. 5)The obtained highest PAUE and PFPP were 16.6% and 343.0 kg/kg, respectively under the treatment of P2O5 37.5 kg/hm2, the highest PAE, PPUE and PHI were 136.7 kg/kg, 777.9 kg/kg and 65.9%, respectively, with P2O5 112.5 kg/hm2. 6)The absorptive amounts of N, P and K were significantly or very significantly and positively correlated with each other, and also positive correlatied to the yield at harvest. 【Conclusions】The application of P fertilizer could increase the yield of sweet potato, but decrease P2O5 efficiency. Under the experimental condition, the most appropriate amount of P2O5 was 112.5 kg/hm2 at N 90 kg/hm2 and K2O 150 kg/hm2 for high yield in sweet potato.