Effects Of Fertilizer Managements On Growth And Nutrients Uptake Of Potato Under Drip Fertigation

Yulin is one of the main planting areas of potato.Under the traditional fertilization model,the climate and soil conditions in the north aeolian sandy areas restrict the growth and water use efficiency of potato.The potato species of �Zihuabai' was chosen as the test cultivar in this study.The growth characteristics of potato tubers in the growth period are combined to be researched,according to the principle of lesser fertilizer ration in the early stage(seedling stage + tuber formation stage,ES),and more in later stage(tuber enlargement stage + starch accumulation stage,LS),that is ES(20%?30%?40%?50%)for LS(80%,70%,60%,50%)respectively,there were eight treatments were set,i.e.,T1(0:20:55:25),T2(0:30:50:20),T3(10:20:50:20),T4(10:20:45:25),T5(10:30:40:20),T6(20:20:40:20),T7(20:30:40:10)and T8(20:30:30:20)to investigate the impact of fertilizer proportion at different growth stages on the growth and nutrients uptake of fertigated potato at the same fertilizer level,based on the proportion of the fertilizer amount at different stages(the seedling stage,the tuber formation stage,the tuber enlargement stage and the starch accumulation stage)to the total fertilizer amount during the whole growth period.Results show that,(1)The LAI,plant height,stem diameter,crown diameter,SPAD value and photosynthetic potential of treatments increased with the increase in the proportion of seedling fertilization,in the tuber formation stage and Seedling Stage.In the seedling stage,the tuber formation stage,the tuber enlargement stage and the starch accumulation stage,with the fertilization rate of 0-20%/30%-55%/50%-25%/20%,the growth and physiological indexes in T1/T2 treatment,were greater than those of other treatments or has no significant difference.The growth and physiological indexes of T1 treatment were significantly higher than those of other treatments at maturity stage and starch accumulation stage.While the growth and physiological indexes in T7 treatment,with the fertilization rate of 20%-30%-40%-10% in the seedling stage,the tuber formation stage,the tuber enlargement stage and the starch accumulation stage,were significantly less than other treatments.It can be concluded that the period of tuber formation and tuber enlargement is the key period for the potato to be fertilized,and the appropriate proportion of increasing the proportion of tuber formation and expansion is beneficial to the growth of potato.(2)The dry matter accumulation of mature tubers was mainly due to the accumulation of dry matter accumulation of photosynthesis after anthesis.Under the condition of experiment,the dry matter accumulation of potato root,stem and leaves before anthesis,and its' transportation and contribution rate after anthesis to the tuber increased with the increase of fertilization ratio at seedling stage.The accumulation of dry matter in T1/T2 after anthesis was significantly higher than that of other treatments.The total dry matter and tuber dry matter accumulation in T1 treatment were significantly higher than those in other treatments at maturity stage and starch accumulation stage.The dry matter translocation of T7 was higher than that of other treatments after anthesis,but the total dry matter and tuber dry matter were significantly lower than those of other treatments.(3)The yield of each fertilizer treatment present as ES0.2>T8(ES0.5)?T2?T6(ES0.4)>ES0.3(except T2 treatment)> T5 >T7.Potato yield was affected by multiple indexes,and single index could not evaluate yield.The results of path analysis showed that the single plant weight and the weight of single commercial potato had great effect on the yield,which could be used as the main index to measure the yield.The correlation of total dry matter and tuber dry matter mass on yield was better than that of leaf area index.The law of IWUE,WUE and PFP of each treatment was similar to that of yield.WUE,IWUE and PFP of T1 treatment were significantly better than other treatments.There was no significant difference in the water consumption under the condition of fertilization experiment(P<0.05).(4)Under the condition of experiment,the T1 treatment was more beneficial to the nutrient uptake of potato.Insufficient fertilizer in the potato starch accumulation period is not conducive to the absorption of nutrients in potato plants.The nitrogen,phosphorus and potassium stored in vegetative organs transport to tuber after anthesis,and more than and 75% to 80% of the nutrients were stored in tubers at maturity stage.The N,P and K translocation of potato was N >K>P,and the transfer rate was that of P >N >K.The amount of nitrogen,phosphorus and potassium,the transfer rate and the contribution rate to the tuber increased with the increase of fertilization ratio at seedling stage.The contribution rate of the accumulated nutrients after the flowering stage >that the nutrient uptake of flowering stage > that of the transfer from vegetative nutrient to the tuber before flowering.Among them,the T1 treatment of tubers accumulated the highest nutrient,followed by T2 treatment,with the least in T7 treatment.(5)In the 0�100cm soil,the contents of nitrate,available phosphorus and available potassium in the same soil layer depth increased with the increase of the proportion of fertilization in the seedling stage and the tuber formation stage,which were decreased with the increase of the proportion of fertilization in seedling stage and tuber formation stage in the0-20 cm soil depth.T1 treatment,the soil nutrient content gradually decreased with the depth of soil layer,the soil nutrient content of 80-100 cm was significantly lower than other treatments.Appropriate increase in the proportion of fertilization can significantly increase the amount of soil nutrient accumulation in cultivation layer.It can be seen that the period of tuber formation to tuber expansion is the key period of potato fertilization,it is beneficial to the rapid growth and increase of potato tubers to provide adequate nutrients at the this period for potato,and more conducive to potato yield.To sum up,under the condition of this experiment,the ratio of fertilization at the stage of seedling to tuber enlargement and starch accumulation being 0-20%-55%-25% of T1,was more favorable for the growth of potato,the accumulation of dry matter,the absorption of nitrogen,phosphorus and potassium,the increase of yield and water use efficiency,and the decrease of nutrient content in deep soil.