Efficient Phosphorus Utilization In Potato With Drip Irrigation Based On Temporal And Spatial Matching Of Fulvic Acid

The main potato producing areas in the northern part of Yinshan Mountain are mostly calcareous soils with high percentage of phosphorus fertilizer fixation loss and low utilization rate,and the accumulated phosphorus in the soil is continuously increasing.Fulvic acid has been proved by the group to have the dual characteristics of activating soil phosphorus and reducing phosphorus fertilizer fixation,and the potential of phosphorus fertilizer reduction by tapping the temporal and spatial matching of phosphorus demand of potato with fulvic acid will become a new way for efficient phosphorus utilization of potato with drip irrigation in the region.In this study,through two consecutive years of field trials from 2021 to 2022,the effects of the period and location of fulvic acid supply on potato phosphorus uptake and utilization patterns and soil phosphorus activation effects were systematically studied.On this basis,the effects of temporal and spatial regulation of fulvic acid combined with phosphorus fertilizer on potato yield composition,root growth,phosphorus utilization characteristics and changes in soil inorganic phosphorus morphology were investigated in depth,the amount of soil phosphorus activated by fulvic acid and reduced phosphorus fertilizer fixation were quantified,and a technical model of potato phosphorus fertilizer application reduction and efficiency enhancement based on temporal and spatial matching of fulvic acid was established,with the following main results:1.Compared with all base applications,fulvic acid split chasing significantly increased potato dry matter accumulation,plant phosphorus accumulation,leaf area index,soil phosphorus activation rate by 17.6%-22.2%,and final yield by 4.5%.2.Under fulvic acid split drip application conditions,drip irrigation tape buried 10 cm deep fulvic acid split drip application could increase the effective phosphorus content of20-40 cm soil and soil phosphorus activation rate,which could continue to improve the yield by 4.4%-7.2%.3.Compared with single temporal and spatial regulation of phosphorus fertilizer,the temporal and spatial regulation of phosphorus fertilizer combined with fulvic acid significantly increased the accumulation of potato dry matter and plant phosphorus,promoted the increase of root length and weight,increased the soil Ca₂-P and Ca₈-P content by 12.91 mg/kg and 23.59 mg/kg on average,further enhancing the match between root phosphorus uptake and soil phosphorus supply,yield increased by 9.4%-15.1%,increasing phosphorus fertilizer utilization by 4.1%-8.9%in season,and reducing phosphorus fertilizer fixation by 12.9%-14.6%.4.Under the temporal and spatial regulation of the combination of fulvic acid and phosphate fertilizer,the dosage of fulvic acid was 450 kg/hm²and the application of phosphate fertilizer was 128 kg/hm²,fulvic acid activated 10.5-15.6 kg/hm²of total phosphorus and reduced 20.8-24.2 kg/hm²of total phosphorus fixed by phosphate fertilizer.5.The drip irrigation belt burial depth of 10 cm and 450 kg/hm²of fulvic acid all chasing planting mode,which can reduce phosphorus fertilizer dosage by 20%on the basis of phosphorus fertilizer temporal and spatial matching technology,potato tuber yield of52-54 t/hm²and phosphorus fertilizer utilization rate of 32.4-34%in the season,which can be the recommended technology for efficient utilization of phosphorus fertilizer in drip irrigated potato.