Fertilizer Nutrient Input,utilization And Spatial Distribution Of Soil Nutrients In Main Potato Planting Regions In China

To solve the extensive potato cultivation but low yield per unit area and unknown nutrient inputs in China,we analyzed the current situation of fertilizer nutrient inputs,utilization and soil nutrient variation,provided a basis for regionalized management of potato production.Based on the National Potato Industry Technology System,this study collected 1850 representative soil samples,potato tuber samples and field questionnaires from 2019-2021 in the main producing counties of 19provinces in Chinese main potato producing areas,analysed the correlation between potato yield,fertiliser application,measured soil nutrient indicators and tuber nutrient uptake,and analyzed the spatial variation of fertilizer application,soil nutrients and fertilizer utilization.The spatial variation characteristics of fertilizer application,soil nutrient and fertilizer utilization were analyzed to evaluate the soil quality of potato production areas in China.The main progress achieved is as follows:（1）Current status and evaluation of nutrient inputs in the main potato production areas.The average annual N,P₂O₅ and K₂O inputs for potato were 252,219 and 224kg ha^-1 respectively,with a chemical fertiliser nutrient ratio of 1.00:0.88:0.94 and an organic fertiliser nutrient ratio of 1.00:0.86:0.74.The proportion of base fertiliser application was over 80%,and the proportion of organic nutrients to total nutrients was only 24.3%.The fertiliser nutrient reduction potential（N+P₂O₅+K₂O）is estimated to be 41.9%according to nutrient expert recommendations,with N,P₂O₅and K₂O having a reduction potential of 15.0%,62.8%and 45.1%respectively.We suggest that future potato fertilisation should follow the following points:1)Total nutrient control and differentiated fertilisation in different regions.Reduce the input of fertiliser nutrients for potatoes in southern winter crop areas,increase the input of nitrogen fertiliser in Heilongjiang,Jilin,Sichuan and Hunan potato production areas,and reduce the amount of phosphorus and potassium fertiliser applied;2)adjust the proportion of nitrogen,phosphorus and potassium nutrients applied,reduce the proportion of basal fertiliser applied,and follow up the fertiliser at the right time according to the nutrient requirements of potatoes;3)promote the application of organic fertiliser in potato production areas such as Hebei,Hunan,Inner Mongolia,Sichuan and Fujian,and develop appropriate（3）promote the application of organic fertiliser in potato production areas such as Hebei,Hunan,Inner Mongolia,Sichuan and Fujian,and develop appropriate organic nutrient replacement rates.（2）Spatial variability in fertiliser utilisation rates in major potato producing areas.The degree of variation in nutrient productivity bias and nutrient balance was high,but there was little inter-annual variation in other indicators between years,except for a significant decline in PFP_N.There were large differences in nutrient bias productivity and nutrient balance between regions,with higher nutrient bias productivity and nutrient balance in northern single cropping areas than in southern winter cropping region and southwestern mixed cropping region.This indicates a higher nutrient utilisation rate in the northern than in the southern potato growing regions of China,which is consistent with the conclusion in Chapter 2 that the potential for fertiliser reduction is greater in the south.The relative importance of the explanatory variables was assessed ranking agricultural management practices（AMP）>topography>climate>soil>crop>economy,indicating that agricultural management practices have the greatest influence on potato nutrient utilisation,which also provides a basis for field cultivation.（3）The spatial differentiation characteristics of soil nutrients and soil quality evaluation in the main potato producing areas.The descriptive statistics of potato yield and seven soil chemistry properties in China were summarized.The coefficient of variation range for all selected parameters is 21.23%-96.39%,indicating a high degree of variability in available nutrients.High yield areas are mainly distributed in the northeast and north China single season cropping areas.The relevant analysis results show that soil sand is one of the factors limiting potato yield.In areas with sufficient irrigation and rainfall,the correlation between yield and soil nutrients is weak,and water is an important factor limiting yield.The limiting factors for yield vary in different regions,and the impact of soil nutrient indicators on yield varies greatly in different regions.In summary,it is important to understand the spatial variation in fertilizer input use,soil nutrient and utilization characteristics in the main potato producing areas of China,and to evaluate soil quality in the most important northern one-season crop regions.To provide regionalised fertiliser application and management options for potato cultivation,increase farmers’incomes while protecting the ecological and soil environment and maintaining the rapid,stable and healthy development of the potato industry.