Effect Of Nitrogen Application On Potato In Chestnut Soil Area

Shanxi is an important potato producing area in the North of China,Tongshu 29 and Datongliwaihuang are two new potato cultivars released in Shanxi Province in recent years.It is of great significance to study the effect of nitrogen application on two new potato cultivars from both production and environment perspectives.A field trial was conducted to examine the effect of N fertilization on two new potato cultivars(Tongshu 29 and Datongliwaihuang)at Maozao experiment base of Institute of the Crops in High Latitude & Cold Climate Area,Shanxi Academy of Agricultural Sciences in 2018 and 2019.The experimental design was a split-plot arrangement with two cultivars as main plots and different N fertilizer rates as sub-plots.The research results showed that:(1)Under the condition of no nitrogen application,the total dry matter and nitrogen uptake of potato were the lowest in each growth period,and the nitrogen application increased with the increase rate of nitrogen application.The difference between the treatment of N225 and N270 was not significant.The total dry matter amount of potato increase with the growth progress,and the growth and development was rapid from inflorescence emergence stage to flowering stage,and it accounted for 40%~60% of the total nitrogen uptake.The total dry matter amount and nitrogen uptake of Tongshu 29 were higher than that of Datongliwaihuang,and these indicated that capacity to absorb nitrogen for Tongshu 29 was higher.(2)The tuber yield and economic benefit of the treatment of without nitrogen application were lowest.The tuber yield and economic benefit could be improved by nitrogen application,and the relationship between tuber yield,economic benefit and nitrogen application could be fitted by quadratic equation.For potato cultivar Tongshu 29,the highest yield of was obtained by nitrogen application of 192~201 kg/ha,the economic nitrogen application was 186~191 kg/ha;and for potato cultivar Datongliwaihuang,the highest yield of was obtained by nitrogen application of 240~267 kg/ha,theeconomic nitrogen application was 225~249 kg/ha.The yield and economic benefit of Tongshu 29 are higher than that of Datongliwaihuang.(3)The SPAD value and petiole nitrate-nitrogen concentration of potato in different growing stage were all the lowest without N fertilizer application,both of them showed an increasing trend with the increase of N fertilizer application,and showed an reduced trend with the progress of the growth stages.The threshold of SPAD and petiole nitrate-nitrogen concentration of potato at different growth stages can be obtained by taking the relative yield of potato at 90%.The SPAD thresholds of 20,30 and 45 days after seedling emergence were 51.3,48.6 and 43.9,respectively.The thresholds of petiole nitrate-nitrogen concentration of Tongshu 29 and Datongliwaihuang at leaf development stage,inflorescence emergence stage and flowering stage were471,149,130mg/L and 404,140,122mg/L,respectively.(4)The nitrate nitrogen concentration and accumulation of soil profile were all the lowest without N fertilizer application,both of them showed an increasing trend with the increase of N fertilizer application.When the N rate exceeds the optimum N rate,the soil nitrate nitrogen appears leaching.The higher N rate,the more serious potential risks to the ecological environment.The study will provide theoretical guidance and technical support for the rational application of nitrogen fertilizer in the chestnut soil area.