Research on the abundance-deficiency index of the soil N,P and K nutrients for oil flax in the middle arid area of Gansu
A field experiment was conducted over a period of five consecutive years to assess the abundance-deficiency index of soil nutrients for oil flax in the middle arid region of Gansu.The results indicated that for local oil flax,the abundance-deficiency index of N,P and K nutrients can be classified into six fertility levels based on relative yield:＜50%(extremely low),[50%-60%)(low),[60%-70%)(lower),[70%-80%)(medium),[80%-90%)(higher),≥90%(high),The corresponding values for total N were＜0.38,[0.38-0.53),[0.53-0.75),[0.75-1.05),[1.05-1.48),and≥1.48 g·kg-1 respectively;for available P were＜4.6,[4.6-7.8),[7.8-13.1),[13.1-22.1),[22.1-37.3),and≥37.3 mg·kg-1 respectively;for available K were＜91.0,[91.0-117.3),[117.3-151.1),[151.1-194.7),[194.7-250.9),and≥250.9 mg·kg-1,respectively.and to put forward in different fertility levels the corresponding ni-trogen fertilizer recommendation rate were as follows:＞130,(115-130],(105-115],(95-105],(75-95],and≤75 kg·hm-2;the corresponding phosphorus fertilizer recommendation rates were as follows:＞110,(95-110],(80-95],(65-80],(50-65],and≤50 kg·hm-2;the corresponding potassium fertilizer recommendation rates were as follows:＞70,(60-70],(50-60],(40-50],(35-40],and≤35 kg·hm-2.According to the long-term survey and monitoring of soil nutrients,since 1983,there has been an upward trend in soil alkali-hydrolyzable N and available P.a slight de-crease in total N,and a significant decrease in available K in the local oil flax producing area.The abundance-defi-ciency indexes obtained from the experiment also indicate that currently,the content of local soil nitrogen and phos-phorus nutrients are still at low levels.However,although the local soil's potassium nutrient content remains at a higher level,it exhibits a significant downward trend compared to the past.This indicates that in local oil flax pro-duction,more attention should not only be paid to increasing nitrogen fertilizer but also to increasing phosphate fer-tilizer and appropriately applying potassium fertilizer.
arid areaflaxsoil N,P and Kabundance-deficiency indexfertilization indexes
万方数据
维普
