液体粪肥配施硫酸钾镁对油菜产量、品质及土壤环境的影响OA

Liquid manure serves as a high-quality substitute for chemical fertilizers.Its scientific application can simultaneously achieve the dual objectives of chemical fertilizer reduction and manure resource utilization.Meanwhile,magnesium fertilizer effectively mitigates magnesium deficiency constraints in Chinese soils that limit rapeseed growth and yield.However,the synergistic mechanisms underlying co-application of liquid manure and potassium magnesium sulfate for rapeseed productivity and the soil environment remain systematically unelucidated.This study comprehensively evaluated the integrated effects of different liquid manure substitution ratios and potassium fertilizer types(conventional potassium fertilizer and potassium magnesium sulfate)on the yield and quality of rapeseed,fertilizer use efficiency,soil acidification and salinization.Seven treatments were established:no fertilizer(CK),full chemical fertilizer(FC),liquid manure substituting 30%N+37%conventional K(MC30),substituting 60%N+71%conventional K(MC60),substituting 30%N+37%potassium magnesium sulfate(ML30),substituting 60%N+71%potassium magnesium sulfate(ML60),and manure fully substituting N and K fertilizer(MK100).Results demonstrated that the application of liquid manure enhanced plant growth performance and stress resistance,improved rapeseed yield and quality,and increased fertilizer use efficiency.Among the treatments,ML60 treatment resulted in the most improvements:grain yield increased by 58.21%,siliques per plant by 25.47%,and unsaturated fatty acids—linoleic acid and linolenic acid—by 3.97%and 3.23%,respectively.It also reduced erucic acid and stearic acid content by 40.05%and 10.36%,respectively.Furthermore,this treatment increased root crown diameter by 13.96%,reduced the height of the first branch by 28.86%,and enhanced lodging resistance.Agronomic use efficiency and partial factor productivity of fertilizers were increased by 3.81 and 1.58 times,respectively.Compared to the MC60 treatment,ML60 treatment significantly increased residual soil total nitrogen and ammonium nitrogen content by 15.04%and 277.16%,respectively,but decreased total potassium content by 6.69%.Liquid manure application did not exacerbate soil acidification.With the exception of ML60 treatment,all manure treatments exhibited lower soil electrical conductivity and total dissolved solids than the full chemical fertilizer treatment,suggesting a reduced risk of salinization.However,in the ML60 treatment,soil electrical conductivity,total dissolved solids,and soluble Mg²⁺content increased by 36.43%,36.37%,and 50.77%,respectively,compared to the FC treatment.The findings suggested that ML60 treatment was the most effective approach for co-applying liquid manure and potassium magnesium sulfate.To minimize salinization risk,subsequent strategies must refine nitrogen and potassium inputs without sacrificing yield performance.