Effects of potassium fertilizer rates on tuber yield,plant physiological characteristics and potassium absorption and utilization of Helianthus tuberosus L.
This study aimed to explore the effects of potassium application rates on tuber yield,plant physiological characteristics,potassium absorption and utilization of Helianthus tuberosus L.,and thus to provide a reference for scientific application of potassium and high-quality and high-yield cultivation of H.tuberosus.A field experiment was conducted in the Science and Education Park of Henan Agricultural University in Yuanyang County,Henan Province,in 2022.Six treatments of 0(K0),45(K45),90(K90),135(K135),180 kg·hm-2(K180),and 225 kg·hm-2(K225)K2O were used.Tuber yield was measured at the maturity stage(206 d after sowing),potassium accumulation,canopy photosynthetic effective radiation(APAR and FPAR),canopy temperature,leaf SPAD value,leaf anatomical structure,and antioxidant enzyme activity were measured during the growth period(60,94,122 d,and 162 d after sowing).In addition,potassium harvest index(PHI),apparent use efficiency of potassium(AUP,%)and agronomic efficiency of potassium(AEP,kg·kg-1)for H.tuberosus were analyzed.The results showed that potassium application could significantly increase the fresh yield of H.tuberosus.The optimal potassium fertilization rate for the growing season was 204 kg·hm-2.With the increase of potassium fertilizer rate,the relevant physiological indicators of H.tuberosus(plant potassium accumulation,APAR,FPAR,leaf SPAD value,upper and lower epidermis thickness,leaf thickness,palisade tissue thickness,cavernous tissue thickness,and antioxidant enzyme activity)showed a trend of first rising and then declining;canopy temperature change showed the opposite trend.All indicators reached their optimal values at a potassium fertilizer rate of 180 kg·hm-2.AUP and AEP showed a trend of first increasing and then decreasing with the increase of potassium fertilizer dosage,whereas PHI showed a gradually decreasing trend.In summary,the yield of H.tuberosus tubers was significantly improved by increasing rates of potassium,and the physiological activity,stress resistance,and potassium fertilizer utilization were also improved.With the conditions of sandy tital soil in northen Henan,the recommended potassium fertilizer rate for H.tuberosus is 180-204 kg·hm-2.
Helianthus tuberosus L.yieldcanopy temperatureanatomical structural characteristics of leafpotassium utilization efficiency
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