土壤养分和酶活性及三七产量、皂苷含量对水肥耦合的响应

Response of soil nutrients,enzyme activities,yield and saponin content of Panax notoginseng to different water and fertilizer combinations

【目的】研究不同灌水量和施肥量组合下三七根增期、苗期、花期和果期土壤养分和酶活性,以及三七产量和皂苷含量,为提升三七产量和品质提供优化的水肥管理方案。【方法】田间试验于2018—2021年在云南省红河州泸西县三七种植基地进行,试验设置3个灌水量:W1(120 mm)、W2(240 mm)和W3(360 mm);使用N-P_(2)O_(5)-K2O为15-15-30的大量元素水溶肥料,设置4个施肥量:F1(48.0 kg/hm^(2))、F2(72.0 kg/hm^(2))、F3(96.0 kg/hm^(2))和F4(120.0 kg/hm^(2)),组成12个水肥组合处理:W1F1、W1F2、W1F3、W1F4、W2F1、W2F2、W2F3、W2F4、W3F1、W3F2、W3F3、W3F4,以当地农民灌溉和施肥方式为对照(CK)。在三七根增期、苗期、花期和果期(成熟期),采集土壤样品测定硝态氮、铵态氮、速效磷、速效钾含量,测定脲酶、蔗糖酶、酸性磷酸酶和过氧化氢酶活性,成熟期测定三七产量和皂苷含量。利用熵权法计算各测定指标的权重,用TOPSIS方法对各处理组合效果进行综合排名,来确定最佳水肥组合。【结果】水肥耦合对三七土壤养分和酶活性影响显著(P<0.05)。在根增期,土壤硝态氮、铵态氮和速效钾含量均在W2F4处理最高,分别为34.6、21.0和132.1 mg/kg。苗期土壤硝态氮含量在W2F3处理最高,为39.4 mg/kg;铵态氮和速效钾含量均在W3F2处理最高,分别为25.4、136.0 mg/kg。花期硝态氮、铵态氮、速效钾含量分别在W1F4(49.9 mg/kg)、W3F3(30.2 mg/kg)、W2F4处理(178.1 mg/kg)最高。果期硝态氮、铵态氮含量分别在W2F4(41.8 mg/kg)、W3F3处理(25.7 mg/kg)最高,而速效钾含量在W2F4(158.0 mg/kg)最高。相同灌水水平下,速效磷含量随施肥量的增加而增加,在W3F4处理含量最高,根增期、花期、苗期和果期分别为23.6、25.9、30.1、26.7 mg/kg。不同生育期,脲酶、蔗糖酶、酸性磷酸酶和过氧化氢酶活性最大值均出现在W3F4处理。三七产量以W2F4处理最高,为2800 kg/hm^(2),水分利用效率以W1F3和W1F4处理最高,均为2.0 kg/m^(3),肥料偏生产力最高在W2F1和W3F1处理,均为1.7 kg/kg。W3F2处理的人参皂苷Rg1和Rb1含量最高,W1F4处理的Rd和三七皂苷R1含量最高。三七产量与土壤硝态氮、速效磷、速效钾含量,脲酶、酸性磷酸酶、过氧化氢酶和蔗糖酶活性,以及人参皂苷Re均显著相关(P<0.05);人参皂苷Rg_(1)和肥料偏生产力呈极显著正相关(P<0.01)。经TOPSIS评价分析,W3F4处理根增期、苗期和果期土壤养分、酶活性和皂苷含量贴近度Ei排名第1,花期W1F4处理排名第1。【结论】综合评价土壤养分、酶活性、产量、皂苷含量及其水肥利用效率,三七最优水肥组合方案为灌水量360 mm和施肥量120 kg/hm^(2)。

【Objectives】We studied the soil nutrient contents,enzyme activities,P.notoginsen yield and saponin content under different water and fertilizer combinations at the main growth stages of P.notoginseng,to optimize the water and fertilizer combination for the P.notoginseng production.【Methods】The experiment was conducted in the P.notoginseng Base of Luxi County,Yunnan Province,China,from 2018 to 2021.The treatment was composed of 3 watering(W)and four fertilization(F)quotas,forming 12 combination treatments:W1F1,W1F2,W1F3,W1F4,W2F1,W2F2,W2F3,W2F4,W3F1,W3F2,W3F3,and W3F4,taking the local irrigation and fertilization as control(CK).The three water quota was 120 mm(W1),240 mm(W2),and 360 mm(W3).The four fertilizer quota were 48 kg/hm^(2)(F1),72 kg/hm^(2)(F2),96 kg/hm^(2)(F3),and 120 kg/hm^(2)(F4).The tested fertilizer was a water-soluble fertilizer with a N-P_(2)O_(5)-K_(2)O ratio of 15-15-30.Soil samples were collected at rooting,seedling,flowering and ripening stage for the measurement of nutrient content and enzyme activity.Plant samples were collected at the ripening stage for the analysis of yield and saponin content of P.notoginseng.The entropy weight method was used to calculate the weight of each measurement index,and the TOPSIS method was used to comprehensively evaluate the effect of each treatment combination.【Results】Water and fertilizer quota significantly affected the content of NO_(3)^(−)-N,NH_(4)^(+)-N,available P and available K,and the activities of urease,sucrase,acid phosphatase,and catalase(P<0.05).At rooting stage,the highest soil NO_(3)^(−)-N,NH_(4)^(+)-N,and available K content was all in W2F4 treatment(34.6 mg/kg,21.0 mg/kg and 132.1 mg/kg).At seedling stage,the highest NO_(3)^(−)-N content was in W2F3(39.4 mg/k),and the highest NH_(4)^(+)-N and available K content in W3F2(25.4 mg/kg,136.0 mg/kg).At flowering stage,the highest soil NO_(3)^(−)-N,NH_(4)^(+)-N,and available K content was appeared in W1F4(49.9 mg/kg),W3F3(30.2 mg/kg),and W2F4 treatment(178.1 mg/kg),respectively,and at ripening stage,appeared in W2F4(41.8 mg/kg),W3F3(25.7 mg/kg),and W2F4 treatment(158.0 mg/kg),respectively.The available P content increased with the increase of fertilizer application rate at the same irrigation level in all the four growth stages,and the highest available P content at the rooting,seedling,flowering and ripening stage was all determined in treatment W3F4 in value of 23.6 mg/kg,25.9 mg/kg,30.1 mg/kg,and 26.7 mg/kg,respectively.The four enzyme activities had a tendency to increase with the increasing of fertilizer rate at the three irrigation quota,and the maximum activity of urease,sucrase,acid phosphatase and catalase was measured in treatment W3F4 at the four growth stages as well.The highest yield was in W2F4 treatment(2800 kg/hm^(2)).Water use efficiency was maximum in W1F3 and W1F4 treatments(2.0 kg/m^(3)),and fertilizer partial productivity was highest in W2F1 and W3F1 treatments(1.7 kg/kg).The highest Rg1 and Rb1 saponin contents were in W3F2 treatment,while the highest Rd and R1 saponin content were in W1F4 treatment.Yield were significantly correlated with soil NO_(3)^(−)-N,available P and available K,urease,acid phosphatase,catalase and sucrase,and Re(P<0.05),while Rg1 and fertilizer partial productivity was positively correlated with each other at extremely significant level(P<0.01).According to the TOPSIS analysis,W3F4 treatment ranked first in terms of soil nutrients,enzyme activities,and saponin content at the rooting,seedling,and fruit stages,while W1F4 treatment ranked first at flowering stage.【Conclusions】Based on the comprehensive evaluation of soil nutrient availability,enzyme activity,yield and saponin content of P.notoginseng,and the water and fertilizer use efficiency,water 360 mm and fertilizer 120 kg/hm^(2)(W3F4 treatment)is the optimum combination.