保护地结球生菜化肥减施的综合效应

Comprehensive Effect of Reducing the Application Rate of Chemical Fertilizer on Head Lettuce in Protected Field

以结球生菜为试材,采用田间小区试验,研究了园区常规施肥CF(化学总养分566.25 kg·hm^(-2))和化肥减施JF1(化学总养分288.45 kg·hm^(-2))、JF2(化学总养分166.20 kg·hm^(-2))对生菜产量、品质、养分吸收、土壤微生物及土壤残留养分的影响,以期为保护地结球生菜生产中的化肥减施方案提供参考依据。结果表明:与CF相比,JF1生物产量增加0.93%,经济产量降低8.27%,净效益降低0.92万元·hm^(-2),差异不显著(P>0.05);JF2生物产量、经济产量和净效益分别显著降低11.63%、30.51%和4.22万元·hm^(-2)(P<0.05)。JF1和JF2维生素C含量分别提高4.65%和10.73%,硝酸盐含量分别降低20.36%和31.46%(P<0.05);JF2生菜吸氮量降低27.11%(P<0.05)。试验结束后,JF1处理0~20、20~40 cm和40~60 cm硝态氮分别较CF低81.77%、59.84%和66.56%,JF2处理分别低87.54%、36.01%和70.02%。JF1和JF2土壤细菌数量分别减少10.26%和9.23%,真菌数量分别减少23.51%和6.55%(P>0.05)。综上,适度减施化肥可维持生菜产量、效益和品质,并减少养分残留。建议磷钾处于中高水平地块,每667 m2施商品有机肥1 t,化学氮(N)193.8 kg·hm^(-2)、磷(P2O5)57.9 kg·hm^(-2),钾(K2O)189.0 kg·hm^(-2)。

Taking head lettuce as test materials,micro-plot field experiment was conducted and the fertilization treatments included conventional fertilizer CF(total chemical nutrient 566.25 kg·hm^(-2))and fertilizer reduction treatments JF1(total chemical nutrient 288.45 kg·hm^(-2))and JF2(total chemical nutrient 166.20 kg·hm^(-2)).The effects of different treatments on lettuce yield,quality,nutrient absorption,soil microbial quantity,and residual nutrients in soil were studied,in order to provide reference for the optimal fertilizer application plan of the production of lettuce in protected areas.The results showed that compared with CF,the biological yield of lettuce under JF1 treatment increased by 0.93%,but the economic yield decreased by 8.27%,the net economic benefit decreased by 9200 RBM·hm^(-2),the difference was not significant(P>0.05),while the biological yield,economic yield and net economic benefit in JF2 treatment decreased by 11.63%,30.51%and 42200 RMB·hm^(-2)(P<0.05).The vitamin C content of lettuce under JF1 and JF2 treatments were increased by 4.65%and 10.73%(P<0.05),respectively,and the nitrate content was significant by 20.36%and 31.46%(P<0.05),respectively.The nitrogen uptake amount of lettuce under JF2 treatment was reduced by 27.11%compared with CF treatment(P<0.05).After the experiment,the soil nitrate content at depth of 0-20 cm,20-40 cm and 40-60 cm under JF1 and JF2 treatments was 81.77%,59.84%,66.56%and 87.54%,36.01%,70.02%lower than that under CF treatment,respectively.The number of soil bacteria in JF1 and JF2 treatments were decreased by 10.26%and 9.23%,and the number of soil fungi were decreased by 23.51%and 6.55%,respectively.Therefore,moderate chemical fertilizer reduction could maintain ideal yield,economic benefits and lettuce quality and reduce nutrient residual surplus.It was suggested that at medium-high fertility level farmland,the optimal yield of lettuce could be achieved by applying 15 tons commercial organic fertilizer per hectare,and supplementing chemical nitrogen(N),phosphorus(P2O,)and potassium(K,O)at level of 193.8 kg·hm^(-2),57.9 kg·hm^(-2),and 189.0 kg·hm^(-2),respectively.