沼液配施化肥对蜜柚产量、品质及土壤重金属的影响

Effects of biogas slurry combined with chemical fertilizers on yield,quality of pomelo and heavy metals in soil

在福建省平和县,以8年生琯溪蜜柚为试验树,田间定位连续3年施用养猪场猪粪沼液,研究等量氮磷钾条件下不同比例沼液与化肥配施对蜜柚产量、品质及土壤重金属和盐分的影响。结果表明,与施用纯化肥(采用普通尿素、过磷酸钙和硫酸钾,每年株施N、P_(2)O_(5)和K_(2)O分别为950.0、600.0和850.0 g)相比较,沼液替代25%化肥(以氮计,不足的氮、磷、钾养分用化肥补足)和替代50%化肥处理有增产优势,同时对果实品质无负面影响,沼液替代100%化肥无增产作用且会使果实品质下降;所有沼液处理会降低裂果率;沼液替代25%化肥不会加重果实粒化率,其他沼液处理会加重果实粒化率。随沼液替代比例和施用年限的增加,土壤中Cu和Zn含量显著增加,但均低于农用地土壤污染风险管控标准(GB 15618—2018),土壤电导率随沼液替代比例的增加而增加。沼液替代25%化肥在蜜柚果园应用的综合效果较好,可在生产上推广,但更长期施用沼液的影响还需进一步评估。

A three-year field experiment was carried out to study the effects of different proportions of pig farm biogas slurry combined with chemical fertilizers on yield and quality of 8-year-old honey pomelo and heavy metals and salinity of soil.The results showed that compared with the application of only fertilizer(TF)(N,P_(2)O_(5)and K_(2)O were 950.0,600.0 and 850.0 g per plant per year in the forms of urea,calcium superphosphate and potassium sulfate,respectively),the replacement of 25%fertilizer with biogas slurry(TFN25)(based on the usage of nitrogen,insufficient N,P and K nutrients were supplemented by fertilizer)and 50%fertilizer(TFN50)treatment increased yield,and had no negative effect on fruit quality.But replacing 100%fertilizer with biogas slurry(TFN100)had no effect on increasing yield,but decreased the fruit quality.All biogas slurry treatments can reduce fruit cracking rate.The replacement of 25%fertilizer by biogas slurry did not increase the granulation rate of fruit,while other biogas slurry treatments increased the granulation rate of fruit.With the increase of biogas slurry replacement proportion and application years,the contents of Cu and Zn in the soil increased significantly,but they were lower than the threshold of risk control standard for soil contamination of agricultural land.The soil electrical conductivity increased with the increase of biogas slurry replacement proportion.In conclusion,application of biogas slurry replacing 25%fertilizer in honey pomelo orchard had better overall effect,which can be popularized in production.However,the effect of long-term application of biogas slurry needs further observation and evaluation.