化肥减量配施有机肥对粤西地区水稻产量和养分利用的影响

Effects of Fertilizer Reduction Combined with Organic Fertilizer on Rice Yield and Nutrient Utilization in Western Guangdong

针对水稻生产过程中化肥施用过量、养分吸收利用率低和面源污染风险高等问题,通过研究化肥减量配施有机肥对植株养分吸收量、肥料偏生产力、土壤养分平衡以及水稻产量的影响,提出稳产条件下适宜的化肥施用量以及有机无机肥配比措施,以期为水稻化肥减量增效与土壤培肥提供理论依据。本研究于2021年在粤西地区早稻生长季开展田间试验,研究了当地4种优化施肥方式:优化施肥处理(OPT)、增有机肥处理+化肥减量处理1(OM1)、增施有机肥处+化肥减量处理2(OM2)、增施有机肥处+化肥减量处理3(OM3)对水稻产量、肥料偏生产力以及养分平衡的影响,从生产目标、环境效应和土壤肥力进行综合评价。结果表明:不同施肥方式下水稻籽粒产量和谷杆比分别在5667~5967 kg/hm^(2)和1.09~1.31之间,氮肥、磷肥、钾肥偏生产力分别在30.4~47.2、96.0~122.1、47.2~105.9 kg/kg之间;农田氮素、磷素、钾素表观平衡在54.2~115.3、17.1~29.8、1.2~67.0 kg/hm^(2)之间。4种施肥措施氮素、磷素和钾素平衡均处于盈余状态。在增施有机肥的处理中,随着化肥施用量的降低,水稻籽粒产量、谷杆比、氮肥、磷肥、钾肥偏生产力、磷素吸收率、钾素吸收率逐渐增加,氮素、磷素、钾素表观平衡逐渐降低。各有机肥替代处理秸秆钾素含量、钾肥偏生产力均显著高于OPT处理(P<0.05)。与农户常规施肥措施相比,优化施肥和增施有机肥措施均可以起到稳产效果,并且谷杆比、籽粒和秸秆含磷量、含钾量均较农户常规施肥措施提高。结合谷杆比、磷、钾肥偏生产力考虑,OM3处理效果最好;从氮肥偏生产力、氮素吸收率、土壤中氮素表观盈余率和产投比考虑OPT处理效果最好。

To solve the problems of excessive application of chemical fertilizer,low crop nutrient utilization efficiency and high risks of non-point source pollution in rice production,the impacts of chemical fertilizer reduction combined with organic fertilizer on nutrient absorption,partial productivity of fertilizer,nutrient balance and rice yield were studied.The optimum management practices were identified in this study,which provided a theoretical basis for reducing fertilizer use,increasing use efficiency and improving soil fertility.A field experiment was carried out in the early rice growing season of western Guangdong in 2021.Four local recommended fertilization methods were tested,including optimized fertilization treatment(OPT),and reducing the rate of farmers’conventional fertilizer application by 10%,20% and 30%while applying organic fertilizer denote as OM1,OM2,and OM3 treatment,respectively.The results showed that the grain yield and grain-tostraw ratio varied from 5667-5967 kg/hm^(2) and 1.09-1.31,respectively.The partial factor productivity of nitrogen(N),phosphorus(P)and potassium(K)fertilizer were 30.4-47.2,96.0-122.1 and 47.2-105.9 kg/kg,respectively.The apparent balance of N,P and K were 54.2-115.3,17.1-29.8 and 1.2-67.0 kg/hm^(2),respectively.All of them were in a surplus state.In the treatments of organic fertilizer application,the rice grain yields,ratios of grain to stem,N,P,K fertilizer partial productivity,P absorption rate and K absorption rate increased along with the decrease of synthetic fertilizer application rate,while the apparent balance of N,P and K decreased.The straw K content and K partial factor productivity of each organic fertilizer substitution treatment were significantly higher than those of OPT treatment(P<0.05).Compared with farmers’conventional fertilizer application,OPT,OM1,OM2 and OM3 treatments could maintain the paddy yield,and improve the ratio of grain to stem,the P content and K contents of grain and straw.Considering the ratio of grain to stem,P and K partial productivity,OM3 treatment was identified as optimum management practice.While considering the partial productivity of N fertilizer,N absorption rate,N surplus rate in soil and outputinput ratio,OPT treatment was identified as optimum management practice.