湘潭镉污染稻田全年粮食作物替代种植模式研究

Study on Annual Substituted Planting Mode of Grain Crops in Cd Contaminated Paddy Field in Xiangtan

为明确湘潭中度镉污染稻田全年粮食作物替代种植的可行性和理想替代种植模式,于2016年开展了双季稻、双季玉米、双季高粱等3种种植模式的生育进程、产量构成、产品镉含量与经济效益比较研究.结果表明:(1)3种种植模式下,晚季作物均能在10月下旬成熟,两季作物总产量以双季稻最高,双季高粱次之,双季玉米最低;(2)两季总纯收入双季稻最高(17 285.2元/hm2),双季高粱降低2.4%,双季玉米降低44.6%;(3)早、晚稻糙米镉含量远超国家标准,而玉米籽粒镉含量仅0.10 mg/kg左右,高粱籽粒镉含量在0.25 mg/kg^0.45 mg/kg之间,低于国家饲料镉含量标准.综合来看,双季高粱(旱季+再生季)虽经济效益较双季稻略有下降,但其产品安全,且具有省工节本优势,是中度镉污染稻田的理想替代种植模式.

To clarify the feasibility of annual substituted planting of grain crops in medium Cd contaminated paddy field and the ideal substituted planting mode in Xiangtan,in 2016 the comparative studies were conducted on growth duration,yield components,Cd content in products and economic benefit among double-cropping rice,double-cropping maize and double-cropping sorghum. The results showed that：（ 1） In the three planting modes,all the late season crops could mature in late October.As for the total yield of two season crops,double-cropping rice ranked first,double-cropping sorghum the second,double-cropping maize the third.（ 2） The total net income of double-cropping rice was highest,17 285.2 $/hm2,which of double-cropping sorghum and double-cropping maize was respectively decreased by 2.4% and 44.6%.（ 3） The Cd content in brown rice of early and late rice was above the national standard,while Cd content in maize grains was only about 0.10 mg/kg and that in sorghum grains was in the range of 0.25 mg/kg ~ 0.45 mg/kg,which was lower than national standard for forage.Comprehensively,double-cropping sorghum（ main crop ＋ ratooning） had slightly lower economic benefit than double-cropping rice,but with safe products and the advantages of saving labor and cost,it was the ideal substituted planting mode in medium Cd contaminated paddy field.