土壤铜污染对水稻产量形成的影响:5年定位试验

Effect of Soil Copper Contamination on Rice Yield Formation:A 5-Year Located Experiment

2006年选用清洁粘质壤土(对照,铜浓度32mg.kg-1)制备200mg.kg-1和400mg.kg-1铜污染土壤,在土培池群体栽培条件下,以"矮仔占"和"两优培九"为供试材料,进行持续5年的长期定位试验,研究水稻产量的年度变化规律及其可能原因。2007—2010年的测定结果表明:200、400mg.kg-1铜处理使前两年水稻成熟期平均分别推迟2～5d和6～7d,但后两年无明显变化。土壤铜污染抑制水稻分蘖的发生,抑制程度逐年减小,两品种趋势一致。200、400mg.kg-1铜处理使2007年水稻产量分别平均减少17%、24%,随着时间推移减产幅度明显下降,后两年处理间没有差异,两品种趋势一致。铜污染条件下水稻减产主要与单位面积穗数和每穗颖花数减少有关,而结实率和千粒重均无显著变化。相关分析表明,水稻成熟期土壤可交换态铜浓度与铜胁迫下对应生长季水稻抽穗和成熟期推迟的天数以及茎蘖发生、单位面积穗数、每穗颖花数和产量的下降幅度均呈显著或极显著正相关。以上结果说明,土壤铜污染抑制水稻分蘖的发生和生长,使单位面积穗数和每穗颖花数下降进而使水稻减产;土壤铜污染对水稻生长和产量的影响逐年减小,这可能与土壤中可交换态铜含量持续降低有关。

In order to investigate the long-term effects of soil copper（Cu）contamination on yield formation of rice,a 5-year（2006—2010） experiment was conducted in cement tanks.Clay loam soil was treated with 3 different Cu levels（CK,32 mg.kg-1;200 mg.kg-1 and 400 mg.kg-1）in 2006,the first year of this long-term trial.No further Cu was added into the experiment plots in the following years.A indica rice variety Aizizhan and a two-line hybrid combination Liangyoupeijiu were used as the testing materials.High Cu treatments delayed rice phenology in the early stage of trial,namely 2007 and 2008.The maturing date was delayed by 2～5 days and 6～7 days for the soil Cu levels of 200 mg.kg-1 and 400 mg.kg-1,respectively.No phenology changes were observed in the late stage of trial.The tilliering ability of two varieties were inhibited by soil Cu contamination,but the inhibition declined by years.An average yield reduction of 17% by 200 mg.kg-1 Cu treatment and 24% by 400 mg.kg-1 Cu treatment were observed in 2007.The rice yield reduction became smaller in the following years,and no treatment effects were detected in the latter 2 years.The rice yield reduction under Cu contaminated conditions were mainly due to the decrease of panicles per unit area and spikelet number per panicle,since Cu treatments did not change filled grain percentage and grain weight of rice.Correlation analysis showed that exchangeable Cu concentrations（ECC）in top soil were significantly correlated with the phenology delay,tiller number,panicle number per unit area,spikelet number per panicle and grain yield.These results indicated that soil Cu contamination could inhibit rice growth and tillering,reduce panicle number and number of spikelets per panicle,and eventually lead to rice yield decrease;The negative effects of soil Cu contamination on rice growth and yield were reduced by years,and it could be attributed to the continuous reduction of ECC in top soil.