施用不同石灰类物质对双季优质稻产量和品质的影响

南方双季稻区土壤酸化日益严重,已经成为制约水稻产量提升的主要因素之一。大量研究表明,施用石灰可以改良土壤酸化和提高水稻产量,但目前关于石灰施用对当地稻米品质的影响研究较少,且不同石灰类物质的施用效果是否存在差异还不是很清楚。于2021年在江西省典型酸性双季稻田上开展田间试验,旨在明确施用不同石灰类物质(氧化钙、氢氧化钙、碳酸钙)对优质稻(早稻为柒两优2012、晚稻为美香占2号)产量和米质的影响。结果表明,不同石灰类物质间的施用效果无显著差异,且施用石灰类物质对早稻产量、品质和氮素吸收亦无显著影响。但与不施石灰对照相比,施用氧化钙、氢氧化钙和碳酸钙处理的晚稻显著增产11.3%、17.3%和17.6%,氮素吸收显著增加16.6%、17.1%和13.5%,精米率和整精米率分别显著提高1.3%~2.1%和6.1%~6.3%,直链淀粉含量显著下降4.7%~4.8%。与不施石灰对照相比,施用氧化钙、氢氧化钙和碳酸钙处理的早季稻田土壤pH值分别显著提升0.52、0.42和0.50个单位,晚季稻田土壤pH分别显著提升0.41、0.57和0.48个单位。可见,在酸性双季稻田上施用石灰类物质,在改良土壤酸化的同时改善了晚稻的加工和食味品质。

Uptake of Organic Phosphorus by Arbuscular Mycorrhizal Red Clover

The capacities of two arbuscular mycorrhizal (AM) fungi, Glomusmosseae and Glomus versiforme, to mineralize added organic P werestudied in a sterilized clacareous soil. Mycorrhizal (inoculated witheither of the AM fungi) and non-mycorrhizal red clover (Trifoliumpratense L.) plants were grown for eight weeks in pots with upperroot, central hyphal and lower soil compartments. The hyphal and soilcompartments received either organic P (as Na-phytte) or inorganic P(as KH_2PO_4) at the rate of 50 mg P kg^-1. No P was added to theroot compartments.