外加碳源和氮源对酸化水稻土温室气体释放的影响

通过室内恒温培养试验,对酸化水稻土单独添加硫酸铵以及同时添加硫酸铵和葡萄糖后发现,添加硫酸铵后短时间内(2 d)就引起pH值下降和铵态氮转化为硝态氮,外源添加葡萄糖后进一步引起pH值下降和促进铵态氮向硝态氮转化,这种差异在长期(120 d)培养后更加显著。硫酸铵显著引起NO和N2O气体释放,外源添加葡萄糖后进一步促进两种气体的释放。测定土壤微生物丰度发现,两种温室气体的释放与土壤中氨氧化细菌、氨氧化古菌和反硝化细菌存在显著相关性。在短期培养时,氨氧化细菌和反硝化细菌丰度的差异导致了同时添加葡萄糖处理的温室气体释放量高于单纯的添加硫酸铵培养组;在长期培养时,则是氨氧化细菌、氨氧化古菌和反硝化细菌导致了这种差异。

益欣荣Ⅱ土壤调理剂对酸化水稻土的改良效果研究

为验证台湾益地股份有限公司提供的益欣荣Ⅱ土壤调理剂应用于酸化土壤的改良效果,为该产品推广应用提供依据,进行了益欣荣Ⅱ土壤调理剂对酸化水稻土的改良、水稻的增产增收试验。结果表明,增施该调理剂20 kg以上,对水稻增产效果显著,增幅超过5%,但因增加的投入相对较高,直接经济效益不明显;用Excel能很好地拟合该调理剂用量与水稻产量的一次、二次、三次回归函数,相关系数差异显著至极显著,利用二次回归函数计算该调理剂最佳经济用量为39 kg/亩,与推荐用量40 kg/亩吻合。该调理剂对酸化水稻土改良效果较好,能有效控制土壤pH的下降幅度和交换性铝的上升幅度,还可降低土壤有效锰和提升盐基饱和度。增施20~60 kg/亩,可使土壤pH少下降0.05~0.12个单位,交换性铝少上升0.10~0.45 cmol/kg,有效锰多下降6.8~19.7 mg/kg,盐基饱和度多提高1.47~6.57个百分点。综合考虑土壤酸度调节及水稻增产增收情况,建议调理剂亩用量为20~40 kg。

化肥配施土壤调理剂对酸化红壤性水稻土改良效果研究

【目的】针对我国南方酸化红壤性稻田,研究化肥配施土壤调理剂对水稻产量及土壤化学性质的影响,以期为土壤调理剂在酸性稻田土壤的改良提供理论依据和技术支撑。【方法】以南方酸性稻田土壤为研究对象,以杂交水稻品种H优518为供试材料,通过大田试验,分析化肥(常量、减10%、20%、30%)配施不同用量土壤调理剂(750,1500,2250 kg/hm^2)对水稻产量及其构成因素、成熟期干物质积累量、土壤pH及土壤养分的影响。【结果】增施土壤调理剂能显著提升土壤pH,相较于常量施肥,处理70%F+150 pH上升0.48个单位,而且增施2250 kg/hm^2土壤调理剂对提高土壤有机质和有效磷含量具有显著效果,但是对土壤氮素养分和速效钾含量影响不明显。水稻产量处理100%F+100和100%F+150最高,且显著高于处理80%F+100和70%F+150,增幅分别为8.79%和9.39%。常量施肥条件下,处理100%F+50、100%F+100和100%F+150产量均高于处理100%F,但未达到显著水平。减施化肥条件下,水稻产量处理90%F+50略高于处理100%F,但差异不显著。各处理的成熟期总干物质积累量差异不显著,水稻产量与成熟期总干物质积累量呈显著直线正相关。【结论】常量施肥添加2250 kg/hm^2土壤调理剂能改良酸性土壤、提高土壤有效养分含量和实现水稻高产。

Effects of Rice Straw Incorporation and Soil Pre－Flooding on the Fate of Applied （^（15）NH_4）_2SO_4－N and Growth of Rice

A pot experiment was conducted to investigate the effects of straw incorporation and soil pre-flooding on the fate of (￣(15)NH_4)_2SO_4-N and the growth of rice. Excessive application of rice straw when incorporated with (￣(15)NH_4)_2SO_4 at the C/N ratio of 40 reduced the loss of (￣(15)NH_4)_2SO_4-N and retarded the growth and development of rice significantly, while no adverse effects were observed on dry weight of panicle and the total recovery of (￣(15)NH_4)_2SO_4-N when rice straw was incorporated with (￣(15)NH_4)_2SO_4 at a C/N ratio less than 25. There were no significant effects of duration of soil pre-flooding within 6 weeks on (￣(15)NH_4)_2SO_4-Nuptake by rice and on rice growth, but, less loss of (￣(15)NH_4)_2SO_4-N was observed in the soil with a longer period of pre-flooding.