不同措施改良反酸田及水稻产量效果

【目的】针对反酸田土壤酸性强、有效磷含量极低、活性铝铁毒性重及结构性差等特征,研究不同措施改良反酸田土壤理化性质,提高水稻产量的效果,为施用合理的改良剂消减各种障碍因素、提高土壤肥力、恢复土壤生产力提供理论依据。【方法】通过三年田间定位试验,设置不施肥(CK1)、专用肥(NPK,CK2)、NK+钙镁磷肥、NK+磷矿粉、专用肥+石灰、专用肥+粉煤灰、专用肥+生物有机肥7个处理,研究不同改良措施对华南稻区反酸田水稻产量、土壤酸度、养分状况、团聚体及腐殖质组分的影响。【结果】连续3年添加改良剂钙镁磷肥、磷矿粉、石灰、粉煤灰和生物有机肥的处理早、晚稻平均产量较CK1处理均显著增加,其增幅分别为38.78%~75.00%和38.31%~56.75%;与CK2处理相比,添加改良剂的处理三季早稻和两季晚稻平均产量均有所增加,其增幅分别为9.15%~26.10%和5.71%~13.33%,且添加石灰、粉煤灰和生物有机肥的处理水稻增产率大于钙镁磷肥和磷矿粉处理。添加改良剂的处理土壤p H、有效磷和速效钾含量较CK1和CK2处理均有所增加,而交换性H+、交换性Al3+、有效硫含量则显著降低。与CK1和CK2处理相比,各添加改良剂处理5 mm粒级水稳性团聚体占团聚体比例均显著提高,而2~1 mm、1~0.5 mm以及0.5~0.25 mm粒级团聚体所占比例均有所下降。添加粉煤灰和生物有机肥处理有利于提高0.25 mm水稳性团聚体数量及稳定性,其团聚体破坏率分别降低至14.11%和16.99%。与CK1处理相比,添加石灰处理土壤有机碳含量略有下降,而其他施肥处理均有增加;各施肥处理土壤胡敏酸碳和胡敏素碳含量较CK1处理均有增加,而富里酸碳含量均呈下降趋势。与CK2处理相比,连续3年添加钙镁磷肥和生物有机肥的处理显著提高了土壤总有机碳含量,添加粉煤灰和生物有机肥处理显著提高了土壤水溶性碳和胡敏酸碳含量。施肥处理HA/FA比值较CK1处理均有所提高,其增幅为16.44%~47.69%;与CK2处理相比,添加粉煤灰、生物有机肥处理其值增幅最大,分别提高26.83%和24.53%。【结论】添加粉煤灰或生物有机肥处理对反酸田土壤的改良效果最佳。

Effects of different ameliorant measures on the chemical and physical properties of soil in acid sulfate paddy field and rice yield

【Objectives】 Based on the current strong acidity, low available P content, high toxicity of available Al, and poor texture of acid sulfate soil, effects of different ameliorant measures were investigated on the improvement of soil physic-chemical properties and increase of rice yield in acid sulfate paddy field, so as to providing a theoretical basis for reasonable application of ameliorant, improving soil fertility, and restoring soil production capacity.【Methods】 A three-year field experiment was conducted in acid paddy soil, seven treatments were included in the experiment: no fertilizer (CK1), compound fertilizer special for rice (CK2), NK+ calcium-magnesium-phosphate fertilizer(CaMgP), NK + ground phosphate rock(GPR), compound fertilizer special for rice + lime(LIME), compound fertilizer special for rice + fly ash(FLA), and compound fertilizer special for rice + bio-organic fertilizer(BOF). The rice yield, soil acidity and nutrients, aggregate, and humus composition were determined.【Results】 After three years’ successive treatments, the average yields were increased significantly by 38.78%-75.00% in early rice and 38.31%-56.75% in late rice, compared with CK1, and increased by 9.15%-26.10% in early rice and 5.71%-13.33% in late rice, compared with CK2. The treatments of LIME, FLA and BOF had higher rice increase rates than the treatments of CaMgP and PGR did. The soil pH, the contents of available P and available K increased while the contents of exchangeable H⁺, exchangeable Al³⁺ and available SO²⁺₄ decreased notably in the treatments added with ameliorants. Compared with CK1 and CK2, the ratio of water stable aggregate larger than 5 mm in size to the total aggregate went up markedly, and those of the aggregate of 2-1 mm, 1-0.5 mm and 0.5-0.25 mm in size decreased. Addition of FLA and BOF facilitated the formation of water stable aggregate higher than 0.25 mm in size and their stability, thereby, the percentage of aggregate destruction in the two treatments was decreased to 14.11% and 16.99%, respectively. Compared with CK1, the soil organic carbon content reduced slightly in the treatment of LIME, but increased in the other treatments. Also, application of fertilizer facilitated the improvement of the contents of carbon from humic acid and humin, reduced those from fulvic acid. Compared with CK2, CaMgP and BOF treatments obviously improved the total organic carbon content in soil, while FLA and BOF treatments raised the contents of water soluble carbon and carbon from humic acid. Compared with CK1, the HA/FA ratio increased by 16.44%-47.69% in fertilization treatments, and this ratio increased by 26.83% in fly ash treatment and 24.53% in bio-organic fertilizer treatment compared with CK2. 【Conclusions】 Fly ash and bio-organic fertilizer are satisfactory and more effective on amelioration of acid soil than other meterials tested.