Supported by the National Key Research and Development Program of China (No. 2016YFD0200402-4), the Key Research and Development Program of Jiangxi Province in China (No. 20161BBF60125) and the Collaborative Innovation of Modern Agriculture Research Program of Jiangxi Province in China (No. JXXTCX2015002-04)
为明确硅钙钾镁肥阻控土壤酸化的效果和作用，采用连续4 a的硅钙钾镁肥田间定位试验，以农民习惯施肥处理为对照（CK），分析在农民习惯施肥基础上增施750、1 125、1 500和1 875 kg·hm-2硅钙钾镁肥对稻田土壤剖面pH、电导率（EC）、交换性酸、交换性盐基离子、酸碱缓冲容量和碱产生量的影响。结果表明：农民习惯施肥降低了0~30 cm土壤pH，导致土壤酸化，酸化率为2.88 kmol·hm-2·a--1；与之相反，硅钙钾镁肥能显著提高土壤pH，较CK处理在0~15 cm和15~30 cm分别提高了1.22~1.58和0.35~0.64个pH单位，并产生大量碱，在0~30 cm达到了9.93~13.82 kmol·hm-2·a-1，其中0~15 cm占80%。与CK处理相比，硅钙钾镁肥能显著增加0~30 cm土壤EC、交换性Ca2+、交换性Mg2+、盐基饱和度及0~15 cm交换性K+，减少0~30 cm交换性酸，特别是交换性Al3+。土壤交换性酸消耗量中硅钙钾镁肥释放的交换性盐基和相应碱贡献了104.3%，是交换性酸减少的主要途径。总之，多次大量施用硅钙钾镁肥在显著提高0~30 cm交换性Ca2+、Mg2+和0~15 cm交换性K+含量的同时，有效改良了表层（0~15 cm）和亚表层（15~30 cm）稻田土壤酸性，用量越大，效果越明显，释放的Ca2+、Mg2+盐基离子和碱是土壤酸化阻控的主要作用机制。
【Objective】In recent years, due to aggravating acid deposition and highly intensive agricultural production, involving steadily growing chemical fertilizer application rate, permanent nutrient removal with harvested crops, etc., soil acidification of farmlands is speeding up. Soil acidification of large areas of paddy fields in South China has become an important problem in rice production. Therefore how to ameliorate or remedy the acidifying paddy soil and to exposit its mechanism has become a subject of important theoretical and practical significance to rebuilding healthy soils and guaranteeing food security of the nation. Although lime has already been extensively used as soil amendment to remedy acidified soils, Long-term application of a large amount of lime would not only cause the soil to harden, but also disturb the balance between calcium, potassium and magnesium in the soil. Silicon-calcium-potassium-magnesium (SCPM) fertilizer may be used as an alternative due to its lower solubility and comprehensive nutrient supply. The purpose of this study is to make clear functions of SCPM and its effects on soil acidification in paddy fields. 【Method】A four-year stationarly field experiment was conducted to investigate effects of SCPM on soil pH, electrical conductivity (EC), exchangeable acidity, exchangeable base cation, pH buffer capacity (pHBC) and net base production in the paddy soil. The experiment was designed to have five treatments, i.e. CK (Traditional fertilization practice of the local farmers): Treatment I (CK plus 750 kg·hm-2 SCPM); Treatment II (CK plus 1 125 kg·hm-2 SCPM): Treatment III (CK plus 1 500 kg·hm-2 SCPM); and Treatment IV (CK plus 1 875 kg·hm-2 SCPM), for comparison.【Result】Results show that CK lowered soil pH in the soil layers (0~30 cm), causing soil acidification at a rate of 2.88 kmol·hm-2·a-1, while the SCPM treatments raised soil pH by 1.22~1.58 and 0.35~0.64 units in the topsoil (0~15 cm) and the subsoil (15~30 cm), respectively, and produced alkali in the two soil layers, as much as 9.93~13.82 kmol·hm-2·a-1, of which 80% was in the topsoil. Compared to CK, SCPM treatments significantly increased soil EC, exchangeable Ca2+, exchangeable Mg2+ and base saturation in the two soil layers, and soil exchangeable K+ in the topsoil layer, and decreased soil exchangeable acid in the two soil layers, particularly soil exchangeable Al3+. In the SCPM treatments, the effects became more significant with rising SCPM, especially in the topsoil layer. The exchangeable base cations and alkali released by SCPM contributed 104.3% to the total reduction of soil exchangeable acid, which suggests that it is the main path to reduction of soil exchangeable acid. In Treatments III and IV, pHBC was significantly increased or by 34.85% and 48.51%, respectively, as compared with CK, which was mainly attributed to the increase in soil cation exchange capacity.【Conclusion】 In a word, SCPM can not only effectively lower soil acidity in the top- and sub-soil layers of paddy fields, but also greatly increase soil exchangeable Ca2+ and exchangeable Mg2+ in the two layers, and soil exchangeable K+ in the topsoil layer. The higher the SCPM application rate, the more significant the effects. SCPM releases Ca2+, Mg2+ and alkali, which is believed to be the main mechanism of dulling soil acidification in paddy fields.
冀建华,李絮花,刘秀梅,侯红乾,刘益仁,王子君,吕真真,蓝贤瑾,陈剑秋,黄祥光.硅钙钾镁肥对南方稻田土壤酸度的改良作用[J].土壤学报,2019,56(4):895-906. DOI:10.11766/trxb201807090296 JI Jianhua, LI Xuhua, LIU Xiumei, HOU Hongqian, LIU Yiren, WANG Zijun, Lü Zhenzhen, LAN Xianjin, CHEN Jianqiu, HUANG Xiangguang. Effect of Si-Ca-K-Mg Fertilizer Remedying Acid Paddy Soil in South China[J]. Acta Pedologica Sinica,2019,56(4):895-906.复制