中国的红土期

前人仅将华南的红土分为5期[1]，且各期的起迄年龄不详。根据全国众多的红土实例及年龄资料，提出我国6个红土发育期的划分方案，从南向北，红土期数减少，历时变短。各期红土尚可分出若干个亚期，有待今后深入研究。

河流阶地红色风化基座发育的时期与机制探讨——以粤北坪石盆地6级河流阶地为例

武江在粤北坪石盆地保留有6级河流基座阶地,是目前广东省内发现级数最多的阶地。阶地基座受后期风化作用影响,发育了深厚的红色风化基座。已有的河流阶地TL年代数据显示,本区风化基座的发育年代符合中国南方红土期的时空变化规律,但其形成机制与我国红土期相应的华南地貌风化壳有别。风化基座发育受到本区构造抬升和夏季风气候的共同影响。在我国南方红色风化壳广泛发育时期,西部地区的泥石流也出现多期活动。总体上看,泥石流发育期滞后于红土发育期,且不存在红土期内多次发育的特征,这说明夏季风气候对华南地区的影响大于西部地区。红色风化壳发育和泥石流发育共同反映出夏季风气候的加强,季风区内的水循环加快,风化侵蚀更加强烈。

元谋盆地的第四纪红土

本文阐述了元谋红土的分布规律、物理化学性质、红土化作用时期以及红土对环境的解释。按成因观点，元谋红土可分风化壳型红土、地下水型红土、坡积红土三种。中更新世中期、晚更新世早期、全新世最佳期，是元谋红土的主要形成特期。作为岩石圈、大气圈、生物圈相互作用的产物，红土的形成发育，与盆地的第四纪发育历史密切相关。同时，红土也记录了盆地过去的环境演化，因而有可能提取红土储藏的信息重塑第四纪环境。

Effects of Long-term Fertilization on Fertility of Lateritic Red Loam Paddy

The change rules of the fertility of red soil paddy under the long-term different fertilization were investigated, and the reasonable fertilization mode to improve the fertility of red soil paddy was discussed. There were eight treatments in the experiment, which were CK （no fertilizer）, N1 （N of 60 kg/hm2）, N2 （N of 120 kg/hm2）, N1P1 （P2O5 of 30 kg/hm2）, N2P1 and N2P2 （P2O5 of 60 kg/hm2）, N2P2K1 （K2O of 45 kg/hm2） and N2P2K2 （K2O of 90 kg/hm2）. All treatments were applied with composted cow dung as the base fertilizer, and each season 50% of the straws were returned to the field. The content of organic matter, nitrogen, phosphorous and potassium in red soil paddy was observed continuously for ten years and their correlation was also analyzed. Under cow manure and straw return to field, organic matter content of different treatments was positively correlated to year. After ten years, organic matter content of surface soil rose by 2.5 g/kg averagely with an annual increase of 0.25 g/kg. Total nitrogen content and organic matter content of different treatments presented similar variation trend. Total nitrogen content rose by 0.35 g/kg averagely with an annual increase of 0.035 g/kg. Among all the treatments, N2P2K1 and N2P2K2 showed the biggest increase, which went up by 0.052 and 0.48 g/kg, respectively. Phosphorous-free treatments （CK, N1, N2） had steady phosphorous content with irregular changes of different years. Total phosphorous content of phosphorous treatments increased year by year. Total phosphorous content of N1P1 and N2P1 rose by 0.008 g/kg every year. The increment range of total phosphorous content of N2P2, N2P2K1 and N2P2K2 was 0.012 -0.013 g/kg annually. Available phosphorous content varied vastly among different treatments. Available phosphorous content of organic fertilizer treatments basically remained stable with irregular changes of different years. Available phosphorous content of organic fertilizer with phosphate fertilizer treatments rose year by year. Available phosphorous content of N1P1 and N2P1 rose approximately by 0.8 mg/kg. Available phosphorous content of N2P2, N2P2K1 and N2P2K2 rose approximately by 1.4 -1.6 mg/kg annually. Potassium fertilizer amount greatly affected total potassium content. Total potassium content of no-potassium treatments （CK, N1, N2, N1P1, N2P1 and N2P2） remained the same. Total potassium content of N2P2K markedly increased year by year, which was 0.014 g/kg annually. Rapid available potassium content of no-potassium treatments （CK, N1, N2, N1P1, N2P1 and N2P2） showed a decreasing trend. With phosphate fertilizer, rapid available potassium content of N2P2K1 and N2P2K2 remained the same or increased year by year. The change trend of slow available potassium content and rapid available potassium content resembled. Rational allocation of organic fertilizer, nitrogenous fertilizer, phosphate fertilizer and potassium fertilizer can significantly improve soil fertility and economic benefits. Balanced fertilization is an effective measure for soil fertility improvement as it＇s shown that nutrients of surface soil accumulate annually.