易旱地区褐土P、Zn形态转化特点及其与持续农业的关系

Transformation of P and Zn in a cinnamon soil and its relation to sustainable agriculture in easily dried region

采用田间微区试验和分级提取测定的方法研究了褐土中Ｐ、Ｚｎ形态转化问题．发现褐土中Ｃａ２－Ｐ和Ｃａ８－Ｐ是转化最活跃的Ｐ素形态．而且Ｃａ８－Ｐ的流通容量很大，可超过作物需Ｐ量９倍以上；在Ｚｎ的各种形态中转化最活跃的是ＥＸ－Ｚｎ和ＣＡＲＢ－Ｚｎ，其中ＣＡＲＢ－Ｚｎ的流通容量亦很大，可超过作物需Ｚｎ量１９倍以上．Ｃａ８－Ｐ库和ＣＡＲＢ－Ｚｎ库形成了褐土中调控Ｐ、Ｚｎ养分供蓄以适应旱地水分波动的主要机构．合理施肥和培肥土壤以丰富Ｃａ８－Ｐ和ＣＡＲＢ－Ｚｎ库将有利于增强作物抵御干旱能力，提高水分养分利用效率，促使旱地农业持续向高产优质高效方向发展．

The characteristics of P and Zn transformations in a cinnamon soil are investigated by field micro-plot experiment and chemical fractional extraction method. It is found that Ca2-P and Ca8-P in this soil are the most active forms, and the circulative capacity of Ca8-P can reach to a large amount which exceeds the P uptake of single cropping plants by more than 9-fold. Among the forms of Zn,EX-Zn and CARB-Zn are the most active forms, and the circulative capacity of CARB-Zn can also reach up to a large amount which exceeds the Zn uptake of single cropping plants by more than 19-fold. Therefore, the mechanism controlling the supply and storage of P and Zn and coordinating the fluctuation of soil moisture is constituted mainly by Ca8-P and CARB-Zn pools. Enriching Ca8-P and CARB-Zn pools by fertilization is beneficial to intensify the drought resistance by crops, to increase the use efficiency of water and nutrients, and to advance the development of sustainable agriculture in easily dived region.