湖南省红黄泥土壤氮矿化特性的研究

A STUDY ON THE NITROGEN MINERALIZATION CHARACTERISTICS OF THE WELL=DRAINED PADDY SOIL FROM QUATERNARY RED CLAY IN HUNAN PROVINCE

1987～1988年采用淹水密闭培养一间歇淋洗方法研究了湖南省的水稻土土属——红黄泥的土壤氮矿化特性。结果表明:采用淹水密闭培养一间歇淋洗法得到的土壤矿化氮量与相同有效积温条件下的田间土壤矿化氮量基本一致。采用该法进行稻田土壤氮矿化的研究是可行的。淋洗液以0.02NKCl100ml+无氮营养液25ml为好。湖南省红黄泥土壤氮矿化过程可用双曲线方程,一级反应动力学方程和有效积温经验式模拟。三种方程均达0.01显著水准。红黄泥土壤氮矿化势No为56～104ppm N。氮矿化速率常数k为0.24～0.28。不同土壤氮矿化量的差异主要由No不同引起,与k关系不大。在影响土壤矿化氮量的几种主要理化性状中。碱解氮对矿化氮量的贡献最大。

The study was conducted by a new approach of sealed anaerobicincubation under 30℃ and intermittent leachings with 100 ml 0.02N KC1 and25 ml 'minus-N' solution. The results showed that the mineral N obtained bythis approach conformed to that determined by field soil under the same effectiveaccumulated temperature conditions, which indicated that the approach was feasi-ble. In the study, nitrogen mineralization processes of the soils under the incu-bation condition fited well with three equations, namely, hyperbolic, first-orderand effective accumulated temperature equations. Except for the N mineralizedduring first two weeks, nitrogen mineralization potentials(N_o)and rate constants(k) of the soils were 56~104ppm and 0.24~0.28 week^(-1) respectively. Differe-nces of the N mineralized between the soils were mainly caused by their Novariances. The N mineralized during incubation was correlated positively withthe total N, hydrolyzed N, organics and particles less than 0.005 mm in theoriginal soils.