耕作模式对河西绿洲灌区夏玉米农田土壤呼吸的影响

Effects of tillage patterns on soil respiration in summer maize field in Hexi Oasis irrigation area

以河西绿洲灌区夏玉米农田土壤为研究对象,设置免耕(NT)和传统耕作(CT)两种耕作方式,玉米间作小麦(W/M)、玉米小麦轮作(W→M)和麦后插播冬油菜还田玉米轮作(W-G→M)3种种植模式,探讨河西绿洲灌区不同耕作模式对夏玉米农田土壤呼吸变化特征的影响。测定夏玉米不同生育时期土壤呼吸速率、土壤温度和土壤含水量。结果表明:河西绿洲灌区不同耕作模式下夏玉米农田土壤呼吸有着明显的单峰型日变化,且峰值出现在15:00左右,玉米生育期峰值出现在拔节期(6月上旬)。土壤呼吸速率与土壤温度、土壤含水量均显著正相关,且土壤呼吸速率日变化主要受5 cm土壤温度影响。6种耕作模式的土壤呼吸的温度敏感性Q10值为1.60~2.70,免耕均高于传统耕作,且依次为NT W→M>NT W/M>NT W-G→M>CT W-G→M>CT W→M>CT W/M。河西绿洲灌区不同耕作模式下夏玉米农田土壤呼吸不仅受土壤温度影响,还受土壤含水量的影响。

In this experiment,summer corn field soil in Hexi Oasis irrigation area was selected as the research object.Two tillage modes were set,namely,no-tillage(NT)and traditional tillage(CT),and three planting modes were maize intercropping wheat(W/M),maize wheat rotation(W→M)and maize rotation(W-G→M)after wheat intercropping and winter rape returning to field.In order to investigate the effects of different tillage modes on the characteristics of soil respiration in summer maize fields in Hexi Oasis irrigation area,soil respiration rate,soil temperature and soil moisture content were measured at different growth periods of summer maize.The results showed that the diurnal variation of summer maize field soil respiration was obvious under different cultivation modes in Hexi Oasis irrigation area,and the peak value appeared at about 15:00,and the peak value of maize growth period appeared at jointing stage(early June).Soil respiration rate was positively correlated with soil temperature and soil water content,and the diurnal variation of soil respiration rate was mainly affected by soil temperature of 5cm.The temperature sensitivity Q10 values of soil respiration under six different tillage modes ranged from 1.60 to 2.70,and the values of no-tillage were higher than those under traditional tillage,in order of NT W→M>NT W/M>NT W-G→M>CT W-G→M>CT W→M>CT W→M>CT W/M.Soil respiration of summer maize field under different cultivation modes in Hexi Oasis irrigation area was affected not only by soil temperature but also by soil water content.