Spatial And Temporal Variability Of Soil Salinity And Its Relationship With Yield Under Conservation Tillage

Conservation tillage technology is beneficial to protecting the environment and restoring land productivity in black soil areas.In addition,Soil salinity,as an important index of soil physical and chemical properties,has been a hot topic in research.Therefore,it is necessary to study the spatial and temporal variation of soil salinity under conservation tillage in black soil region.Based on the black soil region at the corn as the research object,explores the different conservation tillage measures spatial and temporal variation characteristics of soil salt.In this paper,the spatial variation characteristics of soil salinity in different growth periods of maize under straw mulching were analyzed by traditional statistics,geostatistics and multifractal methods,the temporal stability characteristics of soil salinity under straw mulching were obtained by methods of cumulative frequency and mean relative difference.Then the correlation between soil salinity and yield components on a single scale and a multi-scale was obtained by joint multifractal methods.Variance analysis was used to study the variation degree of soil salinity in corn fields under different straw mulching and tillage methods,and to explore the dynamic chan ge of soil salinity with time and depth under different treatments.In order to grasp the spatial and temporal distribution characteristics of soil salinity in black soil area and provide a theoretical basis for the prediction of maize yield.The following conclusions are drawn:(1)Under the condition of straw mulching,the spatial variation degree of soil salinity in the growth period was moderate except for the tassel stage 0-20 cm soil layer.During the whole growth period of maize,the variation degree of soil salinity in 20-40 cm soil layer was higher than that in 0-20 cm soil layer.Except for the jointing stage,the average salinity of 0-20 cm soil was higher than that of 20-40 cm soil.The soil salinity in the 20-40 cm soil layer was strongly spatially correlated from jointing stage to grouting stage,while the soil salinity in different soil layers was moderately spatially correlated in other growing stages.In addition to the jointing stage and tassel stage,the spatial correlation range of soil salinit y in the 0-20 cm soil layer was 75.64 m.The spatial variation of soil salinity in 0-20 cm soil layer was caused by the high-value information,the spatial variation of soil salinity in 20-40 cm soil layer during the maize elongation and milk-maturity period was caused by the low-value information,and the spatial variation of soil salinity in the rest growth period was caused by the high-value information.(2)Under the condition of straw returning,the measuring points with higher soil salinity had lower temporal stability.The mean soil salinity of different soil layers in the study area can be estimated rapidly by using representative soil salinity measurements.(3)Under the straw mulching condition,soil salinity at 0-40 cm depth was significantly correlated with panicle grain weight on a single scale.In the multi-scale,the multi-scale correlation between soil salinity and yield components in the 0-40 cm soil layer was higher than that in the single scale;soil salinity in the 0-40 cm soil layer at the seedling stage,jointing stage,and filling stage was significantly correlated with cob weight and grain weight at multi-scale;soil salinity at jointing stage was significantly correlated with cob weight at multi-scale.On a single scale,the salinity time stability of 0-40 cm soil layer was significantly correlated with panicle grain weight.On multiple scales,the salinity time stability of 0-40 cm soil layer was significantly correlated with cob weight and ear grain weight.The multi-scale correlation between salinity time stability and yield components of soil was significantly higher than that of single scale.(4)Under different straw mulching amount and tillage methods,except CK treatment in 0-20 cm soil layer,the variation degree of soil salinity in other treatments was moderate.Straw mulching treatment can significantly reduce the variation of soil salinity in 0-20 cm soil layer.Compared with no-tillage treatment,traditional tillage treatment can significantly reduce the variation of soil salinity in 20-40 cm and 40-60 cm soil layers.Except for the 20-40 cm soil layer,the variation of soil salinity decreased with the increase of straw mulching.(5)The effects of different straw mulching and tillage methods on soil salinity decreased with the growth period and the deepening of soil.Straw mulching treatment can significantly reduce the soil salinity in the 0-20 cm soil layer during the sowing period,seedling stage,grouting stage and the 20-40 cm and 40-60 cm soil layers during most of the growth peri od.Compared with no-tillage treatment,the traditional tillage treatment can reduce the soil salinity during sowing and seedling stage,and increase the soil salinity during jointing and tassel stage.Under no-tillage condition,soil salinity in different soil layers decreased with the increase of straw mulch.Compared with bare land,straw mulching treatment can reduce the variation range of soil salinity with soil layer from sowing period to seedling stage,and increase the variation range of soil salinity with soil layer from jointing stage to maturity stage.Compared with traditional tillage,no-tillage treatment can increase the variation range of soil salinity with soil layer in the tugging stage and tasseling stage,but there is no significant difference in the other growth stages.With the increase of straw mulching,the variation range of soil salinity in maize sowing period and seedling stage decreased gradually with the soil layer,but there was no obvious pattern in other growth periods.