Dynamics Of Leaf Traits Of Spring Wheat And Their Response To Soil Water Content In Loess Hilly And Gully Region Of Central Gansu Province

Soil and water loss in agricultural land has more and more influence on agricultural production and people's lives,especially on the agricultural production on the Loess Plateau.Spring wheat,as the main dense planting grain crop in the Loess Hilly and gully region of the Loess Plateau,determines the surface coverage and plays an important role in soil and water conservation in the farmland.In order to reveal the dynamics of leaf traits in spring wheat and the response to soil water content,this paper uses the correlation analysis and regression analysis to study the changes of leaf traits and the effect on soil moisture content in the study area,using the data of water control leaves in the Dingxi area of Anjiapo Valley in 2017.The conclusions are as follows:(1)The dynamics of leaf characteristics of spring wheat showed that the number of leaves decreased from the jointing stage,the number of leaves decreased faster in jointing stage and booting stage,and the amount of leaves was not related to the amount of water at the same growth period.During the whole growth period,the dynamic changes of leaf area,leaf area index and specific leaf area of different irrigation treatments in spring wheat were all single peak curves.The maximum value appeared at the booting stage,which were 27.19 cm~2,0.641 and 332cm~2·g-1respectively.The appropriate irrigation in the tillering stage was helpful to increase the number of leaf area,and the irrigation was 100 mm as appropriate and too much.It is not beneficial to the increase of leaf area index.(2)The correlation of leaf traits showed that the leaf length,leaf width,leaf area,dry weight and leaf area index showed significant positive correlation,that is,when the leaf area index increased,the leaf length,leaf width,leaf area and leaf dry weight also increased.The specific leaf area was negatively correlated with leaf width,leaf area,leaf fresh weight and leaf dry matter content,and the ratio of specific leaf area to leaf dry matter content was negatively correlated.(3)The maximum leaf area index and growth season leaf area index of spring wheat under W2 irrigation were the largest.The leaf area index growth rate of spring wheat under the jointing and booting stage of W2 irrigation was the largest,and the decrease rate of W1 irrigation was the largest during the booting and flowering stage.(4)Through the analysis of leaf traits and soil moisture content of 0-40 cm,the results showed that the growth of spring wheat was sensitive to 0-40 cm soil moisture.From tillering to senescence,soil water content significantly affected the leaf traits of spring wheat,but the response of different traits was different.In the water regulation stage,the increase of soil water content at 0-40 cm promoted the leaf area expansion and the specific leaf area.In the tillering and jointing stage,the leaf thickness increased and the leaf water content increased,but the leaf area index increased and the leaf dry matter quality accumulated.In the jointing and flowering period,the leaf thickness,leaf area index and leaf water content decreased with the increase of 0-40cm soil water content;in the flowering and mature period,with 0-40.The increase of soil water content in 0-40cm promoted the increase of leaf thickness and the expansion of leaf area index,but inhibited the accumulation of dry matter and the increase of leaf water content.