Study On Proper Sowing Date And Plant Density Of Wheat Grown On Coastal Saline Alkali Land

There are large area of saline-alkali land especially in the coastal area in Shandong Province,in which about 20%of the province's wheat was produced.With the decrease of cultivated area,the increasing population and the shortage of fresh water resources,how to utilize the large-area saline-alkali soil resources is an urgent problem to be solved urgently.In this study,the effects of Xiaoyan 81 on seedling growth,seedling sprouting,and yield of wheat in salt-alkali soil were studied.Three sowing date(October 3,October 13,October 23)and three plant density(2.25 million/hm,3.75 million/hm2,5.25 million/hm2)were designed.Dry matter accumulation and allocation,grain yield and yield components and saline-alkali soil salinity were analysised.The optimum sowing date and planting density of wheat were discussed in order to provide theoretical basis for simplified cultivation of high yield of wheat in coastal saline-alkali soil of Yellow River Delta.The main findings are as follows:1.The sowing date and planting density of wheat had significant effect on soil salinity.The soil salt content(0-10cm and 10-20cm)increased with the delay of sowing date under the same planting density.Under the same sowing date,the content of soil salt(0-10cm and 10-20cm)gradually decreased with the planting density increasing.There was an interaction effect between sowing date and planting density on the effect of soil salinity.The effect of sowing date on soil salinity was different under different planting densities.The soil salinity increased with the delay of sowing date,and there was no significant difference after flowering.Under the same sowing date,the soil salinity decreased with the increase of planting density in the whole growth period.Therefore,the appropriate increased in planting density to improve soil coverage is to effectively reduce the upper soil salt content of effective measures.2.Sowing date and planting density had significant effects on population size and dry matter accumulation and distribution of wheat.Under the same sowing date,the stem number,leaf area index(LAI)and dry matter accumulation amount of the treatments increased with different planting densities at the turning green period,jointing period and flowering period.Under the same condition,with the delay of sowing date,the stem number,leaf area index and dry matter accumulation of each treatment had a tendency to decrease during the turning green,jointing and flowering period,The effect of accumulation is greater than the planting density.There was a significant interaction effect between sowing date and planting density on the effects of population size and dry matter accumulation and allocation.With the delay of sowing date,the harvest index decreased,the planting density had little effect on it.With the delay of sowing date the planting density had a great influence on the harvest index but the effect rule was inconsistent.There was a trend of increasing first and then decreasing with the planting density increasing.3.Sowing date and planting density had significant effect on wheat yield and yield components.The effect of sowing date on the yield of wheat was obvious,and so was the yield of 1000-grain weight was significantly affected by late sowing.From the perspective of planting density,the appropriate increase in planting density can effectively improve the number of spike,and therefore the wheat yield increases with the planting density.4.The yield of T2D2 treatment and T3D3 treatment was the highest,which indicated that increasing the planting density by delaying the sowing date could effectively reduce the salt content in the upper layer and increase the wheat yield.Saline-alkali wheat can be sown on October 13,suitable for planting density of 3.75 million/hm2.If sowing later,increasing the planting density,can still get high yield.