Effects Of Tractor Traffic, Soil Moisture Content, Tillage On Soil Properties And Growth Of Mechanized Sowing Wheat In Sichuan Hilly Areas

From 2011 to 2013, This study researched the effect of tractor traffic, soil moisture content, tillage on soil properties and growth of mechanized sowing wheat in Renshou county Zhujia townships Tashui village. The main results showed as fellows.l.The results showed that tractor traffic caused soil compaction, soil bulk density and mechanical resistance increased, thus soil porosity and water infiltration amount decreased. The difference of Soil compaction was significant under different soil moisture content condition. Under the condition of soil moisture content by 16.5%, tractor traffic mainly impacted the soil properties in 0-10 cm depth. Under 22.0% and 22.5% soil moisture content condition, tractor traffic mainly impacted the soil properties in 0-20 cm depth, but under 22.5% soil moisture content condition, the change values of soil properties parameters in 0-20 cm depth is maximum. Besides, the higher soil moisture content was, the earlier surface runoff of compacted soil appeared, and soil moisture content in 0-30 cm depth of 16.5%,20.0% and 22.5% soil moisture content treatments decreased significantly by 0.3,1.1, and 1.8 percent, respectively.2.Tractor traffic had no effect on seeding rate and the peak tiller number of mechanized sowing wheat, but tillering time was delayed, percentage of fertile tiller and effective spike number decreased. With soil compaction, wheat seeding quality was weaken significantly. Root length, activity and surface area decreased, root average diameter increased, plant height, leaf area, dry matter and R/S decreased, yield was decreased significantly. The difference of effect of tractor traffic on mechanized sowing wheat growth under different soil moisture content was significant, tractor traffic had little influence on wheat growth and yield under 16.5% soil moisture content condition. However, after soil moisture content rose to 20.0% or 22.5%, tractor traffic caused the significant reduction of the dry matter accumulation, effective spike number,1000 grains weight and grain number per ear. Finally, grain yields of 20.0% and 22.5% soil moisture content treatments decreased by 8.7% and 11.8%, respectively.3.The quality of mechanized sowing wheat was significantly different under different soil moisture content and tillage. Under 16.6% and 19.4% soil moisture content condition, the covering acceptability and seeding uniformity were improved, uncovered seed rate was lowed. Under 22.9% soil moisture content condition, the covering acceptability and seeding uniformity were decreased, uncovered seed rate was increased. With soil moisture content risen, The emergence speed and seeding rate of wheat was improved. The difference of seeding rate under 19.4% and 22.9% soil moisture content was not obvious. Tillage had no effect on seeding uniformity and seeding rate. Compared with no-tillage, the covering acceptability of tillage was increaseed, the uncovered seed rate of tillage was reduced under the same soil moisture content.4.Under the condition of little rain after seeding, The initial soil moisture content was the important factor effect soil moisture content during seedling period. Compared with tillage, no-tillage could improve soil moisture content. In the process of mechanized sowing wheat growth, There was an obvious influence on the growth of wheat seedlings with soil moisture content risen. Compared with rotary tillage, the growth of wheat has obvious advantages under no-tillage condition. In terms of the ground part, the tillering ability, population, height, leaf area of seedling were increased significantly with soil moisture content form 16.6% to 22.9%. The value of seedling leaf SPAD increased significantly under 22.9% soil moisture content condition. The tillage had no effect on height and SPAD of seedling, but no-till made the tillering ability, population, leaf area of seedling increased significantly. In terms of root architecture and function, With soil moisture content risen, The root length, activity and surface area of seedling increased. The root length, surface area, root diameter, root activity of seedling grown under no-till were significantly higher than rotary tillage. In addition, with the soil moisture content rasen, the dry matter weight of root and shoot increased, R/S decreased. The no-till could enhance synthesis of root and shoot dry matter, but had no effect on R/S.5.The yield variance mainly caused by the difference of spike number and grain number per spike under different soil moisture content and tillage condition. With the soil moisture content rasen, the spike number and grain number per spike significantly increased, the yield increased. Compared with rotary tillage, The no-till lead to the spike number, grain number per spike and yield of wheat increased by5.6,2.7, and 8.8 percent, respectively.In conclusion, The tractor traffic, soil moisture content, and tillage had significantly influenced on growth of mechanized sowing wheat in Sichuan hilly areas. In order to ensure normal growth and quality of mechanized sowing wheat, reduce the soil compaction caused by tractor traffic, the no-till planting should be applied under soil moisture content about 19.4% condition, and supplemental irrigation based on rainfall after seeding.