Study On The Effects Of Agronomic Measures On The Newly Reclaimed Saline-alkali Wasteland Of The Irrigation Area Along The Yellow River Of Gansu Province

The irrigation area along the Yellow River plays a very important role in economicdevelopment of Gansu. But saline land exploitation, secondary salinization preventionand the unreasonable utilization of water resources has been one of the key factors torestrict the development of agriculture.Therefor, the soil management and efficientirrigation play a core role in our study,and make a big research on soil salinizationcauses, types, distribution, extent and mechanism under the condition of modernagricultural technology.and puts forward the countermeasures and suggestions ofutilization and improvement.It can be improve the irrigation area of saline alkali landproduction capacity in effective way.There is a theoretical value and realistic meaning inpromote the local agricultural production.In this article the author based on thecomparison and analysis on differences in distribution,with newly reclaimed salinityland, the soil salinity after planting3a and6a,PH and characteristics of saltions.investigate the changes of Soil Salt chemical properties in different planting yearsin comprehensive amelioration condition.In order to solve these problems, the five fieldexperiments had been conducted in Jingtai village, Beitan town, Jingyuan county ofGansu province (37°05′N,104°40′E), the typical area of saline alkali soil in high liftirrigation district of Yellow river in Gansu province, to reveal the effects of differentagricultural methods on soil salt movement, ratio of desalinization and crop productivity.Based on these works, the harness effect of different agricultural methods on soilfertility, soil desalinization, and crop yield would be understood, further to investigatethe usage and management strategy on the salt soil. The main results are below.(1)After planting3a and6a salin on the land0~100cm,the content of Cl-, SO42-,Ca2+, Na+were significantly lower,It show that soil environmental quality has graduallyimproved.Due to a variety of ion migration is different.it lead to the each ion on relativecontent and chemical type has changed.By SO42-·Cl-—Na+type gradually transformedinto Cl-·SO42-—Ca2+·Na+, and has a trend to transform into SO42-—Ca2+.(2) Water saving irrigation technology have effect on conservation of waterresources, the control of soil salinization. When flood irrigated amount increased from300m3/mu to500m3/mu, the content of soil salt in plough layer decreased by2.0-17.2%in flat planting field, by12.5-706.0%in the ridge planting and furrow irrigation field, and the salt accumulated in the deeper soil profile. The saltion elutedbeneath100cm soil profile where flood irrigated amount reach to500m3/mu. Therewere significant effect of different irrigating methods on maize height in jointing stage,the ridge-furrow was significantly higher than flat planting by9.15%～46.79%,the corngrain yield were up19.1%~23.6%,8.4%~12.4%,under the same irrigated amount. Inour study,ridge with plastic film mulching-furrow irrigation has established the coretechnology in Gansu irrigation area along the yellow light moderate saline alkaliwasteland utilization efficiency,The quota for reasonable planting maize irrigation is450m3/mu.(3)Soil cultivation play a role in regulation of soil salt distribution.the obvious saltaccumulating layer was observed in traditional tillage, this would limit the cropdevelopment. The straw return to field, deeper tillage increased desalinization rate by12.2%-778.8%,67.9%-378.8%, as compared with traditional tillage. The desalinizationof ridge planting and furrow irrigation was better than flat planting in0-40cm soilprofile. Base on the better salt desalinization, the different tillage methods increasedcrop yield significantly, the sequence is deeper tillage, straw return to field and ridgeplanting and furrow irrigation, the corresponding maize yield were39.35%,22.4%and12.4%, the significant difference were observed.(4) Ground covers have effect on inhibiting salt, increasing yield and temperature,soil moisture.The salt accumulation appeared in0-20cm profile where without mulch.However, the mulch inhibited salt accumulation in0-10cm and10-20cm soil profile.Especially, the5cm thick fine sand, whole surface plastic mulch, half plastic mulch,and6000kg straw mulch per ha, decreased the salt content in0-100cm soil profile. Themulch affected the height of oil sunflower significantly, the highest height wereobserved in5cm thick fine sand mulching treatment, reached to67.3cm, and thenwhole surface plastic mulch,2cm thick fine sand mulching, and8cm thick fine sandmulching treatment. Although the lower height of oil sunflower appeared in half plasticmulching treatment, was higher than CK significantly. The lowest height of oilsunflower was observed in straw mulch treatment. In whole surface plastic mulch,thecorn grain yield is highest, the yield increased by62.5%-117.39%than CK;Followedby5cm thick fine sand mulching, the yield increased by53.4%-111.3%than CK,the height of oil sunflower of3000kg straw mulching treatment is lowest by38.4%-40%.By considering the index factors of the soil salt movement,desalting effect,cropyield and nutrient uptake.In the study of water saving efficiency,make sure the ridgeplanting is the best treatment model.and the reasonable irrigation is450m3/mu.In adifferent way of covering,the5cm thick fine sand and the whole surface plastic mulchis the best way.In different cultivation measures,the ridge planting can be used becauseof the stability and the minimum of coefficient.