| In order to explore the suitable cultivation mode of oil sunflower in the semi-arid area of Northwest China,this experiment selected the oil sunflower variety"Chi CY102"as the research object to explore the effects of different planting methods and nitrogen application rates on its growth,grain yield and water use efficiency.Three planting methods were set up in the experiment,namely,full film mulching ridges and film furrow sowing(Q),half mulching ridges and film furrow sowing(B)and traditional seeding without mulching(CK),and three levels of fertilization,respectively 0kg/hm~2(N0),120 kg/hm~2(N1),240 kg/hm~2(N2).In 2019 and 2020,a two-year field experiment study was conducted at the Doukou Experimental Demonstration Station of Northwest A&F University,and the following main results were obtained:1.The results of two years of planting are basically similar.With the advancement of the growth process,the oil sunflower plant height,stem thickness,dry matter,etc.are constantly increasing.The performance is best under the treatment of full mulching ridge and furrow sowing,followed by half mulching.Film ridge film furrow sowing,under the same planting method,when the nitrogen application rate is 120kg/hm~2,the agronomic indicators such as plant height,stem thickness,and dry matter reach the maximum value.Further application of nitrogen fertilizer will inhibit plant growth.The leaf area index first increased and then decreased with plant growth,reaching its maximum value 70 days after sowing.When the nitrogen application rate was 240kg/hm~2,it was higher than the leaf area index under other nitrogen application levels.2.The planting method has an extremely significant effect on the soil temperature at 10cm.When the oil sunflower was in the seedling and budding stage,the soil temperature showed the rule of"Q treatment>B treatment>CK treatment".Before and after the flowering period,the temperature difference gradually narrowed,and the temperature at the later stage of the growth period was"traditional seeding without mulching>film mulching".Compared with the flat cropping treatment,the ridge film and furrow sowing planting methods can effectively accumulate rainfall.The two-year test results show that the soil water content of 0-60 cm in each growth period of the oil sunflower shows the rule of Q treatment>B treatment>CK treatment,and as the amount of nitrogen applied increases gradually.The soil moisture content at 0-60 cm of the soil in the mature stage increased by 6.1%and 12.2%in 2019compared with the treatments B and CK in 2019,and increased by 2.8%and 7.4%in 2020.Under the nitrogen application level of N2 and N1,compared with N0,the amount of water decreased by 11.1%and 4.9%in 2019,and decreased by 8.7%and 5.3%in 2020.3.Oil sunflower yields the highest when 120kg/hm~2 nitrogen fertilizer is applied under the whole ridge mulching and furrow sowing,and the highest yields in the two years are2.73t/hm~2 and 2.55t/hm~2,respectively.Compared with CK treatment,Q treatment and B treatment increased by 24.7%-39.5%and 9.4%-37.2%at each nitrogen application rate.With the increasing application of nitrogen fertilizer,the phenomenon of yield suppression appeared.In 2019,oil sunflower seed yield N2 treatment decreased by 75.3kg/hm~2 compared with N1;in 2020,there will be plenty of rain,and the high-yield nitrogen application level will be N2,which is an increase of 18.4kg/hm~2 compared with N1.Compared with the flat cropping treatment without film mulching,the water utilization efficiency of the oil sunflower under the ridge film and furrow sowing treatment is higher.There is no significant difference between the Q and B treatments in 2019.In 2020,the rule of Q>B>CK was appear.Compared with the treatments of B and CK,the water utilization efficiency of oil sunflower under Q treatment increased by 4.7%and 26.1%in 2019,and increased by 11.6%and 49.4%in 2020.There are differences in water use efficiency under different nitrogen application rates,which is expressed as N1>N2>N0.Compared with N0 and N2,the water utilization rate under N1treatment increased by 3.9%and 4.1%in 2019,and increased by 9.1%and 0.4%in 2020.4.The ridge and furrow rain harvesting mode can increase the crude fat content of grains,and it will decrease with the increase of nitrogen application.In 2019,the level of N1 and N2will be reduced by 3.4%and 6.6%compared with N0,and by 2.3%and 1.7%in 2020..The proportion of oleic acid in fatty acids was the highest under Q treatment,followed by B treatment,while linoleic acid was the opposite.In 2019,the oleic acid content of Q treatment increased by 5.1%and 14.5%compared with B treatment and CK treatment,and increased by3.7%and 13.1%in 2020.In terms of nitrogen application rate,oleic acid and linoleic acid have the same law,and both decrease with the increase of nitrogen application rate.In summary,compared with the two treatments B and CK,oil sunflower under the Q treatment obtains higher yield and soil water use efficiency,and the appropriate amount of nitrogen fertilizer also increases these two indicators.From the perspective of grain quality,crude fat,oleic acid,linoleic acid,etc.all decrease with the increase of nitrogen application rate.Among them,the content of crude fat and oleic acid increases under Q treatment compared with B and CK treatments.Therefore,QN1 treatment is the most suitable cultivation combination when planting oil sunflower in the semi-arid area of northwestern China. |
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