The Effect Of Mulching And Ridge Cultivation On The Water Use Efficiency Of Potato In Dry Land

The research mainly relied on field experiments using completely randomized block design for outstanding problems of drought and low production in arid area of central Gansu.The effects of different mulching cropping patterns on potato growth,yield,water use efficiency(WUE),and soil and environmental factors were studied;the optimal cultivation program was achieved initially.The specific results of this research are as follows:1.The potatoes covered by plastic film had latest emergence time,about 28-30 days,which was 12 days earlier than traditional farming;The emergence ratio of potatoes covered by plastic film was 1.06-4.88%higher than that of traditional farming,and the emergence ratio of potatoes covered by straw in autumn was 2.33%higher than that of traditional farming,although seedlings had a good potential growth;The growing period of potatoes covered by plastic film would shorten about 13 days,but straw had no impact on emergence time and quickening growing period.2.The plastic film could significantly increase soil water contents,the treatment of low ridge entirely covered by plastic film and ditch sowed potatoes in autumn or spring would make soil have a higher water storage capacity throughout the whole growth period, especially for soils of 0-40cm.The water storage capacity in 0-40cm soils increased by 30.09%-49.58%,33.51%-36.98%,21.59%-23.25%,20.80%-29.75%,50.03%-64.78%and 37.78%-38.54%respectively when soils covered by plastic film before sowing,at the seedling stage,in tuber formation,in tuber enlargement period and at the harvest time.But other treatments treated by plastic film were higher than conventional farming at seedling and harvest time,moreover,soils of 40-100cm covered by plastic film had higher water storage capacity at seedling time than traditional farming,and soils of 0-100cm covered by straw also had higher water storage capacity.3.The soil temperature of arable layer would rise when the potatoes were covered by plastic film.Covering potatoes with plastic film at 8:00am,the soil temperature of root layer was 0.38-2.04℃higher.If treated at 2:00pm,or at 8:00pm,others were 0.45-2.39℃or 0.42-2.71℃higher,except that treatments of low ridge covered by plastic and ditch sowed in autumn was 1.01℃or 1.11℃lower.All of the soil temperature per day was 0.42-2.39℃higher,except treatments were 0.39℃lower when the treatments of low ridge was covered by plastic and ditch was sowed by potatos in autumn,but straw would decreased soil temperature.4.Coverage plant could increase commodity rate of potatoes,the treatments of high ridge covered by plastic film and ditch covered by straw in spring had the best effect in all of the treatments,the number of the aerial main stem was 2.3,53.33%higher than the number of the aerial main stem in traditional farming land,the weight of potatoes per plant was 942g, 388g higher than potatoes planted though traditional methods.The number of big and medium potatoes were 3.2 and 2.1,respectively,which reached significant levels, comparing with potatoes planted though traditional methods.At the same time,about 48.48%and 31.81%were big and medium potatoes in all of the potatoes per plant, respectively,but only 66.67%was big and medium potatoes gained from traditional farming field.5.The water use efficiency of potatoes could be raised by covered planting.The treatment of high ridge covered by plastic film and ditch covered by grass in spring made the starch to be up to 5.4μmolCO₂/mmolH₂O at storage stage,which is 31.71%higher than traditional farming(4.1μmolCO₂/mmolH₂O).Water use efficiency in the level of production can up to 66.62kg/(hm₂.mm) which is 56.88 percent higher than traditional farming(42.46 kg/(hm₂.mm)),other treatments is all 9.36%-45.58%higher than traditional farming.6.The best combination of covered planting was the treatment of high ridge covered by plastic film and ditch covered by grass in spring.