Adoption of reduced tillage in dryland regions of northern Iraq and Syria

摘要

The agro-ecologies of recent cropping systems in the dryland areas of the Middle East have many similarities to those which prevailed prior to the 1970s in southern Australia.Over the past 50 years Australian farmers have eliminated fallow phases,introduced new crops(e.g.grain legumes,canola),and most importantly,adopted reduced or zero-tillage(ZT)technology which enables earlier sowing,and allows retention of residues from previous crops on the soil surface.During 2005-2012,as part of an ACIAR-AusAID-funded project developing conservation cropping for Iraq,more than 40 adaptive research experiments investigated the suitability of elements of the Australian cropping system to northern Syria and Iraq.It quickly became evident that ZT seeding without prior ploughing produced similar or better crop growth and grain yields than the conventional tillage(CT)system requiring two or three cultivations before sowing.The elimination of ploughing also enabled earlier sowing which resulted in improved water use efficiency and significant yield increases in cereals and legumes in most years.More accurate seed placement and metering with ZT seeders meant seed rates could be reduced.Most imported ZT seeders are heavy,expensive,and complicated to use and maintain,so a number of simple,effective and affordable seeders suitable for small farmers were manufactured in Syria,while in northern Iraq,the focus was on conversion of existing conventional seeders to ZT using parts made locally.Participatory extension groups were established in Iraq and Syria whereby farmers were able to borrow a ZT seeder to test on their farm without making or receiving any payment.In the vast majority of cases,farmers yields were as good,if not better,with the ZT and early sowing system than with fields sown conventionally,and farmers benefited from savings in fuel and labour costs because of the elimination of tillage operations and reduced seed costs.Since 2006/07,the area under ZT has grown from zero to about 30,000ha in Syria and 7,800ha in northern Iraq in 2011/12.Future challenges for conservation agriculture(CA)in this region include the promotion of soil cover and diverse rotations.