The definition of conservation tillage
The international definition：The conservation tillage is a farming technique that uses plenty of straw stubble to cover the surface, and reduced residue while farming to ensure seed germination. The pesticides are mainly used to control weeds and pests. In the past,conservation tillage is called "no-tillage",but with the in-depth study and the expansion of promotion,it is found that no-tillage is only appropriate for part of soil and the natural conditions,so it is renamed conservation tillage after 1980.Meanwhile,as it is conducive to the protection of soil,it is called conservation tillage.
In 2002,in order to make the majority of the peasants to understand easily,according to the contents and objectives of conservation tillage,the China’s Ministry of Agriculture defines conservation tillage as“It is an advanced farming techniques that implements no-tillage、minimum tillage on the farmland and uses crop straw to cover the surface,reduces wind erosion and water erosion,improves soil fertility and drought resistance”.
The principle of conservation tillage
Conservation tillage cancels mouldboard plow tillage to minimize tillage.
How does it accomplish its loose soil cultivation,weeding and other basic tasks?
It can use herbicides spraying to weeding and take deep fertilization.
How to loosen the soil?In order to make the soil water,fertilizer,gas,heat exchange flow smoothly to meet the crop needs,the following are the main four ways(Fig.1):
①Roots loosen the soil:After the crop root rot,leaving behind a large number of pores,the time longer the channels more.But once tillage,all will be damaged.
②Earthworm loosen the soil:Earthworm tap the pore,porous soil,to create a good topsoil
③Structure loosen the soil:Conservation tillage increases soil aggregated structure and it is conducive to form a stable loose topsoil.So the soil will be not compacted easily.
④Swell-shrink loosen the soil:The soil freezes in winter and melts in spring,so the humidity and dryness exchange alternately that tends to loosen the soil and increases porosity.Thus,conservation tillage is different from the conventional tillage.Conventional tillage can rely on machinery,physics external means to loosen the soil immediately. However,the loose soil will continue to be compacted or natural back to hard so it needs regular farming in order to maintain the state of looseness.
Loose soil of conservation tillage does not need external forces and is a slow,natural process.However,after the formation of loose soil it can naturally restore and maintain loose and does not need to re-farming.On the contrary,during this time such ploughed fallow,rotary tillage and other operations will hamper and even undermine the process of loose soil.