保持有效的水分供给，是植树成活的关键。传统的植树方法是将树苗栽好后，在地面上做一土盘，然后浇水于土盘中，从而湿润苗木根部土壤。这一方法在群众性造林生产中，常常是土盘太小，浇水太少，容易形成造林成活率偏低。 坐水返渗法是将树苗（裸根苗）根系直接接触到湿土上， Maintaining an effective supply of water is key to planting trees. The traditional method of tree planting is planting the saplings, making a soil plate on the ground, and then watering the soil plate, so moist seedling root soil. This method in mass afforestation production, often too small soil, watering too little, easy to form a low survival rate of afforestation. Sit back to the water law is to saplings (naked root seedlings) root direct contact with the wet soil,