Returning straw into field
Rice straw returning into field
Returning straw into soil
returning wheat straw to soil
Total wheat straw returning
wheat straw returning soil
incorporation straw into field
ditch-burying straw returning
no-tillage with straw returning
rate of returning field
Returning crop straw into soil
returning into forest and grass in steep slope land
Returning of wheat straw to field
returning stalks into field
Returning straw to field
returning straw to field directly
returning straw to land