Effect of applying zinc fertilizers on rice yield in the cold and muddy paddy fields.

alargamiento del tallo allongement de la tige arroz caracteres de rendimiento composante de rendement crop yield deficiencia de oligoelementos espigueo fertilisation fertilizer application guizhou heading macollamiento paddy soils rendement des cultures rendimiento de cultivos rice riz stem elongation sulfate de zinc sulfato de cinc tallage tillering trace element deficiencies yield components zinc sulphate