Meta-analysis of the effect of minimum tillage and no-tillage on wheat yield in Iran's rainfed conditions

Author

1- Department of Agricultural Engineering Research, Hamedan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension organization (AREEO), Hamadan, Iran.

Abstract

The effect of different tillage methods on wheat yield in Iran's dryland conditions has been investigated in several studies. Most of the conducted studies only cover a small area (field experiments in one area), which in some cases have contradictory and incomplete results. The purpose of this research is to investigate the effect of conservation tillage (reduced tillage and no tillage) on dryland wheat yield using domestic studies with meta-analysis method. For this purpose, articles, research reports and student thesis between 1991 and 2021 were reviewed using key keywords related to tillage in the dryland wheat. Finally, after quality control, 29 studies were selected to compare minimum tillage method with conventional tillage and 22 studies were selected to compare no-tillage with conventional tillage using a random model. Based on the results, according to the effect size in the method of minimum tillage (SMD = +0.42) and no tillage (SMD = -0.43), it can be concluded that the minimum tillage method has increased wheat yield (+1.44%) and no-tillage method has decreased wheat yield (-7.7%) compared to conventional tillage method. It is suggested in dry lands, that one of the minimum tillage methods includes: 1- plowing with combinated tiller (chisel plow equipped with roller), 2- plowing with chisel-packer and 3-plowing with chisel plow + disk should be used instead of the conventional tillage (moldboard ploughing + disc + leveler) by observing plant rotation.

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