Meta-analysis results on the wheat yields for five mulching practices, three rainfalls and four regions using the fixed or random-effects models.

Notes: FM: flat mulching; RFM: ridge–furrow mulching; WSM: wheat straw mulching; MTMC: mulching with two materials combined; MOM: mulching with other materials. K: the number of observations involved in each of the analysis levels including conventional tillage (CT). Several individual studies were excluded because their heterogeneities could not be eliminated.
* P < 0.05;
** P < 0.01.
Meta-analysis results on the wheat yields for five mulching practices, three rainfalls and four regions using the fixed or random-effects models.