Effects of Two Straw Return Methods Coupled with Raising Ducks in Paddy Fields on Stem Lodging Characteristics

Lodging has a negative effect on rice production and leads to a great loss in yield and quality. It is necessary to clarify the effects of straw return measures coupled with rice-duck co-culture on lodging and to explore a measure that can improve lodging resistance. A randomized block experiment with six treatments (rice monoculture (RNN), rice-duck co-culture (RND), direct straw return and rice monoculture (RSN), direct straw return coupled with rice-duck co-culture (RSD), straw carbon and rice monoculture (RBN), and straw carbon coupled with rice-duck co-culture (RBD)) was conducted to investigate the mechanism of the change in lodging resistance. RNN’s rice yield was 6258.02 kg ha −1 . The yield of RND, RSN, RSD, and RBN increased by 15.51, 3.06, 10.23, and 1.59%, respectively, while RBD decreased by 5.01% relative to RNN. Direct straw return and straw biochar return coupled with rice-duck co-culture has both negative and positive effects on lodging resistance because of its properties. The stem’s mechanical properties were mainly decided by weight, length, plumpness, and culm anatomy. The increased bending moment at breaking, lodging strength, and bending strength with the RND, RSN, RSD, RBN, and RBD treatments increased, indicated an increase in lodging resistance. Our results clearly demonstrate that direct straw return and straw biochar return coupled with rice-duck co-culture could increase the lodging resistance. In total, rice-duck co-culture could increase the lodging resistance with a higher yield. Compared to straw biochar application, straw return can stabilize the yield and improve the lodging resistance of rice. Thus, direct straw return coupled with rice-duck co-culture should be explored for improving lodging resistance under the condition of ensuring yield.