Influence of herbicides-pyroligneous acids mixtures on some soil properties, growth and grain quality of paddy rice

The influence of herbicides-pyroligneous acids mixtures on soil chemical properties, growth and grain quality of paddy rice (Japonica cv. Ilpum) was evaluated in a field experiment. There were thirteen treatments including control (hand weeding), 100% and 50% application rate of three herbicides: Azimsulfuron+cafenstrole (AC), Mefenacet+pyrazosulfuron-ethyl (MPE) and Betazone+cyhalofop-butyl (BCB) and 6 combination of three types of herbicides at 50% recommended rate (RR) diluted with two types of pyroligneous acids: wood vinegar (WV) and rice vinegar (RV) at 500× dilutions; laid out in randomized complete block design with four replications. Results showed that lower application rate of herbicides combined with WV or RV gave a comparable effect in controlling weeds and on plant growth and chlorophyll content with their respective 100% RR application rate. Among different treatments, 50% AC + WV increased the number of spikelet per panicle and improved the grain quality compared to 100% AC. Treatment 50%MPE+RV decreased the spikelet number per panicle while 50% BCB+WV also reduced spikelet number per panicle, total protein content, and whole grain yield. After harvest, soil acidity, organic matter (OM), available P and EC increased due to treatments application. Overall, depending on the herbicide type, mixing 50% RR of herbicides with 500× of RV or WV dilutions can effectively control the weeds in paddy rice such as Echinochloa crusgalli, Monochoria vaginalis and Scirpus juncoides without suppressing the growth, and yield of rice with acceptable soil impacts that promotes environment health. © 2015 Friends Science Publishers.