Assessment of weed suppression and straighthead occurrence in plastic mulched and high seed rate water seeded rice under organic condition

Authors: HUANG, BIHU - University Of Arkansas At Pine Bluff; MAHATO, GENA - University Of Arkansas At Pine Bluff; McClung, Anna; ZHOU, XIN-GEN - Texas A&M University

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/4/2019
Publication Date: 1/6/2021
Citation: Huang, B., Mahato, G.R., McClung, A.M., Zhou, X. 2021. Assessment of weed suppression and straighthead occurrence in plastic mulched and high seed rate water seeded rice under organic condition. Proceedings of 38th Rice Technical Working Group Meeting Proceedings, February 24-27, 2020, Orange Beach, Alabama. p 134. Electronic Publication.

Interpretive Summary:

Technical Abstract: Weeds are a major yield limiting factor in organic rice farming and are more problematic than in conventional production system. The lack of effective weed management methods for organic rice growers is the main barrier for expansion of organic rice production in the US. Weed competitive rice varieties were selected for measuring the effectiveness of weed suppress using water seeding, plastic mulching, cover cropping and crop rotation in organic production system, as the potential weed management methods for organic rice farming. Water seeding experiment 2016: A mixter of crimson clover and winter wheat was planted in fall of 2015 and terminated in spring 2016. Fifteen rice varieties were water seeded one month after termination of the cover crop to observe the weed competitiveness of rice varieties. Rice varieties were planted in RCBD design with four replications. Cover crop planning 2017: In fall 2016, mixture of crimson clover + ryegrass and crimson clover + oat was planted in separate section of the field and terminated in the spring 2017. Plastic mulch trial 2017: After termination of crimson clover + ryegrass in spring 2017, plastic mulch trial was conducted using six rice varieties mapped in CRD with four replications and were planted at 15cm x 30cm distance. High seed rate water seeding trial 2017: After termination of mixture of clemson clover and oat in spring 2017, another separate experiment was conducted where 10 rice varieties were water seeded at two high seed rate of 224 kg/ha and 448 kg/ha. Five rice varieties were selected for separate study which were also used in plastic mulch trial. Plastic mulch trial 2018: In spring 2018, plastic mulch trial was conducted using six varieties used in previous year 2017 after the termination of ryegrass planted in fall 2017. Rice varieties were planted at 15cm x 25cm using RCBD with five replications. After data analysis, high seed rate water seeding was effective in suppressing the weeds. However, no yield benefit was obtained because high seed rate resulted high intraspecific competition between rice plants leading to high straighthead score and low yield. Water seeding is effective and current popular method of weed suppression in rice. Plastic mulch was very effective suppressing the weeds during whole growing season of rice.