Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/15/2008
Publication Date: 3/1/2008
Citation: Bryant, R.J., Anders, M.M., McClung, A.M. 2008. Effect of nitrogen application and crop rotation on rice grain quality. In: Proceedings of the 32nd Rice Technical Working Group Meetings, February 18-21, 2008, San Diego, CA. 2008. CDROM. Interpretive Summary:
Technical Abstract: Due to increased cost in rice production, some farmers are trying alternative ways of managing their farm in order to increase production and profit. Crop rotation and increased nitrogen application are two methods tried. Although increased nitrogen application is known to increase protein content and change the processing quality of rice, little is known about the effect of crop rotation and its interaction with nitrogen application on grain quality. Rice cultivars ‘Cybonnet’ and ‘Wells’ were grown in a field experiment near Stuttgart, AR. The rotation systems used were continuous rice (Oryza sativa L.) (R/R), rice after soybeans (Glycine max L.) (R/SB) and rice after corn (Zea mays L.) (R/C). Two fertility rates were used preflood (1) nitrogen (N) = 100 lb acre-1, phosphorus (P2O5) = 40 lb acre-1, and potassium (K2) = 60 lb acre-1 [standard rate] and (2) N = 150 lb acre-1, P2O5 = 60 lb acre-1, and K2 = 90 lb acre-1 [used as the high rate]. After harvesting, the seeds (rough rice) were cleaned, dried and milled and the milled samples were used to determine processing qualities, i.e. apparent amylose content, gelatinization temperature, protein content, lipid content, and pasting properties. As expected, the protein content increased with increased fertility. However, the protein for R/SB rotation was higher than that of R/R rotations. Apparent amylose content, gelatinization temperature, and lipid content were not affected by crop rotation or fertility but were influenced by cultivar. Peak and trough viscosity of the RVA profile were higher for R/R rotation than they were for the R/SB rotation. Increased fertility caused a decrease in all the RVA parameters other than setback 2, although the degree was different depending on crop rotation. The results of this study show that although fertility had an affect on grain quality, i.e. protein and RVA profile, crop rotation systems can determine the magnitude of the impact.