Submitted to: Journal of Sustainable Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2006
Publication Date: 11/1/2007
Citation: Miller, H.B. 2007. Poultry litter induces tillering in rice. Journal of Sustainable Agriculture. 31:151-160. Interpretive Summary: Poultry litter is used as a soil amendment for numerous crops, including rice. While it is known that rice yield is improved by poultry litter, little study has been made to identify the specific growth parameters that are altered. Poultry litter's effects are highly variable in field studies and effects can be seen with numerous parameters such as the crop, condition of the poultry litter, application time, etc. A small-scale, controlled system in the greenhouse to study poultry litter effects would be valuable to reduce the variability encountered in field studies and to separate major from minor factors in poultry litter effectiveness. Early on, we found that tiller (shoot) numbers of rice plants increased in the presence of poultry litter. Tillering is an important trait for grain production as each tiller develops eventually into a seed panicle, and is thereby an important aspect of rice yield improvement. The beneficial effects of poultry litter have traditionally been ascribed to its nutrient composition. However, we have found that the tiller number of plants grown in poultry litter along with complete fertilizer exceeds that of plants grown with fertilizer alone. Thus, poultry litter appears to contain a factor in addition to any fertilizer components that improves rice growth by inducing tillering. A far greater number of tests of the effects of poultry litter on rice growth in the greenhouse can be done in a year since tillers can be counted much earlier than waiting for final yield numbers. As the genetic controls for tillering are not understood, poultry litter then could also be valuable as a triggering mechanism for genetic and biochemical studies of this phenomenon.
Technical Abstract: Poultry litter (PL) is used as a soil amendment for numerous crops including rice (Oryza sativa L.). While it is known that overall rice growth and yield are improved by the addition of PL to the soil, tiller number is here identified as a specific parameter that is increased by PL. The application of either PL or inorganic fertilizer to the soil increases tiller number, but the combination of PL and fertilizer results in a synergistic increase in early tillers. The increased number of early tillers is comparable to the number of seed-bearing panicles produced. The synergistic induction of early tillers is seen across rice cultivars and across PL sources indicating that the induction of rice tillers is chicken-derived.