Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2018
Publication Date: 12/7/2018
Citation: Mahan, J.R., Payton, P.R. 2018. Design and implementation of a rainfed matrix for cotton. Agriculture. 8(12):193. https://doi.org/10.3390/agriculture8120193.
Interpretive Summary: Rainfed crop production is becoming increasingly important. Rainfed cropping is potentially more complex than irrigated and is time consuming and often location specific. Since each year has its own rain pattern multiple years of experiments are needed to understand rainfed systems. In this paper we have designed and implemented a novel approach to understanding rainfed cotton production. The method uses multiple plantings and rain simulations in a single year to produce a rainfed matrix that increases the number of rain:crop interactions that can be investigated by 20-fold. This method may provide a means of significantly accelerating rainfed-cropping research efforts.
Technical Abstract: Global production of agricultural products must continue to increase if shortages are to be avoided. While irrigated production is substantial since water available for both current and future production is limited, rainfed production will become increasingly important. In-season weather variability results in instability in rainfed production and in order to gain information on the mechanisms involved and their potential mitigation, it is important to monitor production over a range of possible environmental scenarios. We designed and implemented a rain matrix experimental approach for cotton based on a series of sequential plantings coupled with a rain-simulation protocol. The rain matrix in 2 years produced 56 growing environments with rain and thermal variability and 44 yield:environment comparisons. The yield:rain relationship was not strong (R2=0.35) Analysis of heat units over the matrix indicated 1) heat units varied with planting date and 2) heat units were sufficient to achieve maturity. Plantings reached maturity with <1250 heat units and reached maturity before a lethal freeze. The rain matrix design increased the number of yield; environment comparisons in a single year and though it is subject to undefined thermal interactions, may prove useful in understanding rainfed cotton production.