A cranberry farm is often a semi-closed water system, where water is applied by means of irrigation and drained using an artificial drainage system. Cranberry bogs must be drained to the water level inside the surrounding ditches in order to maintain an optimal pore pressure within the root zone, which is important for a number of reasons. First of all, Phytophthara causing root rot are commonly associated with irrigation with contaminated surface water (Oudemans, 1999) and enhanced by waterlogging in the root zone (Roberts et al., 2005). Secondly, a deeper rooting depth increases the cranberry's chances of survival during periods of drought. Sufficient drainage early in the season helps to improve rooting depth (Sandler et al., 2004) because the vines extend their root network toward deeper soil layers where flushed nutrients accumulate. For these reasons growers report a generally better yield on bogs with tile drainage where excess soil water is removed through gravity-driven flow.

 

Timely irrigation and drainage are essential, and therefore a proper understanding of the relationship between irrigation and drainage is necessary to increase the production efficiency of cranberry farms. Current diagnostic tools for detecting drainage failure are mostly based on outflow from tile drains: when outflow decreases after a number of years as a result of clogging, drains are either cleaned or replaced. These methods are time-consuming and expensive because it is often necessary to excavate in order to find the tile drains.

 

In order to reduce the risk of crop disease related to waterlogging and optimize the cranberry production process, we here present an alternative diagnostic approach for detecting drainage failure based on the wavelet transform of hydrological time series obtained with soil column experiments. Wavelet transforms can be used to detect singularities in hydrological time series based on specific criteria, such as wavelet period, frequency, and change in the corresponding wavelet coefficient. Examples demonstrated in this paper are (i) wetting front instability characterized by variations in power response for short wavelets, (ii) long-term drifts that could point to specific characteristics of a laboratory experiment, or in the case of field data, weather conditions, and (iii) drainage failure characterized by a primary component in the CWT power response that shifts toward a longer wavelet period over the course of time.CWT power response that shifts toward a longer wavelet period over the course of time.

References:

 

Oudemans, P. V., 1999. Phytophthora Species Associated with Cranberry Root Rot and Surface Irrigation Water in New Jersey. Plant Disease 83 (3): 251-258. DOI: 10.1094/PDIS.1999.83.3.251

 

Roberts, P. D., Urs, R. R., French-Monar, R. D., Hoffine, M. S., Seijo, T. E. and McGovern, R. J., 2005. Survival and recovery of Phytophthora capsici and oomycetes in tailwater and soil from vegetable fields in Florida. Annals of Applied Biology 146: 351–359. doi: 10.1111/j.1744-7348.2005.040120.x

 

Sandler, H. A., DeMoranville, C. J., Lampinen, B., 2004. Cranberry irrigation management. Cranberry station Fact Sheet. Paper 12.