Critical irrigation threshold and cranberry yield components
Yield components are useful for characterizing the impact of crop management parameters on cranberry yield and are known to be influenced by irrigation management. This study was conducted to evaluate the potential contribution of cranberry yield components to maximizing yield, and the influence of the soil water tension threshold used to initiate irrigation (SWTI) on those components. During the 2011 and 2012 growing seasons, tensiometers were installed at three production sites in Quebec to test SWTI values ranging from 5.5 to 10.0kPa. Sites were cropped to cranberries to evaluate the impact of these irrigation treatments on yield components. The four most important cranberry yield components related to final yields were, in order of importance, the number of marketable berries per quadrat (BM/Q), the number of uprights per quadrat (U/Q), the number of marketable berries per upright (BM/U), and the marketable fruit set (BM/F). Significant reductions in BM/Q, BM/U and BM/F were observed when SWTI varied from 8.5 to 10.0kPa while a reduction in U/Q was associated with a SWTI of 5.5kPa. A SWTI ranging from 7.0 to 8.0kPa significantly improved the principal yield components.
Water table level management as an irrigation strategy for cranberry (Vaccinium macrocarpon Aiton)1
Abstract: Cranberry production is a water intensive practice that requires irrigation during summer months to achieve maximum yields. Previous studies have found that root zone tension maintained between -4 and -7.5 kPa allows for maximum yields without over irrigating. The present study looks at the effects of managing a water table to supplement overhead sprinkler irrigation with upward flow. Two drainage systems, controlled and free, were implemented in a cranberry bed constructed of fine sand. The controlled drainage system used existing drain tiles and a sump to maintain an artificial water table, while the free drainage system had no manipulation of the water table. Daily upward flow and water table level were measured in four locations, across the length of the bed, for each drainage system. Comparing upward flow with evapotranspiration (ET) rates, approximately 30% of maximum daily ET can be met by holding a water table between 500 and 600 mm. Numerical simulations indicate that water tables shallower than 500 mm allow for nearly full supply of ET, but at root zone soil water tensions too wet for the best productivity. Field results and model simulations indicate that water table management can be a useful tool in cranberry irrigation.
Fast seismic data compression based on high-efficiency SPIHT
Based on the set positioning in hierarchical tree (SPIHT) algorithm, fast seismic data compression based on the high-efficiency SPIHT (HESPIHT) algorithm is presented. To verify the validity of the algorithm, 10 seismic cross-sections are selected for the experiment. The result shows that the algorithm can reserve the quality of data better, meanwhile improving the efficiency of encoding and decoding.