The Summer of 27: A Look at Niagara By Wayne Heinen (maps generated by Piper McKinnon)
OVERVIEW The summer of 27 was yet another challenging growing season. One look at the inch-wide cracks in the soil, the lack in fruit size, and the substantial number of sunny days and everyone would concur with Niagara growers that it was a dry growing season. Indeed, the Niagara region fell much below the 3-year normals for rainfall this summer. The following maps show how monthly rainfall accumulation, from May through September, was consistently well below normal. The growing season got off to a dry start, as May and June were especially dry. July shows a bit of relief, as values are closer to average. However, even the total rainfall for July was well below average for all of Niagara. The remainder of the summer continued to be extremely dry. The lack of rainfall in the Niagara region this summer led to one certain conclusion: those who had access to water for irrigation were thankful for that option. If you were privileged enough to have access to water this summer, you may have managed to prevent serious losses, although smaller fruit was likely still the outcome. Niagara s farmers definitely experienced lower yields this year. On the positive side, however, the lack of days with rainfall led to much lower disease pressures. This was a warm welcome compared to the contrary conditions in 26. All growers found relief this year compared to the extremely high disease pressures last year. This is no surprise, as fungal disease development is driven by leaf wetness and temperature. In other words, during periods of leaf wetness, the temperature determines how fast the disease infects the plant. The lack of rain this summer led to less leaf wetness hours, inhibiting mildew development. Therefore, although the lack of rainfall was unfavorable to high yields in 27, less fruit was lost to disease.
Temperature Analysis ANALYSIS The following chart illustrates that the lack of rainfall coincided with consistently higher daily maximums. On average, for each NAWN location, maximum daily temperatures were higher than the 3-year normal for the entire summer. Overall, May, August and September average daily maximums were 2-4 C higher than normal. June daily maximums were much hotter than normal, by approximately 4-5 C. July was the closest month to normal, although still slightly above average. Higher-than-normal temperatures are depicted in red in the following tables, while lower-than-normal temperatures are shown in blue. Average Daily Maximums for May- September Compared to Normal May June July Aug Sept Normal (Vineland Station) 17.8 23.1 26.5 25.1 2.9 Grimsby 2.6 27.6 27.6 28.5 24.6 Beamsville 2.9 28.3 27.6 28.6 24.3 Vineland Cherry Ave. 2.4 27.5 27.1 27.6 24.3 Vineland Escarpment 2.7 27.2 26.7 27.7 23.8 Jordan Hwy 8 2.9 27.5 27. 28.1 24.3 Jordan Escarpment 2.8 27.5 26.6 27.6 23.6 West St. Catharines 21.8 28.2 27.4 28.4 24.7 Niagara College 21.4 27.6 27.1 28. 24.4 Virgil 21.3 27.6 27.2 28. 24.3 Queenston 21.6 27.8 27.1 28.1 24.5 Lakeshore 2.3 27.4 27.4 28. 24.9 Parkway 21.4 28.1 27.7 28.3 24.9 In contrast, average daily minimums for these months were mainly below normal, with the exception of the month of June. Almost all stations recorded warmer than normal daily lows in June, while July minimums were consistently cooler. However, although average July minimum temperatures were lower, daily maximums still remained higher than normal. The following table shows how most nights were warmer than normal during the month of June. With average daily maximum and minimum temperatures being well above average already in June, it is not surprising how quickly soil moisture was depleted. Regardless of the amount of rainfall Niagara received, these higher temperatures would increase evapotranspiration rates and thus, soil moisture would deplete faster.
Average Daily Minimums for May- September Compared to Normal May June July Aug Sept Normal (Vineland Station) 7.5 13.1 16.9 16.3 12.5 Grimsby 6.1 11.9 13.1 14.4 9.6 Beamsville 8.3 14.2 15.6 16.7 13.2 Vineland Cherry Ave. 6.7 13.4 14.3 15. 11. Vineland Escarpment 8. 14.1 15.3 16.5 12.7 Jordan Hwy 8 7.4 14. 15.1 16.3 12.1 Jordan Escarpment 7.1 13.1 14.5 16. 11.9 West St. Catharines 6.9 13.2 14.3 15.3 11.7 Niagara College 7.7 14.2 15.4 16.2 12.8 Virgil 6.6 13.3 14.5 15.7 11.8 Queenston 7.1 13.2 14.9 15.5 12.4 Lakeshore 7.1 14. 14.6 15.6 11.3 Parkway 5.8 12.7 14. 15.1 1.6 In fact, the number of days where the temperature soared above 3 C was significantly higher this summer. Normally, there are only 11 days from May through September when the temperature climbs higher than 3 C. This year, all of the NAWN stations recorded this occurring more than twice as often as normal. Remarkably, the Beamsville, West St. Catharines, and Parkway stations recorded this occurring more than three times as often! As shown on the map, Vineland escarpment had the least number of days with these extreme temperatures. Overall, it is quite evident that temperatures were much higher this year than normal.
Number of days 4 35 3 25 2 15 1 5 The Number of Days from May-Sept Where Tmax was Greater Than 3 C Grimsby Beamsville Vineland Cherry Ave Vineland Escarpment Jordan Hwy 8 Jordan Escarpment West St. Catharines NAWN station Niagara College Virgil Queenston Lakeshore Parkway Days Tmax > 3'C Normal # of Days Tmax > 3'C Growing Degree Day Analysis Accumulated growing degree-days from April 1 to October 31 surpassed the 3- year normal for Vineland Station. The Base 1 C GDD 3-year normal for Vineland station is 132.1 heat units, and all stations had between 1466 and 1679 heat units. Likewise, the base 5 C GDD 3-year normal is 2233.1 heat units and all stations had between 247 and 2649 heat units. Beamsville had the highest accumulation, followed by Niagara College. Grimsby had the least accumulation of heat units.
Base 1'C GDD from April 1 - October 31, 27 GDD 18 16 14 12 1 8 6 4 2 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov Date Grimsby Beamsville Vineland Cherry Ave Vineland Escarpment Jordan Hwy 8 Jordan Escarpment West St. Catharines Niagara College Virgil Queenston Lakeshore Parkway Seasonal Accumulation of Base 1'C GDD (April 1 - October 31, 27) Compared to Normal for Vineland Station GDD 18 16 14 12 1 8 6 4 2 Grimsby Beamsville Vineland Cherry Ave Vineland Escarpment Jordan Hwy 8 Jordan Escarpment West St. Catharines Niagara College NAWN Station Virgil Queenston Lakeshore Parkway 3-year Normal (132.1 GDD)
Base 5'C GDD from April 1 - October 31, 27 GDD 3 25 2 15 1 5 1-Apr 1-May 1-Jun 1-Jul 1-Aug Date 1-Sep 1-Oct 1-Nov Grimsby Beamsville Vineland Cherry Ave Vineland Escarpment Jordan Hwy 8 Jordan Escarpment West St. Catharines Niagara College Virgil Queenston Lakeshore Parkway Normal GDD Seasonal Accumulation of Base 5'C GDD (April 1 - October 31, 27) Compared to Normal for Vineland Station 3 25 2 15 1 5 Grimsby Beamsville Vineland Cherry Ave Vineland Escarpment Jordan Hwy 8 Jordan Escarpment West St. Catharines Niagara College Virgil Queenston Lakeshore Parkway NAWN station 3-year Normal (2233.1 GDD)
Rainfall Analysis The following graph shows the May September rainfall deficit, compared to the 3 year normal for Vineland station. Each station across Niagara experienced well below normal rainfall for this time period. Grimsby had the closest to normal rainfall for this time period, with a deficit of 196.3mm (that s still nearly 8 inches!). All of the remaining areas had a rainfall deficit well over 2mm! Vineland escarpment had the greatest lack of rainfall, with a deficit of over 261.1mm (approx. 1.3 inches). Rainfall Below Normal (May 1 - September 3, 27) -5 Rainfall (mm) -1-15 -2-25 -3 Grimsby Beamsville Vineland Cherry Ave Vineland Escarpment Jordan Hwy 8 Jordan Escarpment West St. Catharines Niagara College Virgil Queenston Lakeshore Parkway NAWN station In addition, mainly of the rainfall events that occurred this summer were not significant enough to increase soil moisture. For example, there were quite a number of rainfall events that were so small, most of the moisture evaporated before plants could take it up. Evapotranspiration Analysis Evapotranspiration (ET) is the amount of water lost by transpiration from the crop canopy and evaporation from the soil. If this amount is not equivalent to rainfall, the amount of water drawn from the soil is not replenished. Thus, the soil water balance drops. The estimated ET values on this graph are based on a standard for turf grass. It clearly illustrates how rainfall was lacking this summer since each month s ET losses were much higher than rainfall. June had both the highest ET losses as well as the lowest rainfall total for all the months. In addition, it emphasizes how soil moisture conditions would quickly decline under these circumstances.
Calculated Evapotranspiration Compared to Measured Rainfall for Virgil (May 1 - Sep 3, 27) Monthly totals (mm) 14 12 1 8 6 4 2 Evapotranspiration (calculated) Rainfall May June July August September Month Soil Moisture Analysis The following graph shows the soil moisture profile of a peach orchard in Niagara, via a capacitance probe (c-probe). Unless you are a drip irrigator, this graph would be typical of the soil moisture drying trend Niagara s soils experienced this summer. This particular block was irrigated using a stationary gun. The profile can be broken into seven noteworthy sections (A-G). Section (A) shows the downward soildrying trend at all 1, 3, and 5cm depths, particularly at the 3 and 5cm depths. The rainfall events can be seen at the bottom of the graph and it is clear that the rainfall events were not significant enough to maintain the soil moisture conditions at that time.
It was not until the first irrigation event, on June 2, that the drying trend was halted at the top 1cm soil depth (B). However, although 32.2mm (1.27 ) of water was added, even this amount was not significant enough to infiltrate to the 3 and 5cm depths. Unfortunately, the lack of significant rainfall continued and the drying trend began again. A second irrigation event took place on July 11 (C), adding 35.6mm of water, which again stopped the drying trend, but only at the 1cm level. The rest of July was greeted with a few more rainfall events (D), which maintained the soil moisture conditions at the 1cm depth. However, it is evident in the graph (E) that the 3 and 5cm depths were nearly depleted of available soil moisture, as the drying trend had flat-lined. A third and final irrigation event added 38.6mm of water, and took place on July 21, approximately 1 days before the harvest onset. Finally, due to the 1cm soil depth having sufficient moisture from a slightly wetter (though still dry) July, this irrigation event managed to infiltrate to the 3cm depth (F). August was an especially dry month, lacking any rainfall events to maintain soil moisture conditions and the drying trend continued (G). A few rainfall events in September and October were significant enough to infiltrate the 1cm soil depth; however, the 3 and 5cm depths remained completely dry. Thus, Niagara soils will require a few long and steady rainfall events to replenish the entire soil profile. SUMMARY Overall, the 27 growing season can be summed up as warmer and drier. The summer of 27 can be characterized by having warmer than average days, but cooler nights. The only exception was June, which had consistently warmer-than-normal nighttime lows as well as daytime highs. These above-average temperatures led to increased evapotranspiration. However, effective precipitation was lower; thus, ideal soil moisture conditions could not be maintained by natural rainfall alone. Consequently, soil moisture levels have been of particular interest this year as many needed to determine when and how much to irrigate. Once again, the need for water management has been recognized. The c-probe gives a clear indication of what s happening beneath the soil. A downward sloping line on the graph ending in a flat-line indicates a depletion of soil moisture at that level. One can easily maintain the soil moisture conditions at the rooting zone with the use of this probe. One can also make sure that water is not infiltrating past the rooting zone, and thus, over irrigating. In order to improve upon our services to our clients, WIN welcomes any feedback you may have on the desired frequency, content and delivery of the reports. Comments on the presentation of the data, the usefulness of this information or what you would like to receive in future reports would be greatly appreciated. Please contact Wayne Heinen (wheinen@weatherinnovations.com) or WIN (519-352-5334) with your feedback.