“Crunchy” is not an adjective that one usually wants to apply to one’s lawn. But that’s precisely what the grass is this blazing, thirsty July … crunchy. And yet, according to the weather service, we’re not in a drought. Well, that all depends on how you define a drought, now doesn’t it? What’s a drought?
Hydrologic drought is when the groundwater aquifers, reservoirs, and stream flow are below normal. The massive snows of this past winter recharged the aquifers and while the stream flow for the Christiana River is running between the 24th and 74th percentiles (See http://md.water.usgs.gov/surfacewater/streamflow/christina.html ) this is still normal for this time of year on average. In addition, the large, established trees that rely on subsurface water tables seem in good shape, their leaves full and plentiful. (See http://www.drought.unl.edu/vegdri/VegDRI_Main.htm) So, accordingly, there’s no drought by these measures, close maybe, but not yet.
A meteorological drought is defined as “a period of abnormally dry weather sufficient to cause a serious hydrological balance.” (Huschke, R.E., ed., 1959, Glossary of meteorology: Boston, American Meteorological Society, 638 p.) This can be variously defined as an “absolute drought”, a “partial drought”, or a “dry spell”. An absolute drought is a period of at least 15 consecutive days with less than 0.01 inches of rain or more on any given day. A partial drought is a period of at least 29 consecutive days, the mean daily rainfall of which does not exceed 0.01 inches. A dry spell is a period of at least 15 consecutive days with less than 0.04 inches or more on any given day. If we check the monthly rainfall for June and July, we’ll discover that, meteorologically speaking, we’re not only not in a drought, we’re not even in a dry spell!
But from a farmer’s (or lawn owner’s!) perspective, it’s quite another thing. A more recent delineation of the different types of drought includes “agricultural drought”. Agricultural drought is “A climatic excursion involving a shortage of precipitation sufficient to adversely affect crop production or range production.” (Rosenberg, N.J., ed., 1979, Drought in the Great Plains–Research on impacts and strategies: Proceedings of the Workshop on Research in Great Plains Drought Management Strategies, University of Nebraska, Lincoln, March 26-28: Littleton, Colorado, Water Resources Publications, 225 p.) Agricultural drought occurs when there isn’t enough soil moisture to meet the needs of a particular crop at a particular time. Agricultural drought happens after meteorological drought but before hydrological drought. (From: http://www.drought.unl.edu/whatis/define.htm )
Yep. Our crops and your grass have definitely been adversely affected. Sounds like a drought to me!
For the farmer, the difficulties are threefold: too much warmth too soon, too little or inconsistent, intermittent rain, and too much sun. Warmer than normal temperatures with abundant rain early in the growing season cause plants to put forth lots of top foliage before they are ready to flower. If the rain shuts off later in the season as the blossoms are becoming fruits, then the plant struggles to maintain the greenery it initially grew to the detriment of the fruits we look forward to eating. Warmer than normal temperatures encourage abundant growth, but too much sun, and the tender leaves burn resulting in the loss of entire crops of tender leafy green crops: lettuces, spinaches, etc. and the damaging of newly germinated seedlings. In fact, sometimes the seeds themselves bake in the too warm soil and never germinate at all. Rain could to some degree help, but without it, there isn’t much we can do for the seeds already planted. That’s one reason why we do multiple plantings over time of the various crops and have plenty of additional seed on hand. It’s not a cure-all, but it does mitigate the effects of the drought IF it doesn’t last too long!
So what do we do? Well, last year we could water, and did water, sometimes three times a day. The plants were thirsty, and we were glad to do it. Early in the morning, in the evening, and sometimes even in the dark! With watering cans in hand we walked along the rows, becoming cloudy, indistinct forms after sunset. There’s something very fairy tale like about watering by moonlight while the deer roam nearby in the hush of the night.
But this year, this crunchy July, we’re giving up our water cans for drip irrigation. Hooray! More on that in our next newsletter.