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INSTALLATION AND OPERATING INSTRUCTIONS Soil moisture sensors(IRROMETERS OR WATERMARKS)placed in the active root system of the crop(and in the area wetted by the emitter)are the most convenient way to verify this SSAT - Soil Solution Access Tube condition of field capacity (15-25 centibars of soil water suction). At this time you are also sampling the soil solution,which contains the nitrogen introduced with the irrigation.And,with `y readily available soil water,the time required to draw the solution sample into the SSAT(Soil �-( Solution Access Tube)is lessened.Attempting to draw a solution sample from soil that has dried beyond 35 centibars of suction can be frustrating,because in this condition the soil water environment contains a much greater volume of air. a. Soil Water Sampling-Suction Lysime" This technology is a simple,inexpensive and non-destructive method of extracting a soil water sample for chemical analysis.The early work in this field was principally done in the \• area of salinity monitoring.Today,most of the application of this technology is in the area of nutrient management because of fertigation,the practice of introducing nutrients,principally nitrogen, in soluble form through a low volume (micro/drip/trickle) irrigation system. Many commercial agriculture producers involved in drip irrigated vegetable crops have adopted the use of this technology to monitor and control their nitrogen injection systems. Practical Field Use Depths of Sampling In the area of nutrient management,where drip systems are used by a farmer to"spoon feed"nitrogen to a growing crop, the technique of soil water sampling has proven to be a In drip irrigation,the crop root system tends to be massed more towards the soil surface. This is the area where the crop extracts water and useful tool in manipulating the rate at which soluble nutrients are introduced through the nutrients and thus the top 18"—24 (45- irrigationwater.Tissue analysis is still the baseline practice,but this can be time consuming 60 cm) is the most critical for tree and vine crops. With shallower rooted crops such as and costly.And with the"spoon feeding"of nitrogen,sometimes done with every irrigation vegetables,the top 12" (30 cm)is most significant. Mobile nutrients,such as nitrogen, are cycle,tissue analysis results are always lagging the actual event. Further,the technique of quickly transported beyond the root system if irrigation is excessive. And this fact soil water sampling can help to monitor any excessive leaching of mobile nutrients beyond emphasizes the need to monitor irrigation scheduling very carefully to prevent excessive the root system,which would be caused by over-irrigation. leaching. Sampling of the soil water below the root system can be useful to spot heavy concentrations of nitrogen being lost to deep percolation. But the basic rule, for nutrition Certain cautions should be recognized when using this technique, particularly the fact that adequate sampling sites should be used to mitigate variations that may be management,is to sample the active root system. encountered. Installation When to Sample To install the SSAT(Soil Solution Access Tube)in the soil or container,make a 7/8" The best advice is to extract your solution sample when the soil is at field capacity.This (22 mm) diameter access hole to the desired depth with a soil coring tool, IRROMETER condition usually occurs anywhere from a few hours after,to the day following,an irrigation. Installation tool,a piece of 1/2"galvanized pipe,or 7/8"(22 mm)diameter solid rod.This — 1 — —2 —