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Irrigation Management And Agronomy FAQs

Your questions answered about precision irrigation, crop water use and soil moisture content.

To get optimal results from irrigated crop production, you must be able to predict the onset of plant water stress points. By calculating the amount of water lost from the root zone, you can work out how much needs to be applied at the next irrigation. Quality, accurate and reliable technology is critical to gain the facts to inform smart irrigation.  Sentek soil moisture probes provide the data to make good decisions about the amount of water you need to apply to support plant health without wasting a precious resource.

Not applying enough water, or applying water too infrequently, will have negative effects and can restrict crop growth, yield and quality. A crop’s ability to absorb nutrients from fertilizer applications can also be reduced when plants are under stress resulting in lower yields and wasted inputs. Plants can also become more susceptible to pest and disease attacks. Effective irrigation management is critical because it impacts yields, quality and operating costs.

Applying too much water, or irrigating too often, can also have negative effects. Water can be wasted through surface run off or through excessive drainage past the active root zone. When soil becomes water-logged, pores that normally store air become filled with water which can inhibit plant growth and encourage disease. Overwatering can also cause valuable nutrients to leach from the soil. At ground level, overwatering promotes weed growth resulting in increased management costs. In clay and loam soil environments, too much water can also increase the risk of compaction and may mean machinery use has to either be reduced or stopped. Overwatering can also increase operating costs through fuel wastage as well as higher water and labor expenses. Too much water can also create additional environmental risks associated with rising water tables and salinity as well as pollution from nutrient and pesticide run-off.

Increases in soil moisture can be attributed to:

  • Irrigation
  • Rainfall
  • Overland flow from higher to lower lying areas
  • Rising water tables

Decreases in soil moisture content can be attributed to:

  • Water draining (gravity)
  • Evaporating from soil surface
  • Plants transpiring water

Smarter irrigation scheduling decisions can be made when the manager can identify the amount of soil water available in the root zone, monitor changes in levels at different depths, and understand the causes of the change.

Sentek provides the most effective methods for measuring the water content of soil and our technologies have led to significant improvements in irrigation management. When numerical measures of soil water are recorded using continuous monitoring profiling probes – the data set allows analysis to determine not only what the soil moisture levels are, but what is causing them to change.. At the surface level, a rainfall gauge can help distinguish between rain and irrigation applications but only a soil moisture probe can show you how much of that rain has moved through the soil profile to the plants’ roots.

Our profiling probes can easily establish if rising water tables are causing soil moisture changes because increases will be picked up by the lower- level sensors.

Sentek’s advanced software systems like IrriMAX displays continuous data, to help you build a picture of any changes occurring at different levels within the root zone.  Plant uptake of water at different depths can be clearly seen and measured.   Our software can also be used to calculate moisture loss in situations where water is draining past the root zone and going to waste. IrriMAX has been developed by experienced soil water specialists to better display, and understand, moisture content and salinity dynamics. It is a powerful tool that can be used to graphically measure, analyze and display interactions between plants, water, soils and the atmosphere and any moisture and salinity impacts. Displaying data in a graphical format means information can be better interpretated and understood and graphs can be converted to numerical analysis for theory, concept and strategy validation.

Profiling probes such as EnviroSCAN and Drill & Drop provide valuable information about the stages of crop growth so you can make intelligent decisions about when to irrigate and fertilize.