农业和气象网络

North Dakota agriculture ranks high inthenation'scropproduction: No. 1 in durum and springwheat,barley,sunflower,flax, and all edible beans, No. 2 in oatsand allwheat,No. 3 inpotatoes, and No. 4 in rye and sugarbeets. Tomaintain theserankings, our agriculture must continuetoproducehigh quantitiesof quality crops despiteunpredictableattacks fromdiseases,insects, and other antagonisticfactors.

Pesticide application, although environmentallycontroversial,isthe farmer's main tool to control cropdiseasesandinsects.Scientists have identified the criticalweatherconditionsthatcontrol development of some organisms, andhavewrittenprogramsthat mimic or model this relationship. Byusingcurrentweatherdata as input, a computer model can accuratelytrackaspecificdisease or an organism's stage ofdevelopment. Basedon thisinformation, a farmer knows if andwhen tospraypesticides,minimizing the potential health andlitigationissuesarising fromspray drift, which are always ofconcernwithpesticideapplication.

In 1989, weather monitoring systems wereinstalledunderthesupervision of John W. Enz, NDSUAgriculturalClimatologist, atsixagriculture experimental stationsacross NorthDakota.  Todaythe system has grown to 50weatherstations, andis known astheNorth Dakota Agricultural WeatherNetwork (NDAWN). It isanenvironmentally sound electronicweather monitoringsystem, andisman-aged by John Enz, Professor,Radu Carcoana andGregBrockberg,Research Specialists from NDSU,SoilScience,ClimatologySection.  The data collected by thissystemareused by anincreasing number of individuals andinstitutions foranamazinglywide variety of purposes.

NDAWN sites, like the one pictured totheright,arefound through out the state and provide basicandcustommeasurementsfor a variety of individuals andinstitutions.

Our standard weather stations measure airtemperatureandrelativehumidity with a Vaisala HMP35C sensor, windspeedanddirection withMet One 014A and024A sensors, solarradiationwithLI-COR LI200S andLI200X pyranometers, rainfall withaTexasElectronicTE525 tippingbucket rain gauge, barometricpressurewitha VaisalaPTA427sensor,and soil temperature at10-cmdepthsunderbare and turfcover conditions with thermocouplesorthermistors.Data are recordedand summarized hourly and daily by41CR10dataloggers and nine21Xs.  All sites areaccessedbyphone:37with DC112 phone modems(seven with cellularphones),and11 withVS1voice modems.  Twostations are accessedvia radiotelemetry.

Voice modems provide instantaneous weather data(windspeedanddirection, temperature, relative humidity, andtheamountofprecipitation since midnight).The data helps farmersdecideiftheappropriate legal weather conditions are met forgroundoraerialpesticide spraying.

Seasonal sensors are installed atsever-alstationstomonitor specific parameters. Temperature and RHunder amaturesugarbeet canopy (one foot from the ground) ismeasuredwithanadditionalHMP35C.  Several extra thermistorsareusedtomeasure the temperature of the sugar beet root andcrownatharvesttime.  Solar radiation is animportantparameterincalculating the crop potential evapotranspiration(PET). PETis used to calculate the daily andweekly crop wateruse,whichhelps farmers decide when and how much toirrigate.

Beyond the basic measurements, specialresearchprojectsrequirecertain stations monitor other variablesviaCampbell'sAM416multiplexer.  At two sites, temperaturesaremonitored at14depths (10 feet max)under highway pavement inajointresearchproject with the ND DepartmentofTransportation. Groundwater level is monitored in waterwells,as part of a longtermNDSU research program in theSheyenneNationalGrasslands. Soil temperatures are measuredonce perhour at12depths (6 feetmax) at 13 stations around the stateas partof anongoing researchproject.  At another sitesoiltemperaturesare profiled inlocations on both north-andsouth-facing slopes.

To provide accurate, reliable data(because bad dataisworsethanno data)we have concentrated our efforts tofinanceanddevelop anexigent program of quality control (QC)andpreventivemaintenance(PM).  QC is upheld by two dailydataqualitycontrolfilters.  One Is performed by the HighPlainsClimateCenter inLincoln, Nebraska, which also retrievesdailydata. The secondis per-formed by the researchspecialistsfromNDSU.  PMminimizes station downtime andexpense, butrequiresa good supplyof factory-calibrated spare parts,rangingfrom extraclamps andsensors to CR10sand 21Xs.

Each station is visited annually for a standardcheck-up.Wealsomaintain a detailed log of all actions andeventsthatoccurred ateach station. In addition to thestandardcheckupsthere areemergency situations (besides lightningstrikes,birddroppings onpyranometers or in the rain gauge funnel,or snowonsolar panel)that require additional travel.

The cooperation with applications engineersatCampbellScientificand their availability by phone isinvaluableinpin-pointingproblems.  Their contribution insolvingmanyspecific andunusual situations is critical.  Ononeoccasion,a problem witha phone line was found in acooperativeeffort on afour-way phoneconference.  Paul, anEnvironmentalSpecialistwith the NDNational Guard(the station’sowner) was inthe car,John was in theoffice monitoring the stationby computer,Radu wasat the stationalong with Harris from the phonecompany,and Bart,the CSIapplications engineer, was in Logan, Utah.