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Soil Sampling Techniques. Zone Sampling. G rid Sampling. Management zones NRCS soil type Soil texture determined by soil EC. Break field into grids of choice 0.5 acre 2.5 acre 5 acre 10 acre. Grid Sampling vs Zone Sampling. Soil Type 1. Soil Type 2. Soil Type 3.
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Soil Sampling Techniques • Zone Sampling • Grid Sampling • Management zones • NRCS soil type • Soil texture determined by soil EC • Break field into grids of choice • 0.5 acre • 2.5 acre • 5 acre • 10 acre
Grid Sampling vs Zone Sampling Soil Type 1 Soil Type 2 Soil Type 3
2.5 acre Grid Sampling 4 points per grid 2.5 Acres
Veris EC Mapping 123 points per grid with data-point per second method 2.5 Acres
187 acre Research Field 0.5 Acre Grids 393 Sample Sites 14,769 lbs of DAP 2.5 Acre Grids 77 Sample Sites 14,347 lbs of DAP HyGround 19 Sample Sites 15,008 lbs of DAP K2O Maps P2O5 Maps 0.5 Acre Grids 393 Sample Sites 11, 718 lbs of Potash 2.5 Acre Grids 77 Sample Sites 11, 289 lbs of Potash HyGround 19 Sample Sites 9,648 lbs of Potash
Research Summary • Use of allowed a 75%reduction in sample points compared with 2.5 acre grids without a significant difference in accuracy. • When compared there existed a 1,641 lb difference between the 2.5 acre grids and potash recommendations on a 187 acre field. • When compared there existed a 662 lb difference between the 2.5 acre grid and DAP recommendations on a 187 acre field.
Know What You Are Getting • All Grid Sampling is not the same - What grid size? 2.5, 5, 10, etc..? • All Zone Sampling is not the same - What are zones based on? NRCS map, EC (veris) maps, imagery? - Number samples/zone? - Are samples combined or independent - Even though sampled by zone,are sample correlations done w/in zones only, or based on all samples in field? • What will be delivered to you as a grower? - What maps? pH, CEC, O.M., N,P,K, micros..etc? - How do you get prescriptions, how many, what types, and for how long? - What are rec’s based on? - What controller types can prescriptions be exported to? - How are prescriptions put on your controller? Custom applicators controller? Troubleshooting? • What does it cost for the service? - Everything above goes into the real value of the service - Is $9/ac 10 ac grids, pH, N,P,K maps, the same value as, $11/ac Zone sampling @ 1 sample/10 ac of zone with complete soil type maps, primary, secondary, and micronutrient maps? - When comparing value of services, find out how is it done, what is delivered, how do you get what you need to apply it to your farm - How available is someone to explain information, get you what you need, help with problems? - How is your data secured and back up from year to year?. - Can fertility data be correlated to yield maps?