|Sudduth, Kenneth - Ken|
Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/25/2014
Publication Date: 7/20/2014
Citation: Kitchen, N.R., Baffaut, C., Sudduth, K.A., Sadler, E.J., Veum, K.S., Kremer, R.J., Lerch, R.N. 2014. Production and conservation results from a decade-long field-scale precision agriculture system. In: Proceedings of the 12th International Conference on Precision Agriculture, July 20-23, 2014, Sacramento, California. 2014 CDROM.
Interpretive Summary: For over a decade we used precision agriculture technologies to intensely monitor crop, soil, and water quality information on a typical claypan-soil field in Missouri that had been managed uniformly. We found many field properties varied greatly within this somewhat flat, uniform-looking field, including grain yield, soil fertility, topsoil depth, ground water nitrates, and soil herbicide persistence. We used maps of these and many other field characteristics in developing a crop management plan for the future that addressed site-specific problems in the field. This new crop management plan was called a “precision agriculture system” (PAS) and was initiated in 2004. The PAS plan included no-till, cover crops, growing wheat instead of corn for field areas where topsoil was shallow, site-specific N for wheat and corn using canopy reflectance sensing, site-specific P and K fertilizers from soil sampling, and targeting of herbicides based on weed pressure. The premise of this field-scale research was that PAS management would increase crop production and crop profitability, decrease crop production variability, and improve soil and water quality over the conventional uniform management of the years prior to PAS (pre-PAS). With 10 years of PAS (2004-2013) we have found that yield slightly increased for corn (5%) and soybean (9%) over pre-PAS management. Crop yield risk as measured by year-to-year yield variation decreased 57% where wheat replaced corn, but remained unchanged for soybeans. Using soil quality measurements from adjacent studies, we found that the PAS field soil quality has increased at the rate of one point per year on a 0-100 scaled index. While surface runoff amount was not significantly different between PAS and pre-PAS, sediment loss has been reduced 80% with PAS. This research shows how farmers benefit by using precision agriculture technologies because it improves yields and chemical use efficiency. The general public benefits because practices and inputs are targeted to sub-field areas, reducing over-application of agrichemicals, and minimizing sediment loss into lakes and streams.
Technical Abstract: Research is needed that simultaneously evaluates production and conservation outcomes of precision agriculture practices. From over a decade (1993-2003) of yield and soil mapping and water quality assessment, a multi-faceted, “precision agriculture system” (PAS) was developed and initiated in 2004 on a 36-ha field in Central Missouri. The PAS assessment was accomplished by comparing it to the previous decade of conventional, whole-field corn-soybean mulch-tillage management. The employed PAS plan takes advantage of targeted management that addresses crop production and environmental issues. The PAS plan included no-till, cover crops, growing wheat instead of corn for field areas where depth to the argillic horizon was shallow, site-specific N for wheat and corn using canopy reflectance sensing, variable-rate P, K, and lime using intensively grid sampled data, and targeting of herbicides based on weed pressure. Yield slightly improved for corn (5%) and soybean (9%) with PAS over pre-PAS management. Risk as measured by grid cell year-to-year yield coefficient of variation decreased 57% when comparing where wheat replaced corn with PAS, but has remained unchanged for soybeans. Removing corn from the northern portion of the field for the PAS years resulted in within-year corn CV of 16.6%. Using soil quality measurements on research plots adjacent to PAS, we estimated that PAS soil quality has increased at the rate of one point per year on a 0-100 scaled index. Surface runoff has not been found to be significantly different between PAS and pre-PAS. Sediment loss with PAS has been reduced 80% compared to pre-PAS years.