Late-season corn stalk nitrate measurements across the US Midwest from 2006 to 2018.

The late-season Corn Stalk Nitrate Test (CSNT) is a well-known tool to help evaluate the after-the-fact performance of nitrogen management. The CSNT has the unique ability to distinguish between optimal and excessive corn nitrogen status, which makes it helpful for identifying the over-application of N so that farmers can adjust their future nitrogen decisions. This paper presents a multi-year and multi-location dataset of late-season corn stalk nitrate test measurements across the US Midwest from 2006 to 2018. The dataset consists of 32,025 corn stalk nitrate measurements from 10,675 corn fields. The nitrogen form, total N rate applied, US state, year of harvest, and climatic conditions are included for each corn field. When available, previous crop, manure source, tillage, and timing of N application are also informed. We provide a detailed description of the dataset to make it usable by the scientific community. Data are published through an R package and also available at the USDA National Agricultural Library Ag Data Commons repository and through an interactive website.

Demand management and optimization of clinical laboratory services in a tertiary referral center in Saudi Arabia.

BACKGROUND: Demand for clinical laboratory services in our insti.tution has increased by 7% each year in the past 5 years, while the amount budgeted for services has remained fixed. To address the issue, we conducted a pilot study to curb inappropriate demand by implementing a minimum retest interval (time-based restrictions on the ordering certain tests) and thus reduce costs. OBJECTIVE: Explore the impact (financial and work volume) of restricting overuse of laboratory tests that add to costs but provide no additional clinical value. DESIGN: Pilot study of means to reduce costs and workload. SETTING: Clinical laboratory that provides diagnostic support to a tertiary care center specializing in transplantation and oncology. METHODS: With the engagement of clinical colleagues, we selected 13 tests characterized by high volume, high cost, or a perception of overuse that adds no clinical value. The selection was also based on established lock-out frequencies identified in a literature review. Data was captured on test numbers before and after initiating computer-based lock-outs along with the reference laboratory cost of these tests for the first 6 months of 2016 and 2017. MAIN OUTCOME MEASURES: Alterations in testing patterns (mimimum retest intervals) and frequencies for tests. RESULTS: The number of tests ordered during the 6-month period in 2017 were reduced by an average of 6.6% versus the same period for 2016, saving 2.03 million Saudi Arabian Riyals (SAR). Given a 7% annual growth in the preceding 5 years, the volume was reduced by 13% in real terms. The percentage reduction in number of tests ranged from as little as 0.2% for PT to 70.3% for an enzyme immunoassay. Savings were 1.4 million SAR in hematology and 0.36 million SAR in microbiology over the 6-month period. CONCLUSION: Minimum retest intervals using computer-based rules are effective in supporting strategies to manage demand. LIMITATIONS: This approach may not be applicable to all laboratory tests; however, the success of this pilot study would encourage more widespread use of this approach. CONFLICT OF INTEREST: None.

Testing soils and cornstalks to evaluate nitrogen management on the watershed scale.

High nitrate (NO3-N) concentrations in Iowa rivers have been linked to areas of intensive row crop production, but they have not been experimentally linked to specific management practices used during row crop production. This study demonstrates how the late-spring test for soil NO3-N and the end-of-season test for cornstalk NO3-N can be used to measure N sufficiency levels across many fields and how the results can be used to evaluate management practices within a watershed. More than 3200 soil and cornstalk samples were collected over a 12-yr period from fields planted to corn (Zea mays L.) and already fertilized by farmers using their normal practices. Results showed that early-season rainfall and associated N losses were major factors affecting N concentrations in soils and cornstalks. Evidence for NO3-N movement from fields to rivers was provided by an inverse relationship between annual means for NO3-N concentrations in soils and rivers. Because these losses can be avoided by delaying N applications, the practice of applying N several weeks or months before plants grow was linked to inefficient use of fertilizer and manure N by crops. Results of the study demonstrate how aggregate analyses of soil and cornstalk samples collected across many farms and years make it possible to identify the major factors affecting N management outcomes and, therefore, N management practices that are likely to produce the best outcomes within a watershed or region. This approach seems to have unique potential to interrelate the management practices of farmers, the efficiency of N fertilization, and NO3-N concentrations in rivers.