Mike Rankin
pocket and use to check corn plants? Does this sound like science fiction? The miniaturization of NIRS technology is beginning to enable such a scenario. With funding from the New York Farm Viability Institute, we set out to investigate one such device pictured in Photo 2. The SCiO device was developed by Consumer Physics (Tel-Aviv, Israel) and utilizes a patented technology to glean a spectrum from 740 to 1,070 nanometers (nm). These instruments work on the principle of illuminating the sample and measuring light absorbance. But how do you measure the light that’s not there? We measure the light that’s not absorbed (reflected) and assume that the missing light was absorbed. The light absorbed by the sample is related to several physical characteristics and chemi-
Corn silage harvest timing in your pocket by Matthew Digman, Jerry Cherney, and Debbie Cherney
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ESEARCH advocates for harvesting corn at a defined maturity and moisture content for optimal storage, utilization, and milk per acre. As corn plants mature, they increase in dry matter, and starch accumulates, displacing sugar, fiber, and ash. A study at the University of Illinois observed that corn silage harvested at 30% dry matter (DM) resulted in 7% to 25% less milk per acre when compared with silage harvested at an optimum DM content of about 35%. Determining when to harvest can be time-consuming and expensive. Likewise, relying on visual observations can be deceiving. Stay-green hybrids and field variability can also limit the effecMATTHEW DIGMAN Digman (pictured) is an agricultural engineer at the University of Wisconsin-Madison. Jerry Cherney and Debbie Cherney are the extension forage agronomist and an animal science professor, respectively, at Cornell University.
tiveness of sampling (see Photo 1). As a result, most producers rely on collecting representative samples to determine whole-plant moisture content. Sampling plants generally involves a trip to the field, collecting and chopping whole plants, and then drying in a microwave, Koster tester, air fryer, food dehydrator, or forced-air oven. This limits how many samples can be managed and the time between collecting data. While hand-held and on-harvester near-infrared reflectance spectrometers (NIRS) are effective, they haven’t been widely adopted and are expensive. There are positive independent research data backing NIRS offerings from multiple vendors (see our previous article, “In-hand forage quality,” in the April/May 2018 issue of Hay & Forage Grower). Additionally, moisture varies significantly, and the NIRS technique is strongly influenced by sample moisture content. In fact, samples are routinely dried to use NIRS to predict other chemical components such as protein, fiber, and starch.
NIRS goes mini But what if there was a simple, lowcost device that you could put in your
Photo 1. On the same day and farm, the corn on the left measured in at 67% moisture content, and the corn on the right was at 63% moisture, only 4 percentage points lower.
Photo 2. Attachment to SCiO NIRS instrument to maintain a precise distance between the scan window and corn ear surface and exclude external light. The goal was to relate ear moisture to whole-plant moisture.
16 | Hay & Forage Grower | August/September 2021
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