Do High Input Soybean Production Systems Pay?.

Soybean prices have increased substantially over the past few years, along with associated production input costs. With this increase in soybean commodity prices, new products and practices not typically utilized for soybean production are becoming more common though not having been well evaluated by university agronomists. Some of these practices include the use of a fungicide without evident disease pressure, greater plant nutrition (above university extension recommendations), higher seeding rates, and combinations thereof. Use of high input systems is often based in the opinion that current university extension recommendations are antiquated. A study was conducted at five Kentucky locations in 2011, and one in 2012, to determine: a) soybean yield potential when five additional inputs are combined into a high-intensity production system; b) the impact of each input when removed from this system; and c) the impact of individual inputs when added to a general soybean production system.  Selected fields had yield potentials greater than 4.7 Mg/ha, nil/low levels of soybean cyst nematode, and utilized no-tillage or reduced tillage. Yields typically increased as input intensity increased, with the exception of the higher seeding density. This was consistent across most locations. Poultry litter was the single most yield-influential input. A high seeding rate, as a lone input, was detrimental to yield and if used then additional inputs were needed in order to avoid the yield penalty. The most responsive sites were those that would have received a university extension fertilizer recommendation. Although yields typically increased with greater production inputs, yield gains were small and economic benefit unlikely. Current university extension recommendations appear to be adequate.