Are We Keeping Up with Soil Nutrient Replenishment?

Each bushel of corn removes about 0.67 lb Nitrogen (N) is an essential nutrient for plant growth, development and reproduction. Despite nitrogen being one of the most abundant elements on earth, nitrogen deficiency is probably the most common nutritional problem affecting plants worldwide – nitrogen from the atmosphere and earth’s crust is not directly available to plants. (N), 0.35 lb P2O5, 0.25 lb K2O and 0.08 lb S from the soil.

A bushel of soybeans will remove 3.3 lbs N, 0.73 lb P2O5, 1.2 lbs K2O and 0.18 lb S. In a corn-soybean rotation, based on trend-line yields of 180-bushel corn and 50-bushel soybeans, it would require 191 lbs MAP/ac and 175 lbs MOP/ac to replace the P and K removed in the harvested grain. As yields approach 210 and 60 bu/ac for corn and soybeans, respectively, it will require nearly 226 lbs MAP/ac and 208 lbs MOP/ac to replace the nutrients removed and avoid soil test reductions.

Applying fewer nutrients than are removed in the grain will cause soil test levels to decline over time. In many cases, fields with declining soil test levels may no longer be able to sustain the most profitable yield levels, especially when conditions are right for above-average trend-line yields. –

See more at: http://www.cropnutrition.com/how-record-yields-are-impacting-soil-nutrient-levels#sthash.ajtHQkfi.dpuf