Characterization of nitrogen, phosphorus, and potassium mass balances of dairy farms in New York State

Abstract

A whole-farm nutrient mass balance (NMB) is a useful measure of the nutrient status of a dairy farm. Research is needed to define and determine a feasible NMB range for dairy farm systems in New York State (NY). The objectives of this study were to (1) document the distribution of N, P, and K mass balances of 102 NY dairy farms (including 75 small, 15 medium, and 12 large farms); (2) establish initial NMB benchmarks based on what 75% of the farms achieved; (3) determine the maximum animal density that allows an example NY dairy farm to balance cow P excretions and crop P removal without exporting crops or manure; and (4) identify opportunities to improve NMB over time. Nutrient mass balances of the 102 farms ranged from -39 to 237 kg of N/ha for N without including N2 fixation (N1), from -14 to 259 kg of N/ha when N2 fixation was included (N2), from -7 to 51 kg of P/ha, and from -46 to 148 kg of K/ha. Seventy-five percent of the farms were operating at NMB less than 118 kg of N/ha for N1, 146 kg of N/ha for N2, 13 kg of P/ha, and 41 kg of K/ha (75% benchmarks). Farms with the highest nutrient use efficiencies (lowest NMB per unit of milk produced) operated with less than 8.8 kg of N/Mg of milk for N1, 11.8 kg of N/Mg of milk for N2, 1.1 kg of P/Mg of milk, and 3.0 kg of K/Mg of milk. The biggest contributor to the NMB was the amount of imported nutrients, primarily feed purchases. The example farm assessment (assuming no export of crops or manure) suggested that, when 70% of the feed is produced on the farm and P in feed rations does not exceed 4 g of P/kg of DM, cow P excretion and crop P removal were balanced at a maximum animal density of 2.4 animal units (AU)/ha (~0.97 AU/acre). Dairy farms operating with animal densities <2.4 AU/ha typically had NMB below the 75% benchmark, whereas most dairies with more than 2.4 AU/ha needed to export manure or crops to meet the 75% benchmark. Opportunities to reduce NMB on many farms, independent of size and without changes in animal density, are possible by more tightly managing fertilizer and feed imports, increasing the percentage of farm-produced nutrients, implementing precision feeding, and exporting crops or manure.

Factors of yield resilience under changing weather evidenced by a 14-year record of corn-hay yield in a 1000-cow dairy farm

“…Liquid manure from the dairy has been applied to the soil via injection since 1994. Manure was the only fertilizer nutrient source on this farm from 2007 onwards (Ketterings 2014). The farm seeds winter cereals as cover crops annually on as many corn silage acres as possible (weather determined).…”

“…In the past 10 years, the proportion of forages as a percent of the total ration dry matter (DM) in Northeast dairy farm rations has increased from less than 50 % of the total DM to 55-70 % forage as a percent of the total ration DM (Chase and Grant 2013). Assessments of 102 NY dairy farms in 2006 showed that nearly all the forages fed were produced on the farm (homegrown forages) reducing the farm's cost of production and environmental footprint and increasing its whole-farm nutrient use efficiency (Cela et al 2014). The predominant forages grown for dairy cow rations in NY are corn (Zea mays L.) silage and alfalfa (Medicago sativa L.) and grass hay mixtures.…”

Prediction of drinking water intake by dairy cows

“…The K concentrations showed the greatest variability (1.03 to 3.35% of DM) and included 4 observations (2.0% of the data), which were greater than 3.0% of DM. Considering macrominerals are generally overfed (Castillo et al, 2013) and dietary K can increase up to 3.0% of DM in some US commercial dairy operations (Cela et al, 2014), those observations of high macromineral contents were included in the data set. The dietary Na concentrations were in line with the ranges of commercial farms (e.g., 0.25 and 0.58% of DM at the 10th and 90th percentiles; Castillo et al, 2013).…”

Proximal Sensing to Estimate Yield of Brown Midrib Forage Sorghum

“…Typical forage rotations on dairy farms in the state include 3 to 4 yr of corn followed by 3 to 4 yr of mixed alfalfa (Medicago sativa L.)/grass hay. Although corn silage yields have slowly increased over the past 50 yr (National Agricultural Statistics Service, 2016), recent work has shown that double cropping of corn silage with winter cereals such as cereal rye and triticale has the potential to increase overall yield beyond what could be obtained with corn silage only (Ketterings et al, 2015a(Ketterings et al, , 2015b, reducing the need for feed purchases and improving whole farm mass nutrient balances (Cela et al, 2014;Soberon et al, 2015).…”