Nutrient cycles and flows in agroecosystems Dissipation into the surrounding environment What is missing?

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Cycles Flows Stocks Key terms Fertilizer raw materials Soil nutrient reserves

Total N inputs to IL soils Mg = 1 x 10 6 g = 1000 kg = 1 metric ton 1 metric ton=2204.6pounds 1 metric ton=1.1023US tons (alfalfa and other forage legumes)

Total N outputs from IL soils

Crop specific harvests of N

N inputs vs. river export Net input = Gross inputs - outputs 1993

Mining Prairie N Anthropogenic N inputs

Units are 1000 metric tons N / yr

Why does so much N get into Illinois’ rivers ???

Approximately 40% of IL fields have artificial drainage

Yield maps have made drainage problems much more obvious

Redistribution of nutrients excess

Mid-Atlantic Manure P and N Surplus State P N --Million Lbs in Excess-- DE MD NJ NY PA VA (Source: USDA, 2001)

Nutrient depletion in Africa

Nutrient budgets on organic farms N P K a review of published data Most organic farms in developed countries do not have nutrient deficits even though they don’t use conventional fertilizers.

Daily inputs and outputs of dry matter, P and N

urinefeces N P K 50% 10%90% 10% N 20% maintenance P 13% maintenance K 12% maintenance 60% 20% 60% 27% 75% 13%

Nitrogen budget for a dairy in Florida (lbs of N/acre)

`Number of dairy cows per farm tons of N/year -- Input Purchased Fertilizer Purchased Feed N Fixation by Legumes Purchased Animals Output Milk Animals Sold Crops Sold Surplus Nitrogen budget for 4 dairies in New York

Manure constituentLbs/year/100 cowsProbable $ value Raw manure (feces + urine)5,045,000 Water in fresh manure4,458,990 Total solids586,000 Total N (lb) 23,400$3,510 1 Total P (lb) 4,800$2,880 1 Total K (lb) 15,100$2,265 1 TOTAL VALUE of N, P, and K $8,655 1 Based on assumed values of $.30/lb N, $.60/lb P, and $.15/lb K; N recovered was 50% of excretion, thus, 50% volatilized. Table 3. Annual manure production and nutrient value for 100 cows ~ 2 X in 2008

P inputs for 33 hog and beef operations in NE