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Nitrate accumulation and movement under deficit irrigation in soil receiving cattle manure and commercial fertilizer

Tarkalson, D.D. and Payero, J.O. and Ensley, S.M. and Shapiro, C.A. (2006) Nitrate accumulation and movement under deficit irrigation in soil receiving cattle manure and commercial fertilizer. Agricultural Water Management. 85:201-210.

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Nitrate leaching from agricultural soils can increase groundwater nitrate concentrations.
The objectives of the study were to assess the accumulation and movement of nitrate in the
soil profile over a 2-year period under deficit irrigation conditions following a one time
application of N in cattle feedlot manure and commercial fertilizer to corn at rates to achieve
yield goals expected under conditions of full irrigation. Cattle manure and ammonium
nitrate were applied in 2002 at the University of Nebraska recommended rate (1M and 1F ;
respectively) and cattle manure was applied at twice the recommended rate (2M) for N for
the 2002 corn (Zea mays L.) crop. The recommended rate was based on expected yields under
full irrigation. The manure N treatments were applied to percolation lysimeters and
adjacent plots on a Cozad silt loam soil. Ammonium nitrate was applied only to the
percolation lysimeters. Leachate from the lysimeters was extracted from a depth of
2.1 m and soil samples were collected from field plots in 0.3 m depth increments to
2.1 m on a periodic basis. Water available to the crop was sufficient to meet 89 and 79%
of the potential crop ET in 2002 and 2003, respectively. When averaged over the manure N
treatments, reduced ET resulted in grain yields that were approximately 2.1 and 2.7 Mg ha- 1
less than expected in 2002 and 2003. Under deficit water inputs there was leachate movement
below the root zone. Leachate depths averaged over N treatments were, however,
reduced by 15% (33 mm) in 2002 and 47% (102 mm) in 2003 compared with those reported
under full irrigation. The average nitrate-N (NO3-N) concentrations in leachate were higher
under the 2M treatment (41 mg L- 1) compared to the 1M treatment (17 mg L- 1). The average
NO3-N concentrations in leachate from the 1F treatment (28 mg L- 1) was not different than
the 1 or 2M treatments. There were trends for greater NO3-N mass losses in leachate
averaged over all treatments in 2003 compared to 2002, indicating that NO3-N derived from
the 2002 application leached to at least 2.4 m below the soil surface. There were no mass loss
differences in leachate due to the 2001 crop in 2002. In 2003, mass of NO3-N in lysimeters
cropped to soybean in 2001 were significantly higher (144 kg NO3-N ha 1) than the mass in lysimeters cropped to corn in 2001 (51 kg NO3-N ha-1). Nitrate-N mass increased in the 0.9-
2.1 m soil depth 12-13 months after manure N treatment applications. The 2M treatment had
greater soil NO3-N mass than the 1M treatment for most sampling dates in the surface
0.9 m. This research shows that there can be significant nitrate losses under deficit irrigation
when manure N is over applied. These losses are likely related to water initially stored below
the root zone and preferential flow of water from irrigation and precipitation. Determining
accurate yield expectations under deficit irrigation conditions, correct scheduling of irrigation,
and the use current best management practices for N management can help minimize
nitrate losses in leachate.

Item Type: Article
NWISRL Publication Number: 1220
Subjects: Manure > Chemistry
Soil > Amendments > Fertilizer
Soil > Chemistry > Nitrogen
Mass Import - autoclassified (may be erroneous)
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:49
Last Modified: 31 Oct 2016 17:19
Item ID: 59