zagadjivanje zemljista nitratima

7/16/2019 Zagadjivanje zemljista nitratima

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The Nitrate

Contamination

Concern

The Nitrate

Contamination

Concern



EPAMaximum Contaminant

Level (MCL) for

public water supplies

10 ppm nitrate-nitrogen

EPAMaximum Contaminant

Level (MCL) for


10 ppm nitrate-nitrogen



MCL

(Maximum Contaminant Level)

MCL

(Maximum Contaminant Level)

Enforceable standard for


Enforceable standard for Enforceable standard for

public water supplies public water supplies



Private WellsPrivate WellsPrivate water supplies are not legally

required to meet MCL . . . .

HOWEVER, to ensure safe drinkingwater, test for nitrate-nitrogen

Private water supplies are not legallyrequired to meet MCL . . . .

HOWEVER, to ensure safe drinkingwater, test for nitrate-nitrogen



Nitrate in Drinking Water Nitrate in Drinking Water

Major Health Risk Major Health Risk Methemoglobinemia in infantsMethemoglobinemia in infants

(blue baby syndrome)(blue baby syndrome)



Non-Point Source

Contamination

Non-Point Source

Contamination



Non-Point Source

Contamination

Non-Point Source

Contamination

Single source cannot

be identified

Single source cannot

be identified



Water Table

Nitrate Leaching Loss Nitrate Leaching Loss



Sources for non-point

contamination vary. . . .

Sources for nonSources for non-- point point

contamination vary. . . .contamination vary. . . .



Whereis the nitrate problem

found?

Whereis the nitrate problem

found?



Wells with nitrateWells with nitrate--nitrogennitrogen

concentration greater than 10concentration greater than 10 ppm ppm

WellWell



Why does nitrate loss happen?Why does nitrate loss happen?




The soil is a porous system






Nitrate is highly soluble in water --it goes where the water goes








Excess water draining from the rootzone takes nitrate with it



Excess water draining from the rootzone takes nitrate with it



Some nitrate

leaching willalways occur

under continuou

corn or a corn-soybean rotatio

Some nitrateleaching will

always occur

under continuou

corn or a corn-soybean rotation



Nitrate leaching can occur

under any cropping system

Nitrate leaching can occur

under any cropping system



Nitrate leaching occurs

in both pivot- and furrow-irrigated fields

Nitrate leaching occurs

in both pivot- and furrow-irrigated fields



Nitrate-N in the Top 25 ft of Soil(Hamilton County)

Nitrate-N in the Top 25 ft of Soil(Hamilton County)



Excess nitrogen or

excess water

makes the problem worse

Excess nitrogen or

excess water

makes the problem worse



How much nitrogen loss

occurs per year?

How much nitrogen loss

occurs per year?

Si Y f UNL R hSi Y f UNL R h



Six Years of UNL Research on

Sprinkler-Irrigated Corn at North Platt









Sprinkler-Irrigated Corn at North PlattÎ Avg. N Loss 53 lb/ac over 12 months

Range 18 - 83 lb/ac

Î Avg. N Loss 53 lb/ac over 12 months

Range 18 - 83 lb/ac








Range 18 - 83 lb/ac


Range 18 - 83 lb/ac

Î Avg. Root Zone Drainage 9.3 inches per year Range 3.6 - 15.1 inches of drainage









Range 18 - 83 lb/ac


Range 18 - 83 lb/ac



Î Avg. Drainage Nitrate-N Concentration 25 pp

Range of 19 - 35 ppm

Î Avg. Drainage Nitrate-N Concentration 25 pp

Range of 19 - 35 ppm

UNL R h F I i t dUNL R h F I i t d



UNL Research on Furrow-Irrigated

Conventional Tilled Corn at Clay Center



UNL R h F I i t dUNL Research on F rro Irrigated







Î Avg. N Loss 64 to 70 lb/ac over 12 monthsÎ

Avg. N Loss 64 to 70 lb/ac over 12 months

UNL R h F I i t dUNL Research on Furrow Irrigated









Î Avg. Root Zone Drainage 9 - 11 inches per year Î Avg. Root Zone Drainage 9 - 11 inches per year

UNL R h F I i t dUNL Research on Furrow Irrigated









Î Avg. Root Zone Drainage 9 - 11 inches per year Î Avg. Root Zone Drainage 9 - 11 inches per year

Î Avg. Drainage Nitrate-N Concentration 27 -30 pÎ Avg. Drainage Nitrate-N Concentration 27 -30 pp



Grain Yields, Water Use, and Irrigatio

Continuous corn at North Platte

Grain Yields, Water Use, and IrrigatioGrain Yields, Water Use, and Irrigatio

Continuous corn at North PlatteContinuous corn at North Platte

FulFulDryland Dryland

Limited Limited

Irrigation (in) 0.0 5.7 15.Rainfall (in) 6.5 6.5 6.

Stored Soil Water Used (in) 7.9 6.4 0.

ET (in) 14.4 18.6 22.

Grain Yield (bu/ac) 59.0 135.0 178.0

Irrigation (in) 0.0 5.7 15.6Rainfall (in) 6.5 6.5 6.5

Stored Soil Water Used (in) 7.9 6.4 0.3

ET (in) 14.4 18.6 22.4

Grain Yield (bu/ac) 59.0 135.0 178.0

IrrigationIrrigation

1985-8719851985--8787



How long does it takefor nitrate to

reach the groundwater?

How long does it takefor nitrate to

reach the groundwater?



Shallow Groundwater Shallow Groundwater

30 ft

or less

30 ft

or less

Groundwater Groundwater



30 ft

or less

30 ft

or less

Travel time?

A few days to a few months

Travel time?

A few days to a few months


G d



Deep Groundwater Deep Groundwater

75-100 ft75-100 ft

Fine-

textured

materials

Fine-

textured

materials




75-100 ft75-100 ft

Fine-

textured

materials

Fine-

textured

materials

Travel time?

20-30 years

Travel time?Travel time?

2020--30 years30 years




Nitrate movement belowthe crop root zone . . . .

3 ft/yr under furrow irrigation

on a Hastings Silt Loamnear Clay Center

Nitrate movement belowthe crop root zone . . . .

3 ft/yr under furrow irrigationon a Hastings Silt Loam

near Clay Center



75 ft to water table

25-year transit time

75 ft to water table

25-year transit time



1300 -1500 lbs/acnitrate-nitrogen in transit

to the water table

1300 -1500 lbs/acnitrate-nitrogen in transit

to the water table



The ChallengeThe Challenge

Profitable crop

production while

ensuring safedrinking water

Profitable crop

production while

ensuring safe

drinking water

zagadjivanje zemljista nitratima

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