Experiment 301: Continuous Application of Biosolids in Winter Wheat Production, 1994-2004

Summary

 

        From 1994 to 2004, AN treatments at the same N rate resulted in significantly greater grain yields when compared to biosolids treatments. 

        Poor stand and weed pressure adversely affected yields in 1995 and 1996

        In 5 of 11 years applying 160 lb N/ac resulted in increased yields compared to 80 lb/ac

        RINDVI predicted RIHARVEST in 3 of 6 years, underestimating in the other 3

 

References 

Gavi, F., W.R. Raun, N.T. Basta, and G.V. Johnson. 1997. Effect of sewage sludge and ammonium nitrate on wheat yield and soil profile inorganic nitrogen accumulation. J. Plant Nutr. 20 (2&3): 203-218.

Mullen, R. W., W.R. Raun, N.T. Basta, J.L. Schroder, and K.W. Freeman. 2004. Effect of long-term application of biosolids on molybdenum content and quality of winter wheat forage. J. Plant Nutr. (in press).

Abstract

Environmentally sound management practices for sewage sludge in grain crop production systems are becoming increasingly important.  The objectives of this study were to compare N rates of sewage sludge and ammonium nitrate on yield and heavy metal uptake in winter wheat (Triticum aestivum L.).  One field experiment was established in 1993 that evaluated six N rates (0 to 538 kg ha-1 yr-1) as dry anaerobically digested sewage sludge and ammonium nitrate.  Lime application in 1993 (8.96 Mg ha-1), 1999 (8.96 Mg ha-1) and 2000 (12.99 Mg ha-1) was also evaluated.  In general, wheat yields peaked at the 180 kg N ha-1 rate when N was applied as either sewage sludge or ammonium nitrate.  However, wheat grain yields were significantly higher using ammonium nitrate when compared to sewage sludge at comparable rates.  Averaged over this seven year period, ammonium nitrate treatments resulted in 28.1 bu/ac (1.9 Mg/ha) while sewage sludge resulted in 20.2 bu/ac (1.4 Mg/ha)(both averaged over N rates).  Fertilizer N immobilization was expected to be high in the first few years since this site was previously in native bermudagrass (Cynodon dactylon L.).  Following 2-3 years of applying sewage sludge, we expected to achieve the same yields at comparable rates as that using ammonium nitrate.  Because ammonium nitrate treatments continue to produce significantly higher yields (following 7 years) when compared to sewage sludge, either N mineralization rates are markedly lower than that previously thought (21% for sewage sludge), or the soil-plant system has yet to achieve equilibrium.  Molybdenum concentrations in wheat forage at Feekes growth stage 4 were significantly higher in sewage sludge treated plots when compared to ammonium nitrate.  Alternatively, Cu and Fe levels did not differ in wheat forage as a function of N source (sewage sludge versus ammonium nitrate).  The Cu to Mo ratio in the wheat forage was above 2 for all treatments.  When Cu:Mo ratios are less than 2 in wheat forage, cattle can develop Cu deficiencies.  When lime was applied, forage Mo levels were dramatically higher for sewage sludge plots as compared to ammonium nitrate.

Table  1. Treatment structure and grain yield means (kg/ha), 1994-2004, Stillwater, OK.

TRT

Source

N-rate

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

Mean

1

ck

0

464

499

613

1128

1934

908

924

1246

1677

1621

2157

1197

2

ck

0

378

520

575

1288

1611

903

975

1075

834

1505

1888

1050

3

ss

40

527

571

728

1558

2379

948

1310

1685

1753

2357

2921

1522

4

ss

80

617

574

657

1515

2243

1069

1498

1574

2056

2398

3033

1567

5

ss

160

886

569

1234

1400

3050

1362

1576

1982

1972

2754

3426

1846

6

ss

240

1038

611

919

1390

2832

965

1234

1778

1871

1505

3734

1637

7

ss

480

1505

1027

822

1458

3604

1834

1923

1542

1972

2622

3651

1996

8

an

40

1782

620

339

1369

2055

904

1719

1387

1905

1662

2530

1479

9

an

80

1739

906

512

1763

2863

1608

2887

1843

2731

3581

3818

2205

10

an

160

1921

1196

666

2177

3442

2369

3304

2271

2596

4342

4260

2595

11

an

240

2589

1419

536

2351

3041

2890

2785

1627

1551

3382

3382

2323

12

an

480

2337

1282

557

2557

3106

2477

2052

1791

1728

2936

3416

2204

13

ssl

480

1669

1052

880

1630

3730

2602

1569

1987

2225

3366

4515

2293

14

anl

480

2187

1326

782

2843

3711

2860

2212

1825

2115

4466

4822

2650

 

Mean

 

1442

944

788

1745

2829

1693

1877

1687

1928

2750

3397

1897

 

SS

 

914

670

872

1464

2822

1236

1508

1712

1925

2327

3353

1714

 

AN

 

2073

1085

522

2044

2901

2050

2549

1784

2102

3181

3481

2161

 

 

 

1159

414

-350

579

80

814

1041

71

177

853

128

447

L - lime applied at a rate of 8960 kg/ha (4 tons/acre) in the fall of 1993
L lime applied at a rate of 8960 kg/ha (4 tons/acre) in the fall of 1999 (87% ECCE)
L - lime applied at a rate of 12,992 kg/ha (5.8 tons/acre) in the fall of 2000 (85% ECCE)
SS - sewage sludge obtained from the City of Stillwater
AN - ammonium nitrate (34-0-0)
SED - standard error of the difference between two equally replicated means
CV - coefficient of variation, %

Table 2.  Total nitrogen and moisture content of Stillwater sewage sludge, 1993 to 2000.

1993

1994

1995

1996

1997

1998

1999    

2000

 Avg.

Total N, %

2.02

1.74

1.97

2.73

2.42

2.43

2.02

2.44     

2.22

Moisture, %

60

35

59

na

55

46

45

17

45

  • From 1994 to 1997, AN treatments at the same N rate resulted in significantly greater grain yields when compared to sewage sludge. 

  • Poor stand and weed pressure adversely affected yields in 1996

  • By 1998, no differences in grain yield could be detected between AN and SS treatments

  • In 1999, SS treatments had significantly lower yields when compared to the same N rates using AN

Annually applied biosolids, fall of 1993 to 2002, Efaw Experiment Station, Stillwater, OK 2002.

Annually applied biosolids, fall of 1993 to 2002, Efaw Experiment Station, Stillwater, OK 2002.

Annually applied biosolids, picture taken in the spring of 1996, Efaw Experiment Station, Stillwater, OK 2002.

Dr. N.T. Basta, Presentation, 1999