Effect of Long-Term Application

1
Effect of Long-Term Application of Biosolids
on Molybdenum Content of Winter Wheat Forage
Nick Basta and Bill Raun Department of Plant and
Soil Sciences Oklahoma State University
2
Mo Concerns

• Molybdenosis in Cattle
• Biosolids Mo may increase forage Mo
• May narrow the Cu/Mo ratio.
• High pH soil (liming) may increase concern

3
Experimental Methods
Experimental Design RCB, 3 Reps Treatments 14 N
Sources Biosolid, Ammonium nitrate N Rates 0,
40, 80, 160, 240, 480 kg N/ha/yr Non-factorial
treatments Lime applied at high N rate (both
sources) Norge loam (fine mixed, thermic Udertic
Paleustoll) Planting (October 15, 1998) Forage
Sampling Clipped at ground level (1x1m) Feekes 4
(December 9, 1998) Winter Wheat Variety
Tonkawa Forage Processing Samples dried and
ground to pass 150 uM (100 mesh)
4
Treatment structure and grain yield means,
1994-1998, Stillwater, OK. Trt N rate N
Source 1994 1995 1996 1997 1998 Avg pH kg/ha ---
------------------------- bu/ac
--------------------------- 1 0 - 6.9 7.4 9.1 16.8
28.8 13.8 6.8 2 0 - 5.6 7.7 8.6 19.1 23.9 13.0 3
40 SS 7.8 8.5 10.8 23.2 35.4 17.1 4 80 SS 9.2 8.5
9.8 22.5 33.4 16.7 5 160 SS 13.2 8.5 18.4 20.8 45.
4 21.2 6 240 SS 15.4 9.1 13.7 20.7 42.1 20.2 7 480
SS 22.4 15.3 12.2 21.7 53.6 25.0 6.0 8 40 AN 26.5
9.2 5.0 20.4 30.6 18.3 9 80 AN 25.9 13.5 7.6 26.2
42.6 23.1 10 160 AN 28.6 17.8 9.9 32.4 51.2 28.0
11 240 AN 38.5 21.1 8.0 35.0 45.2 29.5 12 480 AN 3
4.8 19.1 8.3 38.0 46.2 29.2 4.6 13 480 SSL 24.8 1
5.6 13.1 24.2 55.5 26.7 6.6 14 480 ANL 32.5 19.7
11.6 42.3 55.2 32.2 4.8 L - lime applied at a
rate of 8960 kg/ha (4 tons/acre) in the first
year of the study
5
Chemical Characteristics of soil (0-30 cm) prior
to treatment application _________________________
_________________________________________ pH Orga
nic C Total N NH4-N NO3-N K P CEC --------g
kg-1-------- -----------------mg
kg-1---------------- cmol kg -1 6.4 11.9 1
.1 7.0 5.0 25.3 30.2 13.05 _______________________
____________________________________________
6
Biosolids Applied (480 kg N/ha)
Year 1993 1994 1995 1996 1997 93-7 EPA median
Cu (ppm) 928 756 684 454 507 600 741
Mo (kg/ha) 0.47 0.17 0.26 0.15 0.15 0.18
Mo (ppm) 50.2 9.3 25.7 16.7 16.4 17.0 9

• City of Stillwater
• Anaerobic-digestion

7
Forage Collection
Feekes 4 (tillering) Split forage samples washed
and unwashed
8
Growth Stages in Cereals
Ripening Stage
Stem Extension
Heading
Tillering
9
Chemical Analysis
Wet digestion (HNO3/HClO4) ICP analysis TJA
IRIS ICP, 202.0 nm LOQ 10 ppb Mo (0.2 ppm
forage)
10
Results
11
Copper
12
Molybdenum
13
Cu/Mo
14
Copper
15
Molybdenum
16
Cu/Mo