improving soil health and crop productivity in mississippi...
TRANSCRIPT
Improving Soil Health and Crop Productivity in Mississippi Utilizing Cover Crops and Poultry Litter
Dr. Jac J VarcoPlant and Soil Sciences Dept., Mississippi State University
North Mississippi Fruit and Vegetable Growers Conference February 8-9th
Objective
To determine the effects of mono- and bi-culture cover cropping with and without fall applied poultry litter on strip till corn productivity, N cycling, and soil quality and health indicators.
Methods
• Site Description – Alluvial soils mapped as a Marietta fine sandy loam (fine-loamy, siliceous, active, thermic Fluvaquentic Eutrudept) and Leeper silty clay loam (fine, smectitic, nonacid, thermic VerticEpiaquept).
• Experimental Design -Randomized complete block, four blocks with soil classification considered. Land planed for 1 to 2 % slope for furrow irrigation (rainfed only for study duration)
Methods cont.• Cover crops
1. Plant mid-late Oct. (Fall 2013 Leg=Hairy vetch (HV)/Crimson clover mix, rye, Leg-rye; Fall 2014-2015 Leg=HV, rye, Leg-rye; and Fall 2016 Leg=Persian clover, rye, Leg-rye)
2. Poultry litter application @ 2000 lb (dw basis) 3rd week of Nov. each year; source= Mighty-Grow
• Corn• Strip-tilled, rolled plots mid-April• Corn planted @32,000 kernels/acre
• Soil sampling• Enzyme assay (FDA); At planting (Day) , 14 DAP, and 28 DAP at 0- to 5-cm,
and 5- to 15-cm depths• Bulk density and total C and N analysis; post corn harvest;
CoverCrop/PL Cover Crop N Content, kg/ha
CC 2013 2014 2015 2016* 2017 Ave
Legume 91 96 60 14 64 65 (78)
Rye 50 33 29 24 44 36
LegRye 73 78 52 33 49 57 (63)
PL, Mg/ha
0 67 56 41 22 48 47
2 76 82 53 26 56 59
1. Cover crop N content prior to termination and corn planting
* Hairy vetch infested with root rot (Phytophthora sp.)
FDA Results, 2017
Days After Planting0 5 10 15 20 25 30
Enzy
me
Activ
ity, µ
g g-1
0
50
100
150
200
250
300
LSD=20.2
LSD=47.4NS
NS
NS
NS
FNRow
WF Row Leg Row Rye Row
LegRye Row FNMiddle WF Middle Leg Row Middle Rye Middle LegRye Middle
2. Microbial Activity-Fluorescein diacetate (FDA) hydrolysis
3. Soil bulk density 0- to 5-cm, fall 2016/2017
Treatment Row position
N rate (kg/ha) /CC/PL Row Inter-row
g/cm3
2016 2017 2016 2017
168/WF/No 1.36ab 1.36 1.38ab 1.38
Legume 1.36ab 1.30 1.44b 1.34
Rye 1.36ab 1.28 1.43ab 1.36
Leg-Rye 1.30ab 1.34 1.36ab 1.37
PL 1.30ab 1.29 1.42ab 1.34
Legume-PL 1.30ab 1.32 1.39ab 1.30
Rye-PL 1.28ab 1.25 1.35a 1.31
Leg-Rye-PL 1.27a 1.29 1.40ab 1.38
LSD(0.05) 0.10 0.09
Corn row vs. inter-row
Treatment Row Inter-row
N rate (kg/ha)/CC/PL Total N Total C Total N Total C
kg/m3
168/WF/No 1.17 14.1 1.38 17.3
0/Legume 1.26 14.5 1.62 19.3
0/Rye 1.25 14.6 1.52 18.4
0/Leg-Rye 1.26 14.5 1.61 19.3
0/PL 1.15 12.7 1.56 18.2
0/Legume-PL 1.27 14.1 1.61 20.6
0/Rye-PL 1.39 16.0 1.59 19.1
0/Leg-Rye-PL 1.52 17.1 1.73 20.4
LSD(0.05) 0.22 0.29
Total soil N and C content 0- to 5-cm, fall 2016
Corn row vs. inter-row
CoverCrop/PL
Whole plant (stover plus grain) N content, kg/ha
CC 2013* 2014 2015 2016** Ave
Legume 43 71 107 75 74
Legume PL
56 95 138 78 92
Rye 25 48 64 46 46
Rye PL 25 53 80 54 53
LegRye 52 62 97 61 68
LegRyePL 36 68 118 83 76
WF 43 54 88 55 60
WFPL 35 50 69 57 53
LSD(0.05) 27 21 28 17*Grain N content only**Hairy vetch infested with root rot (Phytophthora sp.)
4. Corn N Content
CoverCrop/PL
Fertilizer N Equivalents based on grain yield, kg/ha
CC 2013 2014 2015 2016** 2017 Ave
Legume 6.7 32.9 59.2 41.1 53 38.6
Legume PL
25.4 85.2 117.3 87.1 78 78.6
Rye -27.6 -30.6 -24.4 -5 -14 -20
Rye PL -29.3 -26.8 -5.8 2.6 11 -9.7
LegRye 26.2 -2.9 36.8 13 29 20.4
LegRyePL -12.5 2.5 77.9 35 49.5 30.5
WFPL -4.2 -17.6 -5.5 4 13 2.1
LSD(0.05) 47.3 36.9 50.5
Grain yield based fertilizer N equivalence
*Hairy vetch infested with root rot (Phytophthora sp.)
Year2013 2014 2015 2016 2017
Gra
in Y
ield
, Mg
ha-1
0
2
4
6
8
10
12
14
0 56 112 168 224 Leg LegPL Rye RyePL LegRye LegRyePL PL
5. Grain yield trends
Other Benefits such as wildlife and pollinators
Summary1. Cover crops can be used to increase soil biological
activity.2. Cover crops increased soil organic matter.3. Fall applied poultry litter in combination with legume
cover crops resulted in the greatest nutrient cycling and corn yield.