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Effects of integrated application of plant-based compost and urea on soil food web, soil properties, and yield and quality of a processing carrot cultivar

A. Habteweld
A. Habteweld
, 
D. Brainard
D. Brainard
, 
A. Kravchencko
A. Kravchencko
, 
P. S. Grewal
P. S. Grewal
 and 
H. Melakeberhan
H. Melakeberhan
   | Oct 21, 2020
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Published Online: Oct 21, 2020
Page range: 1 - 17
DOI: https://doi.org/10.21307/jofnem-2020-111
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© 2020 A. Habteweld et al., published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1:

Soil food web condition in plots amended with integrated application of urea and PC, standard urea and non-amended check in sandy loam soil at planting (May, June) and harvest (October) in 2012 to 2014 growing seasons. Numbers 1 to 6 represent treatments: 1 = Urea alone (U1:PC0), 2 = U3:PC1, 3 = U1:PC1, 4 = U1:PC3, 5 = PC alone (U0:PC1), and 6 = non-amended check. The soil food web condition is expressed in four quadrants (A, B, C, and D) according to Ferris et al. (2001). *Treatments significantly increased SI from 50 using one-tail t-test at α = 0.05 for 2014 growing season.
Soil food web condition in plots amended with integrated application of urea and PC, standard urea and non-amended check in sandy loam soil at planting (May, June) and harvest (October) in 2012 to 2014 growing seasons. Numbers 1 to 6 represent treatments: 1 = Urea alone (U1:PC0), 2 = U3:PC1, 3 = U1:PC1, 4 = U1:PC3, 5 = PC alone (U0:PC1), and 6 = non-amended check. The soil food web condition is expressed in four quadrants (A, B, C, and D) according to Ferris et al. (2001). *Treatments significantly increased SI from 50 using one-tail t-test at α = 0.05 for 2014 growing season.

Figure 2:

Means across all sampling time points of soil phosphorus content at the studied treatments across 2012 and 2013 growing seasons. Ratios represent treatments: Urea alone (U1:PC0), 3:1 ratio of urea and PC (U3:PC1), 1:1 ratio of urea and PC (U1:PC1), 1:3 ratio of urea and PC (U1:PC3), PC alone (U0:PC1) and Check = non-amended control. Bars with different letters are significantly different at P ≤ 0.05 using Fisher’s LSD. Error bars represent standard errors.
Means across all sampling time points of soil phosphorus content at the studied treatments across 2012 and 2013 growing seasons. Ratios represent treatments: Urea alone (U1:PC0), 3:1 ratio of urea and PC (U3:PC1), 1:1 ratio of urea and PC (U1:PC1), 1:3 ratio of urea and PC (U1:PC3), PC alone (U0:PC1) and Check = non-amended control. Bars with different letters are significantly different at P ≤ 0.05 using Fisher’s LSD. Error bars represent standard errors.

Figure 3:

Means across all sampling time points of soil respiration (µg CO2-C g−1 day−1) at the studied treatments across 2012 and 2013 growing seasons. Ratios represent treatments: Urea alone (U1:PC0), 3:1 ratio of urea and PC (U3:PC1), 1:1 ratio of urea and PC (U1:PC1), 1:3 ratio of urea and PC (U1:PC3), PC alone (U0:PC1) and Check = non-amended control. Bars with different letters are significantly different at P ≤ 0.05 using Fisher’s LSD. Error bars represent standard errors.
Means across all sampling time points of soil respiration (µg CO2-C g−1 day−1) at the studied treatments across 2012 and 2013 growing seasons. Ratios represent treatments: Urea alone (U1:PC0), 3:1 ratio of urea and PC (U3:PC1), 1:1 ratio of urea and PC (U1:PC1), 1:3 ratio of urea and PC (U1:PC3), PC alone (U0:PC1) and Check = non-amended control. Bars with different letters are significantly different at P ≤ 0.05 using Fisher’s LSD. Error bars represent standard errors.

Figure 4:

Effect of treatments on mean carrot yield by category (marketable and unmarketable) in 2012, 2013, and 2014. Ratios represent treatments: Urea alone (U1:PC0), 3:1 ratio of urea and PC (U3:PC1), 1:1 ratio of urea and PC (U1:PC1), 1:3 ratio of urea and PC (U1:PC3), PC alone (U0:PC1) and Check = non-amended control. There was no significant difference in quality category at P ≤ 0.05 using Fisher’s LSD.
Effect of treatments on mean carrot yield by category (marketable and unmarketable) in 2012, 2013, and 2014. Ratios represent treatments: Urea alone (U1:PC0), 3:1 ratio of urea and PC (U3:PC1), 1:1 ratio of urea and PC (U1:PC1), 1:3 ratio of urea and PC (U1:PC3), PC alone (U0:PC1) and Check = non-amended control. There was no significant difference in quality category at P ≤ 0.05 using Fisher’s LSD.

Figure 5:

Multiple factor analysis of the variables where Dimension 1 (Dim 1) and Dimension 2 (Dim 2) represent the first and second best summary of variability of the information, respectively. (A) Relationships among soil properties (Gc1) (soil pH (pH), organic matter percentage (OM), nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), calcium (Ca), magnesium (Mg), phosphorus (P), potassium (K), moisture percent (MO), bulk density (BD), cation exchange capacity (CEC), and porosity (PO) and abundance of nematode trophic groups (Gc2) (bacterivores (BV), fungivores (FV), omnivores (OV), predators (PR), herbivores (HV)) and non-herbivores (FL) (Yeates et al., 1993). (B) Relationships of soil food web indices (Gc1) (SI, EI, CI, and BI), soil properties (Gc2), and carrot yield and quality (Gc3) (total marketable (MC) and total unmarketable carrots (UNC)) from plots amended with integrated application of urea and plant compost.
Multiple factor analysis of the variables where Dimension 1 (Dim 1) and Dimension 2 (Dim 2) represent the first and second best summary of variability of the information, respectively. (A) Relationships among soil properties (Gc1) (soil pH (pH), organic matter percentage (OM), nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), calcium (Ca), magnesium (Mg), phosphorus (P), potassium (K), moisture percent (MO), bulk density (BD), cation exchange capacity (CEC), and porosity (PO) and abundance of nematode trophic groups (Gc2) (bacterivores (BV), fungivores (FV), omnivores (OV), predators (PR), herbivores (HV)) and non-herbivores (FL) (Yeates et al., 1993). (B) Relationships of soil food web indices (Gc1) (SI, EI, CI, and BI), soil properties (Gc2), and carrot yield and quality (Gc3) (total marketable (MC) and total unmarketable carrots (UNC)) from plots amended with integrated application of urea and plant compost.

Figure 6:

Multiple factor analysis of the variables where Dimension 1 (Dim 1) and Dimension 2 (Dim 2) represent the first and second best summary of variability of the information, respectively. (A) Relationships among abundant herbivores (Gc1) (Malenchus, MAL; Tylenchus, TYL; Helicotylenchus, HEL; Pratylenchus, PRA) and carrot yield and quality expressed as fresh weight (Gc2) (total marketable (MC) and total unmarketable carrots (UNC). (B) Relationships among and abundant herbivore nematodes (Gc1) and carrot yield and quality (Gc2) expressed as number from plots amended with integrated application of urea and plant compost.
Multiple factor analysis of the variables where Dimension 1 (Dim 1) and Dimension 2 (Dim 2) represent the first and second best summary of variability of the information, respectively. (A) Relationships among abundant herbivores (Gc1) (Malenchus, MAL; Tylenchus, TYL; Helicotylenchus, HEL; Pratylenchus, PRA) and carrot yield and quality expressed as fresh weight (Gc2) (total marketable (MC) and total unmarketable carrots (UNC). (B) Relationships among and abundant herbivore nematodes (Gc1) and carrot yield and quality (Gc2) expressed as number from plots amended with integrated application of urea and plant compost.

Soil pH, nitrate-nitrogen (NO3-N) and calcium (Ca) contents (ppm) in plots amended with integrated application of urea and PC to supply 135 kg N/ha recommended for processing carrot cultivars, standard urea application and non-amended check in sandy loam soil at planting (0) and at 133 days after planting (DAP) in 2012 to 2013 growing seasons.

Treatments as a ratio of urea (U) and PC
Variables YR DAP U1: PC0a U3:PC1 U1:PC1 U1:PC3 U0:PC1 Check
pH 2012 0 6.8 ± 0.1 bBb 6.8 ± 0.2 bB 7.2 ± 0.3 bA 7.0 ± 0.2 bAB 7.2 ± 0.1 bA 7.2 ± 0.4 cA
133 6.4 ± 0.3 cB 6.8 ± 0.3 bAB 7.4 ± 0.1 abA 7.2 ± 0.4 bA 7.3 ± 0.5 bA 7.3 ± 0.6 abcA
2013 0 6.9 ± 0.1 bA 7.0 ± 0.2 abA 7.4 ± 0.1 abA 7.2 ± 0.3 bA 7.3 ± 0.5 bA 7.4 ± 0.6 bA
133 6.7 ± 0.2 bB 7.1 ± 0.1 aAB 7.5 ± 0.1 aA 7.4 ± 0.2 aA 7.6 ± 0.3 aA 7.5 ± 0.5 abA
NO3-N 2012 0 1.4 ± 0.3 dAB 0.6 ± 0.2 cB 0.8 ± 0.9 cAB 0.5 ± 0.1 cB 0.7 ± 0.5 cB 1.5 ± 0.6 cA
133 29.2 ± 17 aA 2.9 ± 0.9 bB 3.0 ± 1 bB 3.7 ± 1 abB 4.6 ± 2 bB 3.0 ± 2 bB
2013 0 5.3 ± 0.6 cA 5.4 ± 1.3 aA 6.0 ± 0.9 aA 5.4 ± 0.2 aA 6.5 ± 1.2 aA 7.2 ± 3 aA
133 17.5 ± 8 bA 2.6 ± 1.2 bB 3.4 ± 2.3 bB 4.6 ± 2.5 aB 3.8 ± 1.4 bB 2.7 ± 0.5 bB
Ca 2012 0 1159.7 ± 171 bA 1120.7 ± 123 bA 1263.3 ± 129 abA 1139.3 ± 82 bA 1192.7 ± 115 bA 1295.7 ± 298 bA
133 1057.3 ± 103 bA 1126.7 ± 110 bA 1287.7 ± 122 abA 1193.7 ± 33 bA 1307.3 ± 351 abA 1303.7 ± 433 bA
2013 0 1111.3 ± 91 bA 1108.7 ± 120 bA 1246.7 ± 73 bA 1152.3 ± 129 bA 1345.3 ± 424 abA 1406.3 ± 495 aA
133 1243.3 ± 95 aA 1242.3 ± 121 aA 1471.3 ± 57 aA 1388.3 ± 116 aA 1423.0 ± 186 aA 1450.3 ± 365 aA

List of nematode genera detected in plots amended with integrated application of urea and PC at different levels to supply 135 kg N/ha recommended for processing carrot cultivars, standard urea, and non-amended check plots in sandy loam soil in 2012, 2013, and 2014 growing seasons.

Herbivores Bacterivores Fungivores Omnivores Predators
Basiria (2) Eumonhystera (1) Aphelenchoides (2) Eudorylaimus (4) Tripyla (3)
Boleodorus (2) Mesorhabditis (1) Aphelenchus (2) Mesodorylaimus (4) Clarkus (4)
Cephalenchus (2) Panagrellus (1) Ditylenchus (2) Microdorylaimus (4) Mylonchulus (4)
Malenchus (2) Panagrolaimus (1) Filenchus (2) Pungentus (4) Prionchulus (4)
Paratylenchus (2) Pellioditis (1) Diphtherophora (3) Thonus (4) Nygolaimus (5)
Psilenchus (2) Pristionchus (1) Tylencholaimellus (4) Aporcelaimellus (5)
Tylenchus (2) Rhabditis (1) Prodorylaimus (5)
Dolichorynchus (3) Acrobeloides (2)
Helicotylenchus (3) Cephalobus (2)
Hemicycliophora (3) Cervidellus (2)
Heterodera (J2) a (3) Eucephalobus (2)
Pratylenchus (3) Heterocephalobus (2)
Rotylenchus (3) Plectus (2)
Tylenchorhynchus (3) Microlaimus (3)
Trichodorus (4) Prismatolaimus (3)
Longidorus (5) Alaimus (4)
Xiphinema (5)

Probability values (Pr > F) of treatment (TR), sampling time (T), and interaction of treatment and sampling time (TR × T) effects for nematode trophic group abundances, non-herbivore and total nematodes, nematode community and soil food web indices, soil respiration and soil physiochemical properties for field plots amended with integrated application of urea and PC at different levels to supply 135 kg N/ha and standard urea application and non-amended check in sandy loam soil in 2012 to 2014.

Probability > F
Variables TR T TR × T
Trophic groups
 Herbivores 0.95 < 0.0001 0.60
 Bacterivores 0.95 < 0.0001 0.67
 Fungivores 0.93 < 0.0001 0.77
 Omnivores 0.86 < 0.0001 0.35
 Predators 0.48 < 0.0001 0.82
 Non-herbivores 0.98 < 0.0001 0.62
 Total nematodes 0.97 < 0.0001 0.89
Diversity indices
 H′a 0.99 < 0.0001 0.2
 Hill’s N1 0.97 < 0.0001 0.29
 Hill’s N0 0.99 < 0.0001 0.44
Ecological disturbance indices
 PPI 0.91 < 0.0001 0.43
 MI 0.67 < 0.0001 0.48
 MI25 0.13 < 0.0001 0.64
Food web indices
 EI 0.630 0.0012 0.49
 SI 0.041 < 0.0001 0.48
 BI 0.623 < 0.0001 0.61
 CI 0.940 < 0.0001 0.48
 Soil respiration 0.020 < 0.0001 0.53
Soil physiochemical properties
 Bulk density 0.45 < 0.0001 0.98
 Porosity 0.26 < 0.0001 0.98
 Moisture 0.28 < 0.0001 0.73
 Soil pH 0.18 < 0.0001 0.01
 Phosphorus 0.02 0.005 0.74
 Potassium 0.69 < 0.0001 0.42
 Calcium 0.48 < 0.0001 0.03
Magnesium 0.74 < 0.0001 0.55
Organic matter 0.23 < 0.0001 0.54
Nitrate-nitrogen 0.02 < 0.0001 <0.0001
Ammonium-nitrogen 0.43 < 0.0001 0.99
Cation exchange capacity 0.62 < 0.0001 0.55
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