Soil arthropods play an important role in nutrient cycling and maintenance of soil structure, and their abundance and diversity provide an indication of the biological quality of soil. Land application of livestock manure provides crop nutrients and may also impact the soil arthropod community. This study was conducted to quantify soil arthropod abundance and diversity for a period of one year following swine manure application via broadcast or injection. Arthropods were extracted from plot soil samples using Berlese funnels, identified and counted, and the QBS index (Qualità Biologica del Suolo) was calculated for each soil sample. Collembola (Hypogastruridae and Isotomidae) populations were greater ( p < 0.05) in the broadcast plots than the injection or control plots. Pseudoscorpiones were more abundant ( p < 0.05) in the injection treatment compared to the broadcast and control treatments. Acari populations and the QBS index were not significantly impacted by manure application.
Agricultural soil health is a complex concept lacking a simple, direct method of measurement, making it difficult to quantify or categorize. Generally, the term “soil quality” refers to physical and chemical soil characteristics while the term “soil health” also includes information about the biological well-being of the edaphic environment [
Soil arthropod abundance and diversity can provide information about the biological response of soil to environmental changes [
Mites (Acari) and springtails (Collembola) are two of the most abundant and diverse commonly represented soil arthropod orders and are ubiquitous in most agroecosystems [
Application of livestock manure to agricultural fields is a common method of enhancing soil fertility in crop production systems. Understanding the impact of manure addition and application method on soil biology is an important step towards improving the value and desirability of manure for agricultural cropping systems. This study focused on assessing the impact of swine slurry application method and time following slurry application on soil chemical properties and arthropod abundance and diversity for a period of one year.
This field study was conducted at the University of Nebraska-Lincoln Rogers Memorial Farm (Latitude 40.8484662, Longitude 96.4664023) 18 km east of Lincoln, Nebraska, USA, from June 2014 through June 2015. Soil at the site is classified as an Aksarben silty clay loam (fine, smectitic, mesic Typic Argiudoll), containing 3.5% OM and 1.5% total carbon [
Experimental treatments included two manure application methods (broadcast and injected) and a control. Four 0.75 m × 2 m plots were assigned to each treatment and established with the 2-m plot dimension parallel to the slope in the direction of overland flow. Due to site design and manure application equipment, a randomized complete block design was not possible. Arrangement of treatments along a single field contour allowed for consistent soil properties across all plots. Swine slurry collected from the deep pits of an 8000-head commercial wean-to-finish swine facility in eastern Nebraska were analyzed at a commercial laboratory. Mean measured values of nitrate nitrogen (NO3-N), ammonium (NH4-N), total nitrogen (TN), total phosphorous (TP), water content, electrical conductivity (EC), and pH for the slurry were 3.91 g・kg−1, 0.0024 g・kg−1, 5.49 g・kg−1, 0.58 g・kg−1, 96.57%, 42.35 dS・m−1, and 8.0, respectively. Slurry was applied by a commercial operator on June 30, 2014. For injection, a v-shaped chisel (horizontal sweep) implement was used on a 6-row applicator for manure placement to a depth of approximately 15 cm. For broadcast application, the operator lifted the injection apparatus above the soil while maintaining a constant speed and flow rate to distribute the manure on the soil surface. Slurry for both treatments was applied at a rate of approximately 46,800 L・ha−1. Control plots did not receive any application of manure.
Two types of soil samples were collected twelve days prior to treatment applications, one- and three-week post-application of manure, and every four weeks, thereafter, throughout the study period except when soil was frozen in December 2014 and January, February, and March 2015. The two types of soil samples collected were: 1) 3.8-cm diameter samples collected with a soil probe to a depth of 20 cm and subsequently divided into 0 - 10 and 10 - 20 cm sections, which underwent nutrient analysis at a commercial laboratory; and 2) samples measuring 20 cm in diameter and depth (6280 cm3) collected for arthropod extraction. Laboratory analyses included pH, EC, percent organic matter (OM), NO3-N, P, potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), sulfur (SO4-S), and cation exchange capacity (CEC). Samples collected for arthropod extraction were stored in plastic buckets with air holes in the lids, placed in coolers with ice packs, and transported to the University of Nebraska-Lincoln West Central Research & Extension Center in North Platte, Nebraska within 12 h of collection. Samples were transferred to Berlese-Tullgren funnels for extraction of arthropods, a commonly used technique to assess arthropods in the soil [
The QBS method of classification was employed to assign an eco-morphological index (EMI) score from 1 to 20 on the basis of soil adaptability level of each arthropod order or family [
The impacts of swine slurry application method and time following manure application on soil arthropod populations and soil chemical characteristics was determined by performing tests of hypotheses for mixed model analysis of variance using the general linear model (GLM) procedure [
Manure application method affected all measured soil characteristics (
The pH for the 10 - 20 cm depth on the broadcast treatment and for the 0 - 10 cm depth on the broadcast and control treatments were greater than for the injection treatment (
OM was greater in the control and broadcast treatments when compared to the injection treatment (
pH | EC | OM | NO3-N | P | K | Ca | Mg | Na | SO4-S | CEC | |
---|---|---|---|---|---|---|---|---|---|---|---|
mmho・cm−1 | % | mg・kg−1 | mg・kg−1 | mg・kg−1 | mg・kg−1 | mg・kg−1 | mg・kg−1 | mg・kg−1 | me 100 g−1 | ||
Treatment (TRT) | |||||||||||
Injection | 6.21b | 0.39ab | 2.9b | 16.8a | 18.4b | 286.6c | 3087.3b | 670.6a | 17.9a | 9.9b | 23.7a |
Broadcast | 6.63a | 0.40a | 3.3a | 15.2a | 44.4a | 411.5a | 3181.1b | 425.9c | 11.3b | 11.8a | 21.8b |
Control | 6.48a | 0.35b | 3.4a | 10.2b | 20.1b | 334.6b | 3425.5a | 527.6b | 9.1c | 11.3a | 24.1a |
Depth × TRT | |||||||||||
0 - 10 cm | |||||||||||
Injection | 6.38b | 0.44b | 3.2b | 22.3a | 29.7b | 321.5c | 3082.5c | 564.4a | 16.4a | 12.1b | 22.4 |
Broadcast | 7.08a | 0.49a | 3.7a | 20.7a | 64.4a | 510.2a | 3415.7b | 387.3c | 12.9b | 13.3a | 21.8 |
Control | 7.02a | 0.40c | 3.6a | 13.1b | 32.2b | 393.8b | 3545.7a | 417.0b | 7.3c | 13.0a | 22.5 |
10 - 20 cm | |||||||||||
Injection | 6.04b | 0.34a | 2.5c | 11.4a | 7.0b | 251.8c | 3092.1b | 776.8a | 19.4a | 7.7b | 25.1a |
Broadcast | 6.18a | 0.32ab | 3.0b | 9.6ab | 24.4a | 312.8a | 2946.5c | 464.6c | 9.7b | 10.4a | 21.9b |
Control | 5.94b | 0.30b | 3.2a | 7.3b | 8.0b | 275.3b | 3305.4a | 638.2b | 10.9b | 9.6a | 25.8a |
GLM | Pr > F | ||||||||||
TRT | <0.01 | 0.05 | <0.01 | 0.01 | <0.01 | <0.01 | 0.01 | <0.01 | <0.01 | 0.02 | 0.03 |
Rep (TRT) | <0.01 | 0.06 | 0.03 | 0.14 | <0.01 | <0.01 | <0.01 | <0.01 | 0.02 | <0.01 | <0.01 |
Time | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 |
Depth | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | 0.02 | <0.01 | <0.01 |
TRT*Time | <0.01 | <0.01 | 0.07 | <0.01 | <0.01 | <0.01 | <0.01 | 0.01 | <0.01 | <0.01 | <0.01 |
Time*Depth | 0.16 | <0.01 | 0.51 | <0.01 | 0.02 | 0.20 | 0.55 | 0.22 | 0.04 | <0.01 | 0.19 |
TRT*Depth | <0.01 | 0.03 | <0.01 | 0.10 | <0.01 | <0.01 | <0.01 | <0.01 | <0.01 | 0.02 | <0.01 |
TRT*Time*Depth | 0.46 | 0.72 | 0.26 | 0.57 | 0.50 | 0.87 | 0.90 | 0.82 | 0.43 | 0.14 | 0.55 |
†In each section, data within a column with the same letter are not significantly different (p > 0.05).
in OM in the treatment × time interaction (
Both manure application methods increased soil NO3-N compared to the control treatment (
A total of 13,311 arthropods representing 19 orders were identified, with Acari
(38.7% of total arthropods), Collembola: Isotomidae (26.8%), Collembola: Hypogastruridae (10.4%), Coleoptera larvae (1.6%), Diplura (1.2%), Diptera larvae (0.9%), and Pseudoscorpiones (0.6%) being the most abundant soil-dwelling taxa. Because these taxa were of greatest relative abundance in samples throughout the study, they were chosen for statistical analysis of their response to manure application method and time since application.
Hypogastruridae and Isotomidae abundances increased more markedly in the broadcast treatment (
QBS Score | Hypogastruridae | Isotomidae | Acari | Coleoptera Larvae | Diplura | Diptera Larvae | Pseudoscorpiones | |
---|---|---|---|---|---|---|---|---|
Treatment | ||||||||
Injection | 59.9 | 2.93b | 21.70b | 45.55 | 1.03 | 1.30 | 0.73 | 1.43a |
Broadcast | 59.6 | 20.88a | 52.18a | 40.88 | 2.25 | 1.25 | 0.88 | 0.18b |
Control | 57.2 | 10.68b | 15.20b | 42.20 | 1.93 | 1.30 | 1.25 | 0.38b |
Pr > F | ||||||||
Treatment | 0.8609 | 0.0016 | 0.0001 | 0.8828 | 0.3530 | 0.9800 | 0.7380 | 0.0030 |
Time | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0290 | 0.0001 | 0.0190 | 0.1960 |
Treatment × Time | 0.2687 | 0.0001 | 0.0001 | 0.1514 | 0.9140 | 0.0540 | 0.9460 | 0.5590 |
†In each section, data within a column with the same letter are not significantly different (p > 0.05).
abundance following addition of OM via manure application [
Time following slurry application impacted all measured arthropod populations except Pseudoscorpiones. Application method × time following application interactions were identified for Hypogastruridae and Isotomidae. Hypogastruridae abundance remained low in all plots until approximately 60 days into the study, at which time abundance increased sharply in the broadcast treatment (
fecundity, slow development, and low dispersion ability, making them excellent bioindicators [
Overall arthropod community adaptation to soil-dwelling was quantified using the QBS index (
Daily temperature and precipitation data from throughout the study were obtained from the nearest weather stations to the study site (
QBS Score | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Time (days) | Pre | 7 | 21 | 49 | 79 | 113 | 142 | 298 | 332 | 371 |
Treatment | ||||||||||
Injection | 71.0 | 47.0 | 90.0 | 76.0 | 42.0 | 52.0 | 59.5 | 61.3 | 49.3 | 50.8 |
Broadcast | 78.3 | 43.0 | 87.3 | 63.3 | 58.3 | 66.5 | 50.8 | 61.0 | 49.0 | 39.0 |
Control | 90.3 | 39.8 | 62.3 | 76.5 | 64.3 | 75.3 | 48.5 | 28.8 | 43.3 | 43.5 |
†No statistical differences were found among QBS scores.
appear to be correlated with these abiotic conditions. Spikes in Hypogastruridae and Isotomidae abundances in the broadcast treatment 142 days after manure application (
Differences in pH among treatments may have influenced Collembola and other arthropod populations. Collembolans are strongly sensitive to changes in pH [
Few studies have examined the soil arthropod community in agroecosystems following application of swine slurry as our study did. The use of dairy cattle slurry in agricultural systems has been examined in Europe: Leroy et al. [
Swine slurry application to agricultural fields serves as a beneficial fertilizer source that improves soil properties. Method of manure application and time following application may result in varying changes in soil characteristics. This study investigated the effect of application method and time following application on soil arthropod abundance and diversity. The most significant responses to application method were found for collembolan populations, specifically Hypogastruridae and Isotomidae, with both increasing under broadcast application of swine slurry. Pseudoscorpiones were more abundant in the injection treatment throughout most of the post-manure application period of the study. Time following slurry application impacted most of the analyzed populations including Hypogastruridae, Isotomidae, mites, coleopteran larvae, diplurans, and dipteran larvae. The positive response of Hypogastruridae and Isotomidae to broadcast slurry application was likely due to the addition of nutrients (in the form of OM and nitrates) to the soil provided by this form of agricultural fertilizer. Hypogastruridae abundance remained low in all plots until approximately 60 days into the study, at which time abundance increased sharply in the broadcast and control treatments, peaking at about 115 to 150 days in the broadcast and control plots, respectively, before returning to quantities similar to those at the beginning of the study. Hypogastruridae abundance in the injection plots remained lower and much steadier throughout the study. Isotomidae abundance in the broadcast plots followed a similar trend to the Hypogastruridae. Isotomidae abundance in the injection plots increased slightly two months after manure application, but less drastically than observed in the broadcast plots. Total abundance of Acari (mites) showed no response to the application of swine slurry; however, community structure of this diverse group―dominated in our study by Orabatid mites―may have been affected but was not quantified in this study. Soil chemical characteristics
OM was greater in the control and broadcast treatments when compared to the injection treatment, which likely contributed to greater collembolan populations in these treatments. Soil disturbance by injection equipment may have mitigated any positive impacts on arthropod populations from OM addition.
The utilization of swine slurry as a fertilizer source is beneficial to soil health, but requires consideration of application method, time following slurry application, and the combination of those two factors that will influence the soil micro-organisms present in the soil environment.
Eric Davis, Ethan Doyle, Mitchell Goedeken, Stuart Hoff, Kevan Reardon, and Lucas Snethen are gratefully acknowledged for their assistance with field data collection. Kayla Mollet, Ethan Doyle, and Ashley Schmit are acknowledged for their assistance with data processing.
The authors declare no conflicts of interest regarding the publication of this paper.
This work was supported, in part, by faculty research funds provided by the Agricultural Research Division within the University of Nebraska―Lincoln Institute of Agriculture and Natural Resources.
Schuster, N.R., Peterson, J.A., Gilley, J.E., Schott, L.R. and Schmidt, A.M. (2019) Soil Arthropod Abundance and Diversity Following Land Application of Swine Slurry. Agricultural Sciences, 10, 150-163. https://doi.org/10.4236/as.2019.102013