Turkish Journal of Agriculture and Forestry Turk J Agric For (2018) 42: 288-297 http://journals.tubitak.gov.tr/agriculture/ © TÜBİTAK Research Article doi:10.3906/tar-1709-79 Effects of wheel traffic and farmyard manure applications on soil CO2 emission and soil oxygen content 1, 1 2 Sefa ALTIKAT *, H. Kaan KÜÇÜKERDEM , Aysun ALTIKAT 1 Department of Biosystem Engineering, Faculty of Agriculture, Iğdır University, Iğdır, Turkey 2 Department of Environmental Engineering, Faculty of Engineering, Iğdır University, Iğdır, Turkey Received: 20.09.2017 Accepted/Published Online: 17.04.2018 Final Version: 07.08.2018 Abstract: This 2-year field study investigated the effects of different wheel traffic passes, manure amounts, and manure application methods on soil temperature, soil moisture, CO2 emission, and soil O2 content. To achieve this purpose, three different wheel traffic applications (no traffic, one pass, and two passes) were used. In the experiments, two different methods of manure applications (surface and subsurface) and three different farmyard manure amounts were used with a control plot (N0), 40 Mg ha–1 (N40), and 80 Mg ha–1 (N80). Manure was applied in both years of the experiment in the first week of April. For the subsurface application, the manure was mixed in at approximately 10 cm of soil depth with a rotary tiller. According to the results, soil temperature, soil moisture, penetration resistance, and bulk density increased with increasing wheel traffic except 2CO emission for 2014 and 2015. CO2 emission values decreased with traffic. Subsurface manure application caused more 2CO emission compared to surface application. The increase in manure amounts led to an increase in CO2 emission and soil moisture content. The effects on soil O2 content were observed only during 2015. Maximum oxygen values were obtained in the plots where compaction was not applied. In addition, surface manure application caused more soil O2 content compared to subsurface application. Key words: Compaction, CO2 emission, soil temperature, O2 content, soil moisture 1. Introduction atmosphere (Altıkat, 2013; Akbolat, 2009). Poor gas One of the most important greenhouse gas is carbon exchange causes the anaerobic layer to move closer to the dioxide (CO2) because it makes up to 60% of the total surface and reduces rooting volume. greenhouse gases. CO2 is released from soil by respiration. Application of farmyard manure in the soil generally These respirations can be classified as microbial respiration, increases CO2 emissions (Fangueiro et al., 2008). root respiration, and faunal respiration. Soil respiration Farmyard manure application to the soil can usually be occurs at the soil surface or within the upper layer of soil. performed with two methods: surface and subsurface The level of agricultural mechanization and the applications. In subsurface application, farmyard manure increase in field traffic increase soil compaction (Altıkat, is generally spread on the soil and then mixed with tillage 2013). As a result of soil compaction, soil aggregate size machinery such as a plow and rotary tiller. Liquid manure distribution and soil porosity change. This situation affects can also be injected into the soil. Some researchers have the soil microbial population and functions because of the reported that injection of liquid manure can reduce the decrease in C mineralization (Grigal, 2000) and C-N ratio nutrient transport by run-off (Daverede et al., 2004) and (Li et al., 2004). The soil pore system in compacted soil reduce NH3 emissions compared to surface application is generally unfavorable for oxic microbes because this (Misselbrook et al., 1996). situation generally restricts the gas-water ratio (Beylich et The purpose of this study is to determine the effect al., 2010) and causes a lower O2 diffusion rate (Bilen et al., of wheel traffic, farmyard manure application technique, 2010). and manure amount on soil CO2 emissions, O2 content, Compaction not only prevents O2 from being soil temperature, and moisture content. Our specific transported to the root surface, but also prevents CO2 hypotheses were as follows: 1) an increase in wheel traffic and toxic gases (both evolved and resident) from being will result in a decrease in CO2 emissions from the soil removed from around the roots and vented to the to the atmosphere, and a similar effect will be seen in the * Correspondence: [email protected] 288 This work is licensed under a Creative Commons Attribution 4.0 International License. ALTIKAT et al. / Turk J Agric For soil oxygen capacity; 2) the CO2 emission from the soil A tractor (New Holland TD85D) was driven for soil to the atmosphere will be proportional to the amount of compaction (one pass and two passes) on the plots (20 × 35 fertilizer; 3) maximum CO2 emission will be observed in m) in three blocks to account for spatial variability. The tires subsurface manure application. of the tractor were 47 cm wide, with a diameter of 61 cm, and they were inflated to a pressure of 120 kPa. The total weight 2. Materials and methods of the tractor was 3.4 Mg, applying a mean vertical contact 2.1. Study site pressure of approximately 71 kPa. The mean volumetric water The field experiments were set up in Iğdır (39°48′06.69″N, content of the soil surface was 31% and 30% for the 2014 and 44°34′58.30″E), which is located in the east of Turkey. The 2015 experimental periods, respectively. Fermented solid experimental field’s altitude is 800 m. In the experimental farmyard manure was used in this study. Before the application area the mean annual precipitation, minimum average of manure, farmyard manure was stored for fermentation for temperature, and maximum average temperature are 256 about 1 year. In all plots tilled with the moldboard plow it mm, –3.3 °C, and 25.9 °C, respectively (www.mgm.gov. was followed immediately by two passes with a tandem disk tr). In addition, meteorological data for Julian days are harrow and one pass of a shaped spring tooth harrow for reported in Table 1. avoiding plant respiration, which may otherwise affect CO2 Topsoil samples were collected from depths of 0–30 emissions. Manure was applied both years of the experiment cm before farmyard manure and wheel traffic applications. in the first week of April. For the subsurface application, the The soil classification is Aridisol, the soil texture is clay manure was mixed in at approximately 10 cm of soil depth loam, and the other properties of the soil are as follows: with a rotary tiller. The experimental scheme for the field –1 analysis is given in Table 2. The properties of the manure CaCO3 6.53%, EC 1228 µS cm , pH 8.0, P 27.24 ppm, K 0.037 mEq 100 g–1, and soil organic matter 1.06%. The used in the experiment are: organic matter 352 g kg–1, pH 7.2, experiments started in May 2014 and June 2015. electrical conductivity 3.4 dS m–1, total N 16 g kg–1, P 8.2 g –1 –1 –1 –1 2.2. Experimental design kg , K 6.9 g kg , Ca 65 g kg , and Mg 5.8 g kg . Three different experimental factors, provided to different 2.3. Measurement of CO2 emissions, PAR, O2 content, levels, were studied as follows: i) wheel traffic (C0 = no moisture, temperature, and penetration resistance traffic, C1 = one pass, and C2 = two passes), ii) manure In the study, an automated ACE and Soil CO2 Exchange application rates (N0 = control plot, N40 = 40 Mg ha–1, System (ADC BioScientific Ltd., Hoddesdon, UK) was used –1 and N80 = 80 Mg ha ); and iii) manure application for determining the CO2 emission (Figure 1). Volumetric methods (A1 = surface application and A2 = subsurface soil moisture percentage (%) and temperature (°C) were application). simultaneously measured via CO2 device sensors during The soil was tilled using conventional tillage systems the CO2 measurement period. Soil O2 content levels were before the experiments so that the plants and roots in the determined with an ICT O2 measurement instrument (ICT soil were removed from the experimental area. For this International Pty. Ltd., Armidale, Australia) (Figure 1). purpose, a moldboard plow was set to a depth of 300 mm, The soil CO2 and O2 measurements were taken followed immediately by two passes with a tandem disk approximately 2 to 10 days from 9 May to 30 June in 2014 harrow and one pass of a shaped spring tooth harrow. and from 12 May to 30 June in 2015, between 1000 and Table 1. Meteorological data through the Julian days. First year of the experiment (2014) Julian days 129 131 135 138 141 144 149 159 166 173 180 Max. temperature (°C) 25.4 27.1 25.2 30.7 23.1 26.4 27.9 26.9 32.3 35.2 31.7 Precipitation (mm) 0 0 1 0 0 2.2 10.3 0 0 0 1.1 Moisture (%) 65.9 59.5 59 48.1 60 65.8 57 55.4 31.1 23.5 41.1 Second year of the experiment (2015) Julian days 132 134 138 140 142 146 152 160 166 174 180 Max. temperature (°C) 19.8 20.7 27.4 30.3 26.9 28.8 31.7 30.5 31.1 36.5 35.4 Precipitation (mm) 3.9 0 0.3 0 0.2 7.1 0 0 0 0 0 Moisture (%) 71.2 55 31.9 27.8 46.2 42.4 23.2 32.8 28.5 23.2 26.8 289 ALTIKAT et al. / Turk J Agric For Table 2. Experimental scheme for the field analysis. Wheel traffic (C) Manure amount (N) Method of manure application (A) C0: No traffic N0: Control plot (no manure) A1: Surface application C1: One pass N40: 40 Mg ha–1 manure amount A2: Subsurface application C2: Two passes N80: 80 Mg ha–1 manure amount 2014 CO2 emission, soil temperature, and soil moisture measurements in Julian days 129 131 135 138 141 144 149 159 166 173 180 Oxygen measurements in Julian days 129 131 135 138 141 144 149 159 166 173 180 2015 CO2 emission, soil temperature, and soil moisture measurements in Julian days 132 134 138 140 142 146 152 160 166 174 180 Oxygen measurements in Julian days 132 134 138 140 142 146 152 160 166 174 180 Shaded days are days of measurement.