Comparison of methods for estimating the carcass stiffness of agricultural tyres on hard surfaces

Loading soil via pneumatic tyres is a major cause of compaction of agricultural soils, which causes damage to the soil-water-air-plant system. The loads applied to the soil and the resulting pressure influences the degree of soil compaction. This study was conducted to determine an effective method to measure the pressure distribution under a selection of pneumatic agricultural tyres. This was conducted initially on a non-deformable surface; a later study will consider pressures within the subsoil. From this the tyre carcass stiffness was determined and methods to predict carcass stiffness were evaluated. Tyre carcass stiffness is defined as an equivalent pressure resulting from the stiffness of the tyre carcass. In order to estimate the carcass stiffness of tyres a number of approaches were considered including: (i) footprint area, (ii) tyre load – deflection, (iii) pressure mapping and (iv) tyre manufacturer's specification methods. Carcass stiffness values obtained from the footprint area method gave results significantly lower (30–40%) than those obtained using the pressure mapping system. The method based on the tyre load – deflection characteristics was found to give a better estimation of the tyre carcass stiffness of the smooth rather than the treaded tyre. The technique of using the tyre manufacturer's specification data, where the estimation of the tyre carcass stiffness was calculated using the theoretical load that the tyre could support at zero inflation pressure, produced estimates that were within ±20% of the mean carcass stiffness determined using the pressure mapping system

Controlled traffic farming delivers better crop yield of winter bean as a result of improved root development

This paper reports on the continuation of a long–term experiment on the effects of alternative field traffic systems (STP–random traffic with standard tyre inflation pressure, LTP–random traffic with low tyre inflation pressure and CTF–controlled traffic farming) on soil conditions and crop development as influenced by different tillage depths (DEEP–250 mm, SHALLOW–100 mm and ZERO–tillage), in a randomised 3 x 3 factorial design in 4 replicates launched by Harper Adams University in Edgmond, UK, in 2011. The results from season 2017–2018 revealed that CTF delivered 8% higher crop yield of winter field bean (Vicia faba) cv. Tundracomparing to STP (p = 0.005), i.e. 4.13 vs 3.82 tonnes ha-1respectively (at 14% moisture content). The ZERO–tillage plots featured significantly lower plant establishment percentage comparing to shallow and deep tillage: 79% vs 83% and 83% respectively (p = 0.012). The research showed that roots traits differed significantly between contrasting traffic at depths greater than 50mm with p < 0.05of: tap root biomass, number of lateral roots, biomass of lateral roots as well as total root biomass (tap+lateral roots),delivering significantly greater values of those before mentioned parameters on CTF comparing to STP. Tap root length significantly differed between traffic systems (p < 0.001)giving significantly greater results on CTF comparing to LTP and STP (17.7, 13.4 and 12.6 mm respectively). Significant differences in tap root diameter were found only at the depth of 100 mm (p < 0.001) where again CTF delivered significantly higher root diameter than the remaining 2 traffic systems.In the shallow layer of soil (0–50 mm) a significant difference was found only for tap root biomass, for interactions, where STP ZERO gave significantly higher results than STP SHALLOW and CTF SHALLOW (1.430, 0.733 and 0.716 g respectively)

Results from recent traffic systems research and the implications for future work

This paper reviews the results of recent traffic systems research and concludes that the evidence shows that with sufficient ingenuity by farmers and their equipment suppliers to match operating and wheel track widths, the traffic management systems that reduce soil compaction should improve crop yield, reduce energy consumption and improve infiltration rates (which will reduce runoff, erosion and flooding). These together will improve agronomic, economic and environmental sustainability of agriculture. Low ground pressure alternatives may well be the option that best suits some farming enterprises and should not be discounted as viable traffic management methods. The paper also considers the implications for further work to improve the robustness of the experimental data

Determining trafficked areas using soil electrical conductivity – a pilot study

ncrease in machinery size and its random traffic at fields cause soil compaction resulting in damage of soil structure and degradation of soil functions. Nowadays, rapid methods to detect soil compaction at fields are of high interest, especially proximal sensing methods such as electrical conductivity measurements. The aim of this work was to investigate whether electromagnetic induction (EMI) could be used to determine trafficked areas in silty clay soil. Results of randomized block experiment showed a high significant difference (p <0.01) in EMI data measured between compacted and non-compacted areas. EMI readings from compacted areas were, on average, 11% (shallow range) and 9% (deep range) higher than non-compacted areas, respectively. This difference was determined in both shallow and deep measuring ranges, indicating that the difference in soil compaction was detected in both topsoil and subsoil. Furthermore, the data was found to have a significant spatial variability, suggesting that, in order to detect the increase in EMI (which shows the increase in soil compaction), data within close surrounding area should be included in the analyses. Correlation coefficient of EMI and penetration resistance (average moisture content 32.5% and 30.8% for topsoil and subsoil) was found to be 0.66

Agricultural traffic management systems and soil health

This chapter examines the relationship between agricultural traffic and soil compaction. It begins by reviewing research on how agricultural traffic affects soil compaction as well as ways of measuring soil compaction and its effects. It then discusses a range of potential techniques to avoid soil compaction. These include: controlled-traffic farming, low ground pressure tyre systems as well as tracks and gantry systems. The chapter also discusses the relationship between different tillage practices and soil compaction. It includes a case study based on research conducted by the authors

Summary of the effects of three tillage and three traffic systems on cereal yields over a four-year rotation

This paper reports the design and results of a study to consider the effects of deep, shallow and zero tillage with random conventional and low tyre inflation pressures and controlled traffic systems on the yield of winter wheat, winter barley (×2) and spring oats. The results show that crop yields for zero tillage were significantly less (P<0.001) than deep and shallow tillage for all crops with an overall reduction of 1.0 t ha-1 below the mean of the deep and shallow tillage practices. Controlled traffic farming with a 30% trafficked area produced significantly higher yields than random conventional pressure traffic for the winter wheat and spring oats. Controlled traffic farming, with trafficked areas of 30% and 15% showed overall benefits over random conventional inflation pressure traffic of 0.32 t ha-1 (£41 ha-1) and 0.61 t ha-1 (£77 ha-1) respectively, requiring breakeven areas of 312 ha and 168 ha to cover the costs of three vehicle guidance/auto-steering systems

The effects of traffic management systems on the yield and economics of crops grown in deep, shallow and zero tilled sandy loam soil over eight years.

This paper reports on a 3 × 3 factorial study to consider the effects of controlled traffic (CTF), low tyre inflation pressure (high flexion) tyres (LTP) and standard tyre inflation pressure (STP) farming systems for deep, shallow and zero tillage practices on the yield of wheat, barley, oats and field beans grown in a sandy loam soil in the UK. The main effect of tillage showed that the zero tillage option significantly (***P < 0.001) reduced crop yields in four out of the five of the first crop years, with no significant effect in years two, six and eight and exceeded the yield of the other tillage treatments in year seven. The specific costs of the alternative tillage systems were estimated, from which the cost saving for zero tillage compared to deep tillage was c. £ 60 ha−1 (US$80 ha−1), which compensated for the overall loss in yield. There were no significant differences between the crop yields from the deep and shallow tillage treatments, with shallow tillage offering savings in operational costs of c. £ 30 ha−1 (US$ 40 ha−1). Overall, the controlled traffic farming system, where 30% of the field was trafficked, produced 4% greater crop yields (*P < 0.05), worth £ 39 ha−1 (US$53 ha−1) than standard tyre inflation pressures (STP). The estimated effect of reducing the trafficked area to 15$ 100 ha−1) compared to the STP system. The beneficial effect of low inflation pressure tyres (70 kPa and 80 kPa) on crop yields, for the deep tillage treatment, was significantly greater (*P < 0.05) than those of the standard tyre pressure system (100 kPa to 150 kPa) returning an average 3.9% additional crop yield over the period of the experiment worth £ 39 ha−1 (US$ 53 ha−1)

An economic appraisal of the effect of tire inflation pressure for alternative tillage systems on a silty clay loam soil

Compacting soil has an adverse effect on soil properties, decreases crop productivity, and subsequently reduces farm income. Low tire inflation pressure (LTP) help in managing soil compaction and protecting the soil environment; however, there is scant economic data available on LTP in US Midwest farming systems. Hence, a 3-year study investigated the effects of LTP, compared to tires inflated to the standard tire inflation pressure systems, on crop yield and farm economy for a typical maize/soybean rotation. The effect of the two tire inflation pressure systems was factorialized with three tillage systems: deep tillage (DT, 450 mm), shallow tillage (ST, 100 mm), and no-till systems. The results showed that LTP systems increased maize (Zea mays) yield by 4.51% (2017) and 2.70% (2018) and soybean (Glycine max) by 3.70% in 2018. Annual earnings for both 200- and 800-ha farms increased for all tillage systems with LTP tires based on a partial budget analysis. The payback periods for LTP tires were very short, ranging from 0.32 years for DT on an 800-ha farm to 1.18 years for ST on a 200-ha farm. The net present value of the higher returns with LTP tires was substantial, especially for the DT system. This study shows a strong economic benefit from investments in LTP tires on silty clay loam soils in the US Midwest