Traffic and tillage effects on soil health and crop growth
Kaczorowska-Dolowy, M. (2022) Traffic and tillage effects on soil health and crop growth. Doctoral thesis, Harper Adams University.
|
Text
Magadalena OCR upload.pdf Download (6MB) | Preview |
Abstract
The growing world population demands rise of crop yields, which has resulted in agricultural intensification. This in turn has been accompanied by an increase in machinery size and weight, escalating degrees of soil compaction and has led to soil degradation of an area of 33 million ha in Europe. Compacted soil inhibits root development, water availability, nutrient uptake and causes yield loses. Remedial actions are expensive, and time consuming and require burning additional fossil fuels. Climate change is one of the most urgent problem and requires more sustainable approach to food production. Reducing fossil fuel consumption, whilst maintaining the soil in a good condition to facilitate water infiltration and carbon sequestration resulting from improved root development is of great importance. This thesis reports on a three-year study conducted within a unique long-term 3x3 factorial experiment with four replicates, which started at Harper Adams University (UK) in October 2011. This study quantified the effects of absence of traffic (CTFut) vs traffic with standard and low tyre inflation pressure (STP and LTP respectively), influenced by different tillage depths (deep–250mm, shallow–100mm and zero–tillage) on soil physico-chemical and biological properties, as well as on crop growth and yields. Additionally, it investigated the effect of three common farming traffic systems: Controlled Traffic Farming with 30% of trafficked area (CTF), and two random traffic systems: with standard and low inflation pressure tyres (RSTP and RLTP) subject to three tillage depths (deep, shallow and zero) on plant establishment and combine harvested yields. The analysed soil physico-chemical properties were: soil bulk density, porosity, penetration resistance, moisture content, field saturated hydraulic conductivity and instant infiltration rate, soil microbial carbon, soil organic matter and pH. The soil biological properties included soil fauna feeding activity, Collembola and earthworm abundance. The crop growth indicators included plant establishment, root growth and hand harvested and combine harvested yield. The results from this study demonstrated that agricultural traffic, regardless tyre inflation pressure, had significant negative effects on soil physico-chemical and biological properties in comparison to unwheeled soil. The untrafficked soil (CTFut) featured significantly lower soil bulk density and penetration resistance, at the same time, significantly improved soil porosity, field saturated hydraulic conductivity and instant infiltration rate in comparison to soil trafficked with standard and low inflation pressure tyres (STP and LTP respectively). The absence of traffic also significantly improved soil biological properties namely soil fauna feeding activity, and Collembola abundance in 24 comparison to STP and LTP. The plant establishment and root growth were also significantly enhanced under untrafficked soil (CTFut) vs STP and LTP. All these improvements in soil physico-chemical and biological properties led to the combine harvested yield increase by 4% under CTF system which in the experiment had 30% of trafficked area. This can be recalculated to additional 3% increase for CTF with 15% of trafficked area. Consequently, the adoption of CTF which restricts farming traffic to permanent wheelways covering in farming practice approximately 12-15% of the field area, brings significant improvements in soil physico-chemical and biological properties and as a result, it enhances crop growth and yield in comparison to non-controlled traffic systems (RSTP and RLTP) under which the majority of the field area is covered by at least one wheel pass every year. The main effects of tyre pressures did not have a significant effect on soil physicochemical properties. Nevertheless, LTP significantly improved soil fauna feeding activity (FA) in comparison to standard tyres pressures (STP). Interactions between traffic system and tillage depth revealed that RLTP increased combine harvested yields on deeply tilled soils in comparison to RSTP (104% on average over the 8-year study). The main effect of tillage and the interactions between traffic and tillage were not significant for soil physico-chemical characteristics. Tillage had however significant effects on soil biological properties. Nevertheless, the results do not conclusively indicate one tillage depth which could improve soil biology, as the SOM and similarly earthworms abundance were significantly greater under zero and shallow tillage than under deep tillage, however soil fauna feeding activity in 2019 on zero tillage was significantly lower than on remaining tilled treatments, similarly the Collembola density was significantly lower under zero tillage in comparison to shallow tillage, whereas deep tillage did not differ significantly from the remaining tillage depths. Nevertheless, in 2020 both reduced tillage treatments (zero and shallow tillage) featured significantly greater FA than deep tillage. Interactions between tillage and time revealed that with time, under zero tillage, the crop yields improve and, in the year 7th and 8th yields from zero tillage were significantly greater than from deep tillage (105% and 103% in 2019 and 102% and 112% in 2020 respectively). There was no single aspect of soil physico-chemical and biological properties, as well as crop growth and yields, which would indicate that deep tillage provided better results over 25 shallow tillage, which might suggest that deep tillage is not a recommended practice on sandy loam in West Midlands, UK. This leads to a conclusion that the optimal mechanisation system’s approach (combination of traffic system and tillage depth) consists of CTF with shallow tillage; alternatively, zero tillage system, which is more resilient to agricultural traffic, with the caveat of yields penalties in the first years. The use of low inflation pressure tyres (LTP) is recommended, should deep tillage be required without CTF, as they reduce the impact of compaction and improve the crop yield. This thesis also outlines additional environmental consequences, which in further studies might be developed in a robust environmental economics of traffic and tillage systems.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Divisions: | Agriculture and Environment (from 1.08.20) |
| Depositing User: | Ms Kath Osborn |
| Date Deposited: | 09 Aug 2022 10:34 |
| Last Modified: | 09 Aug 2022 10:52 |
| URI: | https://hau.repository.guildhe.ac.uk/id/eprint/17871 |
Actions (login required)
 |
Edit Item |