Non-inversion Tillage Systems Research Articles

Economic justification of industrial production of a resource-saving unit for strip tillage

It is a well-known fact that the existing methods of continuous plow tillage are associated with high consumption of anthropogenic energy for plowing and with probability of occurrence of degradation in it. The alternative to the continuous plowing is non-inversion tillage systems related to resource-saving agriculture. At present, combined tillage implements are widely used. They are equipped with devices for applying fertilizers to plowed strips, and in spring the seeds of a certain row crop (sunflower or corn, for example) are sown there exactly in line with the upgraded seeder equipped with an agronavigator for precision farming. The task of the study is to make the preliminary economic justification of the expediency of using various implements for soil-loosening by strip conservation plowing and the need for industrial production of a combined unit for simultaneous application of fertilizers and strip plowing. The issues of implementation of modern foreign tillage technology and devices should primarily consider environmental and resource conditions for row crops cultivation in individual Russian regions. This is especially true for the strip tillage technology and the devices for its implementation. Therefore, further studies should be devoted to the economic component considering the terrain, landscape cover, climatic features, composition and type of soil, land reclamation condition. Due to the current situation, it is essential to gradually replace the imported tillage equipment by domestic developments that are not inferior in quality, reliability, performance and safety to foreign analogues. The authors mean the replacement and repair of expensive foreign produced combined units for strip plowing. To this end, it is suggested to use less expensive domestic technologically new products developed with the consideration of natural and climatic peculiarity of an individual region. The authors apply original methodology of the so-called simplified express analysis of key economic indicators. The methodology provides the opportunity to conduct accurate evaluation of the economic expediency of improving technical characteristics of the upgraded device at the beginning of the design before its production by means of a limited number of available parametric data of the machine sample under study. This eventually influences making a correct decision about the expediency of industrial production of a combined tillage device.

Analysing Farmers’ Herbicide Use Pattern to Estimate the Magnitude and Field-Economic Value of Crop Diversification

We present an on-farm approach to measure the effect of crop diversification on farmers’ field economic values. Eleven years of data (2010–2020) on the chemical herbicide use, tillage practices and crop yields of 17 farms in north-eastern Germany were examined for winter wheat (WW) and winter oilseed rape (WOSR). We used a common conceptual framework to classify farmers’ crop sequences according to their susceptibility to weeds (‘riskiness’). Linear mixed models were used to analyse the relationship between crop sequence, tillage practice (inversion/non-inversion) and the response variables ‘total herbicide costs’, ‘crop yield’ and ‘economic income’. Our results indicate that farmers in the area surveyed commonly grow crop sequences with a high risk of weeds. The driving forces behind this classification are high ratios of winter cereals and WOSR in the sequences. The most interesting result of our analysis is that farmers’ total herbicide costs (THCfy) significantly decreased from a higher to a lower riskiness class. Diversified crop sequences decreased the THCfy for WW by up to 12 EUR ha−1 and for WOSR by 19–56 EUR ha−1. Considering the crop diversification effects, the combined influence of tillage and crop sequence seems to be important. Significant differences in crop yield between the riskiness classes were found in WW and WOSR solely in non-inversion tillage systems. Hence, the analysis of farmers’ ‘economic income’ revealed the great impact of crop diversification for non-inversion tillage systems. Indeed, we found that simplifying both crop sequence diversity and tillage intensity implies higher herbicide costs and, thereby, higher economic input. The best strategy for reducing herbicide costs in WW and WOSR cropping is to increase the use of summer crops or field grass as previous crops.

Carbon Footprint and Life-Cycle Costs of Maize Production in Conventional and Non-Inversion Tillage Systems

Given the problem of climate change and the requirements laid down by the European Union in the field of gradual decarbonization of production, it is necessary to implement solutions of reducing greenhouse gas (GHG) emissions into agricultural practice. This research paper aimed to evaluate the carbon footprint and life-cycle costs of grain maize production in various tillage systems. The material for the analyses was data from 2015–2017 collected on 15 farms located in the Wielkopolska region (Poland) and growing maize for grain in three tillage systems: conventional, reduced, and no-tillage. The life-cycle assessment and life-cycle costing methodologies were applied to assess the GHG emissions and costs associated with the grain maize production in the stages from “cradle-to-farm gate”, i.e., from obtaining raw materials and producing means for agricultural production, through the processes of maize cultivation to grain harvesting. The calculated values of the carbon footprint indicator for maize production in conventional, reduced, and no-tillage systems were 2347.4, 2353.4, and 1868.7 CO2 eq. ha−1, respectively. The largest source of GHG emissions was the use of nitrogen fertilizers. Non-inversion tillage with cover crops and leaving a large amount of crop residues in the field increased the sequestration of organic carbon and contributed to a significant reduction of the carbon footprint in maize production. The conventional tillage system demonstrated the highest overall life-cycle costs per hectare.

Tillage System and Crop Sequence Affect Soil Disease Suppressiveness and Carbon Status in Boreal Climate.

The soil-borne plant pathogens cause serious yield losses and are difficult to control. In suppressive soils, disease incidence remains low regardless of the presence of the pathogen, the host plant, and favorable environmental conditions. The potential to improve natural soil disease suppressiveness through agricultural management practices would enable sustainable and resilient crop production systems. Our aim was to study the impact of autumn tillage methods and crop sequence on the soil carbon status, fungistasis and yield in boreal climate. The disease suppression was improved by the long-term reduced and no tillage management practices with and without crop rotation. Compared to the conventional plowing, the non-inversion tillage systems were shown to change the vertical distribution of soil carbon fractions and the amount of microbial biomass by concentrating them on the soil surface. Crop sequence and the choice of tillage method had a combined effect on soil organic carbon (SOC) sequestration. The improved general disease suppression had a positive correlation with the labile carbon status and microbial biomass. From the most common Fusarium species, the predominantly saprophytic F. avenaceum was more abundant under non-inversion practice, whereas the opposite was true for the pathogenic ones. Our findings furthermore demonstrated the correlation of the soil fungistasis laboratory assay results and the prevalence of the pathogenic test fungus Fusarium culmorum on the crop cereals in the field. Our results indicate that optimized management strategies have potential to improve microbial related soil fungistasis in boreal climate.

Strip-Till One-Pass Technology in Central and Eastern Europe: A MZURI Pro-Til Hybrid Machine Case Study

The non-inversion tillage systems, including strip-till (ST), are the key element of conservation agriculture (CA). The aim of the 2012–2018 study has been to demonstrate the application of strip-till one-pass technology (ST-OP) on the farms of Central and Eastern Europe based on the use of Mzuri Pro-Til machines. There has also been an evaluation of the effect of that technology on the soil properties and the effects of crops growing. The scientific observations and field experiments were made, e.g., in Poland, Ukraine, Lithuania, the Czech Republic, Slovakia, the Eastern states of Germany, Belarus, Serbia, and Romania. ST-OP case study with the use of Mzuri Pro-Til machine can be applied for growing all the basic crops. Tillage with a simultaneous basic fertilization application and seeding made regularly for a few years in given field leads to favorable changes in the soil properties. As compared with the soil under conventional plough tillage (CT), the soil moisture, especially in the periods of rainfall deficit, the content of organic carbon and its fraction, the count of microorganisms and earthworms, as well as the enzymatic activity, are higher. This technology saves over 20–30 L ha−1 of fuel, respectively, compared to reduced tillage (RT) and CT. Plant emergence is uniform, dense canopies and crop yields—not lower and even higher than for tillage and seeding commonly applied in Central and Eastern Europe. ST-OP can be thus an important element of field plant production as part of CA and sustainable development.

Climate and tillage system drive weed communities’ functional diversity in a Mediterranean cereal-legume rotation

The first step to develop an environmentally sound weed management is to know how weed communities respond to environmental drivers. Among these, climate and management practices are probably the more determinant factors for annual plants community assembly. In this framework, a trait based approach may be useful to assess weed community responses and the processes behind them. Here, we focused on three non-inversion tillage practices which differently affect soil conditions and the vertical distribution of weed seeds. We also took into account the climate variability across years. We specifically asked whether the type of non-inversion tillage system and the annual variability in climatic conditions explain the differences in the functional structure of weed communities. To assess this question we conducted a nine yearlong field experiment in which three non-inversion tillage systems were compared: subsoil tillage, minimum tillage and no-tillage. We characterized the functional structure of weed communities by first obtaining data on three resource acquisition traits (specific leaf area, plant height and growth habit) and five regenerative traits (seed weight, longevity index, dispersal structures, seed cover and emergence time). Then, we computed the community weighted mean (CWM) and the mean pairwise distance (MPD) of each trait as well as a multi trait MPD index. Climate annual conditions were characterized based on autumn-winter precipitation, average temperature and number of frost days. We found that tillage systems and climatic factors mainly sorted weed species according to their emergence time and seed weight. Weed communities from no-tillage plots were characterized by having an earlier emergence and seeds without pericarp. Regarding climatic conditions, we found that warmer and rainier autumn-winter conditions were related to lower functional diversity of regenerative traits and higher diversity in terms of resource acquisition traits. Our results highlight that factors affecting seedling emergence as well as traits related to these processes are critical during weed community assemblage. Our results also showed that none of the compared tillage systems was clearly outstanding in terms of functional diversity, but that each system benefited certain functional design. Furthermore, the relative importance of these management practices to drive weed functional structure was clearly lower than the effects of climatic inter-annual fluctuations.

Effects of no-tillage and non-inversion tillage on weed community diversity and crop yield over nine years in a Mediterranean cereal-legume cropland

Both no-tillage and non-inversion tillage systems have been proposed within the context of 'conservation agriculture' as alternatives to conventional tillage for weed management and soil conservation. However, little information is available regarding their influence on weed community diversity and crop yield in Mediterranean cereal steppelands. Type of tillage represents a crop abiotic factor that largely influences the environmental conditions at the field scale to which weed communities may respond. The present paper examines the effect of no-tillage, subsoil tillage and minimum tillage (the latter two being non-inversion systems), on arable weed community diversity and composition in a cereal-legume crop rotation over 9 years. Their effects on crop yield are also explored. Inter-annual environmental variability was found to be more important than the tillage system in determining weed species diversity and assembly. None of the studied tillage systems exerted consistent effects, neither on weed community diversity nor on crop yields. In addition, the effect of tillage system on weed community diversity was crop-type dependent. The main effects of tillage systems were related to the composition of weed communities. Less common species resulted particularly affected while core species were consistent across tillage systems.

Oilseed radish/black oat subsidiary crops can help regulate plant-parasitic nematodes under non-inversion tillage in an organic wheat-potato rotation

Soil conservation is one of the major challenges for agriculture in the 21st century. For this reason, non-inversion tillage systems including subsidiary crops have become popular over the last three decades in Europe. However, the adoption of new agricultural practices may change the diversity and abundance of certain pests and diseases. For example, plant-parasitic nematodes that are major threats towards cultivated plants may be promoted if good hosts, such as certain subsidiary crops and weeds, occur more frequently. The indigenous plant-parasitic nematode fauna under organic farming systems is already adapted to diverse crop rotations and usually dominated by nematodes with broad host ranges. These may be further enhanced in organic farming systems if non-inversion tillage is introduced, which generally increases the abundance and biomass of certain weeds. We evaluated the early effects of non-inversion tillage and subsidiary crops in an organic wheat-potato rotation on plant-parasitic nematodes in two field experiments in two successive years. The total densities of plant-parasitic nematodes increased from an initial 1260 nematodes (100 ml soil)−1 at the start of the experiment to 1850 and 1700 nematodes (100 ml soil)−1 after wheat under non-inversion and conventional tillage, respectively. Plant-parasitic nematode densities then decreased on average to 1100 and 560 nematodes (100 ml soil)−1 after subsidiary crops and potatoes, respectively. Parasitic nematode densities tended to be higher under non-inversion than conventional tillage, except where oilseed radish and black oats had been used as cover crops. For the latter, no differences between tillage treatments occurred. In the second experiment, about 1700 free-living nematodes (100 ml soil)−1 were found under conventional tillage without mulch while under reduced tillage with mulch their numbers were significantly higher at 3100 nematodes (100 ml soil)−1. We conclude that an appropriate choice of subsidiary crops can be an important management factor for the long term sustainability of non-inversion tillage systems.

Conventional and non-inversion tillage systems as a factor causing changes in ground beetle (Col. Carabidae) assemblages in oilseed rape (Brassica napus) fields

Background and purpose : Carabid beetles are among the most important elements of the natural environment’s resistance in arable fields. In this paper, the influence of different soil tillage systems on carabid beetle assemblages in oilseed rape plantations was studied. Materials and methods : The experiment was conducted in northeastern Poland. Six fields with oilseed rape cultivated under both conventional and non-inversion tillage systems were chosen. Barber traps were used to capture beetles. Results and conclusions: In total 9,968 individuals belonging to 56 species were collected. Significant differences in the abundance and species richness of ground beetles in two systems of soil tillage were observed. The abundance and species richness were significantly higher in the non-inversion tillage system. Analysis of the life history traits of carabids also revealed statistically significant differences in the seasonal occurrence of carabids related to the type of soil cultivation used.

Vertical distribution and composition of weed seeds within the plough layer after eleven years of contrasting crop rotation and tillage schemes

Tillage methods and crop rotation are probably the two most important cropping factors affecting weed communities, particularly when herbicide use is restricted. This study examined weed dynamics following eleven years of different tillage and crop rotation treatments. The aboveground grass weed flora was recorded each year and the content and vertical location of individual weed seeds within the plough layer (0–20cm) were determined after 11 years of continuous mouldboard ploughing (P), pre-sowing tine cultivation to 8–10cm soil depth (H8-10) and direct drilling (D). The content of weed seeds, especially grass weeds, was determined for three distinct soil layers (0–5, 5–10 and 10–20cm), reflecting the cultivation depths of the tillage treatments. The annual grass weeds, Apera spica-venti and Vulpia myuros, were promoted by non-inversion tillage and in the case of V. myuros also by frequent cropping of winter cereals. The two non-inversion tillage treatments caused a strong stratification of weed seeds within the plough layer, with the majority of the seeds being accumulated in the upper soil layers, at 0–5 and 5–10cm, and markedly less so in the 10–20cm layer. Ploughing resulted in a more even distribution between the three layers. It is suggested that in cases where severe grass weed problems have built up in a non-inversion tillage system and where changes in crop rotation are ineffective or undesirable, inversion of the upper soil layer with the lower one could be considered a management option.

Weed development in spring wheat after contrasting soil tillage and nitrogen management

Soil tillage and nitrogen (N) management effects on weed species composition were evaluated in 2013 and 2014 on a clayey soil after 5-years of organic management at the Royal Agricultural University's Harnhill Manor Farm, UK. Three tillage systems – Conventional Tillage (CT), and High and Low Intensity Non-inversion Tillage (HINiT & LINiT) – were compared at four N fertiliser rates of 0, 70, 140 and 210 kg N ha−1. Broad-spectrum herbicide was applied before soil operations across the site in both years. Previous organic management legacy of high weed biomass promoted greater weed prevalence in 2013 while 2-years of herbicide inclusion reduced weed biomass. Contrasting weather conditions across the seasons affected weed incidence. In the 2014 wet season, early weed dry weight (DM) was higher under HINiT than CT and LINiT, while no differences were observed in the 2013 dry year. At midseason, weed DM was higher under HINiT than CT and LINiT in both years, which was related to higher DM of the dominant weeds Stellaria media (L.) Vill. and Sinapis arvensis L. Grass weed DM was higher under non-inversion tillage than CT. N fertilisation increased midseason total weed DM and weed prevalence at harvest. Spring wheat yield was the highest under CT while LINiT produced 17% higher yields than HINiT. Despite higher but still tolerable weed prevalence under both non-inversion tillage systems and with the application of N, weeds alone was not the only yield-limiting factor. However, results show that CT is the most reliable option for weed control in changing weather, while N fertilisation rates needs to be considered.

Effect of conventional and non-inversion tillage systems on the abundance and some life history traits of carabid beetles (Coleoptera: Carabidae) in winter triticale fields

Soil cultivation is among the principal factors that determine the structure and properties of soil and also affects the species composition and abundance of soil dwelling arthropods. Carabid beetles are a particularly valuable group of arthropods, the species of which are strongly associated with particular soil environments. This paper discusses the effect of soil tillage on carabid beetle as- semblages. The study was carried out near Olsztyn, in northeastern Poland. Six wheat fields, each cultivated using either, conventional or non-inversion, soil tillage, were chosen. Carabid beetles were caught in Barber's traps from early April to the end of October 2011. In total, 7,486 specimens belonging to 55 species of the family Carabidae were captured. The most numerous were Poecilus cupreus, Pterostichus melanarius, Harpalus rufipes, Anchomenus dorsalis and Carabus granulatus. Differences in the abundance of ground beetles and some life history traits were associated with the two soil tillage systems. In particular, ploughing reduced carabid abundance and resulted in the increased activity of medium-sized zoophages and spring breeders.

The effect of soil tillage system on the nitrogen uptake, grain yield and nitrogen use efficiency of spring barley in a cool Atlantic climate

SUMMARYField experiments were conducted between 2009 and 2011 in Ireland to compare the effects of soil tillage systems on the grain yield, nitrogen use efficiency (NUE) and nitrogen (N) uptake patterns of spring barley (Hordeum vulgare) in a cool Atlantic climate. The four tillage treatments comprised conventional tillage in spring (CT), reduced tillage in autumn (RT A), reduced tillage in spring (RT S) and reduced tillage in autumn and spring (RT A+S). Each tillage system was evaluated with five levels of fertilizer N (0, 75, 105, 135 and 165 kg N/ha). Grain yield varied between years but CT had a significantly higher mean yield over the three years than the RT systems. There was no significant difference between the three RT systems. Tillage system had no significant effect on the grain yield response to fertilizer N. As a result of the higher yields achieved, the CT system had a higher NUE than the RT systems at all N rates. There was no significant difference in NUE between the three RT systems. Conventional tillage had significantly higher nitrogen uptake efficiency (NUpE) than RT A and a significantly higher nitrogen utilization efficiency (NUtE) than all three RT systems. Crop N uptake followed a similar pattern each year. Large amounts of N were accumulated during the vegetative growth stages while N was lost after anthesis. Increased N rates had a positive effect on N uptake in the early growth stages but tended to promote N loss later in the season. The CT system had the highest N uptake in the initial growth stages but its rate of uptake diminished at a faster rate than the RT systems as the season progressed. Tillage system had an inconsistent effect on crop N content during the later growth stages. On the basis of these results it is concluded that the use of non-inversion tillage systems for spring barley establishment in a cool oceanic climate remains challenging and in certain conditions may result in a reduction in NUE and lower and more variable grain yields than conventional plough-based systems.

Organic wheat performance following conventional and non-inversion tillage systems

Field trials were conducted from October 2010 to August 2012 on land registered with the Soil Association, UK, for organic production on the Royal Agricultural University's Harnhill Manor Farm near Cirencester, UK, to compare the effects of conventional tillage (CT) involving maximum soil manipulation and 0% soil surface plant residues against conservation tillage strategy including low residue non-inversion tillage (LRNiT) involving minimal soil movements and 30% soil surface plant residues and also high residue non-inversion tillage (HRNiT) with least soil movements and maximum (>50%) retention of soil surface plant residues on organic winter and spring wheat performance. Establishment, growth and the yield response of organic winter and spring wheat for the three cultivation systems were assessed to determine the influence of these tillage treatments. Results showed that the plant establishment and tillers were significantly higher in CT than LRNiT and HRNiT in both cropping seasons. The total number of shoots, ear numbers, dry matter yield, 1000 grain weights and grain yield were significantly higher in the CT and LRNiT than HRNiT for winter wheat, whilst they were significantly higher in the CT than LRNiT or HRNiT for spring wheat. Crop establishment, growth and yield response were influenced by the weather conditions beyond the tillage treatments for the spring wheat compared with the winter wheat. On the basis of these results, a better alternative for CT could be LRNiT for winter wheat. Conversely, for spring wheat, CT had better crop establishment, growth and yield than other forms of cultivation.

European Perspectives on the Adoption of Nonchemical Weed Management in Reduced-Tillage Systems for Arable Crops

Noninversion tillage with tine- or disc-based cultivations prior to crop establishment is the most common way of reducing tillage for arable cropping systems with small grain cereals, oilseed rape, and maize in Europe. However, new regulations on pesticide use might hinder further expansion of reduced-tillage systems. European agriculture is asked to become less dependent on pesticides and promote crop protection programs based on integrated pest management (IPM) principles. Conventional noninversion tillage systems rely entirely on the availability of glyphosate products, and herbicide consumption is mostly higher compared to plow-based cropping systems. Annual grass weeds and catchweed bedstraw often constitute the principal weed problems in noninversion tillage systems, and crop rotations concurrently have very high proportions of winter cereals. There is a need to redesign cropping systems to allow for more diversification of the crop rotations to combat these weed problems with less herbicide input. Cover crops, stubble management strategies, and tactics that strengthen crop growth relative to weed growth are also seen as important components in future IPM systems, but their impact in noninversion tillage systems needs validation. Direct mechanical weed control methods based on rotating weeding devices such as rotary hoes could become useful in reduced-tillage systems where more crop residues and less workable soils are more prevalent, but further development is needed for effective application. Owing to the frequent use of glyphosate in reduced-tillage systems, perennial weeds are not particularly problematic. However, results from organic cropping systems clearly reveal that desisting from glyphosate use inevitably leads to more problems with perennials, which need to be addressed in future research.

Integrated Palmer Amaranth Management in Glufosinate-Resistant Cotton: II. Primary, Secondary and Conservation Tillage

A three year field experiment was conducted to evaluate the role of soil inversion, cover crops and spring tillage methods for Palmer amaranth between-row (BR) and within-row (WR) management in glufosinate-resistant cotton. Main plots were two soil inversion treatments: fall inversion tillage (IT) and non-inversion tillage (NIT). Subplots were three cover treatments: crimson clover, cereal rye or none (i.e., winter fallow); and the sub subplots were four secondary spring tillage methods: disking followed by (fb) cultivator (DCU), disking fb chisel plow (DCH), disking fb disking (DD) and no tillage (NT). Averaged over years and soil inversion, the crimson clover produced maximum cover biomass (4390 kg ha−1) fb cereal rye (3698 kg ha−1) and winter fallow (777 kg ha−1). Two weeks after planting (WAP) and before the postemergence (POST) application, Palmer amaranth WR and BR density were two- and four-times less, respectively, in IT than NIT. Further, Palmer amaranth WR and BR density were reduced two-fold following crimson clover and cereal rye than following winter fallow at 2 WAP. Without IT, early season Palmer amaranth densities were 40% less following DCU, DCH and DD, when compared with IT. Following IT, no spring tillage method improved Palmer amaranth control. The timely application of glufosinate + S-metolachlor POST tank mixture greatly improved Palmer amaranth control in both IT and NIT systems. The highest cotton yields were obtained with DD following cereal rye (2251 kg ha−1), DD following crimson clover (2213 kg ha−1) and DD following winter fallow (2153 kg ha−1). On average, IT cotton yields (2133 kg ha−1) were 21% higher than NIT (1766 kg ha−1). Therefore, from an integrated weed management standpoint, an occasional fall IT could greatly reduce Palmer amaranth emergence on farms highly infested with glyphosate-resistant Palmer amaranth. In addition, a cereal rye or crimson clover cover crop can effectively reduce early season Palmer amaranth emergence in both IT and NIT systems. For effective and season-long control of Palmer amaranth, one or more POST applications of glufosinate + residual herbicide as tank mixture may be needed in a glufosinate-based cotton production system.

N-utilization in non-inversion tillage systems

When changing from ploughing to non-inversion tillage, N rates are of particular importance both for farmers and the environment. A tillage and fertilizer experiment was established in Denmark under temperate coastal climatic conditions to evaluate the N fertilizer responses on yields and N uptake of six crops in different crop rotations, three winter wheat crops ( Triticum aestivum L.), one winter barley ( Hordeum vulgare L.), one winter oilseed rape ( Brassica napus L.) and one spring barley crop during the years 2003–2005. The experiment was established in autumn 2002 on a loamy sand with 92 g clay kg −1. The tillage treatments were stubble cultivating to 8–10 cm or 3–4 cm, direct drilling, or ploughing to 20 cm. Five different fertilizer N treatments were included: 1:50% (0.50N), 2:75% (0.75N), 3:100% (1.00N), 4:125% (1.25N) of recommended N rates, respectively, and 5: application of 15–30 kg N ha −1 of the total fertilizer N amount in autumn to autumn-sown crops (1.00N Aut). In all the crop rotations, straw was chopped and retained after harvest. Different types of N fertilizer responses were observed in the six crops, but generally yields were lower with non-inversion tillage than with ploughing. On two occasions, yields in ploughed plots were significantly ( p < 0.05) higher than yields with direct drilling as an average of N treatments. Increasing the fertilizer application was generally not able to offset the growth reduction, which resulted from poor growth in patches probably caused by soil compaction in plots with non-inversion tillage. Applying some of the N allocation in autumn cannot be recommended for stimulation of growth of winter cereals or winter oilseed rape with either non-inversion tillage or ploughing.

The effect of wheat straw residue on the emergence and early growth of sugar beet ( Beta vulgaris) and oilseed rape ( Brassica napus)

The management of straw residue can be a concern in non-inversion tillage systems where straw tends to be incorporated at shallow depths or left on the soil surface. This can lead to poor crop establishment because straw residue can impede or hinder crop emergence and growth. Small container-based experiments were undertaken using varying amounts of wheat straw residue either incorporated or placed on the soil surface. The effects on days to seedling emergence, percentage emergence, seedling dry-weight and soil temperature using sugar beet and oilseed rape were investigated because these crops often follow wheat in a cropping sequence. The position of the straw residue was found to be the primary factor in reducing crop emergence and growth. Increasing the amount of straw residue (from 3.3 t ha −1 to 6.7 t ha −1) did not show any consistent trends in reducing crop emergence or growth. However, in some instances, results indicated that an interaction between the position and the amount of straw residue occurred particularly when the straw and seed was placed on the soil surface. Straw placed on the soil surface significantly reduced mean day-time soil temperature by approximately 2.5 °C compared to no residue. When the seed and straw was placed on the soil surface a lack of seed-to-soil contact caused a reduction in emergence by approximately 30% because of the restriction in available moisture that limited the ability for seed imbibition. This trend was reversed when the seed was placed in the soil, but with straw residue still on the soil surface, because the surface straw was likely to reduce moisture evaporation and improved seed-to-soil contact that led to rapid emergence. In general, when straw was mixed in or placed on the soil surface along with the seed, sugar beet and oilseed rape emergence and early growth biomass was significantly restricted by approximately 50% compared to no residue. The consequences of placing seed with or near to straw residue have been shown to cause a restriction in crop establishment. In both oilseed rape and sugar beet, this could lead to a reduction in final crop densities, poor, uneven growth and potentially lower yields that could lower financial margins. Therefore, if farmers are planning to use non-inversion tillage methods for crop establishment, the management and removal of straw residue from near or above the seed is considered important for successful crop establishment.

Non-inversion tillage effects on soil mechanical properties of a humid sandy loam

Optimisation of soil tilth is of paramount importance in organic plant production in order to enhance crop growth. Non-inversion and reduced tillage systems are often claimed to be preferable for organic farming. The purpose of this study was to evaluate the early stage effects of converting a mouldboard-ploughed soil to a non-inversion tillage system. A multi-level experimental strategy including in situ, on-site and laboratory methods was followed in order to relate quantitative measures of soil physical properties directly to soil behaviour in the field. A non-inversion deep soil loosening (0–35 cm) tillage system (NINV) was compared to a conventional mouldboard ploughing and harrowing tillage system (CONV). The experimental site was located on an organically managed sandy loam soil. The tillage treatments were applied to plots in two fields (B 3 and B 4) at the experimental site. Limited numbers of measurements were performed in the B 3 field during the 1997–1999 growing seasons. A more comprehensive programme was carried out in the B 4 field in May and September 1998. A root-restricting plough pan was detected in the CONV treated soil. The NINV treatment effectively loosened the plough pan resulting in a visibly improved soil structure and a decrease in soil strength. The penetration resistance in the plough pan was reduced from about 1800 kPa in CONV to less than 1000 kPa in NINV when measured at field capacity. The loosening of the plough pan was still evident after 2 years without tillage operations in a perennial grass/clover crop. The topsoil of the CONV treatment had a more desirable tilth than that of the NINV treatment, which had higher soil strength at the 7–14 cm depth. In accordance with this, the CONV treated topsoil fragmented more readily than the NINV soil in the field. The laboratory measurements on soil from the September sampling showed that the NINV treatment had lower friability index (i.e., friability index of 0.16 and 0.22 for NINV and CONV, respectively) and higher tensile strength of air-dry aggregates. The differences in topsoil tilth were not eliminated by natural soil meliorating processes during the growing season. This paper discusses the early stage effects of converting to non-inversion tillage. A number of years of continued treatment may be required before beneficial effects of non-inversion tillage are manifested in improved topsoil tilth.

Tillage impacts on aggregate stability and crop productivity in a clay-loam soil in central Iran

To take advantage of conservation tillage systems (including direct drilling and non-inversion) in central Iran, it is important to study the effects of different cultivation practices on soil structural stability as a physical indicator. A four-year study was conducted to investigate the effects of seven tillage systems on aggregate properties of a clay-loam soil (Calcic Cambisol) with continuous wheat ( Triticum aestivum L.) production. Crop productivity was also evaluated. Tillage treatments were moldboard plowing+disking (MD) as conventional tillage; chisel plowing +disking (CD); chisel plowing+rotary tilling (CR); chisel plowing (twice)+disking (2CD); plowing with Khishchi (a regional rigid cultivator)+disking (KD) as non-inversion methods; and till-planting with cultivator combined drill (TP); and no-till (NT) as direct drilling methods. A randomized complete block design consisting of four replications was used. Samples were taken from three different soil depths. A wet sieving method was used to determine aggregate size distribution (ASD), and mean weight diameter (MWD) as indices of soil aggregate stability. Soil organic carbon was also determined. For the first three years of the experiment, ASD and MWD at 0–15 cm were similar in different tillage treatments, except for direct drilling which had a significantly higher amount of aggregate greater than 2 mm and 2–1 mm diameter compared to the conventional method. At the second and third sampling depths all treatments had similar influence on ASD and MWD. Tillage treatments showed a significant effect on ASD and MWD in the fourth year of the experiment in all three depths. Almost 70% of the aggregates in the MD system were less than 0.25 mm, while only 55% of the aggregates in the direct drilling methods were less than 0.25 mm diameter. The four-year yield average for conventional and non-inversion tillage systems was 7264 and 6815 kg ha −1, respectively. Although, direct drilling improved soil structural stability, its lower yield (5608 and 4731 kg ha −1 for TP and NT, respectively) potential would indicate that reduced tillage systems (i.e. CD) appear to be the accepted alternative management compared to conventional practice (MD).