Cereal Crop Rotation Research Articles

Weed species within cereal crop rotations can serve as alternative hosts for Fusarium graminearum causing Fusarium head blight of wheat

Abstract Fusarium graminearum is the main causal agent of Fusarium head blight (FHB) of small grain cereals, but the importance of weeds in the FHB disease cycle and the establishment of F. graminearum in agroecosystems are still not fully understood. The objective of this study was to determine the potential role of weeds present within cereal crop rotations as alternative hosts. F. graminearum was isolated from different organs of asymptomatic weeds sampled from six fields with cereal-crop rotations in Lithuania for two consecutive years (2015 and 2016). The fungi were identified using morphological and molecular methods. Out of 57 weed species that were investigated, 41 (71.9%) harboured F. graminearum isolates. Twenty five weed species were identified as new, previously undocumented, hosts. The majority (73.3%) of the isolates of F. graminearum from this study belonged to the 15ADON genotype while a smaller proportion (23.4%) belonged to the 3ADON genotype. All F. graminearum isolates that were assessed induced FHB symptoms on artificially inoculated spring wheat tested in the field.

Theoretical and practical aspects of basic soil treatment in the conditions of modern soil management systems in Russia

The questions of inserting and implementing the different methods of basic soil treatment in the different crop plantings in the conditions of steppe zone in Nizhnee Povolzhye and Central Part of Non-chernozem Belt of the Russian Federation are analyzed. Systemize and complex research of the above questions are caused by multivalued opinions of agrarian scientists that are involved in the practical aspects of agrarian production towards them. On the results of long term researches is defined that the most effective and practice in cereal crop rotations are the basic soil management systems combining the different methods of tillage, mini-till and no-till soil treatment along with usage of modern machines and aggregates. In the conditions of field experiment at Centre of Precision Farming of Russian State Agrarian University - Moscow Timiryazev Agricultural Academy, along with the others, the tasks on economic efficiency and ecological safety that are the basis of precision farming concept are being solved.

Effects of selective herbicide treatment on weed community in cereal crop rotation

The efficacy of different frequently used selective herbicides and their impact on weed community were assessed in the field experiment with cereal crop rotation in 2013–2016. All herbicide treatments provided effective weed control, but community composition changed after 4 years. The density of many weed species increased on the untreated plots. Annual grasses Apera spica-venti and Alopecurus myosuroides had temporal increase at plots treated with 2,4-d, florasulam and aminopyralid, but decline at plots treated with pyroxsulam and/or chlorsulfuron. Significant treatment effect was confirmed only for Shannon’s index (H’), where the highest H’ was found in untreated controls (1.83) and the smallest in plots treated with 2,4-d + florasulam + aminopyralid (1.61). The pyroxsulam + florasulam + aminopyralid showed the greatest efficacy on a broad spectrum of weeds while maintaining reasonable species diversity.

Agro-environmental scheme for segetal plant conservation in Wallonia (Belgium): an assessment in conventional and organic fields

Description of the subject. Segetal plant species are highly threatened in arable land. They are an integral part of agricultural history and biodiversity in Western Europe. In Wallonia (southern Belgium), an agro-environmental scheme (AES) has been adopted for their conservation. It consists of strips on a field margin, with at least 60% cereals in crop rotation, and proscribes spraying and fertilisation. Objectives. This paper assessed the impact of an AES on segetal species conservation. Method. In eight organic fields and six conventional fields, a vegetation survey was performed on an AES strip and on a control margin of each field. Evenness, richness, cover and species composition for both total and segetal species were compared between AES strips and their corresponding control margins. Also, a cover of pernicious weeds was considered to be a factor in the rejection of AES by farmers. Results. In conventional agriculture, species richness (total and segetal) and cover (total and segetal) were higher in the AES than in the respective control; however, pernicious weed cover was also enhanced. In organic fields, total species richness was higher and pernicious weed cover was lower in the AES than in the respective control. Total evenness was higher in organic than in conventional fields, due to the co-dominance of several species. Under the AES, species composition and abundance remained different between conventional and organic fields. In all cases, rare species were hardly found in our survey. Conclusions. AES promote plant diversity in both organic and conventional fields. Sowing AES strips with uncleaned seeds from well-preserved fields, or species introduction, are recommended to enhance rare species recovery.

移牧と農耕が共存する地域の空間構造に関する研究

From the middle ages, Tavoliere plain in Apulia Region was the center of the wool industrial and customs for the sheep farming was placed. Sheeps had moved looking for grass from the settlements of Apennnes during for winter. Tavoliere plain was a grain-growing district in Italy. A peculiarity of agriculture in southern Italy were land-use of extensive agriculture and an existence of a large land owner. The purpose of this study is to clarify the spatial structure of Tavoliere plain where grazing and cultivation coexisted in pre-modern times. In this paper, we look at the atlas of the pasture land in detail, and analyze the spatial structure while comparing it with the statistics and drawings of farmland. In this plain, the sheep tracks and pasture lands for migration were developed by the kingdom of Naples. Three kinds of sheep tracks are decided, the thickest roads extended from the mountains to Foggia. The narrow roads were stretched in Tavoliere plain to move to the assigned pasture land. The grazing area set in 23 blocks was about 15,400 carri (3802.5 km2) in total, of which about 8930 carri (2,205 km2) was pasture. Other than that it was crop cultivated land, vineyard, vegetable field and pasture ground for dairy animals etc. In the atlas “Atlante delle locazioni del Tavoliere di Puglia di Antonio e Nunzio di Michele di Rovere” (1686), roads for movement of sheep, lodging with livestock houses (posta), large-scale farmers (masseria) and dairy pastures (mezzana) ware drawn, but crop cultivation (portata) was hardly drawn. Compared with the drawing of the individual cultivated land, it turns out that there was also rotatable cultivated land in fact. On the other hand, there were few settlements in the plains, many in the surrounding hills. And around the village there were subdivided vegetable fields and fruit tree plantations. In conclusion, there were not only grazing lands for sheeps and posta in Tavoliere plain, fragmented land use including cereal crop rotation cultivated lands, pasture grounds for domestic animals, vegetable gardens and fruit tree plantations were done. And it was the movement of people and sheep from other areas that supported the development of the large-scale farm in the plain and the wool industry in southern Italy.

Catch crop (oil radish) functions in long term cereal crop rotation

The aim of our research work was to study the role of the oil radish catch crop (Raphanus sativus var oleiformis Pers) as second crop or stubble crop for green manuring in winter wheat-winter barley-maize crop rotation. The oil radish was grown after the harvest of winter barley in the crop sequence. The green biomass (t ha-1), nitrogen (N) content in dry material (g kg-1) of catch crop and the N (kg ha-1) taken up by the catch crop were investigated for six years (1997-2002). The main goal was to measure the amount of remained N in the soil left by the main crop (WB) and the amount of N taken up by the oil radish catch crop. The maximum N uptake was about 120 kg ha-1 calculated on the average of the years but in the rainy 1998 the N removal reached the 200 kg ha-1 N. On the basis of the N balance calculation it is proved that incorporation of the catch crop in the crop sequence, the risk of N leaching diminishes, or can be minimal even if the level of N input is high, because the N removal of green biomass retains N in the soil and this way N turnover of the crop rotation remains balanced.

Increase in fertility of serozems in the Golodnaya Steppe of Kazakhstan and productivity of cotton during long-term fertilizer application

The experiments were performed within a 20-year-long period in six variants, including the cultivation of cotton monoculture in four crop rotations without fertilizers and with application of mineral fertilizers and manure. The content of humus, nitrogen, phosphorus, potassium, calcium, magnesium, and sodium in the plow layer and in the entire soil profile (to a depth of 150 cm) was the highest in the cotton–lucerne–cereal crop rotation with application of mineral and organic fertilizers. The productivity of raw cotton in this variant of the experiment was 3.17 t/ha in the first decade and 2.56 t/ha in the second decade.

Effects of crop rotation and field management methods on weed density and species composition in the southeastern part of Latvia

<p class="R-AbstractKeywords"><span lang="EN-GB">Integrated weed management (IWM) is a complex approach to weed control that is based on use of several different methods complementing each other, instead of relying on one single method, like chemical weed control. Weed control methods that can be used as parts of IWM strategy include mechanical weed control, application of herbicides, low tillage, changes in the rate and application time of fertilizers, use of undersown crops and crop rotation. Weed surveys were carried out in 2013 and 2014 in the southeastern part of Latvia. The aim of this study was to assess the effect of crop rotation and other field management practices on weed density and weed species composition using the data collected in the surveys. Survey was carried out in the arable fields of conventional farms within four different size categories. One of the significant factors that explained the variation of weed composition within a field was a proportion of cereals in crop rotation within a four year period. Further surveys are required to estimate the effects of climatic variables. Density-dependence can also be important for practical management decisions for particular weed species and should be investigated.</span></p>

Nitrogen migration in crop rotations differing in fertilisation

Inappropriate use of nitrogen fertilisers is becoming a global problem; however, continuous fertilisation with N fertiliser ensures large and constant harvests. To evaluate the relationships of differently fertilised cultivated plant rotation with N metabolism in the agroecosystem the research was conducted between 2006 and 2013 at Lipliūnai, Lithuania, in fields with calcareous gley brown soil, i.e. Endocalcari Endohypogleyic Cambisol (CMg-n-w-can). The research area covered three drained plots where crop rotation of differently fertilised cereals and perennial grasses were applied. The greatest productivity was found in a higher fertilisation (TII, 843 kg N/ha) cereals crop rotation. With less fertilisation (TI, 540 kg N/ha) crop rotation productivity of cereals and perennial grasses (TIII, 218 kg N/ha) was 11-35% lower. The highest amount of mineral soil N (average 76 kg/ha) was found in TI. It was influenced by fertilisation (r=0.71) and crop productivity (r=0.39). TIII tended to reduce Nmin (12.1 mg/L) and Ntotal (12.8 mg/L) concentrations in drainage water and leaching of these elements (7 and 8 kg/ha). Nmin and Ntotal concentrations in the water depended on crop productivity respectively (r=0.48; r=0.36), quantity of mineral soil N (r=0.65; r=0.59), fertilisation (r=0.59; r=0.52), and N balance (r=0.26; r=0.35). Cereal crop rotation increased N leaching by 12-42%. The use of all crop rotations resulted in a negative N balance. Nitrogen balance depended on fertilisation with N fertiliser (r=0.55). The application of perennial grasses crop rotation in agricultural fields was the best environmental tool, reducing N migration to drainage.

Properties of Luvisol and spring barley yield as affected by peas as a catch crop

The share of cereals in the total area of agricultural crops is currently too high, which leads to deterioration of soil properties and makes it difficult to obtain high yields. The objective of this research was to determine the effect of field pea grown as a catch crop on soil properties and yielding capacity of spring barley cultivated after the catch crop, in a cereal crop rotation. Three treatments of catch crop management were studied: A – catch crop ploughed in in the autumn, B – catch crop left as mulch for the winter, C – control (without a catch crop). Experiments were carried out on a Luvisol (LV) in a randomized block design. The catch crop biomass ploughed in significantly improved moisture and reduced compaction of the topsoil before sowing spring barley. Use of field pea as a catch crop increased enzymatic activity and mineral nitrogen content in the soil before sowing and during tillering of barley. The effect of mulch was stronger than that obtained in the treatment with biomass ploughed in in the autumn. Catch crop significantly improved the yield of spring barley, which was mainly due to increasing the number of spikes and grains per spike in barley grown after the catch crop ploughed in, and due to increasing the number of grains per spike in the treatments with mulch. Physical and biological properties of soil in cereal crop rotations may be substantially improved by catch crop, especially used as mulch. Catch crop influence on spring barley yield was independent of its management method.

The Influence Of Cereal Share In Crop Rotations On The Grain Yield And Quality Of Winter Wheat

Abstract The aim of our study is to find out the influence of different share of cereals and various fertilisation on the grain yield and quality of winter wheat. The long-term field trial with 40, 60 and 80% share of the cereals and two levels of fertilisation (H1 mineral fertilisation + organic manure Veget®; H2 mineral fertilisation only) were carried out in the very warm and dry area of continental weather on luvi-haplic chernozem. In the years 2010–2013, the grain yield, the wet gluten content, gluten index, the falling number and sedimentation index of winter wheat according to Zeleny were investigated. The significantly higher grain yield of winter wheat was recorded after preceding crop of common pea. The yield of cereals in crop rotation with 60% share of cereals (7.00 t/ha) was significantly higher than in crop rotation with 80% share of cereals (6.78 t/ha).The statistically higher wet gluten content after pea fore-crop was found out when the mineral fertilisation and organic fertiliser Veget® were applied (33.4%) with comparison to the treatment with mineral fertilisation only (30.08%).

Designing eco-efficient crop rotations using life cycle assessment of crop combinations

Intensive arable crop production has major impacts on the environment and solutions for their reduction are needed. Diversification of crop rotations together with improved nitrogen management is an option for more eco-efficient cropping systems. The potentials for reducing the environmental impacts cropping systems were investigated by means of life cycle assessment (LCA) in three regions in France (Beauce, Burgundy and Moselle).The crop management data were compiled by the Chambers of Agriculture in the three regions based on field survey data (2002–2009 in Burgundy and Moselle and 2004–2008 in Beauce) and completed by experts. The LCA calculations were carried out by the SALCA-crop tool, using the ecoinvent and SALCA inventory databases and SALCA emission models. The LCAs were calculated for crop combinations, which were an efficient way to analyse a large number of crop rotations. A crop combination is defined as the inventory of a given crop, with a defined preceding crop and eventually including a catch crop.Nitrogen management revealed to be a key driver for the environmental impacts. It dominated the non-renewable energy demand, the global warming potential, the ozone formation potential, the acidification potential, and the eutrophication potential. Strong correlations between N fertilisation and these environmental impacts were found. The introduction of pea allowed to reduce the total eutrophication over the whole crop rotation. The mitigation of environmental impacts was not only possible per hectare, but also per € gross margin II. The eco-efficiency can thus be improved by reducing the level of N fertilisation. A reduction of N fertilisation could be achieved also by a reduction of the fertiliser doses to the non-legume crops, in addition to the introduction of legumes. Both ways proved to be effective and the combination of both was the most promising. However, trade-off between environmental and economic goals was identified.Diversification of cereal intensive crop rotations proved to be generally favourable from an environmental point of view. Catch crops had favourable effects on nutrient leaching a slightly favourable effects on biodiversity and soil quality. The ecotoxicity potentials were dominated by a few active ingredients only; the diversification did not lead to generally reduced ecotoxicity potentials.Diverse crop rotations with reduced N input are a promising way to reduce the environmental impacts of intensive arable crop rotations.

Effects of plastic mulch and crop rotation on soil physical properties in rain-fed vegetable production in the mid-Yunnan plateau, China

Plastic mulch is widely used for vegetable cropping in the mid-Yunnan plateau, southwestern China. However, the effects of plastic mulch on soil physical properties are poorly understood. A field experiment was conducted to evaluate the effects of different plastic mulch patterns (narrow and wide plastic mulch) and rotations (broccoli–zucchini–winter wheat and broccoli–zucchini–fallow) on soil physical properties and soil organic carbon content in a vegetable production system at a research station in the region. The experiment comprised four treatments and laid out in the field using randomized complete block design replicated nine times. The soil (0–20cm) under wide plastic mulch retained more water than the soil narrow plastic mulch under the vegetable growing season over 3 consecutive severe drought years. Significant decline (11%) of surface soil (0–5cm) organic carbon was observed in 2012 compared with in 2010, but soil organic carbon and physical properties did not differ significantly between the two different plastic mulch patterns. The higher macro-porosity, aggregate stability, Ksat and lower bulk density in the plastic mulched ridges imply that the conversion from narrow-plastic-mulch to wide-plastic-mulch increases mulched area thereby conserving larger area soil structure in the croplands. Although increased catch crop stubble retention in the furrows apparently improved surface soil macro-porosity and saturated hydraulic conductivity, the autumn rotary cultivation in broccoli–zucchini–winter wheat rotation system has significantly decreased (5%) surface soil organic carbon. The results suggested that continued use of vegetable–cereal crop rotation system, even with stubble retention, may result in loss soil organic carbon. Further research that covers wetter years should be taken to assess effects of vegetable–cereal crop rotation pattern on soil physical properties in this region.

Effects of pig and dairy slurry application on N and P leaching from crop rotations with spring cereals and forage leys

Two crop rotations dominated by spring cereals and grass/clover leys on a clay soil were studied over 2 years with respect to nitrogen (N) and phosphorus (P) leaching associated with pig or dairy slurry application in April, June and October. Leaching losses of total N (TN), total P (TP), nitrate-N and dissolved reactive P (DRP) were determined in separately tile-drained field plots (four replicates). Mean annual DRP leaching after October application of dairy slurry (17 kg P ha−1) to growing grass/clover was 0.37 kg ha−1. It was significantly higher than after October application of pig slurry (13 kg ha−1) following spring cereals (0.16 kg ha−1) and than in the unfertilised control (0.07 kg P ha−1). The proportion of DRP in TP in drainage water from the grass/clover crop rotation (35 %) was higher than from the spring cereal rotation (25 %) and the control (14 %). The grass/clover rotation proved to be very robust with respect to N leaching, with mean TN leaching of 10.5 kg ha−1 year−1 compared with 19.2 kg ha−1 year−1 from the cereal crop rotation. Pig slurry application after cereals in October resulted in TN leaching of 25.7 kg ha−1 compared with 7.0 kg ha−1 year−1 after application to grass/clover in October and 19.1 kg ha−1 year−1 after application to spring cereals in April. In conclusion, these results show that crop rotations dominated by forage leys need special attention with respect to DRP leaching and that slurry application should be avoided during wet conditions or combined with methods to increase adsorption of P to soil particles.

Health Status of Spring Barley Grown on Alfisol as Affected by Catch Crop

Aims: The aim of this study was to evaluate the effect of field pea grown as a catch crop and used for green manure on the health of spring barley grown in cereal crop rotation. Study Design:The experiment was carried out in the randomized block design with four replications. Place and Duration of Study:A field experiment was carried out in the years 2008-2011 at Mochelek (17∫51 2E; 53∫13 2N), the Experiment Station of the University of Technology and Life Sciences in Bydgoszcz, Poland. Methodology: The experimental factor was made up by the manner and the time of the catch crop biomass incorporation into the soil: the catch crop plowed -in in autumn; catch crop left as mulch for winter and incorporated in spring; control. The evaluation of the health of roots, stem base and spikes was complemented by mycological analysis. Results:Catch crop has anambiguous effect on the health of barley. Averaged over the three years it significantly decreased the stem infection with

Recovery of organic fertility in degraded soil through fertilization and crop rotation

Maintenance and enhancement of the quality of degraded soil are, in essence, dependent upon the improvement of physical, chemical and biological properties of the soil. Improvement in microbial parameters of the degraded soil was studied in the present experiment through the effect of fertilizer sources and levels and cropping patterns in a factorial design in northern Pakistan. The experiment was designed in RCB with split plot arrangements. Cropping patterns i.e. maize–wheat–maize (C1), maize–lentil–maize (C2) and maize–wheat + lentil intercrop-maize (C3) were kept in main plots while fertilizer treatments; the control (T1), 50% NP (T2), 100% NPK or the recommended dose (T3) and 20tha−1 farmyard manure integrated with 50% mineral N and 100% P and K (T4) were tested in sub-plots during the study. Maximum and significant improvement in microbial parameters was recorded in T4 with 44, 24, 27 and 24.6% increase in total nitrogen (total N), mineralizable nitrogen (MN), microbial biomass nitrogen (MBN), and microbial biomass carbon (MBC) after a 10day incubation period over the T3, respectively, in the surface soil and 10%, 21%, 24% and 24.2% increase in the corresponding microbial parameters in the sub soil. The cropping patterns having cereal–legume rotation also improved organic soil fertility by 25%, 11.4%, 13% and 44% increase in total N, MN, MBN and MBC after a 10day incubation period over the cereal-cereal rotation, respectively, in surface and 4%, 11%, 10% and 31% increase in the corresponding microbial parameters in the sub surface soil. The conclusion was that degraded alfisols require 50% N from the organic sources out of its total N requirements along with the inclusion of legumes in the traditional cereal–cereal crop rotation for the recovery of its microbial parameters.

The role of catch crops in the ecological intensification of spring cereals in organic farming under Nordic climate

Catch crops can contribute to nitrogen supply of following crops through uptake of excess soil mineral nitrogen (N) and through biological N fixation. The contribution of catch crops to the ecological intensification of organic arable systems was investigated using data of a 12-year field experiment carried out at three sites in Denmark. This study focused on the yields of spring oats and spring barley in systems with and without manure in two different cropping systems (O2 and O4) that differed in the proportion of legume-based catch crops (O2 lower and O4 higher) and in the rotation composition (grass–clover green manure in O2 and pulse crops in O4). Three consecutive four-year crop cycles were established at three locations representative of different soil types (loamy sand, sandy loam and coarse sand) and climatic conditions. Crop management and soil operations were performed following common practices in organic farming. Measurements of dry matter (DM) and N content of grain cereals at harvest, above-ground biomass in catch crops and green manure crops in autumn and of the green manure crop at the first cutting were performed. The effect of catch crops on grain yield varied with cereal and catch crop species, soil and rotation type, and the application of N in manure. Higher yield increases from previous catch crops were obtained for spring oat than for spring barley with mean estimates of the apparent N recovery efficiency of N in above-ground catch crops of 69% and 46%, respectively. However, lower autumn N in catch crops undersown in high yielding cash crop was also observed. For spring oats mean grain yield benefits of including catch crops varied from 0.2 to 2.4MgDMha−1 depending on location, manure use and cycle of the rotation. In spring barley mean grain yield benefits from catch crops varied from 0.1 to 1.5MgDMha−1. There was a tendency for the effect of catch crop on grain yield to increase over time. These results indicate that in Nordic climates catch crops can contribute to the ecological intensification of spring cereals, not only by reducing the nitrate leaching and increasing N retention, but also by improving yields. Management practices in relation to catch crops must be adapted to the specific soil and cropping systems.

The occurrence of fungal diseases in spring barley, cultivated in cereal crop rotation depending on the intensity of production technologiesWystępowanie chorób na jęczmieniu jarym uprawianym w płodozmianie zbożowym w zależności od stopnia intensywności technologii produkcji

Summary Field experiments were conducted at the Experimental Station Osiny (Institute of Soil Science and Plant Cultivation, Pulawy, Poland) in 2005–2007. Since 1998 spring barley was cultivated in cereal crop rotation under three technologies characterized by different in production intensity. The aim of this study was to determine the occurrence of leaf, stem base and root diseases on spring barley of depending different production intensity (intensive, integrated, economic). The level of production intensity was diversified by plant protection strategy, and did not influence the healthiness of spring barley. The level of infection of spring barley with Gaeumannomyces graminis and the fungal–stem base diseases did not differ between the tested technologies. No leaf infection was recorded in 2005–2006. In the 2007 the percentage of leaf area infected by Pyrenophora teres in all applied technologies was low.

The Grain Yield and Weed Infestation Rate of Winter Wheat by the Different Share of Cereals in Crop Rotations

The Grain Yield and Weed Infestation Rate of Winter Wheat by the Different Share of Cereals in Crop Rotations The aim of the study was to compare the grain yield and weed infestation rate of winter wheat in crop rotations with 40, 60 and 80% share of cereals and in continuous cropping. The trial was situated in the area of continental climate. The trial had two parts. In the first part, there were crop rotations with 40, 60 and 80% share of the cereals. Two levels of fertilization were used: H1 mineral fertilization + organic manure Veget; H2 mineral fertilization only. In the second part, winter wheat and spring barley were grown in monoculture. Three variants of fertilization were used: 1 - mineral fertilization; 2 - mineral fertilization + straw of cereals were ploughed; 3 - mineral fertilization + straw of cereals + organic manure Veget were ploughed in the soil. In the years 2006-2009 the grain yield, thousand kernel weight and weed infestation rate of winter wheat in different crop rotations and by the continuous cropping were investigated. The statistically higher winter wheat grain yield (6.50 t ha-1) was recorded by 40% share of cereals in crop rotation than by 60% and 80% share of cereals (6.23 t ha-1). The grain yield of winter wheat by continuous cropping was lower by 2.24 t ha-1 (34.46%) than in crop rotation with 40% share of cereals. The weed infestation rate by 80% share of cereals in crop rotation was determined 2.4 times higher than by 40% share of cereals.

A new look at an old practice: Benefits from soil water accumulation in long fallows under Mediterranean conditions

The practice of long fallowing, by omitting a year of cropping, is gaining renewed focus in the low rainfall zone of the northern agriculture region of Western Australia. The impetus behind this practice change has been a reduced use of pasture breaks in cereal crop rotations, and the belief that a fallow can improve soil water accumulation and thus buffer the negative effects of dry seasons on crop yields. We evaluated the benefits of long fallowing (full stubble retention, no weed growth allowed) in a continuous wheat sequence via simulation modelling with APSIM at two rainfall locations and five soil types. The simulated benefits to long fallowing were attributable to soil water accumulation only, as the effects on soil nitrogen, diseases or weeds were not evaluated.