Oilseed Radish Research Articles

Economic efficiency of maize crop protection against weeds

The influence of agricultural practices for cultivating corn on the grain yield of this crop was stu- died. It has been shown that in the conditions of the central part of Belarus, with semi-steam tillage after harvesting the previous crop or cultivating stubble oilseed radish and using the herbicides Meister Power, MD (1.5 l/ha), Adengo, KS (0.4 l) in the 3-leaf phase of corn /ha) grain yield, net income and profitability were at the level of using the herbicide Gardo Gold, KS (4.0 l/ha) against the background of post-harvest application of the glyphosate-containing herbicide Volnik Super, BP (2.5 l/ha). At the same time, the herbicide load decreased from 3.38 to 0.09–0.19 kg/ha a. i., i. e., by 94.4–97.3 %, which is of impor- tant environmental significance.

Susceptibility of Oilseed Radish (Raphanus sativus subsp. oleiferus) Cultivars and Various Brassica Crops to Plasmodiophora brassicae.

Oilseed radish (OR; Raphanus sativus var. oleiferus) is grown as a cover crop and develops a unique taproot, absorbing nitrogen left by the previous crop. The aim of this project was to investigate the resistance of OR cultivars (cvs.) to Plasmodiophora brassicae, the causal agent of clubroot disease. Twelve market cvs. were compared with cvs. of clubroot-resistant (CR) winter oilseed rape (OSR; Brassica napus) and other selected species of the Brassicaceae family. The study was performed as a replicated bioassay in a growth chamber using a specially composed mixture of field soils holding the natural inoculum of P. brassicae. The results show that the OR cultivars were infected, which implies that OR multiplies the pathogen. The susceptibility of the OR cultivars was not significantly different from that of the CR OSR cultivars Alister and Archimedes, but it was significantly different from that of the OSR cv. Mendel. The disease severity index (DSI) for OR cultivars ranged from 2.3 to 9.3, and disease incidence was 3-17%. The best performance was shown by black radish (Raphanus sativus var. niger) with a DSI of 0.3. For sustainable brassica crop production, we suggest avoiding OR as a cover crop in crop rotations, including OSR or other brassica crops, since there is a risk of increasing inoculum in the soil.

Oilseed Radish: Nitrogen and Sulfur Management Strategies for Seed Yield and Quality—A Case Study in Poland

Oilseed Radish: Nitrogen and Sulfur Management Strategies for Seed Yield and Quality—A Case Study in Poland

Open-cell bio-based polyurethane foams modified with biopolyols from non-edible oilseed radish oil

Open-cell bio-based polyurethane foams modified with biopolyols from non-edible oilseed radish oil

Total Carbon and Nitrogen and Granulometric Fractions of Soil Organic Matter Under No-Till System and Conventional Tillage with Onion Cultivation

Objective: The objective of this work was to evaluate the total carbon (C) and nitrogen (N) contents and the granulometric fractions of soil organic matter (SOM) under different management systems with single and intercropped winter cover crops in the cultivation of onion in Ituporanga, SC. Theoretical framework: Onion cultivation typically occurs in a conventional tillage system (CTC), which favors the loss of C and N from the soil due to soil mobilization. The vegetable no-tillage system (VNTS) uses sustainable practices with continuous soil cover and restricted soil tillage, promoting improvement of edaphic attributes. Methodology: The experiment was implemented in 2009 and the collection of soil samples took place in 2019 in the layers of 0-5, 5-10 and 10-30 cm in the treatments under VNTS, being black oat (AV); rye (CE); oilseed radish (NB); rye + radish (CE+NB); black oat + oilseed radish (AV+NB) and spontaneous vegetation (VE). In addition to these treatments, two adjacent areas were used, one under CTS and the other in a secondary forest area (MATA). The content of total organic C (TOC), total N (NT), light organic matter in water (LOM), particulate organic carbon (POC), particulate nitrogen (PN), C associated with minerals (COam) and N associated with to minerals (NAM). Results and conclusions: VNTS increased TOC and NT contents with the use of grass and cruciferous intercropping to the detriment of single crops and CTS. The LOM content was higher in VNTS with the use of single grasses and stood out in relation to VNTS with consortium. There were no differences for PN between MATA, CE and CE+NB, demonstrating that VNTS is efficient in raising these levels in substitution of CTS. The CE+NB consortium increased the levels of COam and NAM in the surface layer of the soil after replacing CTS with VNTS. Research implications: In VNTS, the use of intercropping between cover crops is an efficient management in adding C and N to the soil, as the simultaneous cultivation of different species of cover crops produces straw with an intermediate C/N ratio, the roots exploit different soil extracts and nutrient cycling is more efficient. Originality/Value: The results of this study are from a long-term experiment (10 years), which demonstrates the effectiveness of VNTS in recovering and increasing C and N levels in soil previously cultivated for a long period in the CTS, in addition to to match the forest area.

Effects of Tillage and Cover Crops on Total Carbon and Nitrogen Stocks and Particle-Size Fractions of Soil Organic Matter under Onion Crop

Onion (Allium cepa L.) is a food crop of economic importance. In Brazil, the crop typically occurs in a conventional tillage system (CT), which favors the mineralization and decomposition of soil organic matter (SOM) and the loss of carbon (C) and nitrogen (N). On the other hand, the no-tillage vegetable system (NTVS) operates based on sustainable pillars and bypasses the adverse effects of CT. This study evaluated the total C and N stocks and particle-size fractions of SOM in NTVS with single and intercropped cover plants compared to vegetable crops under CT. The NTVS evaluated treatments were as follows: (1) spontaneous vegetation (SV); (2) black oats (BO); (3) rye (RY); (4) oilseed radish (OR); (5) RY + OR; and (6) BO + OR. A treatment under CT with millet cover, a no-tillage system with (NTS) millet + velvet + sunflower cover, and a forested area as the original condition was also evaluated. Soil samples were collected in 0–5, 5–10, and 10–30 cm layers. Stocks of total organic C (TOC), total N (TN), particulate OC (POC), particulate N (PN), mineral-associated OC (MAOC), and mineral-associated N (MN) were evaluated. The highest stocks of TOC, TN, POC, and NM were found in NTVS compared to CT, and RY + OR showed the best results. The NTVS showed higher TOC and TN stocks with grasses and cruciferous intercropped than NTVS with SV and CT. POC and PN stocks increased in areas with single and intercropped RY and OR treatments. MAOC and MN stocks were higher than forest in RY + OR intercrop in the topsoil layer. RY and OR intercrop efficiently added C and N to the soil under NTVS. The consortium of millet + velvet + sunflower in NTS showed higher TOC, TN, POC, and PN stocks compared to the other treatments (0–5 and 0–30 cm). In general, the intercrop of cover plants is ideal for obtaining the NTVS maximum potential, favoring several mechanisms between soil, plant, and atmosphere, resulting in improved soil quality, increased organic matter, and higher stocks of C and N.

Influence of the sowing time and mineral fertilizers on the productivity of annual grass mixtures

The productivity of annual feed grass mixtures (vetch + oats, Sudan grass + white mustard, Sudan grass + oilseed radish), sown after the winter rye harvesting during the “shooting” phase (the 1st time of sowing), during the “heading” phase (the 2nd time of sowing), and during the phase of complete ripeness (the 3d time of sowing), was studied in the conditions of forest-steppe soils of the Volga Region (the Republic of Mordovia). The experiment was carried out in 2018-2020 on heavy loamy soils against the background of three doses of mineral fertilizers use (without fertilizers, N16P16K16 + N30, N16P16K16 + N60). It has been established that the duration of vegetation of feed mixtures according to the time of sowing when harvesting for green mass was: at the first the time of sowing - 63-85 days, at the second - 63-76 days, at the third - 56-62 days. The highest height of the plant was at the first time of sowing with the use of fertilizers at a dose of N16P16K16 + N60, the lowest - at the third time of sowing. The highest growth was achieved by Sudan grass (48-116 cm), the lowest - by the mixture of vetch and oats (18-67 cm). The highest yield of green mass (14.0 t/ha) was observed when cultivating Sudan grass mixed with oilseed radish on the background of N16P16K16 + N60 at the first time of sowing. For mixture of Sudan grass with white mustard, the yield was 2-7 % lower, and for vetch + oats mixture - 32-45 % lower. The same was observed according to the yield of dry matter and feed units. As to the protein content, mixtures of Sudan grass with cruciferous crops exceeded the vetch + oats mixture by 7-26 %. The fiber content in the grass mixtures was decreasing from the first time of sowing to the last. The greatest amount of fiber (28.11-28.72 %) was observed during the second time of sowing. The economic assessment showed that the cultivation of annual grass mixtures after winter rye without mineral fertilizers was the most cost-effective (29-208 %). The highest efficiency (202-208 %) was provided by the mixture of Sudan grass with oilseed radish and white mustard.

DECOMPOSITION OF THE REMAINING STRAW DURING SOYBEAN GROWING IN THE MIDWESTERN PARANÁ, BRAZIL

Crop biomass plays an important role, especially in tropical and subtropical crops that adopt the no-tillage system, whose decomposition is related to material composition and environmental conditions. The objective of this work was to analyze the decomposition of straw remaining from autumn/winter crops in the development of soybean in succession in the Midwest region of Paraná. The experiment was conducted between 2019 and 2021 in a completely randomized design, with eight treatments (spontaneous, black oat, brachiaria, corn, wheat, oilseed radish, corn + brachiaria, and black oat + oilseed radish) and four replications. After autumn/winter cultivation, biomass samples were dried and placed in nylon bags, returning to the original plot during soybean sowing. The decomposition bags were collected in seven periods over 120 days, coinciding with the soybean cycle. The decomposition rate was analyzed by regression. The regression equations and the amount of biomass remaining from the autumn/winter seasons were determinate the half-file and the remaining mass on the soil surface at sowing and at 30, 60, 90, and 120 days after sowing. Biomass production and decomposition rate varied with the season, depending on environmental conditions. Wheat had the lowest decomposition rate with a half-life greater than 100 days. Intercropping crops reduce the decomposition rate.

FORMATION OF YIELD OF OISEED RADISH AT GROWING DOSES OF MINERAL FERTILIZERS BY PRE-SOWING APPLICATION ON GRAY FOREST SOILS

The article reflects the results of studying the effectiveness of options for fertilizing oilseed radish on gray forest soils in the option of their pre-sowing use for the formation of yield of both leafy mass and seed yield, taking into account the complex use of this agricultural crop. A review of the characteristics of the mineral nutrition of oilseed radish over a long-term cycle of its study is made and aspects of its nutrition and the appropriateness of the use of mineral fertilizers are determined. The features of the use of both single-component fertilization options for the introduction of nitrogen, phosphorus and potassium, and the complex use of these nutrients for the mutual binary and complex application have been studied. The specified fertilization options were formed in an increasing order of norms from the control option without fertilizers to the complex application of N180P150K150, which made it possible to systematize the feasibility of each option and determine the possibility of using both the minimum additional mineral nutrition and high doses exceeding the recommendations for oil radish. It has been established that the main growth processes in the oilseed radish of the ‘Zhuravka’ variety, as a combined genotype of fodder and seed-growing use, are determined by high-grade nitrogen nutrition, and the norm is in the range of 60-90 kg/ha of active substance with a more expedient combination with chlorine-free potassium fertilizers type of kalimagnesia –was the most technologically expedient for realizing the yield potential of the leafy mass of oil-bearing radish on gray forest soils. At the same time, it was proved that the effectiveness of the effect of additional mineral nutrition when using oilseed radish to obtain leafy mass depends on the hydrothermal conditions of its vegetation with a reduction of the proposed norms in conditions of insufficient soil and atmospheric moisture for the period of application of pre-sowing fertilizer. It has been proved that the maximum yield of oil-bearing radish seeds in the ‘Zhuravka’ variety is formed in the variants of the pre-sowing application of additional mineral nutrition due to the introduction of N90P30-60K30-90 of the same forms of potash fertilizers, which ultimately ensures maximum yield levels of conditioned seeds with an indicator weight 1000 at the level of 10-11 g with the content of fat in the seeds on an absolutely dry weight at the level of 37-39.5%.

Changes in the root fungal microbiome of strawberry following application of residues of the biofumigant oilseed radish

Biofumigation has been proposed as an environmentally friendly method of plant protection against soil-borne pathogens, but its effects on microbial communities are still incompletely understood. Using high throughput DNA sequencing, we investigated the effects of oilseed radish residues on the root fungal microbiome of strawberry in the presence of a soil-borne fungal pathogen, Verticillium dahliae. Results of our greenhouse study show that early flowering occurred in response to residue addition, suggesting a plant stress-response and there was a significant decrease in berry yield. The fungal microbiome of roots was significantly restructured by both biofumigation and inoculation with Verticillium. In particular, the abundance of root endophyte- and arbuscular mycorrhizal functional guilds was reduced significantly as a result of biofumigant and V. dahliae addition, whereas the abundance of saprotrophs increased significantly when both treatments were applied together. Alpha diversity analyses of fungi associated with roots indicated a significant increase in species richness following Verticillium inoculation, whereas the biofumigant alone or in the presence of V. dahliae resulted in no significant effect, suggesting that apparently some rare taxa may have been enriched/stimulated in the presence of the pathogen. Further investigations should reveal whether negative effects of biofumigation on potentially beneficial root associated endophytes and arbuscular mycorrhizal fungi are host genotype- or soil-dependent.

Soil phosphorus availability and uptake by mycorrhizal and non-mycorrhizal plants in an onion no-tillage system

ABSTRACT: Onion is an important vegetable crop, predominantly grown under conventional tillage system management. Alternatively, the vegetable no-tillage system uses cover crops to form a residue layer, which improves soil physical, chemical, and biological attributes. Aiming to understand the interaction of mycorrhizal and non-mycorrhizal cover crops, phosphatase activity, and soil phosphorus availability and uptake by plants, a no-tillage vegetable production system experiment with onion was carried out in Ituporanga, Southern Brazil. The treatments were black oats (Avena strigosa); rye (Secale cereale); oilseed radish (Raphanus sativus); rye + oilseed radish; black oats + oilseed radish, and a control with spontaneous plants. Additionally, two plots, a conventional tillage system area and a forest, both adjacent to the experiment, were evaluated. We measured cover crop biomass, onion yield, acid phosphatase activity, and resin-extracted phosphorus in the soil, shoot and root phosphorus content, and root colonization in cover crops, spontaneous plants, and onions. The treatments with cover crops had the highest plant biomass in winter and onion yield. Available soil phosphorus and acid phosphatase activity were higher in no-tillage plots than in the conventional tillage system area. The presence of non-mycorrhizal oilseed radish was associated with decreased colonization of rye and onion roots by arbuscular mycorrhizal fungi. No-tillage areas with cover crops or spontaneous plants in winter accumulated more phosphorus than conventional tillage system areas. The conventional tillage system showed adverse effects on most soil attributes, as shown by a Principal Component Analysis.

Microbial activity in soil with onion grown in a no-tillage system with single or intercropped cover crops

ABSTRACT: Microbial biomass is a driving force in the dynamics of soil organic matter, and microbial activity is an indicator of soil quality in agroecosystems, reflecting changes in management practices and environmental conditions. We evaluated the effect of monoculture and intercropped winter cover crops on soil chemical attributes, microbial biomass carbon (MBC), basal respiration (BR), metabolic quotient (qCO2), urease, β-glucosidase, and fluorescein diacetate (FDA) hydrolysis activity, as well as onion yield in a no-tillage system. Soil is a Typic Humudept, and treatments were control with spontaneous vegetation, barley, rye, oilseed radish (OR), OR + rye, and OR + barley. The soil was sampled (0-10 cm) five times between June and December. There were no differences among treatments for MBC and BR, and the highest values for those attributes occurred in June, when cover plants were in their initial stage. Although, qCO2 was not affected by any treatment, it varied among sampling periods, ranging from 0.62 to 10 µg C-CO2 mg-1 MBC h-1, indicating a low- or no stress environment. Cover crops had little influence on enzyme activity, but FDA was lowered in areas with single crops of barley and rye. Average onion yield in cover crops treatments was 13.01 (Mg ha-1), 30-40% higher than in the control treatment.

Increased nitrogen retention by cover crops: implications of planting date on soil and plant nitrogen dynamics

AbstractCover crops are frequently adopted to immobilize residual nitrogen post-harvest, thereby reducing potential N losses. However, the effectiveness of a cover crop depends on the species planting date, and other management practices. Limited information on N dynamics in cover crop systems is available specially in short-season vegetable rotations under temperate climate. From 2008 to 2010, a split-plot field experiment was carried out in a humid, temperate climate with cover crop treatment as the main plot factor [no cover crop control (NoCC), cereal rye, hairy vetch, oat, forage pea, oilseed radish (OSR) and a control with fertilizer N to the cucumber crop (NoCC + N)], and cover crop planting date as the split factor (early and late) to evaluate their impacts on cover crop biomass and N dynamics over the fall and following cucumber crop. All cover crop treatments significantly lowered soil mineral nitrogen (SMN) by 39–87% compared to the NoCC control, which was concomitant with cover crop growth and N accumulation. In the fall, SMN (0–90 cm depth) was less under the early-planted cover crops (avg. 78 kg N ha−1) compared to the late-planted (avg. 100 kg N ha−1). In April, greater plant available nitrogen (PAN, sum of SMN to 60 cm depth and plant N) with cover crops than without demonstrated N conservation over the winter and into the cucumber crop. Crop yield was equal to or better with a cover crop compared with the NoCC in both years; moreover, compared to the NoCC + N control yields were equivalent with OSR and pea. Oat, vetch and pea cover crops benefited the most by having an earlier planting date, while OSR and rye are recommended if the planting date is delayed. Although an early August planting date significantly increased plant N accumulation and SMN by November, this species-dependent interaction did not persist into the following season in yield and N accounted for in the system.

Nitrous Oxide Emissions in No-Tillage Onion ( Allium cepa L.) Crops Are Increased by Oilseed Radish Cover Crop and Poultry Manure Application

ABSTRATO O uso de plantas de cobertura e de esterco de galinha (PM) e uma alternativa para reduzir o uso de insumos sinteticos e pode contribuir para o ciclo de nutrientes em cebolas ( Allium cepa L.) cultivadas em sistema plantio direto. No entanto, esta pratica de gestao pode contribuir para um aumento das emissoes de N 2 O para a atmosfera. Os objetivos deste estudo foram avaliar o efeito imediato sobre as emissoes de N 2 O da adicao [...]

Plantas de cobertura de invierno suprimen malezas y proveen N al maíz cultivado en sucesión

Cover crops (CC) and crop rotation are key components of a sustainable crop production system. The objectives of this study were to (i) evaluate the effect of winter CC on nitrogen (N) supply to the subsequent maize crop, and to (ii) evaluate the effect of CC on soil cover and weed population. Three winter CC were evaluated: black oat (BO) (Avena strigosa Schieb), white lupin (WL) (Lupinus albus), and oilseed radish (OR) (Raphanus sativus L.), as single species and in a mix. The three CC mixes included: BO+WL; BO+OR; and OR+WL. In addition to CC treatments a set of five N application rates (0, 60, 120, 180, and 240 kg N ha-1) were included on plots under winter fallow (WF). The winter CC supplied plant-available N to the subsequent maize crop varying from 25 to 53 kg N ha-1 with BO and WL, respectively. The mix of CC varied less in N supply (38-42 kg N ha-1). Soil cover and weed suppression varied between CC. The results suggest that BO can be used to attain rapid soil cover. Black oats also provided better soil cover after CC flattening, likely due to the higher C:N ratio and slower residue decomposition. The higher C:N ratio may result in some N immobilization and reduced plant available N to the maize crop. However, BO also showed great weed suppression. Mixing CC is an alternative to merge the benefits of the individual species, enhancing the overall ecosystem services provided by them.

Suppression of Glyphosate-resistant Canada Fleabane (Conyza canadensis) in Corn with Cover Crops Seeded after Wheat Harvest the Previous Year

AbstractGlyphosate-resistant (GR) and multiple herbicide–resistant (groups 2 and 9) Canada fleabane have been confirmed in 30 and 23 counties in Ontario, respectively. The widespread incidence of herbicide-resistant Canada fleabane highlights the importance of developing integrated weed management strategies. One strategy is to suppress Canada fleabane using cover crops. Seventeen different cover crop monocultures or polycultures were seeded after winter wheat harvest in late summer to determine GR Canada fleabane suppression in corn grown the following growing season. All cover crop treatments seeded after wheat harvest suppressed GR Canada fleabane in corn the following year. At 4 wk after cover crop emergence (WAE), estimated cover crop ground cover ranged from 31% to 68%, a density of 124 to 638 plants m–2, and a range of biomass from 29 to 109 g m–2, depending on cover crop species. All of the cover crop treatments suppressed GR Canada fleabane in corn grown the following growing season from May to September compared to the no cover crop control. Among treatments evaluated, annual ryegrass (ARG), crimson clover (CC)/ARG, oilseed radish (OSR)/CC/ARG, and OSR/CC/cereal rye (CR) were the best treatments for the suppression of GR Canada fleabane in corn. ARG alone or in combination with CC provided the most consistent GR Canada fleabane suppression, density reduction, and biomass reduction in corn. Grain corn yields were not affected by the use of the cover crops evaluated for Canada fleabane suppression.

An Early-Killed Rye (Secale cereale) Cover Crop Has Potential for Weed Management in Edamame (Glycine max)

AbstractThe potential role of fall-seeded cover crops for weed management in edamame [soybean, Glycine max (L.) Merr.] is unknown. Field experiments were conducted over three edamame growing seasons to (1) determine the extent to which cover crop–residue management systems influence edamame emergence while selectively suppressing weed density and biomass, and (2) determine whether cultivars differed in emergence in cover crop–residue management systems. Cover crop treatments included a winter-killed oilseed radish (Raphanus sativus L.), two canola (Brassica napus L.) treatments (early-killed and late-killed), two cereal rye (Secale cereale L.) treatments (early-killed and late-killed), and a bare-soil control. Two spring timings of a cover crop burndown application created the early-killed and late-killed treatments for canola and cereal rye. Twelve soybean cultivars were tested, including 11 edamame cultivars differing in seed size and a grain-type soybean control. Spring residue biomass in cover crop treatments ranged from 438 kg ha−1 for winter-killed radish to 9,003 kg ha−1 for late-killed cereal rye. Cultivars responded similarly to cover crop treatments, and with the exception of late-killed cereal rye, cover crop treatments resulted in similar crop emergence as the bare-soil control. While all cover crop treatments reduced weed biomass 6 wk after planting compared with the bare soil, winter-killed radish and both canola treatments increased weed density. Early-killed cereal rye has potential for weed management in edamame, as evidenced by the fact that the treatment did not interfere with planting or crop establishment, yet reduced weed density 20% and suppressed early-season weed growth 85%.

Nitrógeno total y sustancias húmicas en agregados del suelo cultivado con cebolla bajo siembra directa y preparación convencional

The objective of this study was to evaluate the soil total nitrogen (TN), and N contents in humic substances (HS) of the organic matter in aggregates of soils cultivated with onion under no-till system for horticulture (NTSH) and conventional tillage system (CTS), comparing with an area of forest. The evaluated treatments were natural vegetation (control), 100% black oats, 100% rye, 100% oilseed radish, intercrop of oilseed (14%) + rye (86%), intercrop of oilseed (14%) + black oats (86%), area under CTS of onion for ±37 years, and area with secondary forest for ±30 years. Five years after the NTSH implementation, undisturbed soil samples from the layers 0-5 cm, 5-10 cm, and 10-20 cm were collected; these samples presented aggregate sizes between 2.0 mm and 8.00 mm. The TN, and N contents of the HS were subdivided into fulvic acids (N-FA), humic acids (N-HA), and humin (N-HU) fractions. The change from CTS to NTSH increases the TN and N-HU contents in the 0-5 cm soil layer. The intercrop of oats and oilseed radish, used as soil plant cover species in NTSH, presented a greater increase in N-HU (0-20 cm) than the other treatments. Black oats, and natural vegetation presented a greater increased in N-HA, and N-FA contents, respectively, in the 10-20 cm layer, than the other treatments in NTSH and CTS. CTS with millet as soil plant cover presented a greater increase in N-FA (0-20 cm) contents than the NTSH treatments.

Efficiency of white mustard and oilseed radish trap plants against sugar beet cyst nematode

Crop damage by the sugar beet cyst nematode (SBCN) can be mitigated by trap plants planting. We studied the effect of planting two commercial cultivars of oilseed radish ‘Adagio’ and ‘Colonel’ and white mustard ‘Luna’ and ‘Accent’ on SBCN population levels in two locations in Iran in 2009–11, and the subsequent response of sugar beets. Trap plants significantly reduced the number of nematode eggs+J2 with differences between cultivars. Reproductive rates reduction were 70 and 82–93% respect to the fallow control plots in the Isfahan and Khorasan Razavi locations, respectively. Sugar beets grown after incorporating oilseed radish and white mustard forage to soil in Isfahan had significantly higher yields (1.29–1.91%) compared with the fallow control. However, in Khorasan Razavi the sugar yield increased by 1.36% only in plots planted with oilseed radish ‘Adagio’. Sugar beet after oilseed radish ‘Adagio’ and ‘Colonel’ and white mustard ‘Accent’ in Isfahan, and after oilseed radish ‘Colonel’ in Khorasan Razavi also had higher sugar content (1.66–1.95 and 1.23%, respectively) compared with the control.

Winter cover crops on processing tomato yield, quality, pest pressure, nitrogen availability, and profit margins.

Much of cover crop research to date focuses on key indicators of impact without considering the implications over multiple years, in the absence of a systems-based approach. To evaluate the effect of three years of autumn cover crops on subsequent processing tomato (Solanum lycopersicum L.) production in 2010 and 2011, a field split-split-plot factorial design trial with effects of cover crop type, urea ammonium nitrate fertilizer rate (0 or 140 kg N ha-1 preplant broadcast incorporated) and tomato cultivar (early vs. late) was conducted. The main plot factor, cover crop, included a no cover crop control, oat (Avena sativa L.), winter cereal rye (hereafter referred to as rye) (Secale cereale L.), oilseed radish (OSR) (Raphanus sativus L. var. oleiferus Metzg Stokes), and mix of OSR and rye (OSR + rye) treatments. Cover crop biomass of 0.5 to 2.8 and 1.7 to 3.1 Mg ha-1 was attained in early Oct. and the following early May, respectively. In general, OSR increased soil mineral N during cover crop growth and into the succeeding summer tomato growing season, while the remaining cover crops did not differ from the no cover crop control. The lack of a cover crop by N rate interaction in soil and plant N analyses at harvest suggests that growers may not need to modify N fertilizer rates to tomatoes based on cover crop type. Processing tomato fruit quality at harvest (rots, insect or disease damage, Agtron colour, pH, or natural tomato soluble solids (NTSS)) was not affected by cover crop type. In both years, marketable yield in the no cover crop treatment was lower or not statistically different than all planted cover crops. Partial profit margins over both years were 1320 $ ha-1 higher with OSR and $960 higher with oat compared to the no cover crop control. Thus, results from a systems-based approach suggest that the cover crops tested had no observed negative impact on processing tomato production and have the potential to increase marketable yield and profit margins.