Methods Of Straw Disposal Research Articles

Soil fertility and nutrient uptake of rice influenced by plant growth promoting microbes, seaweed extract and humic acid fortified in situ rice residue compost

Purpose Intensive rice cultivation, non-addition of organic matter and indiscriminate use of inorganic fertilizers lead to soil fertility deterioration; on other side, farmers are burning huge quantities of rice residue causing severe air pollution warrants pragmatic disposal solution. In situ composting is considered as a potential alternative to destruction of crop residues. Moreover, fortification of crop residue with beneficial microbes and bio stimulants increase the availability of nutrients which constitutes an integral component in sustainable agriculture.The objective was to evaluate the effect of in situ rice residue compost fortification with PGPM consortia, humic acid and seaweed extract on the soil nutrient availability and uptake by rice. Method The experiment was conducted in a RBD at field condition. Rice was grown under 10 treatments comprising a control (100 % NPK) and nine treatments (in situ rice residue, fortified FYM, fortified in situ rice residue along with 100, 75 and 50 % NPK). Results In situ rice residue fortified with PGPM consortia, humic acid and seaweed extract significantly improved the soil carbon, nutrients' availability (macro and micro) and soil fertility. Combined application of fortified rice residue compost with 75% NPK resulted in significantly higher rice yields (grain 6.03 t ha-1 and straw 8.57 t ha-1) and nutrient uptake. Conclusion In situ rice residue composting provides promising straw disposal method as well as recoups lost share of organic matter and nutrients to soil. Farmers may adapt in situ compost to restore soil health without causing environmental hazard and also sustain crop productivity.

Economic Analysis of Selected Paddy Straw Management Techniques in Punjab and West Bengal

Paddy straw has an immense economic value in the form of livestock feed, mushroom material, mulching material, etc. Using Zero till drill and Happy Seeder machines are also economical methods for in-situ management of paddy straw but unfortunately burning of paddy straw is the most promising straw disposal method adopted by the farmers of some Indian states including Punjab. On the other hand, paddy straw is used as animal feed and as a fuel source in West Bengal. This study aimed at exploring the most promising alternatives of paddy straw management techniques in economic terms in the two states. The economic analysis was based on the survey of 20 farmers in each state to work out their economics for the selected paddy straw management techniques used by them. The research findings indicated that in Punjab, Happy Seeder technology proved to be the most economical straw management technique while in West Bengal, animal feed and paddy straw mushroom have emerged as the two most economical techniques for straw management. This analysis can serve as the base for promoting these technologies in both the states in an effective manner to reduce pollution and sustain economic development of the farmers.

Effect of tillage system and straw management on organic matter dynamics

The choice of cultivation system in arable agriculture exerts a strong influence not only on soil health and crop productivity but also on the wider environment. Conservation tillage using non-inversion methods conserves soil carbon, reduces erosion risk and enhances soil quality. In addition, conservation tillage has been shown to sequester more carbon within the soil than inversion tillage, reducing carbon dioxide losses to the atmosphere. Stable, well structured topsoils that develop following long-term conservation tillage lead to more energy efficient systems due to the reduced power requirements for cultivation. Long-term experiments, e.g. more than 20 years, that confirm the impact of conservation tillage over an extended period are not common. Here we evaluate the impact of different tillage methods and winter wheat straw management, either incorporated or removed, on organic matter turnover and soil quality indicators. No-till, chisel and mouldboard ploughing was carried out for 23 years on a silty clay loam soil in South West England that was not considered suitable for non-inversion tillage due to weak soil structure. In order to assess the effect of contrasting cultivation and straw disposal method on soil carbon dynamics, a range of assays were conducted, including water extractable organic carbon, hot water extractable carbohydrate, microbial biomass carbon, activity of β-glucosidase and acid phosphatase enzymes, C sequestration and the natural abundance of 13C. Our results show that the soil organic carbon concentration in the topsoil was greater under no-till than mouldboard ploughing, while a reverse trend was observed in the lower depths. A 14–17% increase in soil organic carbon was observed in the topsoil for chisel plough and no-till treatments compared to mouldboard ploughing. Water extractable organic carbon was found to constitute only 1–7% of the microbial biomass carbon. Hot water extractable carbohydrate was one of the most sensitive indicators of soil quality and had a significant a negative correlation with bulk density and positive correlation with soil organic carbon microbial biomass carbon β-glucosidase and acid phosphatase. The choice of cultivation method exerted a major control on microbial and carbon dynamics. No-till and chisel ploughing maintained carbon in the soil surface horizons, which will benefit the stability of this weakly structured soil, but mouldboard ploughing distributed carbon more uniformly throughout the soil profile, particularly when straw was incorporated, hence leading to the retention of more carbon in the soil profile.

Influence of long-term wheat residue management on acidity and some macronutrients in an Avalon soil

This study was initiated to determine the influence of different wheat residue management practices, that were sustained for about 20 years, on some fertility indicators of an Avalon soil in a long-term trial near Bethlehem in the eastern Free State. The treatments were two methods of straw disposal (burned and unburned), three methods of tillage (ploughing, stubble mulch and no tillage) and two methods of weed control (mechanical and chemical). Soil samples were collected at various depth intervals and pH, P, K, Ca, Mg and Na contents were determined. The effect of either straw burning or tillage practice on these indicators was much greater than that of weeding method. Burning of straw increased pH, P, K and Ca contents to substantial depths, although only pH and K were influenced significantly. The tillage practices affected pH significantly to 450 mm depth, with no-tilled plots having the highest pH values compared to the mulched and ploughed plots. No tillage, and to a lesser extent mulched tillage resulted in an accumulation of P, K, Ca and Mg in the upper 100–150 mm soil when ploughing served as reference. Chemical weeding also followed the same trend of accumulation of nutrients in the upper 100 mm soil when compared with mechanical weeding. This trend was also observed in pH, although it was not significant. No tillage combined with chemical weeding was the most beneficial to restrict acidification. In the case of the nutrients, significant interactions were virtually absent, except for K where burning combined with either no tillage or chemical weeding resulted in the highest K values in the upper 100–150 mm soil.

Influence of long-term wheat residue management on organic matter in an Avalon soil

This study was initiated to determine the influence of different wheat residue management practices, that were sustained for about 20 years, on the organic matter content of an Avalon soil in a long-term trial near Bethlehem in the Eastern Free State. The treatments were two methods of straw disposal (burned and unburned) × three methods of tillage (ploughing, stubble mulch and no tillage) × two methods of weed control (mechanical and chemical). Soil samples were collected at various depth intervals and organic C and total N, as indices of organic matter, were determined on these samples. The effect of either straw burning or weeding method on organic matter was small compared to that of tillage practice. A slightly higher organic C and lower total N content were measured in the unburned than burned plots to a depth of 450 mm. The tillage practices affected organic C and total N significantly in a similar manner to 100 mm depth with no-tilled plots having the highest organic matter content, followed in decreasing order by the mulched and ploughed plots. The organic matter content of the chemically-weeded plots was significantly higher than that of the mechanically-weeded plots to 100 mm depth, as indicated by organic C and total N. Significant interactions between the treatments on either organic C or total N were virtually absent. However, no tillage combined with chemical weeding resulted in the highest organic matter content. The latter combination is therefore recommended to maintain and even increase the organic matter content of this Avalon soil when cropped annually with wheat.

Long-term straw management effects on yields of sequential wheat ( Triticum aestivum L.) crops in clay and silty clay loam soils in England

The incorporation of chopped wheat ( Triticum aestivum L.) straw into soil by tine cultivation (non-soil inversion) or ploughing was compared with burning straw followed by tine cultivation at six sites in England over a period of 11 years. Three sites had clay soils and three silty clay loam soils. Effects of straw management on weed incidence, take-all ( Gaeumannomyces graminis var. tritici) infection and grain yield of following wheat crops and occasional break crops were studied. Soil mineral nitrogen and organic matter contents were measured at the end of the study. Incorporating straw by tines rather than burning reduced mean yield at all but one site. The yield reduction from tine incorporation ranged from 5 to 8% on clay soils and 3–18% on silty clay loam soils. Ploughing straw into soil only had an occasional adverse effect on yield of following crops. Much of the yield penalty associated with tine incorporation of straw was attributed to weed competition by Bromus spp. Difficulties in preparing a good seedbed, resulting in variable plant emergence, was the other main cause of lower yields with tine incorporation and in situations where plough incorporation reduced yields compared to burning straw. Method of straw disposal had no consistent effect on take-all infection. The effects of straw incorporation on soil mineral nitrogen and organic matter contents were small and inconsistent. There was no consistent effect of straw management practice on yield response to additional autumn application of nitrogen fertiliser. These results demonstrate that on those soils where ploughing is preferred, it is a suitable option for disposing of straw. Where non-ploughing methods have traditionally been used after straw burning they can still be employed with success, but occasional ploughing or planting of suitable break crops may be required to control grass weeds.

Effects of long-term straw management and fertilizer nitrogen additions on soil nitrogen supply and crop yields at two sites in eastern England

The effects of straw incorporation (early and late cultivation) and straw burning were contrasted in a split-plot study examining the impact of long-term straw residue management, and six fertilizer nitrogen (N) rates on soil mineral nitrogen, crop fertilizer N requirements and nitrate leaching losses. The experiments ran from 1984 to 1997 on light-textured soils at ADAS Gleadthorpe (Nottinghamshire, UK) and Morley Research Centre (Norfolk, UK).Soil incorporation of the straw residues returned an estimated 633 kg N/ha at Gleadthorpe and 429 kg N/ha at Morley on the treatment receiving 150 kg/ha per year fertilizer N since 1984. Straw disposal method had no consistent effect on grain and straw yields, crop N uptake, or optimal fertilizer N rates. In every year there was a positive response (P<0·001) to fertilizer N in straw/grain yields, N contents and crop N offtakes at both sites. Nitrate leaching losses were slightly reduced by less than 10 kg N/ha where straw residues had been incorporated, while fertilizer N additions increased nitrate leached at both sites.At both sites there was a consistent effect (P<0·001) of straw disposal method on autumn soil mineral N, with values following the pattern burn>early incorporate>late plough. The incorporation of straw residues induced temporary N immobilization compared with the treatment where straw was burnt, while the earlier timing of tillage on the incorporate treatment resulted in slightly more mineral N compared with the later ploughed treatment. Fertilizer N rate increased (P<0·001) soil mineral nitrogen at both sites. At Morley, there was more organic carbon in the plough layer where straw had been incorporated (mean 1·09 g/100 g) rather than burnt (mean 0·89 g/100 g), and a strong positive relationship between organic carbon and fertilizer N rate (r2=93·2%, P<0·01). There was a detectable effect of fertilizer N on readily mineralizable N in the plough layer at both Gleadthorpe (P<0·001) and Morley (P<0·05). At Morley, there was a consistent trend (P=0·06) for readily mineralizable N to be higher where straw had been incorporated rather than burnt, indicating that ploughing-in residues may contribute to soil nitrogen supply over the longer term.

Effects of method of straw disposal and depth of cultivation on populations of Fusarium spp. in soil and on brown foot rot in continuous winter wheat

SummarySoil samples (0–10 cm depth) taken from plots of continuous winter wheat at intervals between January 1993 and July 1996 were dilution‐plated on PCNB agar to identify and enumerate colony‐forming units (cfus) of Fusarium spp. Cfus of the main wheat pathogen, F. culmorum, were more numerous in soil from plots that were shallow‐cultivated to 10 cm after each harvest than in those that were ploughed. They were also usually more numerous in plots in which straw had been chopped and incorporated (by shallow cultivation or ploughing) than in those in which straw had been burnt. Increasing amounts of straw tended to increase the number of cfus. Deeper sampling (15–25 cm) showed that ploughing resulted in a more even, but diluted, distribution of cfus down the soil profile. Populations of some commonly found species that are not pathogenic on wheat {F. oxysporum, F. equiseti, F. flocciferum and F. merismoides) were sometimes also affected by straw disposal or cultivation treatments. Alternative methods of estimating population densities (baiting soil with wheat kernels or wheat seedlings, or plating‐out straw fragments) showed generally similar effects of treatments on populations of F. culmorum; the relative merits of the methods are considered. Large differences in population densities of all species occurred within and between seasons. The smallest populations were found in January 1995 but, in the case of F. culmorum, they increased to relatively large numbers in July 1995. The summer of 1995 was warm and dry and especially favourable for development of fusarium foot rot. Severe disease occurred only in this year and was less frequent after ploughing than after tine‐cultivation but more frequent after straw burning than after straw incorporation. The implications of these observations for understanding the role of propagules of F. culmorum in soil as inoculum for foot rot are discussed.

The Potassium, Sodium, Magnesium, Calcium and Phosphate Nutrition of Sugarbeet (Beta vulgaris) Grown on Soils Containing Incorporated Straw

Between 1990 and 1992, a series of three experiments compared the effects of incorporating or removing straw from a total of five preceding cereal crops on the nutrient concentration, uptake and processing quality of sugarbeet. Incorporated straw increased K concentrations in tops and roots and increased total K uptake by c 40 kg ha-1. Conversely, incorporated straw reduced Na concentrations and reduced total Na uptake by c 10 kg ha-1. Straw incorporation had little effect on root processing quality, because whilst K impurities increased in the straw incorporated treatments, Na impurities were reduced. Generally, any effects of straw disposal method on concentration and uptake of phosphorus, calcium and magnesium were small and of little agronomic or economic significance. In the absence of regular soil analysis it is recommended that when straw has been incorporated that K fertiliser rates for beet are reduced by c 20 kg ha-1. This is less than the allowance made for cereals. Also, contrary to the current cereal recommendation, there was no evidence for reducing P inputs when straw had been incorporated. © 1997 SCI.

Effects of Cultivation Techniques and Methods of Straw Disposal on Predation by Pterostichus melanarius (Coleoptera: Carabidae) Upon Slugs (Gastropoda: Pulmonata) in an Arable Field

1. Interactions between the polyphagous carabid predator Pterostichus melanarius (Illiger) and slugs were investigated from July to September 1992, before and after harvesting a rape crop. The experimental site comprised a long-term field study of the effects of different forms of cultivation (ploughing vs. non-inversion tillage), and methods of straw disposal (baling vs. incorporation of chopped straw) upon invertebrate populations and crop yields. Direct-drilling was also included as a no-tillage base-line. 2. Beetles (total 2078) were collected by pitfall trapping twice weekly. Each beetle was dissected, and its crop contents weighed and tested by enzyme-linked immunosorbent assay (ELISA) to determine the concentration and quantity of slug haemolymph it contained. Slugs [Deroceras reticulatum (Muller) and Arion intermedius Normand] were extracted from soil samples by gradual flooding, to estimate both numbers and biomass. 3. Significantly more P. melanarius were trapped in direct-drilled plots than in the tilled treatments. Within the tilled treatments, greater numbers of beetles were trapped where straw was incorporated by non-inversion tillage. 4. Crop weights were significantly greater in beetles from direct-drilled plots than in those from tilled treatments, as were both the concentrations and quantities of slug haemolymph they contained. Overall, 84% of beetles contained slug remains. 5. Greatest concentrations and quantities of slug remains were detected prior to the disposal of rape residues at the end of July, by baling or shallow incorporation in the soil. Cultivation had both short- and long-term effects upon the proportion of the diet of the beetles that was slugs. 6. Slug biomass declined following disposal of rape residues and it was only after this time that significant treatment differences emerged. 7. Positive relationships were found between the biomass of slugs in the soil and numbers of beetles trapped, the proportion of the beetles' diet that was slugs and the quantities of slug haemolymph in beetle crops. 8. Our results strongly suggest aggregation of P. melanarius to areas of high slug biomass in the soil and preferential feeding in such areas upon slugs. As this carabid is probably the commonest large predatory beetle in arable crops in Britain, these results clearly identify P. melanarius as a potentially important slug control agent.

Factors affecting nitrate leaching from a calcareous loam in East Anglia

SUMMARYThe effects of overwinter cover cropping, delayed ploughing and method of straw disposal on the quantities of nitrate leached (averaged over three winters during 1989–93) from a chalk loam in Eastern England were examined. The recovery of ‘retained’ nitrogen (retained through cover crop uptake, delayed ploughing and immobilization by straw) in a following spring crop was also assessed. In the first two winters, the rye cover crop decreased nitrate leaching by > 90% (28 kg N/ha per year), as compared with bare fallow treatments. In 1992/93 this decrease was only 23% (10 kg/ha), due to the early onset of drainage before cover was well established. Delayed ploughing on bare treatments, to decrease autumn N mineralization and subsequent nitrate leaching, was ineffectual in 1989/90 but had substantial effects in 1990/91 and 1992/93; N mineralization, inferred from soil mineral nitrogen content, and nitrate leaching were decreased by 31 and 35% in 1990/91 and by 36 and 61% in 1992/93, respectively. Nitrate leaching (averaged over three winters) was unaffected by straw incorporation. There was no evidence of recovery of cover crop N in the spring sown test crops (barley or sugarbeet). In the low soil N input situation encountered in this experiment, it was unnecessary to sow cover crops before early September in years of average or below average rainfall to ensure that the average soil solution concentrations remained below the EU drinking water limit of 11 mg NO3-N/1. However, in wetter seasons substantial N leaching occurred before cover had taken up much N. In 1992/93 N retained against leaching by a rye cover crop in previous years was apparently being remobilized and lost through leaching, although if cover was grown again there was less leaching than from bare land. In the future, an increase in the extent of cover cropping might increase transpiration rates and therefore lead to a decrease in aquifer recharge.

Populations of Fusarium spp. in soil growing continuous winter wheat, and effects of long-term application of fertilizers and of straw incorporation

Populations of Fusarium spp. from plots growing continuous winter wheat were estimated by dilution plating of soil samples taken in February, April and July 1993. The plots, from two sections of Broadbalk field, Rothamsted, either had the straw removed, or chopped and incorporated into the soil after every harvest since 1986; the plots also had different fertilizer treatments. Most species were more abundant in July than in February or April. Estimated propagule numbers of F. culmorum , the only cereal pathogen found frequently, were less than in a survey of the same plots in 1964. It occurred in greatest numbers in plots treated with farmyard manure and, in July, with the largest inorganic nitrogen applications. F. oxysporum and F. solani , non-pathogenic on cereals, were most frequent in plots treated with phosphorus, potassium and magnesium but without added nitrogen. Other non-pathogenic species, of which the most abundant was F. merismoides , showed no consistent response to any of the fertilizer treatments. The method of straw disposal had no consistent effects. The results are discussed in relation to perceived changes in fusarium disease in the U.K. and changing cereal husbandry practices.

Influence of straw disposal on distribution of amino acids in soil particle size fractions

Clay (<2 μm), silt (2–20 μm) and sand (20–2000 μm) size samples (isolated by ultrasonic dispersion and gravity sedimentation) and whole soils were hydrolyzed in 6 N HC1 and concentrations of amino acids (excluding S-containing but including diaminopimelic acid) determined. Two soils from an experiment in which straw had either been burned or incorporated annually for 18 yr were used. Amino acid N made up 31–39% of the total N in whole soils, clay and silt. The sand fraction was lower in hydrolyzable amino acid N (straw burned, 21–25%; straw incorp., 26–30%). Straw incorporation increased total N contents, the hydrolyzability of sand N, and the concentrations of most amino acids. Amino acid contents in clay and silt were 5–10 and 2–5 times higher than in whole soils, respectively, while the sand fraction contained 10–20 times less amino acids. The relative distribution of individual amino acids was almost the same for clay, silt, sand and whole soil. Glycine, argin ine. aspartic acid, histidine, glutamic acid and lysine were quantitatively the most important, making up 63–69% of the total amino acid N. Method of straw disposal or differences in decomposability of organic matter in different size fractions were not reflected in the distribution of hydrolyzable amino acids. The distribution of diaminopimelic acid suggested a higher (past or present) microbial biomass in the clay size fraction than in the silt.

A comparison of tine cultivation and ploughing with two methods of straw disposal on the growth, nutrient uptake and yield of winter wheat grown on a clay soil

Abstract. Ploughing and tine cultivation to depths of 5, 15 and 25 cm were used to prepare land before sowing winter wheat. The methods were compared for two years with or without the presence of straw residues from the previous crop and the effects on crop growth and yield were assessed.Some combinations produced large differences in yield. In 1985–86 volunteer cereals were a problem where straw was not burnt, but deeper ploughing controlled them. In both years the concentrations and uptake of nitrogen, phosphorus and potassium differed during the early period of growth but not at maturity.

Título en español

Se realizaron ocho siembras consecutivas de arroz en un estudio en que se variaron las cantidades de nitrógeno y se deshizo de la paja de tres maneras: quemándola, sacándola de las parcelas o incorporándola al suelo. Aunque los rendimientos más altos se obtuvieron cuando la paja se incorporó al suelo, y los más bajos cuando se sacó, las diferencias no fueron estadísticamente significativas. La manera de deshacerse de la paja no afectó el contenido en nitrógeno de la paja o del grano, el porcentaje de nitrógeno aplicado como fertilizante que se recobró en las plantas de arroz, o el contenido en materia orgánica del suelo. La producción de arroz aumentó según aumentó las cantidad de abono nitrogenado hasta más de 100 kg/ha. El contenido en nitrógeno de la paja y del grano aumentó según se incrementó las cantidad de nitrógeno, mientras que el porcentaje que se recuperó en las plantas de arroz disminuyó. Las aplicaciones de nitrógeno no afectaron el contenido en nitratos, en amoníaco y materia orgánica del suelo.

Weed problems of the next decade in Britain

The potential changes in weed problems in British agriculture and horticulture over the next decade are reviewed. The attributes which confer survival and success to weed species are considered, of which the most important for arable weeds is seed behaviour. These attributes are then discussed in relation to the changes which are deemed likely to occur in various cropping systems. In arable land, the main factors influencing weed population composition are method of straw disposal, level of cultivation, season of drilling, crop grown, fertilizer regime, herbicide usage and herbicide resistance. Few major changes in agriculture are foreseen, but there will be a trend towards increasing specialization in many areas. The predominance of winter cereals and oilseed rape will continue, which will favour autumn-generating weeds such as Galium aparine and Alopecurus myosuroides. It is postulated that most weed problems over the next decade will arise from existing weeds or from native plants common in field margins from which they could invade fields through changes in management. A few new aliens, especially grasses, may well appear, e.g. Phalaris paradoxa. Weeds could also arise from recently introduced crop plants, e.g. Bromus willdenowii and B.carinatus, which may present problems in the future, just as cereal volunteers are often a problem at present.

Effects of straw residues on the establishment, growth and yield of autumn-sown cereals

The environmental problems and public concern associated with straw burning have created an urgent need to investigate successful methods of growing crops with unburnt straw residues left in the field. Effects of different methods of straw disposal on the establishment and growth of winter cereals on non-calcareous clay soils are reported. The crops were established by direct drilling, but in two experiments straw incorporation (by rotavation) was also compared. The effects of time of sowing were also investigated in two of the experiments. The highest yields were produced after the straw was burnt; yields were less where straw was present, especially when the straw residues were left on the soil surface and the crop direct-drilled. The lowest yields were obtained when the total previous crop straw was chopped and spread on the soil surface. Delayed sowing diminished yield and the size of these losses increased with increasing amounts of straw. Incorporation by rotavation was effective in lessening the harmful effects of straw, probably through alleviating mechanical drilling problems and improving drainage around the seed during wet periods.

Barley net blotch: influence of straw disposal and cultivation methods on inoculum potential, and on incidence and severity of autumn disease

Effects of ploughing or direct drilling with three methods of straw disposal on amounts of inoculum of Pyrenophora teres, and on frequency of infection and severity of net blotch in the autumn, were studied in winter barley. Prior to ploughing, many conidia of P. teres were caught above areas where infected straw from a previous crop of winter barley had been bated and removed leaving culm bases, or where barley straw had been chopped and left in situ, but relatively few were caught above areas where straw had been burnt. Thereafter, where ploughing had buried surface residues, irrespective of the method of straw disposal, conidia were not caught for at least 3 weeks, and subsequently were substantially fewer than in direct‐drilled areas where many spores were caught. Production of conidia (measured as numbers per unit length of straw) was greatest on chopped straw, less on culm bases and least on burnt straw residues. Sporulation on volunteer barley plants was much reduced by application of paraquat + diquat, but some still occurred on visually‘dead’volunteer barley.All direct‐drilled barley plants were diseased within 27 days of sowing, whereas 42 days elapsed before all plants sown in ploughed areas were diseased. Disease on individual plants was also more severe in direct‐drilled areas: 20% of the area of the first leaf to emerge was diseased 19 days after crop emergence in direct‐drilled plots, whereas less than 9% was diseased in ploughed areas 50 days after emergence.There was an additive effect of straw disposal methods and direct‐drilling on disease, which in turn affected plant vigour. The adverse effect of direct‐drilling on the incidence and severity of net blotch appeared to be far greater than that of the straw disposal methods.

Cephalosporium stripe in winter wheat grown after different methods of straw disposal

<i>Cephalosporium</i> stripe in winter wheat grown after different methods of straw disposal

A study of populations of black‐grass (Alopecurus myosuroides) in winter wheat, as influenced by seed shed in the previous crop, cultivation system and straw disposal method

SUMMARYA two year experiment was conducted in winter wheat infested with black‐grass.In the first year black‐grass was either allowed to develop and shed seed freely or was completely controlled by herbicides.In the second year straw was either burnt or removed by baling and three cultivation systems were compared – ploughing, tine cultivations and direct drilling. No black‐grass herbicides were applied in the second year.The presence of seeds shed in the previous crop greatly influenced the black‐grass infestation in the direct drilled crop where it was calculated that 80–90% of plants were derived from these recently shed seeds. In the crop established after ploughing, the black‐grass infestation was unaffected by seed production in the previous crop. Tine cultivations gave results similar to those found with direct drilling. It is suggested that these differences between cultivations were due to the presence of old seeds in the soil which were brought up to the soil surface by ploughing, but not by cultivations which did not invert the soil.Straw burning destroyed many freshly shed seeds on the soil surface and resulted in less black‐grass in the crop although the effect tended to be masked by cultivations.The practical implications of the results are discussed.