Maize Stubble Research Articles

Mechanical detector for tractors automatic guidance

Automatic guidance systems for tractors improved track accuracy and inter-row operating performance,reduced the intension of driver.The mechanical guidance for tractors detected path by contact crops,stubbles or furrows in the field with simple structure that easy to maintain and lower cost.A low cost equipment of mechanical detector for tractors to auto- matically guide in standing maize stubbles field is presented. The symmetrical frame of the detector and half ellipse shape of the feeler are designed by analyzing characters of detector sensing in stubbles rows.The main parameter such as space between center of ellipse and that of rotation axle is provided on the base of analyzing feeler forces and rotation movement in dynamics.The result of test showed that the automatic guidance equipment with half ellipse shape of the feeler and angle sensor is capable of detecting the guidance rows of standing maize stubbles.

The effects of GMHT crops on bird abundance in arable fields in the UK

Abstract Bird surveys were carried out in summer 2000 and winter 2000/2001 on 24 sugar beet fields, 11 maize fields, 10 spring rape fields and (for winter-only) 23 winter rape fields divided into conventional and genetically modified herbicide tolerant (GMHT) treatments. These fields were a sub-sample of those used in the farm scale evaluation (FSE [Firbank, L.G, Heard, M.S., Woiwod, I.P., Hawes, C., Haughton, A.J., Champion, G.T., Scott, R.J., Hill, M.O., Dewar, A.M., Squire, G.R., May, M.J., Brooks, D.R., Bohan, D.A., Daniels, R.E., Osborne, J.L., Roy, D.B., Black, H.I.J., Rothery, P., Perry, J.N., 2003. An introduction to the farm-scale evaluations of genetically modified herbicide tolerant crops. J. Appl. Ecol. 40, 2–16.]). The study aimed to compare bird abundance between GMHT and conventional crop treatments. In the summer, the abundance of yellowhammers Emberiza citrinella and of granivores collectively was significantly greater on conventional than GMHT sugar beet. Abundance of granivores and species richness was significantly greater on conventional than GMHT maize, but only after the application of herbicides to the GMHT treatment. No significant differences were detected in spring oilseed rape. No significant differences were detected prior to herbicide application in any crop. In winter, granivores were more abundant on bare plough following conventional sugar beet treatment than following GMHT treatment. Woodpigeon Columba palumbus , blackbird Turdus merula and corvids were more abundant on maize stubbles following GMHT treatment. These differences were in accord with likely differences in food availability ascertained from previous research carried out under the FSE.

Origin and fate of soil lipids in a Phaeozem under rye and maize monoculture in Central Germany

Although soil lipids are an important class of soil organic substances, which is involved in numerous soil processes, their origin and fate in soils is insufficiently known. Therefore, this study aimed at investigating the free lipid fraction in crop residues and farmyard manure (FYM), and soils which received these materials for long time. We sampled rye and maize stubble and roots, FYM, and Ap horizon soils from the ‘Unfertilized’ and ‘FYM’ plots of ‘Eternal Rye Cultivation’ experiment at Halle, Saxony-Anhalt, Germany. Free lipids were extracted by dichloromethane/acetone and analyzed by gas chromatography/mass spectrometry. Aliphatics were most abundant in all extracts, accounting for 61 to 77% of the total extractable lipids. By comparing the lipid composition of the added organic materials with that of the corresponding treated soil, the long-chain members of n-alkanols, n-alkanes, α,ω-alkanedioic acids, and unsaturated alkanoic acids from C16 to C19 did not disappear in soil whereas ω-hydroxyalkanoic acids and long-chain branched alkanoic acids were not extracted from soil probably because they were bound to nonextractable forms. It is suggested that the methodological approach can give information on decomposition and retention of free extractable lipids in soil. More information is needed to trace the fate of all lipids in the plant–soil system by the determination of bound molecules, which are nonextractable by organic solvents.

Role of Inland Valleys in the Management of Stem Borers and Their Natural Enemies in Upland Maize Fields in the Humid Forest Zone of Cameroon

During the dry season in the humid forest zone of Cameroon, maize is the most important off-season cash crop grown in hydromorphic inland valleys (IVs), which may also be reservoirs for pests such as the stemborer Busseola fusca Fuller and its natural enemies. Pest and parasitoids were monitored in IVs and close-by upland maize fields from January 2002 through December 2004. Trap catches and oviposition data showed that B. fusca was active throughout the dry season and long and short rainy seasons of 2004. Egg batch densities were considerably lower in the dry than in the rainy seasons. Important natural enemies were the scelionid egg parasitoids Telenomus busseolae Gahan and T. isis Polaszek. B. fusca was the predominant borer species in all seasons in maize in IVs as well as in upland fields, followed by Sesamia calamistis Hampson and Eldana saccharina Walker. B. fusca larval densities were lowest in the IVs and increased in the course of the year in the upland fields. In contrast, S. calamistis densities were higher in IVs than in upland maize fields. At harvest of the IV maize, B. fusca and E. saccharina larval densities were 47.3 and 15.5 times higher, respectively, than on old maize stubbles in upland fields planted during the previous year. Grain yields as well as the marketable ear index were 1.1–2 times higher in the dry season than in the long and short rainy seasons, indicating the importance of IVs for dry season maize production in Cameroon.

Contribution of primary organic matter to the fatty acid pool in agricultural soils

Fatty acids as major compounds of soil lipids may affect many soil properties, but the input and turnover rates in soil are largely unknown. The objective of this study was to identify and quantify fatty acids in soils as a result of input from primary sources such as plant residues, farmyard manure and soil organisms, and to evaluate the corresponding turnover- and stabilization processes. The concentrations of n-C 10:0 to n-C 34:0 fatty acids were determined in the Ap horizon of a Phaeozem with long-term cropping of rye and maize and the treatments ‘Unfertilized’ (‘U’) and fertilized with ‘Farmyard manure’ (‘FYM’). The most important primary sources of fatty acids such as rye and maize stubble and roots, soil micro- and mesofauna, and the applied FYM were also investigated. The quantification of fatty acids by gas chromatography/mass spectrometry (GC/MS) showed that long-term FYM application led to larger concentrations of n-alkyl fatty acids in the plots grown with rye (‘U’: 48.1 μg g −1, ‘FYM’: 57.7 μg g −1, ** P≤0.01, n=3) and maize (‘U’: 17.0 μg g −1, ‘FYM’: 23.4 μg g −1, *** P≤0.001, n=3). The observed bimodal fatty acid distribution in soils from n-C 10:0 to n-C 21:0 and from n-C 21:0 to n-C 34:0 with a predominance at n-C 16:0 and at n-C 28:0 was apparently due to input from crop residues, soil organisms and FYM. The short-chain lengths may have originated from the investigated primary sources. The major contributors to the long-chain lengths, with a maximum at n-C 28:0, were rye stubble and FYM. A change in mono-culture from rye to maize, 38 years prior to sampling, led to a decrease in fatty acid concentrations by factors of about 2.8 (‘U’) and 2.5 (‘FYM’). Therefore, rye-derived fatty acids and soil tillage had a larger impact on fatty acid pools than the input of primary organic matter. The changes in fatty acid distributions and pools under the consideration of the quantified input of primary organic matter led to the conclusion that the short-chained fatty acids were more rapidly decomposed than the long-chains.

Influence of food quality, soil moisture and the earthworm Pontoscolex corethrurus on growth and reproduction of the tropical earthworm Balanteodrilus pearsei

Summary The aim of this study was to test the influence of food quality (FQ) (soil, soil+maize stubble and soil+the cover crop Mucuna pruriens), soil moisture (SM) (25%, 33% and 42%) and the presence of the earthworm Pontoscolex corethrurus on the growth and reproduction of the tropical earthworm species Balanteodrilus pearsei. The experiment was carried out in cultures under laboratory conditions for 100 days. The growth rate of B. pearsei in M. pruriens treatments (10.8 mg ind−1 day−1) was 3.4 and 8.5 times higher than in maize stubble and soil treatments, respectively. The onset of reproductive activity occurred only after mating. Each earthworm fed on M. pruriens achieved a fertility rate 2 times higher (0.58±0.26 cocoons adult−1 day−1) than earthworms fed on maize stubble. M. pruriens also resulted in significant increases of cocoon weights (10.8±1.4 mg). Time of cocoon incubation was the same in M. pruriens and maize stubble treatments (20.4±5 days), with one individual hatching per cocoon. The presence of P. corethrurus had no effect on growth, survival or fertility of B. pearsei. This study demonstrated that M. pruriens had positive effects on the growth and reproduction of B. pearsei. Further research is also needed to determine whether M. pruriens decomposition, N release and crop yields are influenced by the earthworm B. pearsei.

An Automatic Depth Control System for Online Measurement of Spatial Variation in Soil Compaction, Part 1: Sensor Design for Measurement of Frame Height Variation from Soil Surface

A swinging arm type of frame height sensor was designed to measure the distance variation between the soil surface and the frame of a sensor system developed for the online measurement (tractor-based continuous measurement) of the spatial variation in soil compaction. A linear variable displacement transducer (LVDT) with a 0·2 m stroke length was used to connect the frame to a metal wheel of the frame height sensor at the axle of the wheel. An analytical–statistical hybrid model was developed for the direct calculation of the frame height variation. Tests were performed on four surfaces: asphalt road; rough dirt track; and agricultural silty clay loam soil (bare soil and soil with stubble present). The results were compared with ultrasonic measurements to validate the sensor. An excellent correspondence of distance measurement was found between the two sensors with a standard error (SE) of 0·0033 m and with a high determination coefficient R2 of 0·93. However, the measurement of the frame height was found to be exaggerated when using the wheel-LVDT sensor on the dirt track, which was attributed to the wheel sinkage in the loose soil. Although the standard error between the wheel-LVDT measurements and ultrasonic distance measurements was still low (0·0049 m) for the dirt track, this was higher than that found on the asphalt road. Similarly, the trajectories of the frame height measurement performed on the field showed a good correspondence between the wheel-LVDT sensor and the ultrasonic sensor. The wheel-LVDT sensor measured a slightly larger height than the ultrasonic sensor, with mean deviations ranging between 0·018 and 0·021 m. In comparison with the standard error (0·035 m) of the measurement line with maize stubble, lower standard errors of 0·0064 and 0·0088 m with high R2 were found for the bare soil surface without and with subsoiler, respectively. Pressing of the stubble by the relatively large mass of the wheel of 175 N made the measurement of frame height variation with the wheel-LVDT sensor apparently less affected by stubble compared to the measurement with the ultrasonic sensor. Therefore, the wheel-LVDT sensor can be used more accurately than the ultrasonic sensor, in fields covered with plant residues and stubble, providing the input for the position control of the tractor three-point linkage aiming at online measurement of soil compaction at constant depths. Based on a certain soil type, moisture content and dry bulk density, correction factors need to be selected and subtracted from the wheel-LVDT sensor output to compensate for the extra distance measured due to the wheel sinkage on a bare soil surface.

Identification of intermediate and branch metabolites resulting from biotransformation of 2-benzoxazolinone by Fusarium verticillioides.

Detoxification of the maize (Zea mays) antimicrobial compound 2-benzoxazolinone by the fungal endophyte Fusarium verticillioides involves two genetic loci, FDB1 and FDB2, and results in the formation of N-(2-hydroxyphenyl)malonamic acid. Intermediate and branch metabolites were previously suggested to be part of the biotransformation pathway. Evidence is presented here in support of 2-aminophenol as the intermediate metabolite and 2-acetamidophenol as the branch metabolite, which was previously designated as BOA-X. Overall, 2-benzoxazolinone metabolism involves hydrolysis (FDB1) to produce 2-aminophenol, which is then modified (FDB2) by addition of a malonyl group to produce N-(2-hydroxyphenyl)malonamic acid. If the modification is prevented due to genetic mutation (fbd2), then 2-acetamidophenol may accumulate as a result of addition of an acetyl group to 2-aminophenol. This study resolves the overall chemistry of the 2-benzoxazolinone detoxification pathway, and we hypothesize that biotransformation of the related antimicrobial 6-methoxy-2-benzoxazolinone to produce N-(2-hydroxy-4-methoxyphenyl)malonamic acid also occurs via the same enzymatic modifications. Detoxification of these antimicrobials by F. verticillioides apparently is not a major virulence factor but may enhance the ecological fitness of the fungus during colonization of maize stubble and field debris.

Characterization of five agricultural by-products as potential biofilter carriers.

Biofiltration is the most commonly used biological gas treatment technology and is extensively used for the treatment of polluted air with gas flow rates of up to 2 x 10(5) m(3)/h. It involves a filter bed of organic matter serving both as carrier for microorganisms and as nutrient supplier. Polluted gas passes through the filter bed and is cleaned by biological activity. Biofiltration is not being developed in Latin America as in the USA, Canada or Europe; the main reason probably being the absence of specific technology and of potential organic carriers locally available. Five different agriculture by-products available in Latin America: peanut shells, rice husk, coconut shells, cane bagasse and maize stubble, were chemically, physically and structurally characterized for their potential use as biofilter carrier. It was found that peanut shells could be used as biofilter carrier and therefore would have potential biological application.

Effect of nitrogen fertiliser rate on production and nitrogen leaching from Italian ryegrass following a maize silage crop

Dry matter (DM) yield responses and field nitrogen (N) leaching losses were assessed following the application of 4 rates of N fertiliser to an Italian ryegrass (Lolium multiflorum) crop grown after maize. The trial was conducted on a free-draining Horotiu silt loam (typic orthic allophanic soil) at Dexcel's Scott Farm near Hamilton, New Zealand. The grass was direct dr illed into maize stubble on 13 April 2002. Small plots received a total of 0, 40, 100 or 160 kg N/ha as urea, split into 4 equal applications from May to July. Total DM production over 24 weeks for the 0, 40, 100 or 160 kg N/ha treatments was 2730, 3487, 4238 and 4840 kg DM/ha, respectively. Additional kg DM produced/kg N applied was 19, 15 and 13, respectively. The 'apparent' proportion of applied N removed in the herbage from all plots was 55- 60%. Herbage nitrate-N concentrations exceeded the commonly accepted critical level of 0.21% on the 160 kg N/ha treatment at the first harvest on 3 July 2002, when only half of each N rate had been applied. There were no significant treatment differences in leaching losses (range 17-34 kg N/ha). Italian ryegrass grown on a silt loam soil after maize showed an almost linear yield response to N fertiliser over the range 40-160 kg N/ha, without increased inorganic N leaching. Further work is necessary to confirm these results and to establish whether or not higher rates of N fertiliser can be used to increase winter dry matter yields from Italian ryegrass, without increasing N leaching losses. Keywords: annual ryegrass, dairy systems, double cropping, nitrogen leaching

A whole-farm model for economic analysis in a goat production system in Mexico

In north-central Mexico, the production of goat meat is associated to summer cultivation crops for family consumption. The objective of this study was to construct a simulation model for the economic analysis in this goat–agricultural system. Linear programming was used to optimize system net income. Several scenarios were generated varying the price scenario (1992 and 1995) and the use of technology (traditional and recommended). The approach visualized the system general response and the impact of a subsidizing program. The model was limited to a maximum cultivation area of 64 ha and a maximum herd of 200 does. The model proved that recommended technology in 1992 increased the net income of the system, but it did not in 1995. In both cases, it was necessary to buy maize stubble to supply the requirements of dry matter animal intake. Traditional technology was more versatile to goat meat and maize stubble's price changes. The model selected a cultivated area of 64 ha for the 1992 price scenario as well as for 1995 when subsidies were included. However, as subsidies were removed in 1995 the model output was only 8 ha. When the surface of rainfed crops was 16 ha or more, the use of technology helped to increase the net income. Thus, subsidy policy induced an expansion of the agricultural cultivated area in the system. On the other hand, the largest incomes for all the modeled scenarios were noted when the herd size was maintained at 100 does. The scenarios presented express the rationality in the process of decision making by farm owners. For instance, they prefer grain crops instead of forages cultivation due to the subsidy policy; they do not use recommended technology since it is not rewarded economically; and they embrace the traditional system because it is more flexible to price changes.

Occurrence of perithecia of Gibberella fujikuroi mating population A (Fusarium moniliforme) on maize stubble in northern Vietnam

Perithecia of Gibberella fujikuroi were found on old maize (Zea mays) stalks in northern Vietnam. Single ascospores from these perithecia produced cultures of the anamorph Fusarium moniliforme but perithecia were not produced in single spored cultures. Eleven single ascospore cultures originating from 3 perithecia were crossed with known tester strains and were shown to belong to mating population A of G. fujikuroi. Three strains were identified as A+, six as A- and two strains that did not produce perithecia when crossed with the testers. Some combinations when crossed with each other produced fertile perithecia of G. fujikuroi, confirming the potential for perithecial production by these strains in the field. Samples of maize kernels were collected from markets and F. moniliforme was isolated from these sources. These isolates also belonged to the A population and contained both + and - strains. Perithecia produced by compatible crosses and sclerotial-like structures produced by incompatible crosses were sectioned and their morphology examined. Only perithecia produced by compatible strains produced a layer of mother cells capable of producing asci.

Fusarium crookwellense-produced zearalenone in maize stubble in the field

Waste grain and vegetative material (stems and leaves) collected from a maize field several months after harvest was analysed by bi-dimensional thin layer chromatography for the presence of aflatoxins, deoxynivalenol, ochratoxin A, sterigmatocystin, T-2 toxin and zearalenone. Deoxinivalenol (0.7 mg/kg) and T-2 toxin (4.1 mg/kg) were found in the grain and zearalenone (3.0 mg/ kg) was found in the stem and leaf. No other toxins were detected. The stubble was examined for the presence of potentially toxigenic Fusarium species, and F. poae, F. moniliforme var. subglutinans and F. crookwellense were isolated and identified. When these isolates were cultured on cracked corn, only F. crookwellense was found to produce micotoxins and then only zearalenone was detected. As corn stubble is commonly grazed in Argentina and in other countries, these findings identify a further source of mycotoxins that may adversely affect animal health and productivity.

Selection of Foraging Habitat and Flocking by Crow Corvus corone Phenotypes in a Hybrid Zone

Little is known about the ecological mechanisms that maintain the parapatric ranges and narrow areas of hybridization in the Carrion Crow Corvus c. corone and Hooded Crow Corvus corone cornix. The winter ecology of parental populations and of hybrids was studied in an area of intergradation in NW-Italy. Carrion Crows and Hooded Crows showed sharply different foraging habitat preferences. The former selected pastures and meadows whereas the latter selected maize stubbles. The habitat selected by the two morphs corresponded to those prevailing in the areas of allopatry adjacent to the hybrid zone. Hybrids were less selective than the parental populations. Each of the parental morphs showed a significant tendency to avoid heterotypic flocks. It is concluded that the adaptation to different foraging habitats probably contributes to the maintenance of parapatric distributions by the parental populations and that hybrids may be better adapted to live in the hybrid zone. The assortative composition of the flocks could indicate the existence of pre-mating isolating mechanisms between the crow morphs.

Relationship between Maize Stubble Placement in Soil and Survival of Stenocarpella maydis (Diplodia maydis)

AbstractSurvival of and pycnidium production by Stenocarpella maydis in artificially infected maize stalk stubble placed on, half buried into, and buried in the soil were determined in field trials over a nine month period. Survival was higher in stubble which remained on the soil surface than in buried stubble. Pycnidial development increased on surface and buried stubble from September onwards, but subsequently decreased on buried stubble. Conidia retrieved from the variously positioned stubble segments did not vary in viability. More pycnidia were produced over an eleven month period on naturally infected stubble retrieved from the soil surface than from in soil. Reisolation and conidium viability of S. maydis from the surface stubble were higher than from buried stubble.Zusammenfassung Der Zusammenhang zwischen der Lage des Maisstoppels im Boden und dem Überleben von Stenocarpella maydis (Diplodia maydis) Über eìnen Zeitraum von 9 Monaten wurde das Überleben und die Pyknidienproduktion von Stenocarpella maydis in künstlich inokulierten Maisstoppeln unter Feldbedingungen beobachtet. Die inokulierten Stoppeln wurden auf dem Boden, zur Hälfte oder ganz im Boden plaziert. Die höchste Überlebensrate wurde in den Stoppeln, die auf der Bodenoberfläche lagen, festgestellt. Die Entwicklung von Pyknidien erhöhte sich an den Stoppeln ab September, unabhängig von der Lagerung, bei den begrabenen Stoppeln wurde jedoch ein Rückgang der Pykinidienentwicklung zu einem späteren Zeitpunkt beobachtet. Die Viabilität der Konidien alier Stoppeln war gleich. Mit natürlich befallenen Stoppeln wurde eine höhere Anzahl von Pyknidien über eine 11monatige Periode von den Stoppelstücken gewonnen, die von der Bodenoberfläche aufgelesen worden waren, als von denen, die in der Erde begraben waren. Außerdem war die Reisolierung und Konidienviabilität bei den von der Oberfläche stammenden Stoppelstücken höher als von den begrabenen.

Fatty acid composition of subcutaneous fat of sheep grazed on eight different pastures

The levels of eight long chain fatty acids (14:0, 16:0, 16:1 17:0, 17:1, 18:0, 18:1, 18:2) were measured in the subcutaneous fat of S.A. Mutton Merino wethers (5 months old, 20–25 kg live mass, 8 per treatment) and, including 18:3, in eight pastures grazed for 84 days (maize stubble, Z. mays; Triticale; L. multiflorum; L. perenne; D. glomerata; D. eriantha; C. dactylon; M. sativa). Respectively, percentage fatty acid contents of subcutaneous fat and pastures were 14:0 5·04 ± 0·86 and 0·67 ± 0·37, 16:0 22·85 ± 0·81 and 17·83 ± 3·00, 16:1 2·07 ± 0·22 and 2·42 ± 1·17, 17:0, 1·68 ± 0·04 and 0·42 ± 0·16, 17:1 0·75 ± 0·06 and 0·17 ± 0·19, 18:0 25·94 ± 2·02 and 4·95 ± 1·68, 18:1 32·27 ± 0·93 and 8·12 ± 11·70, 18:2 1·59 ± 0·36 and 15·89 ± 5·16, 18:3 measured in pastures only 34·51 ± 15·91. The palmitoleic acid (16:1) content of pastures increased (P < 0·05) as the ether extractable lipid content of the pastures increased. Pasture treatments influenced the levels of 14:0, 17:1 and 18:2 highly significantly (P < 0·01) and of 18:0 significantly (P < 0·05). Increasing levels of fatness of ribcut samples were associated with a decrease in 14:0 and an increase in 17:1 (P < 0·01) and an increase in 18:2 (P < 0·05).

The contribution of forage oats to annual feed production when grown after maize in a double cropping system

Abstract The cool season forage production of Florida oats (FO) was measured in a series of replicated small plot trials at the Ruakura Agriculture Centre over five successive seasons. The oats were grown as part of a double cropping system using maize as the complementary warm season crop. Combined annual forage maize/oats yields averaged 26 t dry matter (DM)/ha. Experiments in 1978 and 1979 showed that forage production of the earlier maturing FO was higher than that of New Zealand-bred oat and wheat cultivars (11–13 t DM/ha v. 9–11 t DM/ha) when sown in April and cut in early October (‘ensiling’ yield). Subsequent experiments from 1980 to 1982 measured the yield response of FO to three rates of nitrogen (N) fertiliser (O, 35 and 70 kg N/ha) applied during tillering, following direct drilling into maize stubble. ‘Ensiling’ yields were high (9–13 t DM/ha) but yield responses to N fertiliser were small except in 1981 when June and July were warmer than average. FO was capable of consistently high yields when grown between successive maize crops. Tolerance to Barley Yellow Dwarf Virus probably contributed to the high yield potential of FO. The annual yield from the double cropping system was restricted by summer moisture stress affecting maize yields and severe frosts affecting winter cereal yields. Despite the high production level from the double cropping system, present costs of its implementation in dairy systems are prohibitive.

Present and Future Utilization of By-products in the Feeding of Ruminants in Hungary

The economic importance of the cost of feeding stuffs in the raising of farm animals needs no emphasis. This article reviews the progress of a large-scale research programme launched in Hungary in 1981 to explore the prospects for making greater use of agricultural and industrial by-products – such as wheat straw, beet slices, and maize stubble – for feeding stock. Although the Hungarian situation is not typical – the ratio of pigs to cows is 4.33:1 compared with a world average of 0.66:1 – many of the substitutes evaluated are potentially relevant to the rearing of ruminants everywhere.

Maize/oats forage rotation under 3 cultivation systems, 1978–83

Abstract Abstract A maize/oats rotation was carried out on a 2-ha site in the Manawatu over 5 years as part of an evaluation of alternative forage production systems to grazed pasture. Maize was established each spring using 3 cultivation methods: (I) plough/disc/harrow cultivation; (2) minimum cultivation using discs and harrows; and (3) noncultivation. In each autumn, oats were direct-drilled into the maize stubble. Both crops were harvested as fine-chopped silage. The mean total forage obtained per year was 24.0, 23.0, and 21.8 t DM/ha for the cultivated, minimum cultivated, and noncultivated systems respectively. In 3 of the 5 years the non-cultivated treatment produced lower maize yields than the cultivated treatment, whereas in the other 2 years yields were similar. Yields of the noncultivated oat crops were also slightly lower in all years. Lower plant populations were often apparent in the non-cultivated crops. However, improved seed-drill coulters and the more timely sowing possible with non-cultivation could give the technique substantial advantages. The trial demonstrated that maize/oats is a feasible forage rotation as both crops can be grown within a year, and high yields obtained.

Efficiency of recycled nitrogen from residues of maize (Zea mays), soybean (Glycine max) and moong (Vigna radiata) on wheat (Triticum aestivum) grain yield

A laboratory incubation experiment followed by a greenhouse experiment was made in a silty clay loam at Pantnagar, India, to recycle plant utilizable N from crop residues such as maize stubble, soybean hay andmoong straw. The beneficial effect of recycled N was tested by a wheat crop. Soybean hay yielded the most NO3−N upon mineralization and also gave the highest wheat grain yield. Maize stubble mineralized the least NO3−N and gave the lowest grain yield.Moong straw occupied an intermediate position. An intervening period of 30–45 days would be required for the residues in question to release plant utilizable NO3−N in sufficient quantities. From a practical view point, soybean hay appears to be an ideal choice of a residue capable of providing sufficient supplemental N for a succeding wheat crop and can be easily fitted into the prevalent cropping sequence.