Disc Harrow Research Articles

Estoques de carbono orgânico do solo em cafezais sob diferentes sistemas de controle de plantas invasoras

Soil organic carbon (COS) is an important indicator of soil quality, as its levels and stocks can change by soil preparation. This study aimed to evaluate COS stocks on a clayey Oxisol cultivated with coffee and subject to different weed control systems in southern Minas Gerais, Brazil. The experimental design was in randomized blocks, and weed control systems were: no weeding, manual weeding, pre-emergence herbicide, post-emergence herbicide, rotary tiller, rotary mowers and disk harrow. Undisturbed soil samples were collected at two positions in the coffee plantation (tire tracks and planting line), at depths of 0-3, 10-13, and 25-28 cm. A nearby native forest was sampled as a reference. A higher bulk density of soils under coffee plantations occurred compared to soil under the forest. There was little difference between COS concentrations in the plating line in relation to the native forest, but for the tire track position, the amount of COS was generally lower. After correction for soil compaction, it was estimated a loss of ca. 20% in SOC stock for te 0-30 cm depth for herbicide post-emergence, rotary tiller, manual weeding and disk barrow, and a 35% loss when using herbicide pre-emergence. SOC stocks under no weeding and rotary mowers did not differ from native forest (37 M-1g ha COS), indicating that the rotary mower, which allows temporary growth of weeds and does not disrupt soil structure, is the most appropriate weed control for the preservation of COS in coffee plantations.

PHENOLOGICAL AND BOTANICAL OBSERVATIONS OF UNTRADITIONAL DROUGHT–RESISTANT ANNUAL FODDER SPECIES FOR FOOTHILL REGIONS OF CENTRAL BALKAN MOUNTAINS (BULGARIA)

PHENOLOGICAL AND BOTANICAL OBSERVATIONS OF UNTRADITIONAL DROUGHT–RESISTANT ANNUAL FODDER SPECIES FOR FOOTHILL REGIONS OF CENTRAL BALKAN MOUNTAINS (BULGARIA)

Mathematical Analysis and Application on Mechanical Image of Hybrid Wavelet Transform Algorithm

To overcome the shortcomings such as significantly de-noising effect and easily losing the details of the image characteristics of the existing image de-noising methods, an image de-noising algorithm based on the hybrid wavelet transform was proposed. The algorithm integrated the advantages of wavelet de-noising retaining image details features and Wiener filter obtaining the optimal solution, and took the images processed by wavelet transform and Wiener filter as male and female of the initial population. The steps of the algorithm are as follows: mapping from image space to coding space, iterating to parents through selection, crossover and mutation operation until the offspring meeting the constraints was obtained, reducing the superior offspring to image space, gaining the approximate optimal solution. Theoretical analyses were made on the core of the algorithm, coding, crossover and mutation. The algorithm was applied to agricultural machinery parts image de-noising such as plough and disk harrow. The results showed that it had the advantages of high peak signal to noise ratio (PSNR), obvious edge characteristics, good vision effect, and so on. The result of the present work implied that the proposed algorithm is an effective and feasible exploration. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2723 Full Text: PDF

POWER BALANCE FOR SOME DIFFERENT TYPES OF TRACTORS USED IN IRAQ

The aim of present study was to determine the most suitable tractor to complete the implementation of the basic agricultural operations through technological time in the agricultural production conditions in Iraq. A field experiment was conducted at the Faculty of Agriculture, Baghdad University during 2011, to evaluate the performance and power requirements for these tractors. To achieve this goal 3 tractors of different powers ranging from 70 – 105 HP were used to execute the commonly mechanized operation in Iraq. Three different operations were used: ploughing with mouldboard plough, harrowing with disc harrow and land levelling by land leveller. The optimum tractor power requirement under Iraqi agricultural conditions was selected according to the evaluation of the following criteria: the performance, and tractor power balance for these tractors, Therefore it might be suggested from the results of this investigation covering many technical aspects that the engine horsepower required for executing must of the main Iraqi agricultural operations. To select the New Holland tractor (80HP) for carrying ploughing and harrowing operations and to select Tumosan tractor (105 HP) for carrying levelling operation.

Effect of cover plants on soil C and N dynamics in different soil management systems in dwarf cashew culture

Inappropriate soil management practices are one of most important constraints on cashew production in Northeast Brazil. This work aimed to evaluate the changes in soil C and N dynamics caused by different management of cover plants (spontaneous or leguminous) in dwarf cashew culture in Northeast Brazil. The evaluated management systems for control of spontaneous vegetation included: disc harrowing (DH), mechanical mowing (MeM), manual mowing (MaM), leguminous cover crop (LEG), leguminous cover crop+mulch of Carnaúba palm (LEG+m), and application of herbicide (HERB). The floristic composition, plant density, biomass production, and the nutrient content of the spontaneous plants that grew between cashew rows were evaluated. Total soil C and N, mineral- and organic-N, light organic matter fraction, microbial biomass, CO2-C emission rates and humic substances were determined. HERB treatment promoted a substantial change in the floristic composition of spontaneous species. Richness index was highest in the LEG treatment in the fifth year of the experiment. Dry matter amount of spontaneous plants was quite similar in MeM, MaM, LEG, and LEG+m treatments, with average values of 2245kgha−1. DH and HERB treatments reduced dry matter by 69 and 80%, respectively. The MeM system resulted in the highest soil C stock, whereas the DH treatment tended to intensify the mineralization process of soil organic matter due to soil disturbance. LEG treatment resulted in the highest mineral-N contents. Our results suggest that the maintenance of soil organic C levels in DH and MeM treatments is strongly dependent on maintenance of light organic matter levels. Soil from treatments which favored input of organic matter (e.g., LEG, LEG+m and HERB) presented greater C-humic/C-fulvic acids ratio, indicating the predominance of humic acids. Our findings reinforce that cover plants (e.g., spontaneous vegetation and leguminous species) play an important environmental role, contributing to organic matter and nutrient cycling in the soil. Management systems that promote soil covering and the use of leguminous species increased soil organic matter stocks.

Nohut Tariminda Farkli Toprak Isleme Yöntemlerinin Ürün Verimi ve Bazi Verim Unsurlarina Etkilerinin Belirlenmesi

This study was carried out to determine the effects of different soil tillage methods on crop yield and some yield components in chickpea cultivation. For this reason, experimental trials were performed in Caykoy and Guzelpinar in Tokat-Kazova during 2008, 2009 and 2010. In this trials Gokce cultivar of chickpea was used. Six different soil tillage methods were applied which were, mouldboard plough tillage in fall + cultivator in the spring + tooth harrow (Method A), mouldboard plough tillage in spring + cultivator + tooth harrow (Method B), rotary tiller in the spring (Method C), chisel in the spring + disc harrow and slider (Method D), strip tillage with router rotary hoe (Method E) and direct seeding (Method F). Trials were set up in completely randomized block design with three replications. The results indicated that the highest average plant and seed yield per square meter was obtained with method A (470.74 g and 260.63 g) and followed by method B (459.43 g and 254.18 g) and method D (447.82 g and 247.23 g). In terms of factors evaluated; A, B and D methods were superior compared to the other methods.

Studies Regarding Comparative Analysis of Main Working Indicators at Primary Soil

The primary soil tillage's are the most energetic consumer. Therefore, depending to agro technical conditions, it is necessary to use adequate working tools in order to reduce energetic consumptions. For primary soil tillage, we used different tools: moldboard plough, chisel plough, paraplaw and heavy harrow disk. For those tools, we determined the main working indicators and compared them which other to establish the best working tool in order to reduce energetic consumptions by keeping agro technical requirements.

Resistência à penetração e rendimento da soja após intervenção mecânica em latossolo vermelho sob plantio direto

A compactação altera, negativamente, várias propriedades do solo, como a capacidade de penetração das raízes e a disponibilidade de água e nutrientes às plantas, restringindo a taxa fotossintética, o crescimento da parte aérea e, por conseguinte, o rendimento da cultura. Nesse sentido, quando a compactação do solo torna-se limitante ao desenvolvimento das culturas, faz-se necessária a adoção de medidas mitigatórias. Nesse contexto, este trabalho objetivou avaliar o efeito residual de intervenções mecânicas mediante aração e escarificação do solo, associadas à semeadora com sulcadores tipo discos e discos + haste, como prática mitigadora da compactação de solo manejado sob sistema plantio direto (SPD), sobre os parâmetros de resistência do solo à penetração e o rendimento da cultura da soja. Para isso, foi realizado um estudo no município de Coxilha, na região norte do Rio Grande do Sul, em um Latossolo Vermelho, em experimento instalado no ano de 2001 em área com histórico de manejo sob SPD. Nessa área, a cada ano um tratamento foi submetido à descompactação mecânica do solo sob SPD mediante uma aração e outro mediante uma escarificação do solo, anterior à implantação da cultura de verão, retornando-se o manejo sob SPD após essa intervenção. O delineamento experimental foi de blocos ao acaso com parcelas subdivididas, com três repetições. Os tratamentos foram compostos pela combinação de 13 sistemas de manejo do solo, alocados na parcela principal, e dois dispositivos sulcadores da semeadora, alocados na subparcela. Assim, os sistemas de manejo avaliados foram constituídos pela testemunha, representada pela manutenção ininterrupta do SPD por 16 anos; seis períodos de tempo de manejo sob SPD (7,5; 6,5; 5,5; 4,5; 3,5 e 2,5 anos) após uma intervenção mecânica com arado de discos + grade de discos (A); e os mesmos seis períodos após uma intervenção mecânica com escarificador (E). Os níveis alocados na subparcela foram constituídos pela ação de uma semeadora de plantio direto equipada com discos duplos defasados atuando até 7 cm de profundidade e de uma semeadora equipada com discos duplos + haste atuando até 13 cm de profundidade. Os resultados obtidos indicaram que a intervenção mecânica em solo manejado sob SPD consolidado, mediante a prática de escarificação ou aração do solo, apresenta potencial efêmero para mitigar a compactação e promover a melhoria da estrutura do solo, com efeito residual de até dois anos e meio para a resistência do solo à penetração. A utilização de semeadora de plantio direto equipada com sulcador tipo haste + disco apresentou potencial para mitigação da compactação do solo, promovendo a redução da resistência mecânica do solo à penetração na camada de 7 - 15 cm de profundidade. Contudo, o efeito residual da intervenção mecânica para descompactação do solo e a adoção dos diferentes dispositivos de aplicação do adubo no sulco de semeadura não foram eficientes em alterar o rendimento de grãos da cultura da soja na safra agrícola 2008/2009.

Tillage Effect on Penetration Resistance, Bulk Density and Saturated Hydraulic Conductivity in a Clayey Soil

Effects of six tillage practices on saturated hydraulic conductivity (HC), soil bulk density (BD), and penetration resistance (PR) were evaluated for a clayey soil ( Typic Haploxererts) under semi-arid Mediterranean conditions in a three year study (2006-2009). The experiment was conducted on a randomized complete block design with three replicates. Treatments were : conventional tillage with residue incorporated (CTS), conventional tillage with residue burned (CTB), reduced tillage with heavy tandem disc harrow (RTD), reduced tillage with rotary tiller (RTR), reduced tillage with heavy tandem disc harrow for the first crop + no-tillage for the second crop (RNT), and no tillage (NT). The study was conducted in wheat- corn, wheat-soybean and wheat crop rotations. The tillage effects on HC, BD and PR were significant at soil depth of 0-30 cm. The hydraulic conductivity was higher in CTS, and followed by CTB, RTR, RTD, RNT and NT practices, respectively. The hydraulic conductivity values under NT in 2007 and 2008 were 20% and 30% lower at 0-30 cm depth compared with CTS, respectively. The conventional tillage treatments in the semi-arid conditions improved the HC by decreasing BD and PR of the clayey soil. The BD and PR values were higher under NT treatment than the tilled plots and increased with depth. The values of soil compaction indicators were significantly greater under no-tillage and reduced tillage as compared to those under conventional tillage in all soil depths studied.

Comparative performance of six planter attachments in two residue management corn production systems

Field performance of six combinations of planter attachments on a conventional row-crop planter in two residue management corn production systems was evaluated. The management systems consisted of baled-out residue plots worked by a single pass of disc harrow (RMS1) or untouched residue plots worked by a single pass of chisel plow followed by a disc harrow (RMS2); both systems were planted by a row crop planter with one out of six attachments. Results revealed that both systems fell within residue cover limits defined for conservation farming. The winged chisel furrow opener preceded by a row cleaner equipped with treader wheels (WCRT) arrangement removed appreciable amounts of residues on the row for both systems, but more residues were removed for RMS2 plots. The WCRT pushed almost double amount of residue aside. In spite of higher initial residue in RMS2, chisel plowing and subsequent disc harrowing reduced more residues paving the way for planting in a more seeding depth. Higher percentage of emergence rate index was noticed for RMS2 plots. For both systems, the WCRT and chisel furrow opener preceded by a row cleaner (CR) showed the maximum and minimum quality of feed index, respectively. However this index was higher for RMS2 plots. The WCRT and CR arrangements had the minimum and the maximum multiple index values, respectively. However this index decreased significantly in RMS2 plots compared to RMS1 plots. The RMS2 treatments showed lower values of precision index, which is favorable. The results suggest that adoption of WCRT to planters in soil prepared under RMS2 is useful for a satisfactory conservation crop production system.

MANAGEMENT OF RED RICE (ORYZA SATIVA) AND BARNYARDGRASS (ECHINOCHLOA CRUS-GALLI) GROWN WITH SORGHUM WITH REDUCED RATE OF ATRAZINE AND MECHANICAL METHODS

SUMMARYThe weedy variety ofOryza sativaoccurs in several rice cultivation areas reducing both grain yield and quality. Prevention and crop rotation are considered the basic means to reduce its presence. Weed control in sorghum is generally attained with atrazine. In this study, the efficacy of both chemical and mechanical methods for control, under different soil tillage conditions, of weedy rice and barnyardgrass during sorghum cultivation was evaluated with the aim to reduce the application rate of atrazine. In the case of chemical control, the atrazine rate (1000, 1500, 2000, 2500 and 3000 ga.i.ha−1) and application timing (pre- and post-emergence) were assessed. With the mechanical control method, the number of interventions (inter-row hoeing with sorghum at 3, 4–5 and 6–8 leaves) to avoid weed competition was determined. The effect of the tillage system on weed population was investigated comparing conventional (ploughing), minimum-tillage (disc harrowing) and sod seeding (no-tillage) in combination with pre- and post-emergence herbicide treatments. The results showed that efficient control of weedy rice and barnyardgrass was achieved in lowlands with sorghum in rotation with rice. Both chemical and mechanical methods of weed control in sorghum gave a level of efficiency higher than 60%. The application of atrazine was more efficient in pre-emergence application, rather than in post-emergence treatments, in all soil tillage systems tested. On both weed species, the most suitable application rate was the pre-emergence treatment with 1500 ga.i.ha−1, and the adoption of higher rates did not significantly increase the herbicidal efficacy. The adoption of two or three mechanical interventions resulted in sorghum yield higher than the chemical post-emergence application, and similar to the application of atrazine in pre-emergence. Higher yield results were in accordance to greater weed control, being obtained in the conventional tillage system.

Preparo do solo e doses de nitrogênio em cobertura em arroz de terras altas

As influências do sistema de preparo do solo e da adubação nitrogenada não estão bem definidas para o arroz de terras altas. Assim, com o objetivo de avaliar os componentes da produtividade e o rendimento industrial do arroz de terras altas irrigado por aspersão, em função do preparo do solo e de doses de nitrogênio em cobertura, conduziu-se o experimento em condições de campo, em Selvíria (MS), por duas safras consecutivas: 2003/2004 (cultivar BRS Talento) e 2004/2005 (cultivar IAC 202). Adotou-se o delineamento em blocos casualizados, constituído pela combinação de três manejos de solo (grade aradora + grade niveladora, escarificador + grade niveladora e plantio direto) e seis doses de N em cobertura (0 kg ha-1, 25 kg ha-1, 50 kg ha-1, 75 kg ha-1, 100 kg ha-1 e 125 kg ha-1), com quatro repetições. Avaliou-se a concentração de N na folha, altura de plantas, componentes de produção, produtividade e o rendimento industrial dos grãos. O preparo do solo com escarificador + grade niveladora propiciou a obtenção de maiores produtividades das duas cultivares, enquanto a adubação nitrogenada em cobertura interferiu apenas na produtividade da cultivar IAC 202, sem afetar o rendimento industrial de grãos.

Crop rotation and tillage effects on selected soil physical properties of a Typic Haploxerert in an irrigated semi-arid Mediterranean region

Physical, chemical and biological attributes of soil surface are significantly affected by tillage practices and crop rotation. The objective of this study was to determine the short-term (2006-2009) effects of conventional and conservational tillage practices on selected soil physical properties of a heavy clay soil under two wheat-corn and wheatlegume rotation in a semi-arid Mediterranean Region. Treatments included conventional tillage with residue incorporated in soil (CT1), conventional tillage with burned residue (CT2), reduced tillage with heavy tandem disc-harrow (RT1), reduced tillage with rotary tiller (RT2), reduced tillage with heavy tandem disc harrow fallowed by no-tillage (RNT) and no tillage (NT). Disturbed and undisturbed soil samples were collected to determine saturated hydraulic conductivity (HC), bulk density (BD), mean weight diameter (MWD), available water content (AWC) and total porosity at 0-10, 10-20 and 20-30 cm depths. The highest HC values of 0-10 cm and 10-20 cm depths were obtained with CT1 (9.70×10 -6 m s -1 , 8.74×10 -6 m s -1 ) and CT2 (9.39×10 -6 m s -1 , 8.58×10 -6 m s -1 ) applications. CT2 treatment destructed the soil aggregates and resulted in greater bulk density and low total porosity at 0-10 cm depth. The available water content at 0-10 cm depth was significantly reduced with the CT1 (P<0.01) and CT2 applications (P<0.05). Although three years of no-tillage application in clay rich soils caused higher bulk density and low porosity, increase in MWD is an indication of soil and water conservation. Therefore, no till and reduced till applications should be adapted to the farmers’ conditions for sustainability in agriculture.

The impact of different tillage systems and nutrient levels on the biomass and Brix values of sweet sorghum (Sorghum bicolor L. Moench)

The biomass and Brix content of sweet sorghum was investigated in 2009 and 2010 to determine the most suitable tillage and fertilization treatments. The experiment was carried out at the Biomass Utilization and Crop Production Demonstration Centre of Szent Istvan University. Both humus content and nitrogen (N) supply of the topsoil was insufficient. In 2009, which was a typical drought year, the yields ranged from 12.14 t/ha (direct drilling) to 56.11 t/ha (ploughing). There were significant differences between the tilled and non-tilled plots. In 2010 as in 2009, the highest yield of 63.52 t/ha was measured in case of ploughing, however cultivating and disk harrowing treatments showed similar biomass results. This study indicates that fertilizers had a significant effect on yields, as in both years highest biomass was obtained at 100 kg ha-1nitrogen rate. The highest Brix values were measured in 2009 (18.21%) and in 2010 (9.01%) in case of cultivation treatments. In the examination years, direct drilling showed the lowest results for biomass and also regarding Brix values. The results demonstrate that the fertilisation and suitable tillage is very important in the cultivation of sweet sorghum. Key words: Sweet sorghum (Sorghum bicolor), tillage, biomass, Brix.

Long term effect of tillage system and crop residue management on soil carbon content of a luvisol under rainfed Mediterranean conditions

Under Mediterranean conditions, soils under conventional tillage farming usually have very low contents of organic matter. This situation is due to intensive soil tillage, low biomass production under rainfed conditions, and removal of cereal straw for alternative use off the field. In order to study strategies to improve soil organic matter content (SOM), a long term experiment (11 years) was established in 1995 to evaluate the effect of four different tillage systems (conventional tillage (CT) based on moldboard plough (25 cm) + disc harrow with removal of cereal straw; reduced tillage (RT) based on non-inversion tine cultivation with removal of cereal straw; no-till (NT) with removal of cereal straw; and no-till with cereal straw retained (NT+S). The crop rotation was lupine – wheat – forage oat – barley. Soil organic carbon (SOC) (0-30 cm) and crop yields (grain and straw) were measured every year. In addition, yield response of the wheat crop to nitrogen fertilization was studied, in order to evaluate the interactions with SOC accumulation. Under CT and RT, SOC remained almost unchanged over the experimental period. NT improved SOC by 18% in relation to CT and NT+S increased SOC by 62%. There were no significant differences between CT and NT in the amount of residues left in the field over the experimental period, but NT+S significantly increased the amount of residues retained in relation to the other treatments. The results indicate that NT reduced SOM mineralization, but that maximum increase of SOC can only be achieved if crop residues are retained on the field. Nitrogen use efficiency was significantly improved with greater SOC contents, i.e. from 19.1 kg of wheat per kg of applied N at 0.58% SOC to 104 kg of wheat per kg of applied N at 1.74% SOC.

Impact of soil tillage and land use on soil organic carbon decline under mediterranean conditions

Soils under Mediterranean climate conditions frequently have low to very low levels of soil organic matter (SOM), as a result of low biomass production under the predominantly rainfed conditions and the intensive tillage operations commonly practiced. In order to assess both short and long-term impacts of soil tillage and land use on soil organic carbon, two sets of experiments were performed. One consisted in the identification and soil analysis of 3 pairs of sites under different soil types and land use over 5 to 30 years; in the second experiment a long-term fallow area was repeatedly submitted to different types of soil tillage management (mouldboard plough + disc harrow; non-inversion tine cultivation; no-till) over 3 years. Soil texture, bulk density and SOM were analysed along the whole soil profile in the first experiment, whereas bulk density and SOM to a depth of 30 cm was measured before the first tillage operations and at the end of the observation period in the second experiment. The results clearly indicate that tillage based land use, irrespective of the type of land use, caused a considerable decline in SOM content in the tilled soil layer. Very small and inconsistent differences in SOM between paired soil profiles were observed in the lower part of the profiles. In the second experiment with three types of tillage systems, SOM content decreased with tillage intensity. Avoidance of soil disturbance is an important step towards halting SOM decline under Mediterranean climate conditions.

Soil Stabilization in the Fill Project of the Olympic Rowing-Canoeing Park in Beijing

AbstractThe Olympic Rowing-Canoeing Park is one of 11 new venues constructed for the 2008 Olympic Games in Beijing. The soil materials excavated during its construction were primarily silty sand and sandy silt. Laboratory tests were carried out on these two soil materials with and without cement stabilization. A test embankment was constructed, and a 6-m high geogrid-reinforced retaining wall was built with the sandy silt material as the backfill, in which soil pressure and strain in the geogrid were measured. Sandy silt material was found to be more desirable than the silty sand for use as the backfill material in building the rowing-canoeing course and ancillary buildings. Shear strength, especially cohesion, increased after cement stabilization, and resistance against water erosion also greatly increased. Construction of the test embankment indicated that higher uniformity of the cement-treated soil layer may be achieved by a mixer than by disc harrow. For the geogrid-reinforced retaining wall, the str...

Effects of various tillage systems on soil CO2-C fluxes and on bacteria and fungi populations in Zea mays

The objective of this study is to determine the effects of strip tillage and full-width tillage treatments on soil carbon (IV) oxide-carbon (CO2-C) fluxes, bacterial and fungal populations in growing period of Zea mays. A row-crop rotary hoe with C type blades was used to create three strip widths by changing the connection of blades of the rotary hoe on the flanges. Strip widths were 22.5 (T30), 30 (T40) and 37.5 cm (T50). The full-width tillage practice (moldboard plow + disc harrow + leveler) gave 100% surface soil disturbance (T100) and was included in the experiment to make comparisons with the strip tillage system. During the growth of theZea mays, periodic measurements of CO2-C fluxes, bacterial and fungal populations were made. Statistically significant differences in CO2-C fluxes, microbial populations and soil bulk density were observed between the different tillage systems. Highest CO2-C fluxes and bacteria populations were observed with the full-width T100 treatment and the lowest values were observed in the T30 treatment during flowering and harvesting periods. Increasing tillage intensity increased soil CO2-C fluxes and bacteria population, but decreased fungi population and soil bulk density. Key words: Carbon IV oxide-carbon flux, strip tillage, strip width.

Techniques for Cynodon dactylon (L.) Pers. control suitable for use in fallow organic transition in the southeastern U.S. coastal plain

Cynodon dactylon (L.) Pers. is a troublesome perennial grass and extremely difficult to control in organic crop production systems. Research trials were conducted to evaluate systems of C. dactylon control during fallow organic transition. Treatments evaluated were all possible combinations of two primary tillage implements (power spader, disk harrow), summer weed management (solarization, fallow tillage with a peanut digger, and non-treated control), and winter tillage (fallow tillage with a peanut digger and non-tilled control). C. dactylon densities were reduced by combinations of summer solarization or summer tillage with a peanut digger, followed by winter tillage with a peanut digger. The peanut digger displaced C. dactylon and exposed the vegetative material to desiccation. However, control using these systems for one season was not sufficient enough to prevent re-infestation by survivors.

INFLUENCE OF TILLAGE SYSTEMS ON SOIL PHYSICAL PROPERTIES UNDER LIBYAN CONDITIONS

Soil tillage is carried out with the objective of changing the soil physical properties and to enable the plants to show their full potential. Physical degradation of the soil may be defined as the loss of the soil’s structural quality. The field experiment was conducted at El-Gefara,Tripoli, Libya. To test the tillage systeme by uesing conventionaltillage system(S1) using moldboard, rotary plowand disc harrow, Minimum tillage by using rotary cultivator(S2) ,disc harrow (S3), chisel plough(S4) and Zero tillage as a control on soil physical properties, under libyan conditions. Four tillage systems S1, S2, S3,and S4. were used to determiend soil moistur, density and porosity percentage.The results show that with the use of tillage systems S1, S2, S3,and S4.Results show that, the change soil porosity percentage, were 36.2, 32.4, 26.1and 28.9%.,the change soil moisture percentage, were 11.6, 13.2, 5.3and 9.6%., the change soil density percentage, were 15.7, 14.3.11.9and 10.8%.,