Effect Of Soil Tillage Systems Research Articles

Effect of Soil Tillage Systems and Crop Seasonality on the Sediment Geochemical Properties Transferred into a Headwater: A Case of Study in Tobacco Plantation

ABSTRACT The global impacts of agricultural land conversion on soil erosion and pollution, particularly in tobacco cultivation areas, are well-recognized as significant contributors to soil degradation. These areas are identified as hotspots for environmental concerns due to practices that lead to increased erosion and pollution. From this perspective, this case of study explores fine sediment samples from two areas with tobacco cultivation under different tillage systems and seasonal variations, transport into a headwater, and evaluates, on a local scale: (1) the impact of tillage systems on the geochemical signature of sediments; (2) if whether crop seasonality affects these sediment geochemical signatures. The Conventional Ridge Tillage (CRT) system involves extensive soil exposure and machinery for soil management, while the Mulch Ridge Tillage (MRT) system prioritizes soil conservation and relies on herbicides for weed control. The analytical methodology used to assess the sample element characteristics was Energy Dispersive X-ray Fluorescence (EDXRF). It was applied on the twenty fine sediments (ten of harvest and ten of inter-harvest season of tobacco) to quantitatively assess their inorganic composition. Additionally, Pearson correlation analysis, Hierarchical Cluster Analysis (HCA), and Principal Component Analysis (PCA) were applied on the EDXRF data to highlight the similarities and, thus, providing information to assess the complex data clustering patterns. As a result, the sediment compositions from the two studied soil systems are not similar. The PCA showed that the CRT sediments are characterized by the P, S, K, Ca, and Mn content, presenting a geochemical signature related to manure and fertilizer compared to the MRT, which is correlated with Al, Ti, Fe, Cu, and Zn contents, exhibiting a geochemical signature characterized by the natural soil composition. Therefore, the sediment geochemical signatures might be affected by two phases in the study area: a) tillage system characteristics and b) seasonal soil erosion. These findings underscore the importance of managing soil nutrients to mitigate soil pollution and nutrient exportation to aquatic systems. Moreover, the results emphasize the recommendations for sustainable agricultural practices in tobacco-growing areas to protect environmental quality.

The Assessment of Soil Quality in Contrasting Land-Use and Tillage Systems on Farm Fields with Stagnic Luvisol Soil in Estonia

Soil quality indicates the soil’s ability to provide ecosystem services. Reducing the tillage intensity has been suggested as an alternative to conventional tillage for sustaining soil quality. This study aimed to evaluate the effect of soil tillage systems on individual soil quality indicators in comparison to those on grassland with Stagnic Luvisol soil in Estonia. Four soil management systems were compared: no-tillage (NT), minimum tillage (MT), conventional tillage (CT) and grassland (G) as a reference. Soil quality indicators included physical (bulk density, water-stable aggregates, porosity, air-filled pores, moisture content, water-holding capacity, penetration resistance and water permeability), chemical (total N, total soil organic C, permanganate oxidisable C, pH, P, K, Ca and Mg) and biological (earthworm abundance) parameters. CT soils had a significantly lower aggregate stability compared to MT and G soils. The higher penetration resistance of CT under an arable layer suggested the presence of a plough pan. NT improved the soil’s physical quality at 5–10 cm, which was indicated by higher moisture content, water-holding capacity and porosity and a lower bulk density, whereas penetration resistance exceeded 2 MPa in the lower part of the topsoil. NT also had significantly lower total soil organic C and total N compared to MT and G. The absence of tillage in the NT and G systems may have improved the soil’s resistance to moisture loss under dry conditions, which, in turn, improved the soil habitability for earthworms a despite higher density. In general, NT or MT stabilised or increased the soil quality compared to CT.

INFLUENCE OF SOIL TILLAGE SYSTEM, FERTILIZER AND TREATMENT APPLIED TO SEEDS ON SOYBEAN CHEMICAL COMPOSITION

"In order to evaluate the effect of soil tillage system, fertilization and also different treatments applied to seeds on chemical composition in soybean crop, a field experiment was conducted at Research and Development Station for Agriculture Turda in 2020. Teo TD, an early soybean variety developed at RDSA Turda and registered in 2017 was used as a biological material. The compared tillage systems were: conventional tillage (plowing), reduced tillage (chisel or disk) and also no-tillage system. Four different mineral and organic fertilizers (N40P40, N40P40 + gulle, N40P40 + green fertilizer, N40P40 + gulle + green fertilizer) and various treatments applied to seeds (fungicide, insecticide, fungicide + insecticide, untreated) were also studied. All data were subjected to ANOVA using Polifact. Chemical composition (protein content, oil content, stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3)) of Teo TD seeds was analyzed using NIR spectroscopy. Significant differences between some tillage systems and fertilizers were recorded in protein content, fat content and also stearic, oleic and linolenic acids content. The treatments applied to seeds influenced very significant the stearic acid and oleic acid, distinct significant the linoleic acid and significant the protein content."

Effect of tillage systems and tillage direction on soil hydrological properties and soil suspended particle concentration in arable land in Uganda

The 2030 Agenda for Sustainable Development addressing the issues of environmental degradation has been challenged by human developments and activities. Crop production systems and technologies (e.g. soil tillage) are among the leading factors causing environmental degradation. In this study, the effect of soil tillage systems (i.e. no-tillage (NT); stubble-mulching (SM); deep tillage (DT); and conventional tillage (CT)) on surface runoff volume (SRV), suspended sediment concentration (SSC), infiltration rate (IR), and soil moisture content (SMC) in the common bean (Phaseolus vulgaris L.) farms, Mukono District, Uganda was evaluated. The effect of soil tillage direction on SRV was also assessed. The SRV, SSC, IR, and SMC were monitored under Complete Randomized Block Design (CRBD) experiments with four soil tillage systems in Goma and Kimenyedde experimental sites during two wet seasons. The results showed that SRV, SSC, IR, and SMC were significantly (p < 0.05) influenced by the soil tillage system, season, and site. The highest total SRV was observed during the first season in Goma experimental site under CT with soil tillage along the slope (1071.3 mm). The lowest SRV was observed during the second season in Kimenyedde experimental site under NT (165.0 mm). The highest and lowest mean SSC was observed in the CT (2.41 ± 0.3 g L−1) in Goma experimental site during the first season and NT (0.43 ± 0.1 g L−1) in Kimenyedde experimental site during the second season, respectively. The SSL was highest under CT in both Goma (147.17 kg ha−1season−1) and Kimenyedde (114.93 kg ha−1season−1), and lowest under NT with the means of 11.25 and 9.19 kg ha−1season−1 in Goma and Kimenyedde experimental sites, respectively. Both SRV and SSC increased linearly with both rainfall amount (RF) and rainfall intensity at 10 min (RI10). The highest and lowest IR and SMC were observed in the NT and CT treatments, respectively. No significant (p > 0.05) variations were observed in the SMC under the NT and SM treatments. Overall, soil tillage systems, soil type, and rainfall characteristics are among the key factors influencing the magnitudes of SRV and SSC in both time and space. This particular study suggests that NT and SM would help reduce the magnitudes of SRV and SSC, in agricultural fields.

The effect of light-gray forest soil tilling systems on the yield and quality of oat grain in the Nizhny Novgorod region

The research was conducted in the Nizhny Novgorod region in 2019 on light gray forest soil in the pea-oat crop rotation link. Studied was the effect of soil tillage systems (traditional mouldboard tillage with mouldboard plow; non- mouldboard deep tillage with boardless plow; non-mouldboard surface tillage with a Pottinger Synkro 5030 K chisel cultivator; minimal tillage with a disc harrow Discover XM 44660 nothad; zero tillage (No-till) with a Sunflower 9421-20 seeder) and the influence of mineral fertilizers (N 60 P 60 K 60 kg a. i.) and straw destructors (ammonia saltpeter in a dose of N 10 kg. a.i. per 1 ton of straw and Stimix ® Niva biologics, 2 l/ha) on changes in the yield and quality of Yakov variety oat grain. The traditional system of soil tillage provided the yield of oat of 4.82 t/ha when using mineral fertilizers in a dose of N 60 P 60 K 60 together with ammonium nitrate as a straw destructor, which was 1.04 t/ha (LSD05 =0.72) higher than the best result in terms of the yield of this crop obtained when it was cultivated using the No-till technology with the Stimix@Niva biological product on the background of N 60 P 60 K 60 (3.78 t/ha) . Use of the studied straw destructors is more effective for the N 60 P 60 K 60 background than for the non-fertilized background for all the studied soil tillage systems. When growing oat using No-till technology, the largest mass of 1000 grains was obtained when using ammonium nitrate - 46.5 g compared to other studied variants of using fertilizers and biologics (40.8-43.9 g, LSD 05 =1.1). Due to the unfavorable weather conditions of the growing season in 2019, the indicators of oat grain-unit were low. The lowest average grain-unit was found in oat cultivated using zero technology - 228.4 g/l, which is 16.2-18.4 g/l (LSD 05 - 3.0) lower than this indicator of grain quality when cultivated according to the rest of the studied tillage systems (244.6-246.8 g/l).

Respirasi Tanah Akibat Sistem Olah Tanah dan Aplikasi Mulsa In Situ pada Pertanaman Kacang Hijau (Vigna radiata L.) di Laboratorium Lapang Terpadu, Universitas Lampung

Soil respiration is an indicator of the activity of microorganisms in the soil. The treatment of soil tillage system and the use of organic mulch given to the soil will affect the activity of soil microorganisms. The research aims to study the effect of soil tillage systems, application of in situ mulch, and the interaction between both in soil respiration. This research was conducted from April to July 2017 at the Integrated Field Laboratory, Faculty of Agriculture, University of Lampung, using a Randomized Block Design (RBD) factorially prepared with two treatment factors. The first factor is the soil tillage system (T), which consists of minimum tillage (T0) and conventional tillage (T1). The second factor is the treatment of mulch (M), which consists of no mulch (M0) and the application of in-situ mulch 5 t. ha-1 (M1). The data obtained were tested for various homogeneity by the Bartlett test and additivity by the Tukey test. Data were analyzed by analysis of variance and continued with LSD test at a 5% level. The relationship between soil temperature, soil moisture content, soil organic matter, and soil pH with soil respiration was tested by correlation test. The results showed that the soil tillage system and application of in-situ mulch had no significant effect on soil respiration, and there was no interaction between the soil tillage system and application of in-situ mulch in soil respiration on observations before tillage, 1 day after planting (HST), 41 HST, and 88 HST. There is no correlation between soil temperature, soil moisture content, soil organic matter, and soil pH with soil respiration on pre-tillage observations, 1 HST, 41 HST, and 88 HST.

Influence of various systems of soil tillage on agrophysical properties of leached chernozem

The paper presents the results of research into the effect of different soil tillage systems on soil density and structure. The research was conducted in a long-term stationary experiment on the crops of Nikita spring barley. The soil of the experimental plot is classifi ed as leached, mediumtextured, medium-humus, heavy-loam chernozem. The following soil tillage systems with peas as a forecrop were studied: deep moldboard, deep combined, minimum combined and zero. The years of research (2015-2018) differed in heat availability and amount of precipitation. This allowed to study and carry out comparative assessment of the effect of various soil tillage systems of leached chernozem on agrophysical properties of soil. Yearly weather conditions had no signifi cant effect on soil density with all the studied soil tillage systems in single and binary crops of spring barley, whereby the indicators varied from 1.87 to 6.72%. Compared to deep moldboard tillage (control), there was an increase in soil density with zero tillage in singlecrop sowings of spring barley by 6.2%, and in binary crops – by 9.4%. However, the indices were not beyond optimum values of 1.02-1.05 g/ cm3. The optimum equilibrium soil density for the main subtypes of chernozems is 1.0-1.25 g/cm3. Minimum combined soil tillage system resulted in the stable content of valuable structural soil units 0.25-10 mm both in single-crop and binary sowings of spring barley at 68.3% and 68.9%, and the coeffi cient of soil structural properties – 2.15 and 2.21 respectively. It was established that the effect of soil tillage system on the creation of valuable structural units in soil was 21.4%, yearly weather conditions – 11.8%, type of crops – 25.5%.

The effect of soil tillage system and weeding time on the growth of weed and yield of soybean (Glycine max (L.) Merril)

The growth and yield of soybeans can decrease due to competition from weeds. Various efforts have been made to control the growth of weeds such as land preparation and weeding periods. An experiment to study the effect of soil tillage systems and weeding time on the growth of weeds and soybean crop yield ( Glycine max (L.) Merril) has been done in Wringinsongo Village, Tumpang Sub-District, Malang Regency from February to May 2017. The split-plot design with three replicates was used with the soil tillage system as the main plot consisting of three levels, T0: no tillage, T 1 : minimum tillage, and T 2 : conventional tillage, and weeding time as the sub plot consisting of 4 levels, P 0 : no weeding, P 1 : weeding 1 time, P 2 : weeding two times and P 3 : weeding three times. The results showed that the dominant weed species before treatment were Amaranthus spinosus (Spiny amaranth), Cynodon dactylon (Bermuda grass), Cyperus rotundus (Purple nutsedge), Ageratum conyzoides (Billygoat weed ), and Portulaca oleracea (Common purslane). After treatment, the dominant weed species were Cyperus rotundus (Purple nutsedge), Amaranthus spinosus (Spiny amaranth), Ageratum conyzoides (Billygoat weed ), Physalis peruviana (Cape gooseberry), and Eclipta alba (False daisy). There was no significant difference of the dry weight of weeds in conventional tillage followed by weeding 3 times at 15, 30 and 45 days after planting, and minimum tillage and no tillage. For the yield of soybeans, conventional tillage followed by weeding 3 times at 15, 30 and 45 days after planting were not significant with that of minimum tillage. The yield of soybeans was lower than that of with no tillage and no weeding.

Pengaruh Sistem Olah Tanah dan Residu N Tahun ke–29 pada Beberapa Sifat Kimia Tanah dengan Tanaman Indikator Leguminosa

Degradasi lahan akibat pengolahan tanah intensif secara terus menerus dapat menurunkan produksi pertanian. Penelitian ini bertujuan untuk mendapatkan pengaruh sistem olah tanah, pengaruh berbagai dosis pupuk N pada sifat kimia tanah, dan pengaruh antara sistem olah tanah dan residu N pada sifat kimia tanah tahun ke-29 dengan tanaman indikator leguminosa. Penelitian dilakukan di Politeknik Negeri Lampung mulai dari Mei 2016 sampai dengan November 2016. Penelitian menggunakan Rancangan Acak Kelompok dengan dua faktor. Faktor pertama adalah berbagai sistem olah tanah yang terdiri atas olah tanah intensif (OTI), olah tanah minimum (OTM), dan tanpa olah tanah (TOT). Faktor kedua adalah residu pupuk N (Urea) yang diberikan pada tanaman sebelumnya, yang terdiri atas 3 taraf, yaitu 0kg N/ha (N0), 100 kg N/ha (N1), dan 200 kg N/ha (N2). Perlakuan diulang empat kali. Peubah yang diamati yaitu pH, C-organik, Nitrogen total, P tersedia (H2O), kalium tersedia, dan bobot tajuk. Data di analisis dengan analisis ragam diikuti dengan uji BNT pada taraf α = 0,05. Hasil penelitian menunjukkan bahwa tidak terdapat interaksi antara sistem olah tanah dengan residu pupuk N. Tanpa olah tanah menghasilkan P tersedia tertinggi (10,713). Residu nitrogen dengan taraf dosis 200 kg N/ha menghasilkan pH terendah (5,980).

Soil fertility and nutrient budget after 23-years of different soil tillage systems and winter cover crops in a subtropical Oxisol

Growing cover crops to recycle soil nutrients in no-tillage systems provide nutrients accumulation in more labile forms in the soil surface reducing the demand for fertilizers. This study aimed to evaluate the long-term (23-yrs) effect of soil tillage systems and winter cover crops on (i) soil acidity, (ii) nutrient availability, and (iii) P and K budget in a subtropical Oxisol from Southern Brazil. The experiment was established in 1986 with six winter treatments (blue lupine, hairy vetch, oat, radish, wheat, and fallow) and two tillage systems (conventional tillage - CT and no-tillage - NT) in a very clayey Rhodic Hapludox in Southern Brazil. Nutrient availability (P, K, Ca, and Mg) and soil acidity (pH, potential acidity, base and Al saturation) were evaluated in five soil depths (0–5, 5–10, 10–20, 20–30, and 30–40cm). Nutrient budget was calculated considering the inputs (amount of P and K applied via fertilizer) and outputs of P and K from the system (exported by the grains), and the soil available P and K before and after 23-years of experiment. Continuous NT system for 23-years resulted in higher soil fertility in the topsoil (0–10cm) compared to CT, but with some limitations of nutrient availability and soil acidity below 10cm depth. Long-term NT builds up a strong gradient of nutrient availability, with higher concentration of nutrients on the soil surface layers that abruptly decrease with soil depth, unlike CT. Surface application of lime in NT reduced soil acidity up to 20cm compared to CT. The budget of P was negative for all treatments, highlighting the P-sink behavior of this strongly weathered subtropical Oxisol. However, NT system resulted in less negative budget compared to CT and, therefore, higher efficiency of use of P. Growing cover crops in the winter is effective to increase P and K availability through plant cycling, but the plants grown in winter did not affect soil acidity. Nutrient cycling by winter cover crops reduced P and K losses, especially when the soil is not plowed. Fallow in the winter decreases the use efficiency of P and K. Among the cover crops tested, black oat stood out by its greater production of biomass, resulting in higher P and K availability in the soil surface. Lupine resulted in a greater cycling of P possibly due to its ability to absorb P from less labile forms in the soil.

Is Better Minimum than Standard Mouldboard Ploughing Tillage from Viewpoint of the Pore-Size Distribution and Soil Water Retention Characteristic Changes ?

Abstract At present time exists a lot of soil tillage practices with different effects on soil productivity, therefore the effects of two tillage systems (conventional: CT, and miminum: MT) and two different soil types (Chernozem and Mollic Fluvisol) on soil physical quality indicators and water availability were evaluated in an on-farm study in the Krakovany (Danube Lowland, Slovakia). We evaluated pore-size distributions and selected hydro-physical properties (capillary rise, maximum capillary water capacity and retention water capacity). The total porosity (P) on average by 23% and by 14%, non-capillary pores (Pn) by 271% and by 114% and semicapillary pores by 102% and by 192% were significantly greater for CT than MT in Chernozem and in Mollic Fluvisol, respectively. The content of capillary pores (Pc) was significantly greater for MT than CT on average by 13% and 8% in Chernozem and in Mollic Fluvisol, respectively. The average content of capillary rise (ΘCR), maximum capillary water capacity (ΘMCWC) and retention water capacity (ΘRWC) were higher by 6, 10 and 13% under MT than CT in soil profile of Chernozem. The same effect of soil tillage systems in Mollic Fluvisol was not observed. In Chernozem under MT with increased P, ΘCR significantly increased, however, under CT, the ΘCR significantly decreased. At the same time we determined negative correlations between Pn and soil water retention characteristics under CT. Higher content of Pc resulted in higher values of capillary rise, maximum capillary water capacity and retention water capacity in both soil types under both tillage systems.

The effect of soil tillage system on the nitrogen uptake, grain yield and nitrogen use efficiency of spring barley in a cool Atlantic climate

SUMMARYField experiments were conducted between 2009 and 2011 in Ireland to compare the effects of soil tillage systems on the grain yield, nitrogen use efficiency (NUE) and nitrogen (N) uptake patterns of spring barley (Hordeum vulgare) in a cool Atlantic climate. The four tillage treatments comprised conventional tillage in spring (CT), reduced tillage in autumn (RT A), reduced tillage in spring (RT S) and reduced tillage in autumn and spring (RT A+S). Each tillage system was evaluated with five levels of fertilizer N (0, 75, 105, 135 and 165 kg N/ha). Grain yield varied between years but CT had a significantly higher mean yield over the three years than the RT systems. There was no significant difference between the three RT systems. Tillage system had no significant effect on the grain yield response to fertilizer N. As a result of the higher yields achieved, the CT system had a higher NUE than the RT systems at all N rates. There was no significant difference in NUE between the three RT systems. Conventional tillage had significantly higher nitrogen uptake efficiency (NUpE) than RT A and a significantly higher nitrogen utilization efficiency (NUtE) than all three RT systems. Crop N uptake followed a similar pattern each year. Large amounts of N were accumulated during the vegetative growth stages while N was lost after anthesis. Increased N rates had a positive effect on N uptake in the early growth stages but tended to promote N loss later in the season. The CT system had the highest N uptake in the initial growth stages but its rate of uptake diminished at a faster rate than the RT systems as the season progressed. Tillage system had an inconsistent effect on crop N content during the later growth stages. On the basis of these results it is concluded that the use of non-inversion tillage systems for spring barley establishment in a cool oceanic climate remains challenging and in certain conditions may result in a reduction in NUE and lower and more variable grain yields than conventional plough-based systems.

Effect of Soil Tillage System upon the Soil Properties, Weed Control, Quality and Quantity Yield in Some Arable Crops

Effect of Soil Tillage System upon the Soil Properties, Weed Control, Quality and Quantity Yield in Some Arable Crops

Efeito do sistema de preparo do solo sobre características agronômicas da mandioca (Manihot esculenta Crantz)

Neste trabalho se propôs avaliar o efeito de sistemas de preparo de um Latossolo Vermelho distrófico sobre as características agronômicas da mandioca durante quatro anos agrícolas de 1999/2000, 2000/2001, 2001/2002 e 2002/2003, em Araruna, Noroeste do Estado do Paraná. O delineamento experimental foi o de blocos completos casualizados com oito repetições. Os tratamentos se constituíram de três sistemas de preparo do solo: plantio direto; preparo mínimo (escarificador com rolo nivelador) e preparo convencional (arado de aivecas + grade niveladora). O sistema de preparo convencional do solo propiciou maior altura de plantas e maior produção de parte aérea e de raízes tuberosas em relação ao preparo mínimo e ao plantio direto. O teor de massa seca nas raízes tuberosas não foi influenciado pelos sistemas de preparo de solo.

Características físicas do solo e produtividade da batata dependendo de sistemas de preparo do solo

Foi avaliado o efeito de sistemas de preparo do solo sobre o diâmetro médio dos agregados (DMA), porcentagem de cobertura da superfície do solo (CSS), profundidade da camada arada (PCA) e produção de tubérculos de batata. Foram instalados dois experimentos em solo argiloso com os mesmos tratamentos, sendo um irrigado por gotejamento e outro por aspersão. Os tratamentos foram: T1 = apenas abertura do sulco de plantio, prática comum aos demais tratamentos; T2 = uma subsolagem (SS); T3 = duas passadas de enxada rotativa (ER); T4 = uma aração com disco (AD) + duas gradagens niveladoras (GN); T5 = 1AD + 2GN + 1ER; T6 = 1AD + 2GN + 2ER; T7 = 1SS + a sequencia de T6; T8 = uma aração com aiveca (AA) + 2GN. Os tratamentos foram distribuídos em blocos ao acaso com quatro repetições e o plantio foi manual. Os maiores valores de DMA e de CSS foram observados em T1 e T2 e o maior valor de PCA, 29,6 cm, foi observado em T8. Em ambos experimentos, a produção de tubérculos comerciais (PCT) foi maior em T8, menor em T1 e T2 e intermediária nos demais tratamentos. Na média dos experimentos, o aumento médio da PCT pela aração com aiveca (T8) foi 52% em relação ao disco (T4).

The Effect of Soil Tillage Systems on Wheat Growth and Yield in the Dry-Land Region of Turkey

The Effect of Soil Tillage Systems on Wheat Growth and Yield in the Dry-Land Region of Turkey

Efeito prolongado de sistemas de preparo do solo com e sem cultivo de soqueira de cana crua em algumas propriedades físicas do solo

Este trabalho foi conduzido em Latossolo Vermelho distrófico típico, sob cultivo de cana crua, com o objetivo de avaliar o efeito prolongado de sistemas de preparo do solo, com e sem cultivo da soqueira, e épocas de amostragem sobre algumas propriedades físicas do solo. O delineamento experimental foi o de blocos ao acaso, em esquema de parcelas subsubdivididas, sendo os tratamentos principais quatro sistemas de preparo do solo: (i) controle da soqueira com duas gradagens, subsolagem e mais uma gradagem de nivelamento; (ii) controle da soqueira com herbicida e uma subsolagem; (iii) controle da soqueira com herbicida; (iv) controle da soqueira com herbicida, aração com arado de aivecas e uma gradagem de nivelamento. Os tratamentos secundários foram: com cultivo e sem cultivo da soqueira. Os tratamentos ternários foram as épocas de avaliação: dois dias antes e após a quarta colheita da cultura. A porosidade total, macroporosidade, microporosidade e densidade do solo foram avaliadas, além do perfilhamento e da produtividade da cultura. Após quatro sucessivas colheitas de cana crua, houve redução da macroporosidade com aumento da microporosidade nas camadas abaixo de 10 cm e aumento da densidade do solo entre 20 e 50 cm. A densidade do solo não foi alterada de modo consistente em função de todos os tratamentos testados. O cultivo da soqueira favoreceu o aumento da macroporosidade com decréscimo na microporosidade, e o efeito inverso foi observado após a colheita. Os sistemas de preparo do solo e de cultivo da soqueira não afetaram o perfilhamento e a produtividade da cultura.

Fracionamento densimétrico da matéria orgânica do solo sob diferentes sistemas de manejo e cobertura vegetal em Paty do Alferes (RJ)

Sistemas de manejo conservacionistas aumentam o conteúdo de carbono (C) e nitrogênio (N) orgânico do solo. Todavia, os efeitos sobre as frações leves da matéria orgânica do solo (MOS) ainda são pouco conhecidos, especialmente em ambiente tropical. O objetivo deste trabalho foi avaliar o efeito dos sistemas de preparo do solo, cultivado com oleráceas, na distribuição das frações leves (livre e intra-agregado) da matéria orgânica em Latossolo Vermelho em Paty do Alferes (RJ). Os tratamentos estudados foram: preparo convencional (PC), preparo em nível (PN) e cultivo mínimo (CM). Como referência, foram utilizadas uma área com cobertura vegetal de gramíneas (GR) e uma parcela sem cobertura vegetal (SC). As amostras de terra foram coletadas no verão 1998/99, nas profundidades de 0-5 e 5-10 cm. A distribuição do peso das frações leves diferiu significativamente entre os tratamentos. Em relação ao tratamento PC, houve aumento de 70 e 58 % na quantidade das frações leves livre e intra-agregado, respectivamente, no sistema CM. O conteúdo de C orgânico e N total das frações leves foi maior na parcela GR. Considerando os atributos avaliados, os tratamentos PN e cm são recomendados para as condições de solo e ambiente para o cultivo de oleráceas em Paty do Alferes.

Variabilidade de micronutrientes, matéria orgânica e argila de um Latossolo submetido a sistemas de preparo

O objetivo deste trabalho foi estudar os efeitos dos sistemas de preparo do solo, arado de aiveca, grade aradora e plantio direto, sobre a variabilidade de atributos físico-químicos do solo. O trabalho foi conduzido em Latossolo Vermelho perférrico, textura argilosa, cultivado com milho no verão e feijão no inverno, durante cinco anos consecutivos. As amostras de solo foram coletadas em 49 pontos, de uma malha quadrada de 7x7, espaçados de 4x4 m, nas profundidades de 0-5 cm e 5-20 cm de solo. Os valores de Cu, Zn, Fe, Mn, B, matéria orgânica (MO) e argila do solo variaram nos diferentes tratamentos. Na profundidade de 0-5 cm, os valores de Cu, Mn, B, MO e argila foram maiores no sistema plantio direto. Os valores de Cu e de Zn apresentaram as maiores variabilidades, e os de MO e argila, as menores. Utilizando-se o procedimento de coletar 20 subamostras para formar uma amostra composta, os teores de argila, MO, B e Mn estariam sendo estimados com erro em torno de 10% do valor médio. Para o Cu e o Zn a variação em torno da média atingiu mais de 25%.

Influência de sistemas de preparo do solo na produtividade da mandioca (Manihot esculenta, Crantz)

Realizou-se este estudo no noroeste do estado do Paraná, durante os anos agrícolas de 1994/95 e 1996/97, para avaliar os efeitos de sistemas de preparo em algumas propriedades físicas e químicas de um Nitossolo Vermelho distrófico latossólico e na cultura da mandioca (Manihot esculenta, Crantz). Os tratamentos utilizados constituíram-se de três sistemas de preparo de solo: plantio direto; preparo mínimo (escarificação + gradagem niveladora) e preparo convencional (arado de aiveca + gradagem niveladora). O delineamento experimental utilizado foi o de blocos completos casualizados, com seis repetições. Na camada de 0-0,10 m, os maiores valores de macroporosidade foram obtidos com os sistemas de preparo mínimo e preparo convencional, enquanto o plantio direto apresentou os maiores valores de densidade do solo. O preparo mínimo propiciou as maiores concentrações de P disponível, de K+ e de Ca2+, bem como menor concentração de Mg2+, na camada de 0-0,05 m do solo. O teor de matéria orgânica do solo não sofreu influência dos sistemas de preparo. O preparo mínimo e o convencional propiciaram maior altura de plantas e maior produção de raízes tuberosas, nos dois anos de avaliação. Comparado aos outros sistemas de preparo, o plantio direto propiciou menores produtividades de parte aérea e de raízes tuberosas.