The role of Collembola for litter decomposition under minimum and conventional tillage

Ecosystem services driven by soil biota in agricultural landscapes - Effects of farm-based soil management practices

Status of humus in soil under various long-term tillage systems

The recent interest in the adoption of minimum tillage for crop production in the humid tropics for better soil and water conservation has raised questions concerning crop yield and nutrient absorption. There is lack of information on the most suitable method of P application with minimum tillage as compared to conventional tillage with tropical soils. The present study was therefore undertaken to investigate the interaction between soil tillage and P application methods on (a) P movement in the soil profile, (b) maize root distribution, (c) P content, and (d) maize yield.The experiment was conducted on Egbeda soil series (Oxic Paleustalf) in southern Nigeria in 1974 and 1975 using a split‐plot design with four replications. Conventional and minimum tillage were the main plots, P rates and placement were the sub‐plots.Root density of maize was increased with P application. There was a tendency of higher root concentration in the upper 10 cm of the soil surface with minimum tillage. Movement of broadcast P in the soil profile was observed to be slow with minimum tillage. However, broadcast, band, and hill methods of P application was observed to be equally effective in supplying adequate P to the maize crop at P rates of 20 kg P/ha on the Egbeda soil. Therefore, no effect of P placement method on maize yield was observed with both minimum and conventional tillage methods. The lower maize yield with minimum tillage in 1974 was attributed to early N‐ stress. In 1975 with 160 kg N/ha, maize yield was equal with conventional and minimum tillage methods.

Changes in root growth within successive wheat crops in a cropping cycle using minimum and conventional tillage

SUMMARYThe present study compared slug, earthworm and carabid beetle abundance and slug damage to plants in minimum tillage (MT) and conventional tillage (CT) autumn-sown cereals. Winter barley was sown by CT and MT for 3 years followed by winter wheat for 6 years on a light-textured soil (Trial 1). Each cultivation was split so that straw was incorporated into the soil during cultivation in one split while the other did not receive straw. A similar investigation with winter wheat, over the same period, was undertaken on a nearby heavy-textured soil (Trial 2). The effects of method of cultivation and soil incorporation of straw on slug abundance and damage, and on earthworm populations were measured. Additionally, at Trial 1, the effects of cultivation and straw treatments on carabid beetle occurrence were measured in years 5–9. Over the 9 years, the method of cultivation had a significant effect on slug numbers in each trial. Slugs were more numerous in MT than CT plots, significantly so in 3 of the 9 years in Trial 1 and in 5 years in Trial 2. In Trial 1, slug numbers were significantly greater on no-straw than straw plots in 3 years as well as for the 9 years combined. Slug numbers did not differ between straw and no-straw plots in Trial 2. Slug numbers varied significantly between years and were influenced by factors other than the method of cultivation and straw application. Slug damage to seed and seedlings was quite low in each year (1–2%). Slug damage to cereal leaves at GS 23 was widespread in both trials, and severe in some years. MT had more leaf damage than CT in 5 of the 9 years in each trial, significantly so in 3 years in Trial 1 and in 4 years in Trial 2. Straw did not affect leaf damage in either MT or CT. Slug damage was not related to, nor did it affect either ear density or grain yield. The dominant slug species wasDeroceras reticulatum.Earthworm numbers were significantly greater in MT than CT, for combined years, in each trial. Annually, these differences were significant for 5 years in Trial 1 and 2 years in Trial 2. Straw plots had significantly more earthworms than no-straw, for combined years, in each trial. The latter differences were significant for 5 years in Trial 1 and 3 years in Trial 2. In MT, the positive effect of straw on earthworm numbers was significant in Trial 2 but not in Trial 1. In CT, the latter effect was significant in each trial.Lumbricusspecies were more numerous in MT than CT and in straw than no-straw treatments. The impact of cultivation on numbers of carabid beetles was species-specific. The large beetle,Pterostichus melanarius, was significantly more numerous in MT than CT in 2 of the 5 years and for the aggregate of 5 years. Small carabids (Bembidionspecies andTrechus quadristriatus) were significantly more abundant in CT than MT in 3 of the 5 years as well as for the aggregate of 5 years. Straw did not affect the number of any or all carabid species either for combined cultivations (MT + CT) or within either MT or CT. It is concluded that MT increases slug numbers, slug damage and earthworm numbers relative to CT cultivations. MT favours large carabid beetles and CT favours small beetles. Straw incorporation increases earthworm numbers but not slugs, slug damage or carabid beetles. Slug damage to cereal leaves does not affect ear density or grain yield in either MT or CT crops when sown to a depth of 40 mm and before 18 September.

Sugarbeets (Beta vulgaris L.) are grown on intensively tilled-irrigated land in southern Alberta, which is subject to soil erosion by wind. Experiments were conducted on commercial fields near Burdett, AB, to determine the effect of the tillage system and previous crops on sugarbeet production. The previous crops were dry bean (Phaseolus vulgaris L.) or wheat (Triticum aestivium L.) and the tillage systems were conventional (moldboard plow, vibrashank cultivator, harrow, packer), minimum (double disc, self-cleaning harrow, glyphosate) or no tillage (glyphosate). After dry beans, sugarbeet fresh weight and extractable sugar yields were similar with all tillage systems. All of the tillage systems left less than 100 g m-2 of plant residue on the soil surface in the spring following dry beans, which is insufficient to protect the soil from wind erosion. After wheat, sugarbeet yields were similar with minimum and conventional tillage but lower with no tillage. Both minimum and no-tillage systems left sufficient plant residue on the soil surface to protect the soil from erosion (> 200 g m-2). Sugarbeet stand density following wheat was lower with no tillage than conventional or minimum tillage, reflecting poor seed placement and daily maximum soil temperature (5 cm depth) of up to 10°C lower under no tillage than conventional tillage. After wheat, there was a trend toward lower densities of hard-seeded annuals, such as redroot pigweed (Amaranthus retroflexus L.), after no tillage than conventional tillage. Of the cropping systems tested in this study, only the minimum tillage system after wheat provided optimum sugarbeet yield and left enough plant residue to protect the soil from wind erosion. Key words: Crop rotation, bean, wheat, sugarbeet, no-tillage

We investigated the difference of work performance and crop yield in the two transplanted paddy fields applied minimum tillage (MT) and conventional tillage (CT). The obtained results were as follows.Although travel reduction of transplanter in CT was higher than that in MT, transplanting did not effect on qualities of rice seedling in both MT and CT. From the survey on plant growth, there were significant differences in plant length, number of tiller and value of SPAD (Index of chlorophyll content in leaf). Kind of weeds in MT was more than that in CT and quantity of weeds in MT was much than that in CT. There was no clear difference of grain yield between in MT nad in CT.From the measurement of soil penetrating resistance, monotonous change was observed in CT, but distinctive change was observed in MT with the lapse of time. There was no clear difference of three phases of soil between in MT and in CT except for some measured values. There was no difference of contents of nitrogen and carbon between in MT and in CT.The total required work time in MT was 70% less than that in CT. Finally the sampling numbers of hill required in a survey on grain yield for MT were decided.

Effect of fertilizers and soil tillage on corn yield under dry farming and irrigated conditions

Crop yield and weed growth under conservation agriculture in semi-arid Zimbabwe

Tillage impacts on microbial biomass and soil carbon and nitrogen dynamics of corn and cotton rotations

Conservation tillage is often discussed as an effective tool to improve the soil quality in agriculture. Four sites across Europe (in Germany, Romania, Spain, and Sweden) were investigated as case studies for country-specific reductions in tillage intensity. Conventional tillage (CT) by mouldboard ploughing was compared with shallow and deep non-inversion minimum tillage (MT) and/or no-tillage (NT). In Sweden, NT and MT had positive effects on the concentrations of soil organic carbon (SOC), total nitrogen (N), and microbial biomass carbon (MBC) in the upper 20 cm compared with CT. At the German site, MT increased SOC, N, and MBC concentrations in the top 10 cm. In contrast, CT increased MBC contents and bulk density between 20 and 30 cm soil depth. At the Romanian site, soil parameters showed no differences between inverse tillage (CT) and non-inverse tillage (MT), both with a working depth of 25 to 30 cm. At the Spanish site, the use of NT significantly increased the concentrations as well as the stocks of C, N, and MBC compared to CT. In conclusion, reduced tillage improved soil microbial properties in most cases. However, the effectiveness of reduced tillage appears to be highly dependent on site conditions such as pH, soil texture, and climatic conditions.

Baixas produtividades e deficiências de nitrogênio coexistem na cultura do milho, sobretudo em sistemas voltados para a agricultura de subsistência. Diante disso, com esta pesquisa buscou-se avaliar os efeitos da utilização de diferentes adubos verdes em sucessão com o milho, sob manejo de cultivo mínimo e convencional, quanto ao aporte de nutrientes ao solo, ao estado nutricional e às características produtivas do milho para a produção de espigas. O experimento foi conduzido em campo, no Norte de Minas Gerais, em esquema de parcelas subdivididas com fatores dispostos no delineamento de blocos ao acaso, com três repetições. Os tratamentos principais foram: crotalária-juncea (Crotalaria juncea), feijão-de-porco (Canavalia ensiformes), nabo forrageiro (Rafhanus sativus), coquetel (crotalária, feijão-de-porco e nabo forrageiro) e plantas daninhas. As subparcelas foram constituídas pelos manejos da adubação verde, no cultivo mínimo ou convencional. Observou-se menor produtividade do milho quando da utilização do tratamento com plantas daninhas. De modo geral, foi identificado maior crescimento das plantas de milho no cultivo mínimo e maior estande no cultivo convencional, sem, contudo, efeito desses manejos na produtividade de espigas. Houve incremento nos teores superficiais de P e K no solo quando no manejo de cultivo mínimo, mas melhor balanço K/Mg nas plantas de milho no cultivo convencional.

Conservation tillage is increasing on the Canadian prairies and its long-term effect on soil physical properties warrants investigation. Tension infiltrometer measurements were conducted on conventional tillage (CT), minimum tillage (MT) and no-till (NT) loam to clay loam soils in southern Alberta to determine if 26 yr of conservation tillage (MT, NT) modified the unsaturated hydraulic conductivity, K(ψ), relative to CT. Tillage of CT and MT plots was performed using a wide-blade cultivator. Measurements were performed on tillage treatments that were replicated on two adjacent parcels of land, with readings taken at the west parcel (Site 1) in 1993 and at the east parcel (Site 2) in 1994. Infiltration rates were determined at water potentials (ψ) of −0.3, −0.6 and −1.5 kPa. The K(ψ) values at −0.3, −0.6, −1.0 and −1.5 kPa (equivalent circular pore diameters of 1000, 500, 300 and 200 µm, respectively) were estimated from infiltration data using the nonlinear regression method of Logsdon and Jaynes. Tillage had a significant (P < 0.10) effect on K(ψ). Geometric mean K(ψ) values for NT (12.8 × 10−8 m s−1) were significantly (P < 0.05) lower than for CT (21.9 × 10−8 m s−1), but there was no significant difference between MT (13.6 × 10−8 m s−1) and CT, or between MT and NT. Although there was no significant tillage × site-year interaction (P > 0.10) for K(ψ), there was a trend for higher K(ψ) values at −0.6, −1.0 and −1.5 kPa in CT than MT and NT for Site 1 in 1993 compared to Site 2 in 1994. This trend was consistent with a shorter lag time between the most recent tillage event and subsequent infiltration measurements in CT for Site 1 in 1993 (1–16 d) compared with Site 2 in 1994 (28–45 d). Key words: Tillage, tension infiltrometer, unsaturated hydraulic conductivity

SUMMARYWinter barley was sown by conventional-tillage (CT) and minimum-tillage (MT) cultivation over three seasons. Each cultivation treatment was split so that straw was incorporated into the soil during cultivation in one split, while the other did not receive straw. Aphid occurrences in autumn and incidence of barley yellow dwarf virus (BYDV) in spring were compared. Similar investigations on winter wheat were made over a further three seasons. The method of cultivation affected the number of aphids on barley and wheat plants in autumn and on wheat heads in summer; MT had fewest aphids. Soil incorporation of straw during cultivation had a similar effect. Method of cultivation affected the incidence of BYDV disease, with MT having least infection. Straw-treated cereal plots had fewer aphids and less BYDV than no-straw plots. Aphids and virus reached damaging levels only in the first barley crop. In this season, MT barley had significantly fewer aphids (48% fewer) and significantly less BYDV (71% less) than CT. Straw-treated plots within the CT system had rather similar aphid infestation and BYDV incidence as no-straw plots. Barley grown in the MT system with straw added had significantly fewer aphids (68%) than in the case when no straw was added. Overall, aphids in autumn were significantly fewer on MT relative to CT cereals in three of the six seasons and significantly fewer on straw relative to no-straw plots in two seasons. Aphids on wheat heads in summer were significantly fewer in MT relative to CT plots in one of the three seasons. Aphids on heads were also significantly fewer on straw-treated plots within each system of cultivation in two seasons, while MT wheat with straw had significantly fewer aphids/head than those without straw in one season. BYDV was lower each season in MT barley and wheat when compared with CT crops. These differences were significant for two of the three seasons in which each crop was grown. There was a lower incidence of virus in straw-treated plots than in no-straw plots. This effect was significant for one of the three seasons in which barley and wheat were grown. Plant and tiller density did not differ significantly between MT and CT barley either with or without straw incorporation. Plant density of wheat in autumn was significantly lower for straw-treated plots relative to no-straw plots in one season. Wheat head density was lower for MT relative to CT in one season, while MT with straw had significantly fewer heads than CT plots with straw in two seasons. BYDV significantly reduced grain yield only in 2001/02 when incidence of the disease was high. Grain yield in 2001/02 was 0·95 t/ha (16%) greater for MT barley, due to less BYDV, than for CT. Straw-treated CT barley outyielded no-straw plots by 0·45 t/ha, while the comparable value for the MT system was 0·3 t/ha. The combined effect of MT plus straw had a 1·24 t/ha (21%) yield advantage over CT without straw.It is concluded that MT cereals sown at the same time as CT crops in autumn have a lower risk of aphid infestation and BYDV infection than CT crops. The soil incorporation of straw further enhances the beneficial impact of MT in reducing aphids and virus.

Long-term (1983–2012) assessment of three tillage systems on the energy use efficiency, crop production and seeding emergence in a rain fed cereal monoculture in semiarid conditions in central Spain