Reduced Tillage Systems Research Articles

Tillage effects on soil microbial biomass, SOM mineralization and enzyme activity in a semi-arid Calcixerepts

Soil microbial properties are considered important indicators for assessing and comparing soil quality and degradation under tillage systems due to their early responses to environmental changes. The main objective of this study was to determine the medium-term (6 years) influence of tillage practices on soil microbial attributes in a semi-arid Calcixerepts from Central Iran with a similar plant residue input rate. The experiment was organized as a randomized complete block design with three replicates of each tillage regime. Tillage treatments consisted of moldboard and disk plows as conventional tillage (CT), and chisel and rotary plows as reduced tillage (RT) regimes over a period of six years (2005–2011). Soil microbial biomass carbon C (MBC) and nitrogen (MBN) contents, C (CMR) and N (NMR) mineralization rates; and urease, alkaline phosphatase (ALP) and catalase activities at the 0–20cm depth were determined only in 2008, 2009 and 2011. Less disturbed soils by both chisel and rotary plows under RT had higher MBC (25–43%), MBN (7–13%), MBC/MBN (17%) and enzyme activities (urease 2.0-fold, ALP 31–53% and catalase 18–59%) when compared with more disturbed soils by moldboard and disk plows under CT. In contrast, RT soils had lower microbial turnover rate (9–17%), metabolic quotient (qCO2, 37%), CMR (17–30%) and NMR (24–28%) than CT soils. However, the magnitude of the changes in soil MBC, MBN, CMR, NMR and catalase activity due to tillage effect were more greater during the later years of tillage implementation. The positive effect of RT practices on soil microbial biomass and enzyme activity was most likely due to improved environmental conditions, since soil organic matter (SOM) content was unaffected by tillage treatments. Soils under RT systems were characterized by a higher microbial biomass and enzyme activity, but development of less metabolically active microorganisms; most probably as a result of changes in the microbial community composition and lower microbial turnover rate. Furthermore, increased microbial enzyme production and biomass size with RT does not necessarily lead to higher microbial activity and SOM mineralization rate. It is suggested that the reduced SOM mineralization under RT is largely controlled by changes in the composition of microbial community and microbial turnover. In conclusion, microbial attributes were improved under RT after six years, and hence are regarded as early and sensitive indicators of changes in soil quality induced by tillage systems in this semi-arid environment.

Identification of soil quality indicators for assessing the effect of different tillage practices through a soil quality index in a semi-arid environment

Tillage is known to potentially affect soil quality in various ways. In this study, a soil quality index (SQI) was developed by quantifying several soil attributes either sensitive or insensitive to physical disturbance, using factor analysis as a dimension reduction technique, in order to discriminate different tillage systems. Soil properties including physical (MWD), chemical (pH, organic C, total N, available P and POM contents) and microbial (MBC, MBN, PCM, PNM and three enzymes) parameters were measured to establish a minimum data set (MDS) for the assessment of overall SQI. The soil attributes were determined on samples (0–20cm depth) collected under moldboard (MP) and disk (DP) plows as conventional tillage (CT), and rotary (RP) and chisel (CP) plows as reduced tillage (RT) systems with a similar plant C input rate and cover crop over a period of six years (2005–2011) in a semi-arid calcareous soil (Calcixerepts) from Central Iran. Results indicated a clear difference in soil quality among the tillage systems with a significant increase of SQI under RT over time, particularly under CP practices. Although RT improved most soil microbial attributes, not all attributes contributed to SQI because of their close interrelationship. The final SQI consisted only of geometric mean of microbial activity (GMA, the square root of the product of PCM and PNM) and geometric mean of enzyme activity (GME, the cube root of the product of enzyme activities). Soil GME and GMA were found to be as key indicators contributing 55% and 36% to SQI, respectively. Therefore, the GME and GMA were the most important indicators effectively discriminating tillage systems, and could be used to monitor the enhancement of soil quality under RT in this semiarid environment. The influence of tillage year on SQI was greater than that of tillage practices. In conclusion, RT systems were characterized by a higher value of SQI, suggesting a good recovery of soil capacity and functions after abandoning CT in the studied area. Smallholder farmers should therefore be aware of the potential for high soil quality in future as a result of continuing RT systems, especially with surface tillage using CP practices.

Effects of reduced tillage and fertilizer application method on plant growth, yield, and soil health in organic bell pepper production

Concerns over soil erosion and nitrate leaching have generated interest in cover crop-based reduced tillage systems. A 2-year field study was conducted in Ames, IA in 2013–14 and 2014–15 to compare cover crop-based no tillage (NT) and strip tillage (ST) with conventional tillage (CT) in production of organic bell pepper (Capsicum annuum L.). Two fertility treatments – preplant fertilizer only, or application split between preplant and post-planting fertigation – which applied the same amount of total N (90kgha−1), were also evaluated. The experimental design was a split plot randomized complete block design with tillage as the whole plot (NT, ST, or CT) and fertility as the subplot treatment (preplant or split). A mixture of cereal rye and hairy vetch was seeded in September 2013 and September 2014 in all plots. The cover crop was terminated in mid-May using tillage in CT plots and in early June using a roller-crimper in NT and ST plots. Data were collected on plant growth, yield, soil temperature and moisture, weed suppression, nitrate leaching, and microbial biomass and diversity. Marketable yields were equal among tillage treatments in 2014, but higher for CT in 2015, with no difference between NT and ST. Preplant fertility increased yield in 2014, but yields were lower in the preplant fertility treatment in 2015. Leaf N concentration was higher in CT than NT and ST, but plant height, stem diameter, and dry weight were similar across all treatments. Soil temperature was generally highest for CT and higher in ST than NT in one out of three instances. Soil moisture was unaffected by tillage in 2014, but was higher under NT and ST from June to late-August in 2015. The rolled cover crop mulch in NT and ST plots effectively suppressed annual weeds during period between planting and the first weeding event, reducing weed biomass and density compared to CT. Nitrate-N concentration in leachate was reduced under NT and ST only during early sampling dates in 2014. Soil microbial biomass and diversity were similar among tillage treatments on most sampling dates, but consistently higher in the 0–7.5-cm than the 7.5–15-cm soil profile. Results indicate the potential for NT and ST yields to be comparable to CT, but temperature and nitrogen may limit yield under some circumstances. Though observed only periodically in this study, benefits of cover crops and reduced tillage to soil health and water quality make organic NT and ST systems promising in addressing current environmental concerns in agriculture.

Effects of Arkansas Cotton Production Systems on Soil Strength

Abstract. In recent years, many Arkansas cotton producers have adopted conservation tillage, often including winter cover crops, to improve soil quality and prevent erosion. However, no-till and reduced tillage systems do not allow the frequent tillage that has historically been used to help alleviate deep soil compaction problems in this region. To better understand the effect of tillage system on soil compaction, a three-year experiment was conducted in eastern Arkansas to compare effects of the following three tillage systems on soil strength: conventional tillage, no-till, and reduced tillage with a cover crop. A soil probe was used annually after cotton harvest to obtain a full set of cone index (CI) and electrical conductivity (EC) data at five locations across the row, with six replications of each plot x row position combination. Soil moisture for each treatment was determined from soil cores collected at two depths. First-year CI values indicated possible root-limiting conditions below the 30-cm depth in all treatments, but were greater in no-till and cover crop treatments than in conventional-tillage plots. However, tillage treatment showed very little effect on CI in the second year, and no-till treatments had the lowest overall CI values in the third year, regardless of row position, indicating the no-till system gradually decreased compaction in the soil profile at 20-cm depths and below. Although relatively high CI values were still detected from the surface down to a 20-cm depth in all treatments, cotton lint yields did not indicate that soil compaction caused any severe restriction on cotton root growth. Furthermore, these high CI values were shallow enough in the no-till system that in-row chiseling or strip-till that does not disturb more than 30% of the soil surface may be a viable option for decreasing soil compaction if it begins to limit crop production in these systems.

Nutrient concentration and yield of maize (Zea mays L.) after vetch (Vicia sativa L.) in conventional and reduced tillage systems

ABSTRACTThe effects of tillage on plant availability nutrients are critical to develop nutrient management strategies to optimize yield. The objective of this study was to evaluate differences in the concentration of 19-nutrient and yield after 4-year of conventional [moldboard plough (MT)] and two reduced [rototiller (ST) and chisel (CT)] tillage systems in maize (Zea mays L.) after winter vetch (Vicia sativa L.) in double crop one year. Three tillage systems were compared from 2005 to 2008 in area located in the western region of Turkey under semi-arid Mediterranean clay-loam soils. Nutrients were determined in maize leaves, stems, roots and soils. Results show that the concentration of macronutrients were found to be higher in leaves and stems of maize than roots in three tillage systems of all years, while the opposite was true for micronutrients. Among the macro and micro-nutrients, there was no effect of tillage on nutrient concentration in all maize tissues for sulfur, magnesium, sodium and copper (S, Mg, Na and Cu). However, the nitrogen, potassium, calcium, boron, zinc, manganese, iron, aluminum, barium, cadmium, cobalt, chromium, nickel, lead and selenium (N, K, Ca, B, Zn, Mn, Fe, Al, Ba, Cd, Co, Cr, Ni, Pb and Se) were affected by tillage. ST increased N in stems of 2006 compared with other systems. K in roots of 2006 was 52 and 30% greater in CT than in ST and MT, respectively, while ST and MT of 2007 resulted in 38 and 41% greater than CT. In two of four years, ST contributed to higher grain yield compared with other systems. In general, ST can effectively contribute to increase maize yield following winter vetch compared with MT under this region. Results suggested the need for different management systems associated with reduced tillage including rotation, particularly for basic nutrients. Further, results showed similarities and differences with other studies under tillage with maize following winter vetch.

Effect of sugarcane cropping systems on herbicide losses in surface runoff

Herbicide runoff from cropping fields has been identified as a threat to the Great Barrier Reef ecosystem. A field investigation was carried out to monitor the changes in runoff water quality resulting from four different sugarcane cropping systems that included different herbicides and contrasting tillage and trash management practices. These include (i) Conventional – Tillage (beds and inter-rows) with residual herbicides used; (ii) Improved – only the beds were tilled (zonal) with reduced residual herbicides used; (iii) Aspirational – minimum tillage (one pass of a single tine ripper before planting) with trash mulch, no residual herbicides and a legume intercrop after cane establishment; and (iv) New Farming System (NFS) – minimum tillage as in Aspirational practice with a grain legume rotation and a combination of residual and knockdown herbicides.Results suggest soil and trash management had a larger effect on the herbicide losses in runoff than the physico-chemical properties of herbicides. Improved practices with 30% lower atrazine application rates than used in conventional systems produced reduced runoff volumes by 40% and atrazine loss by 62%. There were a 2-fold variation in atrazine and >10-fold variation in metribuzin loads in runoff water between reduced tillage systems differing in soil disturbance and surface residue cover from the previous rotation crops, despite the same herbicide application rates. The elevated risk of offsite losses from herbicides was illustrated by the high concentrations of diuron (14μgL−1) recorded in runoff that occurred >2.5months after herbicide application in a 1st ratoon crop. A cropping system employing less persistent non-selective herbicides and an inter-row soybean mulch resulted in no residual herbicide contamination in runoff water, but recorded 12.3% lower yield compared to Conventional practice. These findings reveal a trade-off between achieving good water quality with minimal herbicide contamination and maintaining farm profitability with good weed control.

Investigation of soils of stubbles of winter wheat and winter peas in conventional and reduced tillage systems

The effect of reduced and conventional tillage on soil compaction, soil moisture status and carbon-dioxide emission of the soil was studied on a meadow chernozem soil with high clay content in the soil cultivation experiment started in 1997 at Karcag Research Institute. Our investigations were done on stubbles after the harvest of winter wheat and winter peas after the very droughty vegetation period of 2014/2015.
 We established that the soil in both tillage systems was dry and compacted and the CO2-emission was very low. The positive effects of reduced tillage could be figured out only in the soil layer of 40–60 cm in the given weather conditions of that period.

Rainfall risk and the potential of reduced tillage systems to conserve soil water in semi-arid cropping systems of southern Africa

Improvement of household food security in the Limpopo Basin has been elusive due to a combination of factors related to information and market constraints, but also farmers’ risk aversion induced by the high variability of rainfall during the growing season. The purpose of this study was to (1) characterize the rainfall and growing season patterns experienced by smallholder farmers, and (2) measure soil water dynamics in ripper and basin tillage systems being promoted in the semi-arid Limpopo Basin of southern Africa. The results show that the second half of the growing season receives more rainfall than the first half in the Limpopo Basin. However, rainfall is more variable during the January-March than the October-December period. Growing seasons start earlier and end later in the Mozambique part of the basin which is closer to the Indian Ocean. The Limpopo Basin is prone to two and three week dry spells with chances of 14 day spells higher (34–42%) than the 21 day spells (8–12%). The chances of 14 and 21 day dry spells increase substantially during the second half of the growing season. The 1980–1990 was one of the driest decades in the Limpopo Basin. Planting basin system conserved more soil water on sandy loam (18–24%) and clay loam (4–12%) soils than the conventional practice during flowering and grain filling maize growth stages. Ripper had 17–29% more soil water than conventional practice during flowering and grain filling maize growth stages. There is a high risk of dry spells and soil water deficits in smallholder cropping systems of the Limpopo basin. There is therefore scope in promoting rain and soil water management technologies, and good land husbandry in order to reduce risk of crop failure in the smallholder cropping systems.

Dissolved Nitrogen, Chloride, and Potassium Loss from Fields in Conventional and Conservation Tillage

Losses of soluble nutrients from cropland and their transport to surface and groundwater are a continuing water quality concern. In this study, we evaluated tillage impacts on dissolved losses of ammonium (NH4-N), nitrate nitrogen (NO3-N), chloride (Cl), and potassium (K) during rotational cotton and peanut production. Tillage treatments were strip tillage (ST), in which crops were planted into 15 cm strips tilled into cover crop residue mulch, and conventional tillage (CT), in which all crop residues were turned into the soil prior to planting. Winter cover crops were used in both tillage systems. Tillage and irrigation treatments were uniformly applied within two 0.6 ha fields located on a moderately sloping hillslope in the southern Atlantic Coastal Plain region of south-central Georgia. Tile drains were installed at the base of the slope of each field to capture and measure lateral subsurface flow. Each field was subdivided into three 0.2 ha plots, with the three plots making up a single tillage block. H-flumes were used for flow measurement and sample collection. During the five-year study, annual precipitation ranged from 910 to 1488 mm, with an annual average of 1201 mm. Annual surface runoff averaged 17% of annual rainfall from the CT field and 11% from the ST field. Because of relatively low variability in concentrations, surface runoff loads closely tracked surface runoff volumes. Annual surface runoff loadings of NH4-N, NO3-N, and Cl from the ST treatment were found to be significantly less than those from the CT treatment. The total five-year load of N (NH4-N and NO3-N) in surface runoff from CT was 8.3 kg ha-1, while it was 5.6 kg ha-1 from ST, equivalent to 1.5% of the total N applied to CT and 1.0% of that applied to ST. Annual subsurface flow averaged 12% of annual precipitation for CT and 21% for ST. Annual average subsurface flow loadings of NH4-N, NO3-N, and K from ST were significantly greater than from CT. The total five-year load of N (NH4-N and NO3-N) in subsurface flow was 45 kg ha-1 from CT and 99 kg ha-1 from ST, equivalent to 8.3% and 18.4% of the total N applied to CT and ST, respectively. Data showed that subsurface flow was the primary hydrologic pathway for dissolved N and Cl loss in both tillage systems. Overall, ST was found to be an effective method for reducing surface runoff and associated soluble losses, but increased infiltration with this practice significantly increased subsurface losses. This introduces a challenge to nitrogen management in reduced tillage systems such as ST in the region.

Long‐term effect of different tillage systems on the emergence and demography of Bromus diandrus in rainfed cereal fields

SummaryThe adoption of no‐tillage systems in semi‐arid cereal fields in northern Europe has resulted in difficulties in controlling Bromus diandrus. However, in some fields, lower densities are observed in continuous long‐term no‐tillage management than in other reduced tillage systems. A cumulative effect on the seedbank could promote changes in the period of seedling emergence and in population demography. This study evaluated the effect of long‐term mouldboard plough (MbP), chisel plough (ChP), subsoiler (SS) and no‐tillage (NT) on the population dynamics of B. diandrus. The work was carried out in a barley (Hordeum vulgare)–wheat (Triticum aestivum)–barley rotation during three seasons where these soil management systems had been applied for the last 22 years. Cumulative emergence (CE) and densities of B. diandrus followed a gradient of ChP > SS > NT > MbP. This cumulative effect over time resulted in significant differences in population demography. A previous hydrothermal emergence model developed for this species estimated the percentage of emergence prior to the date of sowing to be: 71%, 92% and 53% for the seasons 2008–2009, 2009–2010 and 2010–2011 respectively. Furthermore, the reduction in CE observed was on average 53% in SS, 92% in NT and 98% in MbP in comparison with that recorded in ChP. The long‐term effect of different tillage systems tended to cause changes to soil characteristics (photo‐inhibition of germination, soil temperature, water availability) affecting B. diandrus demography, reaching equilibrium in weed densities over years, which were significantly lower in MbP and NT than in ChP or SS.

Weed suppression by green manure in an agroecological system

ABSTRACT Green manure promotes efficient suppression of weeds, but green manure species can exhibit distinct behaviors, depending on the environmental conditions. This study aimed to evaluate the potential of soil mulching and weed suppression by spring/summer green manure species grown in the spring/summer season, at different growth stages and after management (cut), for 90 days during the cassava crop cycle. The study was carried out in the 2010/2011 season, in a system managed under agroecological principles. The treatments consisted of different green manure species and arrangements: Crotalaria juncea, Cajanus cajan, Canavalia brasiliensis, Canavalia ensiformis, Pennisetum americanum, Crotalaria juncea and Pennisetum americanum intercropped; Mucuna aterrima, Sorghum bicolor, a mixture of all the green manures in study and a control plot under fallow. The experiment was arranged in a randomized block design with four replications. The evaluations of the soil cover either by the green manures or weeds were performed at 45, 90 and 105 days after the emergence of the green manures. The cassava crop was planted under reduced tillage system at 11 days after the cut of the green manures. The percentage of soil covered by weeds and the dry matter produced were evaluated at 30, 60 and 90 days after planting. The results showed that the green manures had a suppressive effect on weeds during their life cycle, as well as during the first months after its management (cut), composing the mulch.

Long-term effect of tillage systems, straw and green manure combinations on soil organic matter

Nowadays the priority in agriculture is given to the soil tillage systems which enable reduction of organic matter decomposition. Our investigation was aimed to assess the long-term impact of reduced intensity tillage systems, straw and green manure combinations on soil organic matter quantity and quality. Since 1999, a long-term field experiment has been done at the Experimental Station of Aleksandras Stulginskis University (former Lithuanian University of Agriculture) at 54o52′50′′ N latitude and 23o49′41′′ E longitude. The results presented in this paper were obtained in the 12 th and 14 th years of investigations. The soil of the experimental site is Epieutric Endocalcaric Endogleyic Planosol. Continuous long-term (12 and 14 years) straw application increased soil organic carbon (SOC) content by 9.3% and 12.0% compared with the plots without straw. Reduced tillage systems without primary tillage (shallow rotovating before sowing, catch cropping for green manure with rotovating, no-tillage) were even more effective. Compared with conventional ploughing, SOC increased by 19.4% to 33.9%. These tillage systems increased soil quality too, since SOC stratification ratio between 0–10 and 10–20 cm layers increased by 1.14 till 1.21. Reduced tillage systems with primary tillage (shallow ploughing and shallow loosening) had no effect both on SOC and stratification process in the soil. SOC pools over the experimental years tended to increase by 9.3% and 11.6% in the treatments of long-term application of straw compared with the plots without straw. Notillage and catch cropping for green manure with rotovating compared with conventional ploughing significantly increased the pools of organic carbon by 31.7% to 33.3% in the plots without straw and by 28.9% to 32.7% in the plots with straw. Continuous straw application increased the quantity of mobile humus substances by 22.7% compared to the plots without straw. Straw in combination with catch crop for green manure incorporation and rotovating and no-tillage increased mobile humus substances by 53.2% and 58.8% compared with conventional ploughing. Only long-term application of straw increased the quantity of mobile humic acids by 40.6% compared with the plots without straw. The rate of mobile humic acids from total amount of mobile humus substances in the treatments without straw amounted to 39.8%, while with straw this content increased to 45.6%. Reduced tillage systems without primary tillage had no significant effect on mobile humic acids but tended to increase soil organic matter quality.

Soil physical quality in contrasting tillage systems in organic and conventional farming

Reduced tillage can improve soil physical quality relative to mouldboard ploughing by lessening soil disturbance, leaving organic matter at the soil surface, and stimulating soil biological activity. In organic farming, continuous ploughing may negate benefits to soil structure and function from increased use of manures and more diverse crop rotations, which are particularly important components of organic farming. The current study examined soil physical quality (i.e., properties and functioning) of a 4-year old reduced tillage system under organic and conventional farming with crop rotations that included root crops. Reduced tillage was compared to conventional mouldboard ploughing (MP) in 2 organic fields at different points of the same crop rotation (Org A and Org B) and 1 conventional field (Conv A). Reduced tillage consisted of non-inversion tillage (NIT) to 18–23cm depth whereas MP was characterised by annual mouldboard ploughing to 23–25cm depth. NIT improved soil water retention in Org B but had no effect in Org A. NIT increased soil aggregate stability at 10–20cm depth compared to MP in all fields, and additionally at 0–10cm in Conv A. Penetration resistance was higher in NIT in all fields. Furthermore, soil organic matter content was higher in NIT than MP at 0–10cm depth in all fields and at 10–20cm in Org B and Conv A. NIT increased carbon stocks in Org B but not in Org A. NIT statistically increased crop yields in spring wheat/faba bean mixture in Org A, and there was no yield penalty from NIT in Org B spring wheat nor Conv A sugar beet. In contrast, field-saturated hydraulic conductivity in all fields in autumn was lower in NIT. Differences in crop (i.e., phase of rotation) and associated organic inputs between Org A and B likely accounted for the differences in effects of tillage system. Overall, the NIT system improved or imposed no penalty on soil physical quality (except field-saturated hydraulic conductivity) and improved or imposed no penalty on crop yields and could therefore be considered as a viable alternative for farmers.

The main physical properties of planosol in maize (Zea mays L.) cultivation under different long-term reduced tillage practices in the Baltic region

The impact of sustainable reduced tillage (RT) on the physical properties of soil is well documented worldwide; however, there is no precise information about the influence of long-term RT or no-till (NT) on the soils at the boundary for grain maize-growing in the semi-humid subarctic climate conditions of the Baltic states, especially on the formation of a hard-ened upper soil layer (10–15 cm in depth) — “loosening hardpan”. This study was carried out at the Research Station of Aleksandras Stulginskis University, Lithuania from 2009–2012. The investigations were based on a long-term (since 1988) field experiment. The aim of the investigation was to ascertain the influence of reduced primary tillage on the main soil's physical properties. This study examined soils that were deep ploughing (DP), shallow ploughing (SP), deep cultivation (DC), shallow cultivation (SC), and no-till (NT). Reducing the tillage intensity to NT had no significant effect on the structural soil's composition; however, the stability of the structure of the >1 and >0.25 mm-size fractions was significantly higher in the non-reversibly tilled (DC, SC) and NT plots. The penetration resistance of the DP soils was less after primary tillage and wintering, and became similar to the NT plots at the end of the maize growth season. After primary tillage and wintering, the soil moisture content in the upper soil layer (0–5 cm depth) of the NT plots was 17–49 and 16–18% higher than that in the DP. Long-term reduction of primary tillage up to NT generally had no significant effect on the moisture content and soil bulk density of the 0–10 and 10–20 cm layers. The results showed that long-term RT stabilized the physical quality of soil. Less soil penetration resistance was established in the DP plots compared to both RT and NT, however, indicators of the formation of a uniform “loosening hardpan” layer were not found. It is summarized that long-term RT or NT systems stabilize, or may increase, the physical quality of soil in crop cultivation with low inter-row coverage potential (maize), and could be applied in semi-humid subarctic climate conditions as a good option to prevent soil degradation.

Effect of different tillage methods on the nutritional status, yield and quality of sugar beets

Optimal nutrition of sugar beets at critical growth stages is one of the crucial factors for the achievement of their highest yield potential. In the present study, it was presumed that reduced systems of sugar beet cultivation had no effect on the plants’ nutritional status at critical growth stages, on their yield or technological quality. In 2012-2013, two series of one-factorial field experiments with different beet crop husbandry were carried out in order to verify this hypothesis. The cultivation systems of sugar beet crops differed in the postharvest cultivation technology, mulch types and seedbed tillage. Conservation tillage systems were compared with the control treatment, which represented the conventional cultivation system with an application of manure and 35 cm deep autumn ploughing. The plant nutritional status assessment was carried out at two dates corresponding to the following growth stages: BBCH 16/17 (6-8 fully unfolded true leaves) and BBCH 39/40 (row closing). Regardless of the methods of tillage or the year of observation, the results showed that the plants at BBCH16/17 stage were well-nourished with macroelements but malnourished with microelements, mainly iron and zinc. The microelement deficiency in the plants was a result of adjusted soil reaction, which varied from slightly acidic to neutral. At the BBCH 39/40 stage, there was a decreasing trend in the content of leaf macronutrients in the no-tillage systems treatments compared to the conventional tillage with the ploughing depth to 35 cm and manure application. The reduced tillage systems in sugar beet cultivation did not result in either a yield decrease or a worse technological quality of roots. The experimental factor had no significant effect on the content of molassegenic compounds in beet roots. A decreasing trend was observed in the content of α-amino nitrogen and potassium when compared to the traditional cultivation system. The study showed that the choice of a cultivation technology is of secondary importance as long as the plant grows in optimal conditions resulting from an appropriate site selection.

Impact of Location, Cropping History, Tillage, and Chlorpyrifos on Soil Arthropods in Peanut.

Demand for agricultural production systems that are both economically viable and environmentally conscious continues to increase. In recent years, reduced tillage systems, and grass and pasture rotations have been investigated to help maintain or improve soil quality, increase crop yield, and decrease labor requirements for production. However, documentation of the effects of reduced tillage, fescue rotation systems as well as other management practices, including pesticides, on pest damage and soil arthropod activity in peanut production for the Mid-Atlantic US region is still limited. Therefore, this project was implemented to assess impacts of fescue-based rotation systems on pests and other soil organisms when compared with cash crop rotation systems over four locations in eastern North Carolina. In addition, the effects of tillage (strip vs. conventional) and soil chlorpyrifos application on pod damage and soil-dwelling organisms were also evaluated. Soil arthropod populations were assessed by deploying pitfall traps containing 50% ethanol in each of the sampled plots. Results from the present study provide evidence that location significantly impacts pest damage and soil arthropod diversity in peanut fields. Cropping history also influenced arthropod diversity, with higher diversity in fescue compared with cash crop fields. Corn rootworm damage to pods was higher at one of our locations (Rocky Mount) compared with all others. Cropping history (fescue vs. cash crop) did not have an effect on rootworm damage, but increased numbers of hymenopterans, acarina, heteropterans, and collembolans in fescue compared with cash crop fields. Interestingly, there was an overall tendency for higher number of soil arthropods in traps placed in chlorpyrifos-treated plots compared with nontreated controls.

Guidelines of Sustainable Soil Tillage System in Croatia (Contribution to Sustainable Land Management in 2015 - International Year of Soils)

Within soil degradation processes soil erosion is on the first place, as consequence of improper land man-agement, first of all soil tillage system and practices. Results of 10 years (1995-2004) of our investigation (investigation endure now 21st year) show guidelines in tillage practices. At first; traditional tillage practiced in this agricultural region up/down the slope on Stagnogley on slopes of 9 % and more is unsustainable in growing of row crops-maize and soybean, because of disastrous or extreme soil erosion. But, in growing of crops of high density, like wheat this practice is sustainable. On the other side, No-tillage and contour tillage resulted in much lower water erosion in comparison with up/down the slope tillage. At the beginning of experiment in the first two years No-tillage as system was not sustainable. Stabilization of yields of growing crops on the level which is statistically the same or higher than on other tillage treatments on notillage plot started after ten years of no-tillage practice. These investigations suggest the conclusion that high density crops like winter wheat, spring barley and oilseed rape are relatively suitable crops for growing under reduced tillage systems. Soybean tolerates no-till practices in climatically favourable years, but with higher risk in dry years. Maize was shown as a very risky crop without tillage even in climatically average years. We agree with assertion of Solbrig [1] that no tillage is a process, a new philosophy and way of thinking in arable farming of Europe, and not a technology.

Effects of tillage, cultivar and fungicide on Phomopsis longicolla and Cercospora kukuchii in soybean

It has become a standard practice for farmers to use a no-till production system where crop residues are left on the soil surface rather than incorporated into the soil. This practice helps reduce soil erosion, conserve energy, increase soil moisture, and reduce erosion. However, many plant pathogens survive in the previous year's crop residue, increasing disease risk in reduced-tillage systems. The effect of tillage on seed borne diseases has not been objectively evaluated in side by side comparisons of till and no-till culture. We evaluated the impact of tillage and foliar fungicide on percent seed infection by Phomopsis Seed Decay (PSD) and Purple Seed Stain (PSS) over 4 years at the Milan Research and Education Center, Milan, TN. Analysis of variance indicated there was no significant difference (P≤0.05) in PSD and PSS infection due to tillage. However, there was a significant interaction between fungicide and tillage where fungicide significantly reduced PSD in tilled but not in no-till plots. On the contrary, PSS increased in both tilled and no-till plots with fungicide application. These results suggest that fungicide programs under both till and no-till systems may alter the level of severity of these two seed borne diseases and may require further research to minimize the risk.

Tillage and Cover Cropping Affect Crop Yields and Soil Carbon in the San Joaquin Valley, California

Rising costs and air quality regulations have created interest in California's San Joaquin Valley (SJV) in production systems that reduce tillage operations and soil disturbance. From 1999 to 2009, we evaluated conventional (CT) and reduced tillage (RT) systems for a cotton (Gossypium hirsutum L.)/tomato (Solanum lycopersicon Mill.) rotation with (CC) and without (NO) cover crops in a Panoche clay loam soil (fine‐loamy, mixed, superactive, thermic Typic Haplocambid) in Five Points, CA, in terms of yield, soil C, and the NRCS soil conditioning index (SCI). The RT reduced tractor operations by 50% for tomato and 40% for cotton. Cover cropping produced 38.7 t ha−1 of biomass. Tomato yields were 9.5% higher in RT vs. CT systems and 5.7% higher in NO vs. CC systems. The CT cotton yields were 10.0% higher than RT yields and 4.8% higher in NO systems, but yield patterns were not consistent from 2005 to 2009. Soil C content was uniform (0–30‐cm depth) in 1999 (19.72 t ha−1) and increased in all systems in 2007 (t ha−1): RTCC 29.11, CTCC 26.36, RTNO, 24.09, and CTNO 22.65. Soil C content of RT and CT systems did not differ, but was greater in CC than in NO systems. In the 0‐ to 15‐cm depth, RT increased soil C, indicating stratification, and also increased C in the occluded light and mineral fractions. The SCI was positive for RT treatments, predicting a soil C increase, and negative for CT systems, predicting a soil C decline, but measured soil C content increased in all systems. Results show that RT maintains or increases yields relative to CT, and CC stores more soil C than NO.

Evaluation of monocropped and intercropped grain legumes for cover cropping in no-tillage and reduced tillage organic agriculture

Intensive tillage by means of mouldboard ploughing can be highly effective for weed control in organic farming, but it also carries an elevated risk for rapid humus decomposition and soil erosion. To develop organic systems that are less dependent on tillage, a two-year study at Reinhardtsgrimma and Köllitsch, Germany was conducted to determine whether certain legume cover crops could be equally successfully grown in a no-till compared with a reduced tillage system. The summer annual legumes faba bean (Vicia faba L.), normal leafed field pea (Pisumsativum L.), narrow-leafed lupin (Lupinus angustifolius L.), grass pea (Lathyrus sativus L.), and common vetch (Vicia sativa L.) were examined with and without sunflower (Helianthus annuus L.) as a companion crop for biomass and nitrogen accumulation, symbiotic nitrogen fixation (N2 fixation) and weed suppression. Total cover crop biomass, shoot N accumulation and N2 fixation differed with year, location, tillage system and species due to variations in weather, inorganic soil N resources and weed competition. Biomass production reached up to 1.65 and 2.19Mgha−1 (both intercropped field peas), and N2 fixation up to 53.7 and 60.5kgha−1 (both common vetches) in the no-till and reduced tillage system, respectively. In the no-till system consistently low sunflower performance compared with the legumes prevented significant intercropping effects. Under central European conditions no-till cover cropping appears to be practicable if weed density is low at seeding. The interactions between year, location, tillage system and species demonstrate the difficulties in cover crop species selection for organic conservation tillage systems.