Plow Tillage Research Articles

Glyphosate Efficacy of Different Salt Formulations and Adjuvant Additives on Various Weeds

In many crops, weeds are managed by herbicides, mainly due to the decrease in crop yields and farmers’ incomes caused by them. In general, chemical control of weeds is considered to be an easy, relatively cheap, and highly effective method. However, not all weeds can be successfully controlled, either because of their natural tolerance or their herbicide resistance. Glyphosate is one of the most widely used herbicides in the world. It can manage effectively a broad spectrum of weeds, and promotes conservation agriculture by significantly reducing conventional plough tillage. Unfortunately, its extensive use has led to the evolution of glyphosate resistance, which has evolved into a major problem for global crop production. Alternative herbicides are, in some cases, available, but they do not usually control certain weeds as efficiently as glyphosate. The transmission of herbicides to the target site is a complex process, and consists of several stages. Each herbicide is affected and can be manipulated by the product formulation for the optimization of its use. Many experiments have confirmed that different glyphosate salts and adjuvant additives are instrumental in the optimization of herbicide absorption and delivery processes. The objective of this paper is to provide a brief overview of these experiments and summarize the literature related to the effect of various glyphosate formulations and adjuvants on weed control. Determining the differences among formulations and adjuvants may lead to the further optimized long-term use of glyphosate.

Long-term tillage and nitrogen fertilization: Consequences for nitrifier density and activity

Nitrification is the biological oxidation of NH3 to NO2− and then NO3−. Understanding soil management consequences for nitrifier ecology could improve nitrogen (N) fertilizer use, decrease NO3− leaching, and minimize NO and N2O emissions. This study examined how long-term N fertilization and tillage influenced nitrifier density, ratios, and nitrification rate. The study site had > 40years of continuous maize (Zea mays L.) with three nitrogen fertilization rates (0, 168, and 336kgha−1) and either no-tillage or plow tillage. The Most Probable Number (MPN) method was used to estimate the cell density of ammonia-oxidizing (AOB) and nitrite-oxidizing (NOB) bacteria and the shaken slurry method was used to measure potential nitrification rates. Tillage, fertilization, and their interaction significantly influenced the ammonia oxidizer and nitrite oxidizer cell densities and the potential nitrification rate. Nitrifier cell densities increased with increased nitrogen fertilization; nitrite oxidizer density increased more than ammonia oxidizer density leading to a decreasing AOB:NOB ratio. There were positive correlations between ammonia oxidizer and nitrite oxidizer cell densities, especial in plow tillage. The trends for nitrifier cell density and potential nitrification rate were not consistent. Fertilization increased ammonia oxidizer and nitrite oxidizer densities and potential nitrification rate, but the influence of tillage differed for different fertilization rates. This long-term field trial demonstrated that specific soil management practices differentially influence not only the cell density of nitrifiers, but their relative ratios and their response to increased inorganic nitrogen in the environment.

Soil Hydraulic Properties: Influence of Tillage and Cover Crops

Understanding the effects of cover crops and tillage on soil physical properties is important for determining soil productivity. This study was conducted at Lincoln University's Freeman Center, USA to evaluate the effects of tillage and cover crop management on soil hydraulic properties. The field site included three replicate blocks in a randomized complete block design with each plot measuring 21.3 m in length and 12.2 m in width. Treatment factors were tillage at two levels (moldboard plow tillage vs. no tillage) and cover crop at two levels (cereal rye (Secale cereal) cover crop vs. no cover crop). Soil samples were collected in late spring/early summer from each treatment at 10-cm depth increments from the soil surface to a depth of 40 cm using cores (76.2-mm diameter and 76.2-mm length). Soil bulk density was 13% lower with tillage compared with no-tillage. Volumetric water content was significantly higher at 0.0 and −0.4 kPa pressures with tillage compared with no tillage. Tillage increased the proportion of coarse mesopores by 32% compared with no tillage, resulting in 87% higher saturated hydraulic conductivity (Ksat). Cover crop increased the proportion of macropores by 24% compared with no cover crop; this can potentially increase water infiltration and reduce runoff. As a result of higher macroporosity, Ksat was higher under cover crop compared with no cover crop. This study demonstrated that tillage can benefit soil hydraulic properties in the short term, but these effects may not persist over time. Cover crops may slightly improve soil hydraulic properties, but longer term studies are needed to evaluate the long-term effects.

Straw return and appropriate tillage method improve grain yield and nitrogen efficiency of winter wheat

AbstractStraw return is an important management tool for tackling and promoting soil nutrient conservation and improving crop yield in Huang-Huai-Hai Plain, China. Although the incorporation of maize straw with deep plowing and rotary tillage practices are widespread in the region, only few studies have focused on rotation tillage. To determine the effects of maize straw return on the nitrogen (N) efficiency and grain yield of winter wheat (Triticum aestivum L.), we conducted experiments in this region for 3 years. Five treatments were tested: (i) rotary tillage without straw return (RT); (ii) deep plowing tillage without straw return (DT); (iii) rotary tillage with total straw return (RS); (iv) deep plowing tillage with total straw return (DS); (v) rotary tillage of 2 years and deep plowing tillage in the 3rd year with total straw return (TS). Treatments with straw return increased kernels no. ear−1, thousand-kernel weight (TKW), grain yields, ratio of dry matter accumulation post-anthesis, and nitrogen (N) efficiency whereas reduced the ears no. ha−1 in the 2011–2012 and 2012–2013 growing seasons. Compared with the rotary tillage, deep plowing tillage significantly increased the grain yield, yield components, total dry matter accumulation, and N efficiency in 2013–2014. RS had significantly higher straw N distribution, soil inorganic nitrogen content, and soil enzymes activities in the 0–10 cm soil layer compared with the DS and TS. However, significantly lower values were observed in the 10–20 and 20–30 cm soil layers. TS obtained approximately equal grain yield as DS, and it also reduced the resource costs. Therefore, we conclude that TS is the most economical method for increasing grain yield and N efficiency of winter wheat in Huang-Huai-Hai Plain.

Quantitative soil profile-scale assessment of the sustainability of long-term maize residue and tillage management

Both surface and subsoil layers can be a significant source of soil moisture and nutrients for crop growth, but the changes in subsoil properties due to management are rarely assessed. This study was conducted to determine tillage and residue management effects on soil nutrient availability, as well as soil biological and physical conditions throughout soil layers ranging from 0 to 60cm. We utilized an experiment with 40-year long continuous maize (Zea mays L.) cropping under crossed plow-till (PT) vs. no-till (NT) and residue removed (Harv) vs. residue returned (Ret) treatments on a silt loam soil in Chazy, NY. We assessed soil properties that are indicative of soil processes important for crop growth. Soil physical indicators (texture, bulk density (BD), water stable aggregation (WSA), available water capacity (AWC), and air-filled porosity (AFP)), soil biological indicators (soil organic matter (SOM), permanganate oxidizable carbon, mineralizable carbon, and soil protein), and soil chemical indicators (pH and plant available nutrients) were measured at five depth increments (0–6, 6–18, 18–30, 30–45, and 45- to 60-cm depth). A novel statistical approach of marginal R2 (R2m) was used to show percent variance of each measured soil indicator explained by tillage and residue management as well as the depth of soil sample. R2m was higher for soil biological indicators (0.66<R2m<0.91), compared to AWC and those nutrients that are not applied through fertilizer application (0.11<R2m<0.53). NT-Ret showed the highest concentration of majority of the measured soil nutrients, and higher accumulation of SOM related properties across depths. This was partly explained by favorable soil physical conditions indicated by BD, WSA, and AFP at the transition layer (18- to 30-cm depth) that allowed for the vertical exchange of soil water, nutrients, and SOM related properties between the topsoil and the subsoil layers. The PT treatments showed the absence of SOM transfer across the transition layer, whereas NT-Harv showed nutrient depletion at the transition and subsoil layers. This study revealed significant alteration of soil biological, chemical, and physical indicators depending on the treatment combinations, which can be ignored if surface sampling is solely used. Benefits of residue return appear more significant when combined with no-till for 1) providing better soil physical conditions and 2) maintaining adequate nutrient availability across a soil profile especially when considering subsoil properties.

Tillage and crop residue effects on the energy consumption, input–output costs and greenhouse gas emissions of maize crops

Improving energy use efficiency (EUE) is critical for increasing farmers’ incomes, developing sustainable agriculture, and mitigating greenhouse gas (GHG) emissions. However, data on EUE, net income, and GHG emissions across various tillage and crop residue (straw) treatments remains scarce. This study aimed to estimate these variables across different tillage and straw treatments used in summer maize production in a winter wheat-summer maize cropping system in China’s Loess Plateau. Tillage treatments included chisel plowing, no tillage, and moldboard plowing. These were studied both with straw returned to the soil, or removed. All activities and production processes were recorded. The results demonstrate that fertilizer especially nitrogen fertilizer, and to a lesser extent, the fuel used for tillage, sowing and harvesting, were the two major consumers of energy and producers of GHG emissions. These results indicated that the use of chisel plow or conducting no tillage with straw returned to the soil, can reduce energy consumption and GHG emissions, and improve the economic benefits of summer maize production in the region, compared with conventional moldboard plow tillage without straw (which is typically burned off). The results show that further improvements could be facilitated by improving the utilization of nitrogen fertilizer, returning straw to the soil, and reducing tillage. These practices can reduce GHG reductions, and improve EUE and farmers’ incomes.

Effects of long-term tillage practices on the quality of soil under winter wheat

These studies were done in 2013–2016 on the effects of two tillage systems on the quality of a loamy sand soil (Eutric Fluvisol) and were based on a field experiment started in 2002. Winter wheat was grown in conventional tillage (CT) with mouldboard ploughing (inversion) tillage; and reduced (non-inversion) tillage (RT) based on soil crushing-loosening equipment and a rigid-tine cultivator. Chopped wheat straw was used as mulch in both treatments. The physical, chemical and biological properties of the soil were investigated. RT increased soil bulk density in the 0–5 cm and 5–10 cm depth layers in comparison with CT. The greatest content of soil organic carbon (SOC) was found in the 0–5 cm layer under RT. The BIOLOG EcoPlate System showed that soil under RT had a greater metabolic activity and diversity of microbial communities than soil under CT. RT improved the quality of the surface soil as shown by the greater content of SOC and microbial activity measured in terms of dehydrogenases. However, the mean yields of winter wheat under RT and CT were similar. This suggests that the effects of increased bulk density (BD) on yield can be compensated by the effects of the improved microbial status.

Effects of tillage practices on photosynthetic performance diurnal variation during filling stage and grain yield of winter wheat

Photosynthesis characteristics of winter wheat under different tillage practices during fil-ling stage are vital for dry matter accumulation, transfer, and yield development. A field experiment, including no-till with residue removal (NT), no-till with residue retention (NTS), rotary tillage with residue removal (RT), rotary tillage with residue retained (RTS), subsoiling with residue removal (DT), subsoiling with residue retained (DTS), plow tillage with residue removal (CT), and plow tillage with residue retained (CTS) was conducted at Wuqiao experimental station of China Agricultural University since October 2008. The diurnal variation of photosynthetic characteristics of flag leaf, photosynthetic response curve, and crop yield under different tillage practices were evaluated during winter wheat filing stage in this study. The results showed thatthe net photosynthetic rate and stomatal conductance of flag leaf both diurnally varied with the bimodal curve, and the net photosynthetic rates were higher under treatments with residue retained than those under with residue removal. Diurnal variation of intercellular carbon dioxide concentration was observed with a "V-shaped wide mouth" bimodal curve under all treatments. Daily transpiration rate exhibited "double peak curve", except for the "single peak curve" under DTS, RTS and RT. The stimulated net photosynthetic rate was increased by 20.0%, 21.7%, 19.7%, 21.5%, 0.8%, 12.1% and 4.2% under NT, DT, RT, CT, CTS, RTS, and CTS, compared with DTS, respectively. Photosynthetic response curves were fitted better under treatments with residue retained than under treatments with residue removal. As for crop grain yields, the highest one was observed under DTS, following by RTS and CTS, and the lowest under CT. Crop grain yield was increased by 10.8%, 1.3%, 2.1%, 5.4%, 11.9%, 12.4%, and 12.6% under DTS, compared with NTS, RTS, CTS, NT, DT, RT, and CT, respectively. Thus, residue retaining under different tillage practices (e.g. NTS and DTS) could mitigate the mid-day depression of photosynthesis, maintain a high photosynthetic rate of winter wheat, and improve the dry matter accumulation and crop production.

Yield, Weed Infestation and Seed Quality of Soybean Glycine max L. Merr. under Different Tillage Systems

Soybean is a very valuable crop plant and the soybean crop area is continually increasing in the world and in Poland. The effectiveness of soybean cultivation depends on soil and climatic conditions as well as on appropriate tillage. An alternative for plough tillage in the cultivation of soybean is to grow this crop using no-tillage, the popularity of which is constantly growing. The aim of this study was to compare the effect of conventional tillage (CT) and no-tillage (NT) on yield, weed infestation and qualitative seed composition of soybean grown under the conditions of the Lublin Upland. A field study was carried out over the period 2009-2012 at the Czeslawice Experimental Farm (51° 18′ 23″ N, 22° 16′ 2″ E). The experiment was set up on loess-derived grey-brown podzolic soil as a split-block design in four replicates. The experimental factors were the following tillage systems: conventional tillage (CT) and no-tillage (NT). The soybean cultivar Nawiko was grown in the experiment. The present study showed that the soybean seed yield obtained under CT was higher by 24.3% than under NT. The main reason of the seeds yield decrease in the NT was less soybean plant density. The significant higher number and weight of weeds were recorded in NT, relative to CT. The oil content in seed harvested from the NT plots was found to be higher by 0.3%.

Strip-tillage reduces productivity in organically managed grain and forage cropping systems in the Upper Midwest, USA

AbstractTillage is decreasing globally due to recognized benefits of fuel savings and improved soil health in the absence of disturbance. However, a perceived inability to control weeds effectively and economically hinders no-till adoption in organic production systems in the Upper Midwest, USA. A strip-tillage (ST) strategy was explored as an intermediate approach to reducing fuel use and soil disturbance, and still controlling weeds. An 8-year comparison was made between two tillage approaches, one primarily using ST the other using a combination of conventional plow, disk and chisel tillage [conventional tillage (CT)]. Additionally, two rotation schemes were explored within each tillage system: a 2-year rotation (2y) of corn (Zea mays L.), and soybean (Glycine max [L.] Merr.) with a winter rye (Secale cereale L.) cover crop; and a 4-year rotation (4y) of corn, soybean, spring wheat (Triticum aestivum L.) underseeded with alfalfa (Medicago sativa L.), and a second year of alfalfa. These treatments resulted in comparison of four main management systems CT-2y, CT-4y, ST-2y and ST-4y, which also were managed under fertilized and non-fertilized conditions. Yields, whole system productivity (evaluated with potential gross returns), and weed seed densities (first 4 years) were measured. Across years, yields of corn, soybean and wheat were greater by 34% or more under CT than ST but alfalfa yields were the same. Within tillage strategies, corn yields were the same in 2y and 4y rotations, but soybean yields, only under ST, were 29% lower in the fertilized 4y than 2 yr rotation. In the ST-4y system yields of corn and soybean were the same in fertilized and non-fertilized treatments. Over the entire rotation, system productivity was highest in the fertilized CT-2y system, but the same among fertilized ST-4y, and non-fertilized ST-2y, ST-4y, and CT-4y systems. Over the first 4 years, total weed seed density increased comparatively more under ST than CT, and was negatively correlated to corn yields in fertilized CT systems and soybean yields in the fertilized ST-2y system. These results indicated ST compromised productivity, in part due to insufficient weed control, but also due to reduced nutrient availability. ST and diverse rotations may yet be viable options given that overall productivity of fertilized ST-2y and CT-4y systems was within 70% of that in the fertilized CT-2y system. Closing the yield gap between ST and CT would benefit from future research focused on organic weed and nutrient management, particularly for corn.

Comparison of conventional and conservation rice-wheat systems in Punjab, Pakistan

Adoption of resource conservation technologies such as direct seeded aerobic rice (DSAR) and no-till wheat (NTW) seems to be a farmer and ecofriendly option to sustain the productivity of rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping systems (RWCS) on long term basis. This study was conducted to evaluate the impact of conventional and conservation rice-wheat cropping systems on soil properties, grain yield, and water/system productivities established at two experimental sites (Nankana Sahib and Sheikhupura). There were two rice production systems viz. DSAR, and puddled transplanted flooded rice (PudTR). After rice harvest, wheat was planted after plough tillage (PTW) or through no-till. The study was repeated over time and space. At both sites, higher total nitrogen (N), soil organic carbon (SOC), soil microbial biomass carbon (MBC) and soil microbial biomass nitrogen (MBN) were recorded in DSAR than PudTR. The DSAR yielded 3.8Mgha−1, against 3.6Mgha−1 in PudTR at Sheikhupura, while the similar paddy yield of 4.2Mgha−1 was harvested in DSAR and PudTR at Nankana Sahib. Overall, the adoption of DSAR saved 19% water compared with PudTR. Net benefits of US $729 and 601ha−1 were obtained from DSAR, against US $604 and 403ha−1 in PudTR, at Nankana Sahib and Sheikhupura, respectively. The highest water productivity of 3.01 and 3.43kgha−1mm−1 was recorded in DSAR compared to 2.41 and 2.50kgha−1mm−1 in PudTR at Nankana Sahib and Sheikhupura, respectively. The performance of wheat was better when grown after DSAR than PudTR for both experimental sites during both years. The higher total N (0.32gkg−1), SOC (3.75gkg−1), soil MBC (165μgg−1) and soil MBN (611.4μgg−1) were recorded for DSAR-NTW at both sites. The system productivity (output: input ratio) was 1.89 for DSAR-PTW at Nankana Sahib, and 1.87 for DSAR-NTW at Sheikhupura. In conclusion, DSAR followed by NTW was the best resource conservation technology to sustain the productivity of RWCS, and improve the net profit and the soil properties.

Tillage, mulch and fertiliser impacts on soil nitrogen availability and maize production in semi-arid Zimbabwe

Conservation agriculture has been promoted widely in sub-Saharan African to cushion smallholder farmers against the adverse effects of soil fertility decline, stabilize crop yields and increase resilience to climate change and variability. Our study aimed to determine if aspects of CA, namely tillage and mulching with manure and fertiliser application, improved soil mineral N release, plant N uptake and maize yields in cropping systems on poor soils in semi-arid Matobo, Zimbabwe. The experiment, run for three seasons (2012/13–2014/15), was a split-split plot design with three replicates. Tillage (animal-drawn ploughing and ripping) was the main plot treatment and residue application was the sub plot treatment with two levels (100% residues removed or retained after harvest). Five fertility amendments (mineral fertiliser at 0, 20 and 40kgN ha-1, 5tha-1 manure only and 5tha-1 manure+20kgNha-1) were sub-sub plot treatments. Plough tillage stimulated N mineralisation by 4–19kgNha-1 and maize N uptake 13–23% more than the ripper tillage. When mulch was added to the plough tillage, mineralisation was slowed resulting in less crop N uptake (by 5–19%) compared with no mulch application. N uptake was highest in the manure treatments. N recovery and agronomic N efficiency by maize were highly variable over the three seasons, reflecting the uncertainty complicating farmers’ decision making. Nitrogen recovery in the manure treatments was generally poor in the first season resulting in low grain yields in the range 100–260kgha-1 regardless of tillage, though higher in subsequent seasons. In the second season manure application gave the largest grain yields under the ripper tillage, both with and without mulch averaging 1850 and 2228kgha-1 respectively. Under the plough tillage, the 40kgNha-1 treatment gave the highest grain yields of 1985kgha-1. In the third season yields were generally poor under all treatments due to low and poorly-distributed rainfall. The CA principles of minimum soil disturbance and maintenance of a permanent mulch cover resulted in reduced soil mineral N availability for crop uptake and poor maize yields. Nutrient inputs through mineral fertilisers and manure are key to ensuring production in such infertile, sandy soils which predominate in semi-arid regions of southern Africa.

Modeling soil organic carbon in corn ( Zea mays L.)-based systems in Ohio under climate change

Soil organic carbon (SOC) is a key indicator of soil quality. Knowledge of the effects of land management and climate change on SOC stocks is of vital importance in creating future sustainable land use systems. This study presents both the promise and current challenges of modeling SOC in mineral soils under climate change. Soils data from two long-term agricultural research sites in Ohio under no-till (NT) and plow-till (PT) management, the RothC soil C model, and climate data from the Canadian Regional Climate Model were used to project future SOC content in agricultural soils using low-emissions (LE) and high-emissions (HE) climate change scenarios. It was hypothesized that from 2015 to 2070, SOC levels in soils under NT management in Ohio will show increasing trends under the LE scenario, decreasing trends in NT under the HE scenario, and decreasing trends in PT under both scenarios, with lower levels of SOC for both treatments under the HE scenario. The results of this study projected total SOC content in the topsoil layers (0 to 25 cm [0 to 10 in] at Wooster and 0 to 23 cm [0 to 9 in] at Hoytville) to decrease at all sites and under all management and climate projections, with the exception of NT at Wooster and Hoytville and PT at Wooster under the LE scenario. Starting at 32.4 Mg C ha⁻¹ (14.5 tn C ac⁻¹) in 1962 at Wooster, by 2070, soil under NT management is projected to have 45.4 and 32.1 Mg C ha⁻¹ (20.3 and 14.3 tn C ac⁻¹) for LE and HE scenarios, respectively, while PT management starting at 31.5 Mg C ha⁻¹ (14.1 tn C ac⁻¹) would have 29.4 and 21 Mg C ha⁻¹ (13.1 and 9.4 tn C ac⁻¹) for LE and HE scenarios, respectively. Starting at 65.2 Mg C ha⁻¹ (29.1 tn C ac⁻¹) in 1963 at Hoytville, by 2070, soil under NT management would have 65.9 and 51 Mg C ha⁻¹ (29.4 and 22.8 tn C ac⁻¹) for LE and HE scenarios, respectively, and PT starting at 63.5 Mg C ha⁻¹ (28.3 tn C ac⁻¹) would have 36.9 and 28.7 Mg C ha⁻¹ (16.5 and 12.8 tn C ac⁻¹) for LE and HE scenarios, respectively.

Functional Predictions of Microbial Communities in Soil as Affected by Long‐term Tillage Practices

Core Ideas Microbial function is important but difficult to assess in soil. An omics‐driven tool, PICRUSt, was used to characterize functions of soil microbial communities. No‐tillage compared with plow tillage was functionally enriched for most nutrient cycles. Many other functions integral to soil health can be explored by the PICRUSt omics approach. Soil microbial communities affect the soil's biological, chemical, and physical properties, but there is still a knowledge gap regarding the long‐term impact of tillage practices on soil microbial dynamics. Additionally, the accurate identification of belowground microbial functions is a topic of active interest. In this study, microbial community profiles and functions in soil from a 50‐plus‐year‐old experiment in Ohio, representing one of the world's longest running comparisons of a plow‐tillage system and a continuous no‐tillage system, were compared. The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) algorithm was used to predict associated functional traits from 16S rRNA gene sequences. Analysis of the sequences revealed a large number of unidentified operational taxonomic units (67%), which is consistent with expectations of the soil ecosystem. Next, we investigated gene and enzyme predictions for nitrogen, sulfur, and methane metabolism and hydrocarbon degradation in soil. Results indicated that no‐tillage was functionally enriched for most nutrient cycles. This study has allowed us to predict distinct functional profiles as a result of legacy land uses. It serves as an example of improved analysis of the functional differences in soil managed by long‐term tillage versus no‐till.

Crop yields under no-till farming in China: A meta-analysis

Abstract No-till (NT) farming is popular globally, however, the effects on crop yields remain debatable. A meta-analysis was conducted on crop yield responses to NT in China based on 1006 comparisons from 164 studies. Results showed that a decrease of 2.1 ± 1.8% on crop yield was observed under NT with residue removed (NT0) compared with that under plow tillage with residue removed (PT0), but the decreases can be diminished to 1.9 ± 1.0% when residue retention was combined with both the two tillage practices. On the contrary, NT with residue retention (NTR) may significantly increase crop yields by 4.6 ± 1.3% compared with that under PT0 (P

Changes in soil organic carbon during 22 years of pastures, cropping or integrated crop/livestock systems in the Brazilian Cerrado

In Brazil’s central savanna region, government policy is to encourage the conversion of conventional plough tillage (PT) agriculture to no-till (NT) and raise the productivity of under-utilized pastures, including their conversion to integrated crop-livestock (ICL) systems, with the objective of increasing soil organic carbon (SOC) at the expense of atmospheric carbon dioxide. An experiment was established in 1991 by liming and fertilizing at two levels an area of native vegetation (NV). The treatments, replicated in randomized plots, included pastures, continuous cropping and ICL systems under PT or NT. The aim of this study was to quantify the SOC accumulation to 100 cm depth under these treatments over time. The high C:N ratios suggested that there was a high proportion of charcoal present in the soil. Increasing fertilizer inputs had no overall significant effect on SOC stocks. Stocks of SOC changed little under pastures. Analyses of 13C abundance showed that higher fertilizer inputs increased the decomposition rate of C derived from NV under pure grass pastures. Continuous cropping under NT preserved SOC and under PT there were significant losses. The highest SOC stocks were found under ILP treatments, but not all ILP treatments accumulated SOC even under NT. These results indicate that government initiatives to substitute PT with NT and to intensify beef cattle production will have only modest short-term gains in SOC accumulation.

Effect of tillage practices on net carbon flux and economic parameters from farmland on the Loess Plateau in China

It is important to evaluate the effect of tillage practices on carbon flow and economic parameters in order to better understand soil carbon sequestration and mitigation of carbon release into the atmosphere, and to increase income for farmers. A 2-year field experiment was conducted in a winter wheat-summer corn rotation system on dryland farmland on the Loess Plateau in Northwest China with four treatments; zero tillage with straw mulching (zero tillage), rotary tillage with straw incorporation (rotary tillage), chisel plow tillage with straw incorporation (chisel plow), and conventional mouldboard plow tillage without crop straw (conventional tillage). Results showed that zero tillage reduced carbon emissions, mainly through reduction of emissions from tillage practices, and served as a net carbon sink, as did rotary tillage and chisel plow, while conventional tillage served as a net carbon source. Specifically, zero tillage reduced carbon emissions from farm inputs by 168.8 and 75.0 kg C ha−1 yr−1 compared with conventional tillage and rotary tillage (or chisel plow), respectively. The difference in annual rate of carbon sequestration between 2013 and 2015 was 1.21-fold higher with zero tillage than with conventional tillage, suggesting zero tillage released less CO2 and was therefore better able to mitigate against global warming. Chisel plow significantly (P < 0.05) improved net return values by 10.7%–63.2% in the 2013-14 cropping year and by 12.8%–93.7% in the 2014–15 cropping year, respectively when compared to other tillage treatments. Zero tillage was the most effective method for reducing carbon inputs and increasing carbon sequestration, and chisel plow was the best option for provision of economic parameters on dryland farmland in this region. Therefore, the application of conservation (zero, rotary and chisel plow) tillage could be a C-smart and effective economic agricultural practice for winter wheat-summer corn ecosystems under rain fed condition.

English

The aim of this study was to assess the decomposition rate of crambe straw under different soil management practices based on no-tillage system. The experiment was carried out at the experimental area of the Agronomic Institute of Parana - IAPAR, regional center of Santa Tereza do Oeste, Parana, Brazil. Treatments consisted of four soil management practices: Traditional No-tillage System - TNTS – Chisel Plowing Tillage System - CPTS – No-tillage System with Application of Gypsum - NTSG - and Quality No-tillage System - QNTS. The treatments were distributed in randomized order in parts subdivided on time with fifteen macro-plots of 20 m x 25 m. The assessments took place on 0 (zero), 7, 15, 30, 60, 90, and 120 days after crambe crop harvest. Decomposition was determined quantitatively through the analysis of the decomposition rate of crop residues using litter bags. Average loss of crambe phytomass was significantly different (p>0.05), mainly for CPTS and NTSG, around 0. 63% day-1 and 0. 71% day-1, respectively. The longest half-life period (66 days) was observed on QNTS with bristle oat and white lupin consortium, and the shortest half-life period (45 days) was observed on CPTS. Key words: Crambe abyssinica, litter bags, half-life period.

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.

Redistribution of Soil Organic Carbon Triggered by Erosion at Field Scale Under Subhumid Climate, Hungary

Soil organic carbon (SOC) has primary importance in terms of soil physics, soil fertility and even of climate change control. One hundred soil samples were taken from an intensively cultivated Cambisol to quantify SOC redistribution triggered by soil erosion under a subhumid climate, by the simultaneous application of diffuse reflectance (240–1 900 nm) and traditional physico-chemical methods. The representative sample points were collected from the solum along the slopes at the depth of 20–300 cm with a mean SOC content of 12 g kg−1. Hierarchical cluster analyses were performed based on the determined SOC results. The spatial pattern of the groups created were similar, and even though the classifications were not the same, diffuse reflectance had proven to be a suitable method for soil/sediment classification even within a given arable field. Both organic and inorganic carbon distributions were found to be a proper tool for estimations of past soil erosion processes. The SOC enrichment was found on two sedimentary spots with different geomorphological positions. Soil organic matter composition also differed between the two spots due to selective deposition of the delivered organic matter. The components with low-molecular-weight reached the bottom of the slope where they could leach into the profile, while the more polymerised organic matter compositions were delivered and deposited even before on a higher segment of the slope in an aggregated form. This spatial difference appeared below the uppermost tilled soil layer as well, referring the lower efficiency of conventional ploughing tillage in soil spatial homogenisation.