Effect of Different Tillage Systems on Soil Organic Carbon and Enzymatic Activity

The aim of the study was to compare the effect of conventional, simplified, and organic farming systems on changes in the content of soil organic carbon, organic matter fractions, total nitrogen, and the enzymatic activity. The research was conducted from 2016–2018 on arable land in the south-eastern part of Poland. The selected soils were cultivated in conventional tillage (C_Ts), simplified tillage (S_Ts), and organic farming (O_Fs) systems. The analyses were performed in soil from the soil surface layers (up to 25 cm depth) of the experimental plots. The highest mean contents of soil organic carbon, total nitrogen, and organic matter fractions were determined in soils subjected to the simplified tillage system throughout the experimental period. During the study period, organic carbon concentration on surface soil layers under simplified tillage systems was 31 and 127% higher than the soil under conventional tillage systems and organic farming systems, respectively. Also, the total nitrogen concentration in those soils was more than 40% and 120% higher than conventional tillage systems and organic farming systems, respectively. Moreover, these soils were characterised by a progressive decline in SOC and Nt resources over the study years. There was no significant effect of the analysed tillage systems on the C:N ratio. The tillage systems induced significant differences in the activity of the analysed soil enzymes, i.e., dehydrogenase (DH) and catalase (CAT). The highest DH activity throughout the experiment was recorded in the O_Fs soils, and the mean value of this parameter was in the range of 6.01–6.11 μmol TPF·kg−1·h−1. There were no significant differences in the CAT values between the variants of the experiment. The results confirm that, regardless of other treatments, such as the use of organic fertilisers, tillage has a negative impact on the content of SOC and organic matter fractions in the O_Fs system. All simplifications in tillage reducing the interference with the soil surface layer and the use of organic fertilisers contribute to improvement of soil properties and enhancement of biological activity, which helps to maintain its productivity and fertility.

Zero Tillage, Residue Retention and System-Intensification with Legumes for Enhanced Pearl Millet Productivity and Mineral Biofortification

Pearl millet-based cropping systems with intensive tillage operations prior to sowing have limited sustainable productivity in the low-irrigation conditions of semi-arid farming ecologies, such as those in the north Indian plains. The adoption of improved management practices such as zero tillage with residue retention (ZTR) and diversification with the inclusion of summer pulse crops has the potential to improve cropping system sustainability. Therefore, an experiment was designed to compare two improved management practices, zero tillage (ZT) and ZTR, to conventional tillage (CT), across three pearl millet-based cropping systems: pearl millet–chickpea (PM–CP), PM–CP–mungbean (MB), and PM–CP–forage pearl millet in a two-year experiment. Experimental treatments were compared in terms of pearl millet productivity, mineral biofortification, and greenhouse gas emissions. Results showed a significant increase in pearl millet yield attributes, grain and stover productivity, nutrient uptake, and micronutrient biofortification in the PM–CP–MB cropping system under ZTR relative to other treatment combinations. On-farm evaluation at different locations also showed that the intensification of PM–CP system using summer crops enhanced pearl millet productivity across diverse tillage systems. Overall, zero tillage practices combined with diversified pearl millet-based cropping systems are likely to be management practices, which farmers can use to sustainably maintain or increase cropping system productivity in the various semi-arid areas of the world.

Nitrogen storage in density and size fractions varied with tillage practices and cropping systems under residue return

Residue return can prevent or restore the degradation of cropland, meanwhile, additional N input from residue return inevitably result in the changes of soil nitrogen (N) pools. Our objectives were to evaluate these changes in a 16-year field experiment. The residue return experiment consisted of no-tillage (NT) and mouldboard plough (MP), combined with continuous maize (Zea mays L.) (MM) and maize-soybean (Glycine max Merr.) rotation (MS) cropping systems, that is, NTMM, NTMS, MPMM, MPMS; conventional tillage (removal of crop residue and deep plough) with continuous maize (CTMM) was included as a control. The soil was separated into density (LF, light fraction) and particle size (sand, silt and clay) fraction. In 0-5 cm and 5-10 cm layers, soil TN content in NT was higher than MP, whereas the opposite trend was observed in 10-20 cm. Thus, the stratification ratio of soil TN was greater under NT. Cropping system affected soil TN as MM > MS. Residue return increased soil N storage by 6.44%-24.85% in the plough layer. Taking CTMM as the baseline, NTMM and MPMM increased the N storage in all physical fractions, while the decrease of silt-N storage was observed in NTMS and MPMS. Under residue return, the distribution of N storage changes in LF and sand fraction was affected by tillage practice, and that in silt and clay fraction was affected by cropping system. In summary, NTMM is effective for soil N accumulation due to its highest N storage and all physical fractions of N storage was enhanced.

Conservation agriculture in the southern highlands of Tanzania: learnings from two decades of research for development.

Since its introduction into the Southern Highlands of Tanzania by researchers 25 years ago, Conservation Agriculture (CA) has been well received, researched and the concept proven to be increasing productivity and incomes, enhancing resilience of livelihoods and contributing to reducing greenhouse gas emissions. CA research, as defined by the three interlined principles, was introduced into the Southern Highlands by the Tanzania Agricultural Research Institute (TARI) Uyole, formerly Agricultural Research Institute (ARI) Uyole around 1995. Research results showed a labour saving of up to 70% in CA compared to conventional tillage, yield increases of 26%-100% and 360% for maize and sunflower, respectively, partly attributed to higher moisture content (18%-24%) in CA systems. CA was also found to be much more effective in mitigating dry spells and increasing productivity in maize production in areas where average annual rainfall is less than 770 mm. Economic analysis of maize production showed that profits in CA were three times more than in conventional tillage production at US$526.9 ha-1 and US$ 176.6 ha-1, respectively. Profits were twice as much for beans under CA at US$917.4 ha-1 compared to US$376.3 ha-1 for conventional practice. Studies confirm that 5% of farmers in the Southern Highlands have adopted CA. Increased uptake requires addressing challenges including resistance to change in mindset, inaccessibility of appropriate mechanization and cover crop seeds, traditions of free-range communal grazing of livestock (which makes it difficult for farmers to retain crop residue in their farms) and shortage of investment capital. A holistic value chain approach is recommended in CA interventions, bringing together various stakeholders including scientists, trainers, extension workers, administrators, policy makers, agro-inputs and machinery dealers, machinery service providers, agro-processors and financial institutions. The innovations adaptation set-up brings service providers closer to farmers for co-innovation. Long-term CA programmes are recommended, with farmers being taken through the complete learning cycle in testing CA technologies under their own farm environments. This should be complemented by entrepreneurial CA machinery hire services provision to increase the availability of farm power to smallholders unlikely to have the capital or skills to buy and manage their own machinery. The proof of application of the CA concept in the Southern Highlands has set the stage for further scaling the adoption of CA through support from national policies and programmes.

A Multivariate Approach to Evaluate Reduced Tillage Systems and Cover Crop Sustainability

The evaluation of the effects of conservation agriculture during the transition from conventional tillage to no-tillage requires numerous indicators to be considered. For this purpose, we monitored changes in a multi-parameter dataset during a three-year experiment that combined three tillage intensities (conventional tillage—CT; minimum tillage—MT; and no tillage—NT) with three soil covering managements (tillage radish cover crop, winter wheat cover crop and bare soil). Using a multivariate analysis, we developed a Relative Sustainability Index (RSI) based on 11 physical (e.g., bulk density and penetration resistance), chemical (e.g., soil organic carbon and pH) and biological soil properties (e.g., earthworm density) to evaluate cropping systems sustainability. The RSI was most affected by tillage intensity showing higher RSI values (i.e., better performances) in reduced tillage systems. Specifically, the RSI under NT was 42% greater than that of CT and 13% greater than that of MT. Soil covering had little impact on the RSI. Among the tested parameters, the RSI was increased most by saturated hydraulic conductivity (+193%) and earthworm density (+339%) across CT and NT treatments.to. Our results suggest that conservation agriculture and, particularly, reduced tillage systems, have the potential to increase farm environmental and agronomic sustainability.

Mineral Uptake, Total Polyphenols and Total Flavonoids of Barley as Affected by Tillage Practices under Semi-Arid Conditions

Aims: Conservation agriculture has been recommended as an option to mitigate climate change impact when practicing conventional, to ensure sustainability and food security This study examined the effect of conventional tillage (CT) and no tillage (NT) on mineral elements uptake, total phenolic content (TPC) and total flavonoid content (TFC) of barley. Study Design: Split-plot design was applied for this study. Place and Duration of Study: The experiment was conducted in ESAK station (Boulifa, kef, North West Tunisia) during 2016/2017 cultivation year. Methodology: Mineral elements uptake, total phenolic content (TPC) and total flavonoid content (TFC) of barley were studied as affected by conventional tillage (CT) and no tillage (NT) for tillering and grain filling stages. Results: The results showed that tillage practices (T) had no significant effect on mineral uptake, total phenolic content and total flavonoids content under rainfed conditions. The stage (S) had showed significant effects on P, Ca and Na amounts for both tillage practices when it had no effect on K amount. The interaction T x S had no significant effect on mineral elements concentrations and TFC. However, this interaction had affected TPC significantly. Phosphorous (P) showed high significant positive correlations with Ca and Na. In addition, P presented high significant negative correlations with TPC and TFC. For partial correlation based on Tillage practices, similar correlations values were noted. Considering the partial correlation based on plant stages, no significant correlations had been noted. Conclusion: This work enlarges our knowledge on barley mineral elements uptake, TPC and TFC as influenced by tillage practices aiding decision makers in increasing no tillage adoption in Tunisia under rainfed conditions.

Contribution of land use practices to GHGs in the Canadian Prairies crop sector

The global crop sector is estimated to contribute about 10.4% of global GHGs annually. The Canadian crop sector is assessed as adding about 6.5% to total national emissions. These estimates over report the impact of farming as they ignore the complex interaction of cropping with the environment and the role land use, land use change and forestry (LULUCF) play in sequestering carbon. This study quantifies the contribution of land use to GHG emissions and removals in the Canadian Prairies crop sector between 1985 and 2016. The modeling effort explores how different farming practices (i.e., conventional tillage (CT), minimum tillage (MT), zero tillage (ZT), summerfallow, crop rotations, and residue retention) and input usage rates (i.e., fertilizer and fuel) affect GHG emissions in different soil climate zones and provinces in the Prairies region. The adoption of sustainable practices led to an 80% decline in GHG emissions in the crop sector between 1985 and 2016. Since 2005, the baseline for Canada’s Paris commitment, sectoral emissions dropped 53%, more than is required to meet the 2030 target. Most promising, the crop sector was a net GHG sink between 2013 and 2016 in Alberta and between 2006 and 2016 in Saskatchewan. As positive as these developments have been, more can be done by directing research to identify options for reducing GHGs in Manitoba (which made only minimal improvements as farmers there faced conditions requiring continuous use of conventional tillage practices), to explore better nitrogen management (a major continuing source of GHG from cropping) and by searching for low carbon transport options.

Seeding System Configuration Effects on Sunflower Seedling Emergence and Yield under No-Tillage

No-tillage farming can improve crop productivity and the reliability of cropping compared with conventional tillage. The effects of three different seeding system configurations on surface residue handling, sunflower emergence and stand establishment, yield, and gross income were investigated over three cropping seasons. The seeding system configurations comprised a (1) turbo coulter blade, (2) notched disc row cleaner before turbo coulter blade, and (3) no residue handling unit installed in front of a double-disc opener. For all three seeding system configurations, crop residue cover on sown rows (after seeding) was greater than the minimum recommended value of 30% for no-tillage. Residue cover was best with the notched disc row cleaner in front of the turbo coulter blade compared to the other two seeding systems. Furthermore, the notched disc row cleaner in front of the turbo coulter blade produced the highest plant emergence counts and the most uniform stand establishment. Sunflower yield and gross income were highest with the notched disc row cleaner in front of the turbo coulter blade (3.16 Mg·ha−1 and 902 USD·ha−1) compared to when only the turbo coulter blade (2.38 Mg·ha−1 and 680 USD·ha−1) or no residue handling unit (1.69 Mg·ha−1 and 482 USD·ha−1) was used.

Effect of Climate-Smart Agriculture Practices on Climate Change Adaptation, Greenhouse Gas Mitigation and Economic Efficiency of Rice-Wheat System in India

Conventional rice–wheat (RW) rotation in the Indo-Gangetic Plains (IGP) of South Asia is tillage, water, energy, and capital intensive. Coupled with these, crop residue burning contributes significantly to greenhouse gas (GHG) emission and environmental pollution. So, to evaluate the GHG mitigation potential of various climate-smart agricultural practices (CSAPs), an on-farm research trial was conducted during 2014–2017 in Karnal, India. Six management scenarios (portfolios of practices), namely, Sc1—business as usual (BAU)/conventional tillage (CT) without residue, Sc2—CT with residue, Sc3—reduced tillage (RT) with residue + recommended dose of fertilizer (RDF), Sc4—RT/zero tillage (ZT) with residue + RDF, Sc5—ZT with residue + RDF + GreenSeeker + Tensiometer, and Sc6—Sc5 + nutrient-expert tool, were included. The global warming potential (GWP) of the RW system under CSAPs (Sc4, Sc5, and Sc6) and the improved BAU (Sc2 and Sc3) were 33–40% and 4–26% lower than BAU (7653 kg CO2 eq./ha/year), respectively. This reflects that CSAPs have the potential to mitigate GWP by ~387 metric tons (Mt) CO2 eq./year from the 13.5 Mha RW system of South Asia. Lower GWP under CSAPs resulted in 36–44% lower emission intensity (383 kg CO2 eq./Mg/year) compared to BAU (642 kg CO2 eq./Mg/year). Meanwhile, the N-factor productivity and eco-efficiency of the RW system under CSAPs were 32–57% and 70–105% higher than BAU, respectively, which reflects that CSAPs are more economically and environmentally sustainable than BAU. The wheat yield obtained under various CSAPs was 0.62 Mg/ha and 0.84 Mg/ha higher than BAU during normal and bad years (extreme weather events), respectively. Thus, it is evident that CSAPs can cope better with climatic extremes than BAU. Therefore, a portfolio of CSAPs should be promoted in RW belts for more adaptation and climate change mitigation.

Effect of tillage and fertilizer doses on growth and growth indices of soybean (Glycine max L.) under conservation tillage systems

A field experiment was conducted during kharif season of 2019 at the Research Farm, Department of Agronomy, CSKHPKV, Palampur to study the effect of tillage and fertilizer doses on growth and growth indices of soybean under conservation tillage systems. The experiment consisted of twelve treatment combinations which included three tillage systems minimum tillage, minimum tillage with crop residue and conventional tillage and four fertility levels viz; 25 % recommended dose of fertilizer (RDF) , 50 %(RDF) , 75 % RDF and 100% RDF and which were tested in split plot design with tillage system in main plots and fertility levels in sub plots.The soil texture of experimental site was silty clay loam. Minimum tillage along with crop residues (T2)recorded significantly taller plants and higher dry matter accumulation followed by conventional tillage. Absolute growth rate, crop growth rate, dry matter efficiency, relative growth rate and unit area efficiency were significantly higher with minimum tillage + crop residue treatment. Application of 100 % followed by 75 % recommended dose of fertilizer resulted in significantly higher growth parameters and growth indices.