No-till Conservation Agriculture Research Articles

Long-Term No-Till Conservation Agriculture and Nitrogen Fertilization on Soil Micronutrients in a Semi-Arid Region of South Africa

Knowledge of the long-term complex relationship between soils, crops, and management practices, such as conservation agriculture, is critical in developing nutrient management strategies to optimise crop yields. This study examined the concentration, and the distribution of, soil micronutrients along the soil profile (0–10, 10–20, and 20–30 cm depths) under different tillage practices: no-till (NT), rotational tillage (RT), and conventional tillage (CT), and nitrogen fertilizer application rates (0, 100, 200 kg/ha) in a semi-arid environment after 17 years of implementation of the trial. The results found the lowest concentration (p < 0.05) of copper (Cu) (1.254 mg/kg) and iron (Fe) (22.671 mg/kg) in CT compared to NT [Cu (1.447 mg/kg), Fe (41,156 mg/kg)] and RT [Cu (2.389 mg/kg), Fe (120,437 mg/kg)] treatments. This correlated with the lower soil pH in NT compared to CT treatment, and slightly higher (p > 0.05) under NT (1.782 mg/g) compared to RT (1.715 mg/g) and CT (1.750 mg/g). There were no differences (p > 0.05) in zinc (Zn) in NT (2.856 mg/kg) and RT (2.782 mg/kg) but CT (2.010 mg/kg) treatment was significantly (p < 0.05) lower compared to these treatments. Manganese (Mn) also followed a similar trend whereby CT still had the lowest concentration (p < 0.05) of Mn (8.01 mg/kg) compared to RT (10.71 mg/kg) and NT (11.98 mg/kg). The concentration of Mn, Zn, and Fe was found to be similar (p > 0.05) with an increase in sampling depths. On the other hand, Cu was found to be different (p < 0.05) at different sampling depths. Manganese (10.46 mg/kg) and Soil Organic Carbon (SOC) (2.026 mg/g) were found to be concentrated near the 0–10 cm soil surface depth while Zn (2.558 mg/kg), Fe (66,217 mg/kg) and Cu (1.867 mg/kg) were more at the 20–30 cm depth in reduced tillage treatments. The results also showed no differences (p > 0.05) in the concentration of Cu, Mn, and Zn at different levels of nitrogen fertilizer under all tillage treatments. It was concluded that NT and rational tillage with mulch, favoured the availability of micronutrients (Cu, Mn, Fe, and Zn) in the studied cropping system.

Soil Macrofauna Abundance and Taxonomic Richness under Long-Term No-Till Conservation Agriculture in a Semi-Arid Environment of South Africa

Soil macrofauna are a critical component for ecosystem function and strongly affect production sustainability. The effect of fertiliser management practices, in different cropping systems, on soil macrofauna communities remains poorly understood in semi-arid to arid regions. The objective of this study was to investigate the effect of tillage practices i.e., no-till (NT), rotational tillage (RT) and conventional tillage (CT) and nitrogen fertiliser application rates (0, 100 and 200 kg/ha N) (urea) on abundance and order diversity of soil macrofauna in a maize continuous monocropping system. The sampling of macrofauna in the trial was conducted in April 2019, August 2019 and March 2020 using 25 cm × 25 cm × 25 cm steel monoliths in randomly selected positions, and this was replicated four times. The study found a significant (p < 0.05) increase in the abundance of soil macrofauna in NT (127 ind/m2) and RT (110 ind/m2) compared to CT (51 ind/m2) treatment. The abundance of macrofauna was also negatively affected by increasing the rate of fertiliser, with 0, 100 and 200 kg/ha resulting in 133, 94 and 62 ind/m2. Orders Haplotaxida and Diplopoda were found to be sensitive to increases in the fertiliser application rate. Haplotaxida (48.4%) was the most abundant order, followed by Coleoptera (18.2%). Other orders included Diplopoda (9.2%), Gastropoda (6.3%), Isoptera (4.7%), Chilopoda (4.7%), Araneae (4%), Hymenoptera (3.2%), Orthoptera (0.9%) and Dermaptera (0.3%). No-till (NT) and rotational tillage (RT) with mulch favoured the establishment of various macrofauna communities in the studied cropping system.

Seed germination ecology of Bidens pilosa and its implications for weed management

It is now widely recognized that Bidens pilosa has become a problematic broadleaf weed in many ecosystems across the world and, particularly in the light of recent climate change conditions, closer management strategies are required to curtail its impact on agricultural cropping. In this investigation, experiments were conducted to evaluate the effect of environmental factors on the germination and emergence of B. pilosa, and also on the response of this weed to commonly available post-emergence herbicides in Australia. The environmental factors of particular interest to this current work were the effect of light and temperature, salinity, burial depth and moisture on B. pilosa since these are key management issues in Australian agriculture. In addition, the effects of a number of commonly used herbicides were examined, because of concerns regarding emerging herbicide resistance. In the tested light/dark regimes, germination was found to be higher at fluctuating day/night temperatures of 25/15 °C and 30/20 °C (92–93%) than at 35/25 °C (79%), whilst across the different temperature ranges, germination was higher in the light/dark regime (79–93%) than in complete darkness (22–38%). The standard five-minute temperature pretreatment required for 50% inhibition of maximum germination was found to be 160 °C, and it was further shown that no seeds germinated at temperatures higher than 240 °C. With regard to salinity, some B. pilosa seeds germinated (3%) in 200 mM sodium chloride (NaCl) but all failed to germinate at 250 mM NaCl. Germination declined from 89% to 2% as the external osmotic potential decreased from 0 to −0.6 MPa, and germination ceased at −0.8 MPa. Seeding emergence of B. pilosa was maximum (71%) for seeds placed on the soil surface and it was found that no seedlings emerged from a depth of 8 cm or greater. A depth of 3.75 cm was required to inhibit the seeds to 50% of the maximum emergence. In this study, application of glufosinate, glyphosate and paraquat provided commercially acceptable control levels (generally accepted as >90%) when applied at the four-leaf stage of B. pilosa. However, none of the herbicide treatments involved in this study provided this level of control when applied at the six-leaf stage. In summary, B. pilosa germination has been clearly shown to be stimulated by light and thus its emergence was greatest from the soil surface. This suggests that infestation from this weed will remain as a problem in no-till conservation agriculture systems, the use of which is increasing now throughout the world. It is intended that information generated from this study be used to develop more effective integrated management programs for B. pilosa and similar weeds in commercial agricultural environments which are tending toward conservation approaches.

Long-term changes of soil chemical characteristics and maize yield in no-till conservation agriculture in a semi-arid environment of South Africa

Soil management practices may change soil chemical properties and thus fertility. The magnitude of change varies depending on soil type, cropping system, climate, fertilizer application and management practice. The objectives of this study were to evaluate the effects of no-till (NT), rotational tillage (RT), conventional tillage (CT) treatments, and three N-fertilizer application rates (0, 100 and 200 kg ha−1) on soil chemical properties and maize yield in a semi-arid environment, Haplic Ferrasol in South Africa, Bergville. This was evaluated in 0–10, 10–20 and 20–30 cm depths. Soil chemical properties were measured 13 years after the implementation of the trial. Marginal differences (p > 0.05) were found in total soil organic carbon (SOC) with NT having the highest concentration (27.1 t.ha−1) compared to RT (26.0 t.ha−1) and CT (26.5 t.ha−1). The concentration of Nitrogen (N) followed the same trend (p = 0.024) where it was found to be higher under NT (1.54 t.ha−1) than RT (1.30 t.ha−1) and CT (1.42 t.ha−1), respectively. SOC and N were found to be highly concentrated in the 0–10 cm depth in both NT and RT treatments. Phosphorus was significantly higher (p < 0.001) under NT (0.0213 t.ha−1) than RT (0.0127 t.ha−1) and CT (0.00704 t.ha−1). A large amount of phosphorus was in the 0–10 cm depth in NT and it was distributed more uniformly under RT and CT. Potassium was also higher (p < 0.05) under NT (9.73 t.ha−1) than RT (9.52 t.ha−1) and CT (8.00 t.ha−1). It was found to be uniformly distributed across the soil depths in all tillage treatments. No significant differences were found in the concentration of calcium across the tillage treatments, however, it was observed to increase with depth under NT and RT and to decrease with increase in depth in CT. The soil of NT and RT treatments had lower pH values (5.80 and 5.86) than CT (6.68) at 0–10 cm depth while in the lower depths, 10–20 and 20–30 cm depth was observed to increase significantly, by 1.2 and 0.9 units in NT and RT respectively. Similar trends were observed in CEC. Yield across the years averaged at 12.3, 12.4 and 11.8 t.ha−1 in NT, RT and CT treatments respectively, under 200 kg.ha−1 N-application. However, yields gains under NT diminished significantly than in RT and CT treatments in 100 (10.6, 11.3 and 11.4 t.ha−1, NT, RT & CT, respectively) and 0 kg.ha−1 N-application rate (6.6, 7.6 and 8.3 t.ha−1, NT, RT & CT, respectively). This suggested the application of correct fertilizer proportion to increase yield. The results of this study indicated that SOC takes time to improve in conservation agricultural practices in a semi-arid environment and its increase is only confined to the soil surface. This increase in the soil surface is also associated with increased availability of the soil important nutrients which may reduce the application of these nutrients as a starter.

Long-term impact of no-till conservation agriculture and N-fertilizer on soil aggregate stability, infiltration and distribution of C in different size fractions

Soil degradation associated with the loss of soil organic carbon (SOC) has been a major concern in sub-Saharan Africa because of the subsequent yield reduction. It is not fully understood how long-term additional C through biomass and N-fertilizers impact on C distribution in soil aggregates and its effects on soil aggregate stability and infiltration in sub-tropical maize monocropping system. The study, therefore, assessed long-term changes in total SOC (TSOC), aggregate-associated C, particulate organic C (POC), aggregate stability and infiltration in the 0–10, 10–20 and 20–30 cm depths under different tillage systems after 13 years of implementation of the trial. The three tillage systems were no-till (NT), rotational tillage (RT) both with permanent residue cover and conventional tillage (CT) with residue removed. N-fertilizer was applied at a rate of 0, 100 and 200 kg/ha. On average TSOC did not vary (p > 0.05) across the tillage treatments, 27.1 t/ha NT vs 26.0 t/ha RT and 26.6 t/ha CT, but varied with depth where it was stratified in the 0–10 cm depth in NT and RT. Particulate organic C, however, varied significantly (p < 0.05) across the treatments where it decreased with increase in tillage intensity but only in the 0–10 cm depth. Carbon associated with large aggregates (>2000 μm) differed marginally (p = 0.085) with tillage treatment with NT having 38.0 t/ha, RT 36.6 t/ha and CT 29.7 t/ha. However, differences (p < 0.05) were observed in small macroaggregates (250–2000 μm) with NT having 37.8 t/ha, RT 33.5 t/ha and CT 30.4 t/ha in the surface depth. Fertilizer application rate did not seem to affect soil aggregate stability & SOC. The results found a strong effect of residue retention in NT and RT in the soil surface with aggregate stability which, was correlated with the high rate of infiltration rate in these treatments. The results of this study indicate that reduced soil disturbance improves physical protection of SOC, soil structure and infiltration, however, it also indicated that TSOC takes time to improve in maize continuous monocrop system in the studied soil.

Farmers’ Perceptions and Factors Influencing the Adoption of No-Till Conservation Agriculture by Small-Scale Farmers in Zashuke, KwaZulu-Natal Province

The adoption of conservation agriculture among small-scale farmers is still low despite the proven economic and environmental benefits of the technology. This study was conducted in Ingwe Municipality in Kwa-Zashuke, Ward 8, in KwaZulu-Natal province. The main aim of the study was to determine the factors that influence the adoption of no-till conservation agriculture (CA) in the study area and to explore farmers’ perceptions of no-till CA and the impact of no-till CA on maize yield. A quantitative approach employing a cross-sectional design was used to gather data. Stratified random sampling was employed and a total of 185 small-scale farmers (97 adopters and 88 non-adopters) were sampled. Data analysis was done through descriptive and inferential statistics and econometric modeling using the logistic regression model. Findings show that farmers’ positive perceptions were positively correlated with higher maize yields. While an increase in extension visits, age, education and farmers’ positive perceptions significantly increased the likelihood of a farmer adopting no-till CA, an increase in land size was negatively related to no-till CA adoption. The findings confirm the important role of extension in the promotion of no-till CA, particularly the intensity of the extension services. The study recommends a deliberate effort by all stakeholders to promote the participation of young people in farming and tailor-make current no-till CA programs to suit the illiterate households. The capacity of extension programs to adequately support farmers should be enhanced through improvements in extension services. There is also need to change people’s mindsets and the way they view no-till CA.

Long-term impact of no-till conservation agriculture on abundance and order diversity of soil macrofauna in continuous maize monocropping system

ABSTRACTUnsuitable soil management in agriculture is known to results in the deterioration of soil health and the decline of biodiversity. The experiment tested whether no-tillage with mulch (NT), could boost biological activity of soil macrofauna population in continuous maize monocropping system compared with rotational tillage with mulch (RT) and conventional tillage (CT). Soil macrofauna was sampled at the end of the 2014/2015 growing season using 25 × 25 × 25 cm steel monoliths. The mean density of individual orders was higher (p < 0.001) under NT (46%) and RT (38%) compared with CT (16%). However, the Shannon-Weaver index revealed that the diversity and evenness of orders were similar for all treatments. Macrofauna patterns revealed that NT and RT contained higher (p < 0.001) population of Isoptera and Diplopoda. Isoptera was 51% and 17% higher in NT than CT and RT, while in Diplopoda, NT was 39% and 2% higher than CT and RT, respectively. It was concluded that NT and RT systems favoured the development of macrofauna communities in the studied maize continuous monoculture cropping system but did not favour order diversity of macrofauna. This suggests the importance of crop rotation for the development of the more diverse macrofaunal population.

Sustainable Agricultural Mechanization for Smallholders: What Is It and How Can We Implement It?

Smallholder farmers are the main producers of the world’s food and they will have to increase production by up to 100 percent by 2050 to feed the growing population. This must be achieved while preserving natural resources and that is why sustainable agricultural mechanization (SAM) will be fundamental to the process. SAM is climate-smart and environmentally benign and essentially means no-till conservation agriculture, which requires specific mechanization inputs. Principally, these are seeders and planters capable of penetrating soil surface vegetative cover to deposit seed and fertilizer at the required depth and spacing; and equipment for management of cover crops and weeds. Mechanization is required not only for crop production, but also for processing and along the entire value chain. Mechanization inputs are usually expensive and so specialist service provision will be the indicated way forward. This will need collaboration from both the private and public sectors and will involve public-private partnerships to be developed in one form or another. Given the poor track record of public sector mechanization provision, the delivery of SAM should be firmly in the hands of the private sector that should be committed to SAM principles or otherwise be incentivized to the concept through smart subsidies. Improved information flows via smallholder farmer-friendly innovation platforms; and continuing development and testing of SAM technologies via regional centres of excellence will both be required—especially for sub-Saharan Africa.

Brazil’s Tropical Solutions for Africa: Tractors, Matracas and the Politics of ‘Appropriate Technology’

This article focusses on mechanical farming technology sponsored by Brazil’s South-South cooperation in Africa. Tractors and matracas are taken as symbols of different agricultural development pathways promoted by Brazilian players. One stark contrast is between high-powered mechanised farming and no-till conservation agriculture. Another is between large-scale agriculture and small-scale family farming. Embrapa, widely known as the champion of the Green Revolution in Brazil, has also encouraged a conservation route and the use of no-till and small-scale equipment, such as matracas. The Brazilian Ministry of Agrarian Development, leading advocate of family farming and of political opposition to large-scale farming, has inadvertently sponsored tractors, feeding a new wave of mechanisation across Africa that overlooks the potential of smaller-scale alternatives. Brazilian actors and their African counterparts have instrumentally deployed technology, and tractors particularly, in the pursuit of their interests, whereas considerations about technological appropriateness to local conditions have hardly played a role.

Proteomics of Durum Wheat Grain during Transition to Conservation Agriculture.

Nitrogen management in combination with sustainable agronomic techniques can have a great impact on the wheat grain proteome influencing its technological quality. In this study, proteomic analyses were used to document changes in the proportion of prolamins in mature grains of the newly released Italian durum wheat cv Achille. Such an approach was applied to wheat fertilized with urea (UREA) and calcium nitrate (NITRATE), during the transition to no-till Conservation Agriculture (CA) practice in a Mediterranean environment. Results obtained in a two-years field experiment study suggest low molecular weight glutenins (LMW-GS) as the fraction particularly inducible regardless of the N-form. Quantitative analyses of LMW-GS by 2D-GE followed by protein identification by LC-ESI-MS/MS showed that the stable increase was principally due to C-type LMW-GS. The highest accumulation resulted from a physiologically healthier state of plants treated with UREA and NITRATE. Proteomic analysis on the total protein fraction during the active phase of grain filling was also performed. For both N treatments, but at different extent, an up-regulation of different classes of proteins was observed: i) enzymes involved in glycolysis and citric acid cycles which contribute to an enhanced source of energy and carbohydrates, ii) stress proteins like heat shock proteins (HSPs) and antioxidant enzymes, such as peroxidases and superoxide dismutase which protect the grain from abiotic stress during starch and storage protein synthesis. In conclusion N inputs, which combined rate with N form gave high yield and improved quality traits in the selected durum wheat cultivar. The specific up-regulation of some HSPs, antioxidant enzymes and defense proteins in the early stages of grain development and physiological indicators related to fitness traits, could be useful bio-indicators, for wheat genotype screening under more sustainable agronomic conditions, like transition phase to no-till CA in Mediterranean environments.

Towards sustainable use of water in rainfed and irrigated cropping systems: review of some technical and policy issues

Water sustainability in agriculture is the main topic of this review. However, moving from studies carried out at worldwide level, the main focus of the paper is the Mediterranean farm which practices irrigated and/or rainfed cropping systems. On the basis of the state of the art on this matter, a lack of knowledge in some areas has come to light that calls for new policies and further research. Basically, the review provides feasible agro-technical solutions for using water in the most efficient and productive way. Alternative ways to use water resources rationally in growing crops are discussed. They are based mainly on progress due to agronomy (No-Till Conservation Agriculture), information technology (Decision Support System and Precision Irrigation) and genetics. Agronomic options are analysed taking into account recent European agricultural and environmental trends of policies which conjugate the issues related to sustainability and production intensification. In perspective, the review encourages discussion on how to relocate farming systems within natural cycles, specifically those of the water cycle, based on No-Till Conservation Agriculture principles and practices which apply to all land-based agro-ecologies in all continents where agriculture is practiced.