EFEITOS DE DIFERENTES TIPOS DE CONTROLE DE PLANTAS INFESTANTES SOBRE A MIRMECOFAUNA EM Eucalyptus grandis

Este estudo teve como objetivo avaliar os efeitos de diferentes tipos de controle de plantas infestantes sobre a mirmecofauna em um plantio inicial de Eucalyptus grandis . Para tanto, em março de 2011 foi realizado o início da implantação da cultura, em uma área localizada no município de Santa Maria - RS. Os seis tratamentos constituíram-se em controle químico total de plantas infestantes, na linha e na entrelinha de plantio, com glifosato (T1); controle químico total de plantas infestantes, na linha de plantio, com glifosato (T2); controle químico de monocotiledôneas na linha e entrelinha de plantio, com setoxidim (T3); controle químico de dicotiledôneas na linha e entrelinha de plantio, com bentazona (T4); controle químico total de plantas infestantes em faixa de um metro paralela à linha de plantio, com glifosato, e de um metro na parte central da entrelinha, sem controle (T5); e testemunha, sem controle de plantas infestantes (T6). O levantamento da mirmecofauna foi realizado no período de um ano utilizando-se três métodos de coleta: isca atrativa, armadilha de solo e funil de Berlese, com seis repetições por tratamento, em cada data de coleta. Nesse período foram coletadas 46.675 formigas, distribuídas em 37 espécies, não sendo verificada diferença significativa entre o total de espécimens coletados. Na área do tratamento constituído pelo controle de plantas infestantes somente na linha de plantio verificou-se eficiência amostral de 99,0% e Sobs = 35. Entre os índices de Diversidade de Shannon (H’), destacou-se o valor encontrado para a área do tratamento T2 (H’= 1,34) em detrimento dos valores das áreas nas quais foram instalados os tratamentos T1 (H’= 1,25) e T5 (H’= 1,23). Havendo assim, uma maior coexistência de espécies de formigas entre as áreas com estrutura florística menos alterada e entre as áreas mais simplificadas. Não tendo sido verificada correlação significativa (r = 0,0463) entre a riqueza de espécies de formigas coletadas e o número de plantas infestantes encontradas ao final do experimento. Assim, conclui-se que os efeitos indiretos da ação dos herbicidas afetam mais a composição local de espécies de formigas do que sua riqueza.

A review of weed management in wheat using crop competition

Wheat occupies a principal place in the diet of humans globally, contributing more to our daily calorie and protein intake than any other crop. For this reason, preventing weed induced yield losses in wheat has high significance for world food sustainability. Herbicides and tillage play an important role in weed control, but their use has often unacceptable consequences for humans and the wider environment. Additionally, the range of herbicides effective on key weeds is dwindling due to the evolution of herbicide resistance. Elevating crop competitiveness against weeds, through a combination of wheat breeding and innovative planting design (planting density, row spacing and orientation), has strong potential to reduce weed-induced yield losses in wheat. The last decade of research has provided a solid foundation for the breeding of weed suppressive wheat cultivars, and continued research in this area should be a focus for the future. In the interim, there is cause for optimism that weeds can be effectively suppressed using existing wheat varieties, through careful cultivar selection and choice of planting design. Further research is required to define the nature of relationships between cultivar traits and competitive planting strategies, across diverse weed flora in multiple countries, sites and seasons. Investment in such innovation promises to produce benefits, not only in terms of sustained wheat yields, but also in terms of human and ecosystem health, through ameliorating chemical and sediment contamination, soil degradation, and CO2 pollution.

Glutathione Transferases as Detoxification Agents: Structural and Functional Studies

Glutathione transferases (GSTs) are a diverse family of enzymes that catalyze the glutathione-dependent detoxification of toxic compounds. GSTs are responsible for the conjugation of the tripeptide glutathione (GSH) to a wide range of electrophilic substrates. These include industrial pollutants, drugs, genotoxic carcinogen metabolites, antibiotics, insecticides and herbicides. In light of applications in biomedicine and biotechnology as cellular detoxification agents, detailed structural and functional studies of GSTs are required. Plant tau class GSTs play crucial catalytic and non-catalytic roles in cellular xenobiotic detoxification process in agronomically important crops. The abundant existence of GSTs in Glycine max and their ability to provide resistance to abiotic and biotic stresses such as herbicide tolerance is of great interest in agriculture because they provide effective and suitable tools for selective weed control. Structural and catalytic studies on tau class GST isoenzymes from Glycine max (GmGSTU10-10, GmGSTU chimeric clone 14 (Sh14), and GmGSTU2-2) were performed. Crystal structures of GmGSTU10-10 in complex with glutathione sulfenic acid (GSOH) and Sh14 in complex with S-(p-nitrobenzyl)-glutathione (Nb-GSH) were determined by molecular replacement at 1.6 Å and 1.75 Å, respectively. Major structural variations that affect substrate recognition and catalytic mechanism were revealed in the upper part of helix H4 and helix H9 of GmGSTU10-10. Structural analysis of Sh14 showed that the Trp114Cys point mutation is responsible for the enhanced catalytic activity of the enzyme. Furthermore, two salt bridges that trigger an allosteric effect between the H-sites were identified at the dimer interface between Glu66 and Lys104. The 3D structure of GmGSTU2-2 was predicted using homology modeling. Structural and phylogenetic analysis suggested GmGSTU2-2 shares residues that are crucial for the catalytic activity of other tau class GSTs–Phe10, Trp11, Ser13, Arg20, Tyr30, Leu37, Lys40, Lys53, Ile54, Glu66 and Ser67. This indicates that the catalytic and ligand binding site in GmGSTU2-2 are well-conserved. Nevertheless, at the ligandin binding site a significant variation was observed. Tyr32 is replaced by Ser32 in GmGSTU2-2 and thismay affect the ligand recognition and binding properties of GmGSTU2-2. Moreover, docking studies revealed important amino acid residues in the hydrophobic binding site that can affect the substrate specificity of the enzyme. Phe10, Pro12, Phe15, Leu37, Phe107, Trp114, Trp163, Phe208, Ile212, and Phe216 could form the hydrophobic ligand binding site and bind fluorodifen. Additionally, side chains of Arg111 and Lys215 could stabilize the binding through hydrogen bonds with the –NO2 groups of fluorodifen. GST gene family from the pathogenic soil bacterium Agrobacterium tumefaciens C58 was characterized and eight GST-like proteins in A. tumefaciens (AtuGSTs) were identified. Phylogenetic analysis revealed that four members of AtuGSTs belong to a previously recognized bacterial beta GST class and one member to theta class. Nevertheless, three AtuGSTs do not belong to any previously known GST classes. The 3D structures of AtuGSTs were predicted using homology modeling. Comparative structural and sequence analysis of the AtuGSTs showed local sequence and structural characteristics between different GST isoenzymes and classes. Interactions at the G-site are conserved, however, significant variations were seen at the active site and the H5b helix at the C-terminal domain. H5b contributes to the formation of the hydrophobic ligand binding site and is responsible for recognition of the electrophilic moiety of the xenobiotic. It is noted that the position of H5b varies among models, thus providing different specificities. Moreover, AtuGSTs appear to form functional dimers through diverse modes. AtuGST1, AtuGST3, AtuGST4 and AtuGST8 use hydrophobic ‘lock–and–key’-like motifs whereas the dimer interface of AtuGST2, AtuGST5, AtuGST6 and AtuGST7 is dominated by polar interactions. These results suggested that AtuGSTs could be involved in a broad range of biological functions including stress tolerance and detoxification of toxic compounds.

Controlo de infestantes monocotiledóneas com diferentes doses de herbicidas em pós-emergência de trigo mole (Triticum aestivum L.) de sementeira directa

Neste trabalho estudou-se a eficiência dos herbicidas Herbipec 500 FL (s.a. Clortolurão) e Dopler Super (s.a. Diclofope-Metilo+Fenoxaprope-P-Etilo+Mefenepir-Dietilo) no controlo, em pós-emergência de infestantes Monocotiledóneas, e na produção de grão e suas componentes, na cultura do trigo mole em sementeira directa, combinando doses inferiores às recomendadas pelos fabricantes. Os ensaios decorreram nos anos agrícolas de 2006/2007 e 2007/2008, na Herdade do Louseiro no concelho de Évora e na Herdade da Revilheira no concelho de Reguengos de Monsaraz, respectivamente. Na experimentação efectuou-se o estudo dos dois herbicidas, com 3 níveis cada, correspondentes a nove tratamentos. O delineamento experimental foi em blocos casualizados com quatro repetições cada. Verificou-se uma maior eficiência no controlo das plantas infestantes de Lolium rigidum Gaud. e de Juncus bufonius L. e, consequentemente, um maior número de grãos e uma produção de grão de trigo elevada com 2 litros ha-l de Herbipec 500 FL e 0,5 litro ha-1 de Dopler Super. ABSTRACT: The purpose of this work was to study the efficiency of the herbicides Herbipec 500 FL (a.i. chlorotoluron) and Dopler Super (a.i. diclofop-methyl + fenoxaprop-P-ethyl + mefenpyr-diethyl) to control grass weeds at post-emergence in no-till bread wheat and consequently to do the evaluation of potential grain yield combining reduced doses to the recommended ones by the manufacturers. The trials were carried out over two growing seasons (2006/2007 and 2007/2008) on the farm "Revilheira" and on a private farm "Louseiro", both in the district of Évora. Trials to study effects of three doses of a two herbicides, with three levels each, corresponding to nine treatments were executed. The experimental design was a randomized block with four replications each. The results showed a great efficiency and grain yield wheat with the mixture with 2 l ha-1 Herbipec 500 FL and 0,5 1 ha-1 Dopler Super to controlling Lolium spp. and Juncus bufonius L..

Uso da glicerina oriunda da síntese do biodiesel em sistemas microemulsionados visando aplicação de herbicidas

The program PROBIODIESEL from the Ministry of Science and Technology has substantially increased glycerine, obtained as a sub-product of biodiesel production process, making it necessary to seek alternatives for the use of this co-product. On the other hand, herbicides although play a role of fundamental importance in the agricultural production system in force, have been under growing concern among the various segments of society because of their potential environmental risk. In this work, we used glycerin in microemulsion systems for application of herbicides, to improve efficiency and lower environmental pollution caused by the loss of those products to the environment. To obtain the systems of microemulsinados were used Unitol L90 NP and Renex 40 as surfactants, butanol as co-surfactant, coconut oil as oil phase and aqueous phase as we used solutions of glycerin + water. Through the determination of phase diagrams, the microemulsion region was found in the system E (L90 Unitol, coconut oil and glycerin + water 1:1). Three points were chosen to the aqueous phase rich in characterization and application in the solubilization of glyphosate and atrazine. Three experiments were performed in Horta, Department of Plant Sciences, Plant Science Sector, UFERSA, Mossoró-RN. The first experiment was conducted in randomized complete blocks with 20 treatments and four replications. The treatments consisted of five doses of the herbicide glyphosate (0.0, 0.45, 0.9, 1.35 and 1.8 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity of Brachiaria brizantha was measured at 7, 14, 28 and 60 DAA (days after application). At 60 DAA, we evaluated the biomass of plants. The second experiment was developed in randomized complete blocks with 20 treatments and four repetitions. The treatments consisted of five doses of the herbicide atrazine (0.0, 0.4, 0.8, 1.6 and 2.4 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity on Zea mays and Talinum paniculatum was evaluated at 2, 7, 20 DAA. The experiment III was developed in randomized complete blocks with 16 treatments and three repetitions. The treatments consisted of 16 combinations among the constituents of the microemulsion: Unitol L90 surfactant (0.0, 1.66, 5.0, 15 %) and glycerin (0.0, 4.44, 13.33 and 40.0 %). The phytotoxicity on Zea mays was evaluated at 1, 7 and 14 DAA. At 14 DAA, we evaluated the biomass of plants. The control plants using the microemulsions was lower than in the water due to the poisoning caused by the initial microemulsions in the leaves of the plants, a fact that hinders the absorption and translocation of the herbicide. There was no toxicity in Zea mays plants caused by the herbicide, however, were highly intoxicated by microemulsions. T. paniculatum was better controlled in spraying with the microemulsions, regardless of the dose of the herbicide. The glycerine did not cause plant damage. Higher poisoning the plants are caused by tensoactive Unitol L90 and higher rates occur with the use of higher concentrations of surfactant and glycerin, or microemulsion. The microemulsions used hampered the action of glyphosate in controlling B. brizantha and caused severe poisoning in corn, and these poisonings attributed mainly to the action of surfactant

Obtenção de álcool alílico (PROP-2-EN-1-OL) a partir da glicerina derivada do biodiesel de óleo de mamona

In this work, biodiesel was produced from castor oil that was a byproduct glycerin. The molar ratio between oil and alcohol, as well as the use of (KOH) catalyst to provide the chemical reaction is based on literature. The best results were obtained using 1 mol of castor oil (260g) to 3 moles of methyl alcohol (138g), using 1.0% KOH as catalyst at a temperature of 260 ° C and shaken at 120 rpm. The oil used was commercially available, the process involves the reaction of transesterification of a vegetable oil with methyl alcohol. The product of this reaction is an ester, biodiesel being the main product and the glycerin by-product which has undergone treatment for use as raw material for the production of allyl alcohol. The great advantage of the use of glycerin to obtain allyl alcohol is that its use eliminates the large amount of waste of the biodiesel and various forms of insult to the environment. The reactions for the formation of allyl alcohol was conducted from formic acid and glycerin in a ratio 1/1, at a temperature of 260oC in a heater blanket, being sprayed by a spiral condenser for a period of 2 hours and the product obtained contains mostly the allylic alcohol .. The monitoring of reactions was performed by UV-Visible Spectrophotometer: FTIR Fourier transform, the analysis showed that these changes occur spectrometer indicating the formation of the product allylic alcohol (prop-2-en-1-ol) in the presence of water, This alcohol was appointed Alcohol GL. The absorption bands confirms that the reaction was observed in (υ C = C) 1470 -1600 cm -1 and (υ CO), 3610-3670 attributed to C = C groups and OH respectively. The thermal analysis was carried out in a thermogravimetric analyzer SDT Q600, where the mass and temperature are displayed against time, that allows checking the approximate rate of heating. The innovative methodology developed in the laboratory (LABTAM, UFRN), was able to treat the glycerine produced by transesterification of castor oil and used as raw material for production of allyl alcohol, with a yield of 80%, of alcohol, the same is of great importance in the manufacture of polymers, pharmaceuticals, organic compounds, herbicides, pesticides and other chemicals

A era glyphosate.

A molécula de glyphosate. Manejo de plantas daninhas. Resistência das plantas daninhas.

Resistência de plantas daninhas a herbicidas no Brasil: histórico, distribuição, impacto econômico, manejo e prevenção.

Histórico e distribuição da resistência de plantas daninhas a herbicidas no Brasil. Impacto econômico da resistência de plantas daninhas a herbicidas no Brasil. Manejo e prevenção da resistência de plantas daninhas a herbicidas no Brasil. Manejo e controle de azevém com resistência múltipla. Manejo e controle de buva com resistência múltipla. Manejo e controle de capim-amargoso resistente ao glifosato.

Transcriptional profiling in Saccharomyces cerevisiae relevant for predicting alachlor mechanisms of toxicity

Alachlor has been a commonly applied herbicide and is a substance of ecotoxicological concern. The present study aims to identify molecular biomarkers in the eukaryotic model Saccharomyces cerevisiae that can be used to predict potential cytotoxic effects of alachlor, while providing new mechanistic clues with possible relevance for experimentally less accessible eukaryotes. It focuses on genome-wide expression profiling in a yeast population in response to two exposure scenarios exerting effects from slight to moderate magnitude at phenotypic level. In particular, 100 and 264 genes, respectively, were found as differentially expressed on a 2-h exposure of yeast cells to the lowest observed effect concentration (110 mg/L) and the 20% inhibitory concentration (200 mg/L) of alachlor, in comparison with cells not exposed to the herbicide. The datasets of alachlor-responsive genes showed functional enrichment in diverse metabolic, transmembrane transport, cell defense, and detoxification categories. In general, the modifications in transcript levels of selected candidate biomarkers, assessed by quantitative reverse transcriptase polymerase chain reaction, confirmed the microarray data and varied consistently with the growth inhibitory effects of alachlor. Approximately 16% of the proteins encoded by alachlor-differentially expressed genes were found to share significant homology with proteins from ecologically relevant eukaryotic species. The biological relevance of these results is discussed in relation to new insights into the potential adverse effects of alachlor in health of organisms from ecosystems, particularly in worst-case situations such as accidental spills or careless storage, usage, and disposal.

A machine learning approach for recognising woody plants on railway trackbeds

The purpose of this work in progress study was to test the concept of recognising plants using images acquired by image sensors in a controlled noise-free environment. The presence of vegetation on railway trackbeds and embankments presents potential problems. Woody plants (e.g. Scots pine, Norway spruce and birch) often establish themselves on railway trackbeds. This may cause problems because legal herbicides are not effective in controlling them; this is particularly the case for conifers. Thus, if maintenance administrators knew the spatial position of plants along the railway system, it may be feasible to mechanically harvest them. Primary data were collected outdoors comprising around 700 leaves and conifer seedlings from 11 species. These were then photographed in a laboratory environment. In order to classify the species in the acquired image set, a machine learning approach known as Bag-of-Features (BoF) was chosen. Irrespective of the chosen type of feature extraction and classifier, the ability to classify a previously unseen plant correctly was greater than 85%. The maintenance planning of vegetation control could be improved if plants were recognised and localised. It may be feasible to mechanically harvest them (in particular, woody plants). In addition, listed endangered species growing on the trackbeds can be avoided. Both cases are likely to reduce the amount of herbicides, which often is in the interest of public opinion. Bearing in mind that natural objects like plants are often more heterogeneous within their own class rather than outside it, the results do indeed present a stable classification performance, which is a sound prerequisite in order to later take the next step to include a natural background. Where relevant, species can also be listed under the Endangered Species Act.

FY2015 Ambient Groundwater Quality Monitoring Summary, September 3, 2015

This report summarizes the results of groundwater monitoring that took place from October 2014 - April 2015. Raw, untreated groundwater was sampled from forty-five municipal wells generall characterized as vulnerable to contamination from surface activities. Samples were analyzed for basic water quality parameters, nutrients, atrazine and two of its breakdown products, chloroacetanilide herbicides and their ethanesulfonic and oxanalic acid degradates, and a suite of sixteen pharmaceutical compounds.

IDNR Ambient Groundwater Quality Monitoring: Summary for Fiscal Year 2016, August 31, 2016

This report summarizes the results of groundwater quality monitoring conducted at 68 public water supply wells in Iowa between October 2015 and March 2016. Raw groundwater samples were analyzed for basic water quality parameters, nutrients, atrazine and its degradates, and chloroacetanilide herbicides and their ethanesulfonic and oxanilic acid degradates. In addition, a subset of samples were analyzed for radionuclides including gross alpha and gross beta radioactivity, radium-226, and radium-228.

2013 survey of Iowa groundwater and evaluation of public well vulnerability classifications for contaminants of emerging concern (2015)

Studies in Iowa have long documented the vulnerability of wells with less than 50 feet (15 meters) of confining materials above the source aquifer to contamination from nitrate and various pesticides. Recent studies in Wisconsin have documented the occurrence of viruses in untreated groundwater, even in wells considered to have little vulnerability to contamination from near-surface activities. In addition, sensitive methods have become available for analyses of pharmaceuticals and pesticides. This study represents the first comprehensive examination of contaminants of emerging concern in Iowa’s groundwater conducted to date, and one of the first conducted in the United States. Raw groundwater samples were collected from 66 public supply wells during the spring of 2013, when the state was recovering from drought conditions. Samples were analyzed for 206 chemical and biological parameters; including 20 general water-quality parameters and major ions, 19 metals, 5 nutrients, 10 virus groups, 3 species of pathogenic bacteria, 5 microbial indicators, 108 pharmaceuticals, 35 pesticides and pesticide degradates, and tritium. The wells chosen for this study represent a diverse range of ages, depths, confining material thicknesses, pumping rates, and land use settings. The most commonly detected contaminant group was pesticide compounds, which were present in 41% of the samples. As many as 6 pesticide compounds were found together in a sample, most of which were chloroacetanilide degradates. While none of the measured concentrations of pesticide compounds exceeded current benchmark levels, several of these compounds are listed on the U.S. Environmental Protection Agency’s Contaminant Candidate List and could be subject to drinking water standards in the future. Despite heavy use in the past decade, glyphosate was not detected, and its metabolite, aminomethylphosphonic acid, was only detected in two of 60 wells tested (3%) at the detection limit of 0.02 μg/L. Pharmaceutical compounds were detected in 35% of 63 samples. Of the 14 pharmaceuticals detected, six had reported concentrations above the method reporting limit, with the maximum reported concentration of 826 ng/L for acetaminophen. Diphenhydramine was the only pharmaceutical to have two detections above the reporting limit, at 24.5 and 145 ng/L. Eight pharmaceuticals had confirmed detections at concentrations below the method reporting limit. Caffeine was the most frequently detected pharmaceutical compound (25%), followed by the caffeine metabolite, 1,7-dimethylxanthine (16%). Microorganisms were detected in 21% of the wells using quantitative polymerase chain reaction methodologies. The most frequently detected microorganism was the pepper mild mottle virus (PMMV), a plant pathogen found in human waste. PMMV was detected in 17% of samples at concentrations ranging from 0.4 to 6.38 gene copies per liter. GII norovirus, human polyomavirus, bovine polyomavirus, and Campylobacter were also detected, while adenovirus, enterovirus, GI norovirus, swine hepatitis E, Salmonella, and enterohemmorhagic E. coli were not detected. No correlations were found between viruses or pathogenic bacteria and microbial indicators. Wells with less than 50 feet (15 meters) of confining material were shown to have greater incidence of surface-related contaminants; however, significant relationships (p<0.05) between confining layer thickness and contaminants were only found for nitrate and herbicides.

Alteraciones cutáneas de miembros superiores por exposición a agroquímicos en cultivos de arroz, departamento de La Guajira 2016

Introducción: la vida, salud y trabajo del agricultor tienen sus propias particularidades, estilos y actividades, su calidad de vida puede afectarse por exponerse a sustancias químicas, convirtiéndola en una labor muy riesgosa. Objetivo: establecer la prevalencia de las alteraciones cutáneas de miembros superiores por exposición a agroquímicos en cultivos de arroz. Material y método: estudio de corte transversal, población de 100 trabajadores, ubicadas en zona rural de Fonseca La Guajira, durante el año 2016. Se analizaron variables sociodemográficas, laborales y clínicas relacionadas. Para el análisis estadístico se aplicaron las pruebas de Shapiro-Wilk, Ji-Cuadrado de Pearson, medidas de asociación con OR y sus respectivos intervalos de confianza del 95%, análisis multivariado con una Regresión Logística Incondicional, nivel de significancia del 5% (p<0.05) para pruebas estadísticas. Resultados: el 98,9% fueron hombres, las edades oscilaron entre los 18 y 83 años (media de 43,7 años). El 40,91% reporto fumigar y el, 15,15% abona. Reportaron tener rinitis alérgica el 21,2%, alergia ocular 25,3%, asma 16,41%, eczemas en las manos 19,15% y ronchas o habones 17,95%; el 40,31% uso herbicidas, 8,77% fungicidas, 35,09% insecticidas, 14,04% fertilizante y 1,75% coadyuvante. La dependencia es prácticamente nula entre la aparición de eczemas y categoría toxica (p=0,021); R de Pearson (R=0,121; p=0,247) con correlación positiva; no existe una relación entre el número de personas con alergias dérmicas y la toxicidad (X2= 2,271; p=0,518), el R de Pearson (R=-0,152; p=0,150). Conclusión: la exposición a agroquímicos sin las condiciones mínimas de seguridad y salud en el trabajo, se relaciona con la aparición de alteraciones cutáneas.

Local Understandings of Soil Fertility, Rainfall and Conservation Agriculture in Laikipia, Kenya: A Qualitative Analysis.

Conservation Agriculture (CA) is mostly referred to in the literature as having three principles at the core of its identity: minimum soil disturbance, permanent organic soil cover and crop diversity. This farming package has been described as suitable to improve yields and livelihoods of smallholders in semi-arid regions of Kenya, which since the colonial period have been heavily subjected to tillage. Our study is based on a qualitative approach that followed local meanings and understandings of soil fertility, rainfall and CA in Ethi and Umande located in the semi-arid region of Laikipia, Kenya. Farm visits, 53 semistructured interviews, informal talks were carried out from April to June 2015. Ethi and Umande locations were part of a resettlement programme after the independence of Kenya that joined together people coming from different farming contexts. Since the 1970–80s, state and NGOs have been promoting several approaches to control erosion and boost soil fertility. In this context, CA has also been promoted preferentially since 2007. Interviewees were well acquainted with soil erosion and the methods to control it. Today, rainfall amount and distribution are identified as major constraints to crop performance. Soil fertility is understood as being under control since farmers use several methods to boost it (inorganic fertilisers, manure, terraces, agroforestry, vegetation barriers). CA is recognised to deliver better yields but it is not able to perform well under severe drought and does not provide yields as high as ‘promised’ in promotion campaigns. Moreover, CA is mainly understood as “cultivating with chemicals”, “kulima na dawa”, in kiswahili. A dominant view is that CA is about minimum tillage and use of pre-emergence herbicides. It is relevant to reflect about what kind of CA is being promoted and if elements like soil cover and crop rotation are given due attention. CA based on these two ideas, minimum tillage and use of herbicides, is hard to stand as a programme to be promoted and up-scaled. Therefore CA appears not to be recognised as a convincing approach to improve the livelihoods in Laikipia.