Explaining farmers'reluctance to adopt green manure cover crops planting for sustainable agriculture in Northwest China

Green manure cover crops(GMCCs)planting has a potential for mitigating greenhouse gas emissions(GHG)in agroecosystems and provides important ecosystem services,thereby achieving the Sustainable Development Goals(SDGs)stipulated by the United Nations.However,the advantages of cultivating GMCCs on arable land are not widely recognized.For example,in the whole of China,the GMCCs planting area is less than 3.5%of total arable land.The aim of this study is to explore reasons for the low adoption rate of GMCCs planting.Using best–worst scaling(BWS)approach,farmers ranked their preferred conservation practices including three types of GMCC cropping systems.Taking Gansu Province in Northwest China as a case study,a survey with 276 farmers was conducted.The findings indicated that three factors are related to the low adoption rate of GMCCs:1)farmers preferred improving farmland irrigation facilities and substituting chemical fertilizers with organic rather than planting GMCCs;2)lack of awareness and understanding of government policy on GMCCs and limited access to training courses;3)financial support and subsidies from the government are insufficient.This study provides insights and strategic implications for policymakers on how to further promote GMCCs in the future.

Influence of Tillage and Deep Rooted Cool Season Cover Crops on Soil Properties, Pests, and Yield Responses in Cotton

Soil compaction is a significant problem in the Southeastern USA. This compacted zone or hardpan limits root penetration below this layer and reduces potential yield and makes plants more susceptible to drought induced stresses. Soil compaction in this region is managed using costly annual deep tillage at or before planting and there is a great interest in reducing and/or eliminating annual tillage operations to lower production costs. Deep rooted cool season cover crops can penetrate this compacted soil zone and create channels, which cash crop roots, such as cotton, could follow to capture moisture and nutrients stored in the subsoil. The cool season cover crop roots would reduce the need for annual deep tillage prior to planting, increases soil organic matter, which provides greater water infiltration and available water holding capacity. Field studies were conducted for two years with three different soil series to determine the effects of tillage systems and cool season cover crops on the soil chemical and physical properties, yield responses, and pest pressure. Results showed that cool season cover crops significantly reduced soil compaction, increased cotton lint yield and soil moisture content, reduced nematode population densities, and increased soil available P, K, Mn, and organic matter content compared to the conventional no-cover crop.

Effect of Rye and Mix Cover Crops on Soil Water and Cotton Yield in a Humid Environment

In recent years, the use of cover crops is becoming a popular technology among growers in many regions of the United States, which is expected to deliver various benefits such as improving soil health, increasing soil organic matter, controlling weeds, and helping conserve soil water and nutrients. Although expecting these benefits seems reasonable, it is challenging to know how much of these benefits to expect under specific situations. The potential effect of cover crops on soil water conservation is especially significant because of the documented impact of soil water on crop yield, especially for dryland cropping systems. Some researchers have found that planting a cover crop tended to increase soil water, while others have reported the opposite effect. Information on the impact of cover crops on soil water in cotton (Gossypium hirsutum L.) production systems in South Carolina is currently lacking. Therefore, the objective of this study was to quantify the effect of cover crops on soil water and cotton yield. A field experiment was conducted in South Carolina during winter, spring, and summer of 2015, with three cover crop treatments. The treatments included: 1) rye (Secale cereale L.), planted alone;2) a mix of six cover crop species;and 3) a control treatment with no-cover. The cover crop was established in the winter, terminated in the spring, and cotton was grown during the summer. Soil water was measured at different depths using capacitance probes and a neutron probe. Our results showed no significant differences in soil water and cotton yield among the cover crop treatments. These results suggest that under the humid conditions of this study, any short-term effect of the cover crop on soil water was masked by timely rain.

Hairy Vetch and Triticale Cover Crops for N Management in Soils

Over-application of fertilizer to cropland adversely affects both environmental and agricultural ecosystems. This study examined whether planting a legume-based winter cover crop mix offsets fertilizer application via natural nitrogen inputs. The influence of the cover crop mixture on available nutrients was also assessed. Hairy vetch (Vicia villosa) and winter triticale (×triticosecale) cover crops were planted in fall and terminated in May. Soil fertility data was collected before and after planting the winter cover crop to determine the effect on fixing nitrogen and soil phosphorus, potassium and organic matter levels. Increases of soil ammonium were observed in plots with cover crop treatments. A triticale-hairy vetch cover crop mix was successful at scavenging P for future crops and appears to hold promise for long-term soil fertility benefits.

Environmental benefits and farmers' adoption of winter cover crops in the North China Plain

The introduction of cover crops into monoculture systems to improve soil health has been widely adopted worldwide. However, little is known about the environmental risks and application prospects of different cover crops in spring maize(Zea mays L.) monocultures proposed in the North China Plain. A pot experiment was conducted to evaluate the effects of different winter cover crops on subsequent maize yield, soil fertility, and environmental risks of nitrogen(N) loss, and a questionnaire survey was conducted to examine factors influencing farmers' willingness to adopt cover crops in the North China Plain. Based on the same fertilization regime during the maize growing period, four winter cover crop treatments were set up, including bare fallow, hairy vetch(Vicia villosa Roth.), February orchid(Orychophragmus violaceus), and winter oilseed rape(Brassica campestris L.). The results indicated that winter cover crops significantly increased subsequent maize yield and soil organic carbon, total N, and microbial biomass carbon and N compared with the bare fallow treatment.The incorporation of cover crops led to a negligible increase in nitrous oxide(N_(2)O) emissions and had a very limited effect on ammonia(NH_(3)) emissions.The incorporation of February orchid and winter oilseed rape decreased nitrate leaching compared with the hairy vetch treatment in the maize growing season.The N losses via N_(2)O and NH_(3) emissions and N leaching accounted for 71%–84% of the N surplus. However, yield increase and environmental benefits were not the main positive factors for farmers to accept cover crops. Financial incentive was rated by 83.9% of farmers as an “extremely important” factor, followed by other costs, when considering winter cover cropping. These results indicate that the environmental benefits depend on the type of cover crop. Maintaining high levels of soil fertility and maize yield, providing sufficient subsidies, and encouraging large-area cultivation of cover crops are critical measures to promote winter cover cropping in the North China Plain.

Adding Value to Crop Production Systems by Integrating Forage Cover Crop Grazing

In addition to their value as cereal grains, wheat (Triticum aestivum L.) and triticale (× Triticosecale Wittmack) are important cool-season annual forages and cover crops. Yearling steer (Bos taurus) performance was compared in the spring following autumn establishment as for age cover crops after soybean [Glycine max (L.) Merr.] grain harvest. Replicated pastures (0.4 ha) were no-till seeded in three consecutive years into soybean stubble in autumn, fertilized, and grazed the following spring near Ithaca, NE, USA. Each pasture (n = 3) was continuously stocked in spring with four yearling steers (380 ± 38 kg) for 17, 32, and 28 d in 2005, 2006, and 2007, respectively. In 2005, average daily gain (ADG) for steers grazing triticale exceeded the ADG for wheat by 0.31 kghd-1d-1. In 2006, wheat ADG exceeded that for triticale by 0.12 kghd-1d-1. In 2007, steers grazing wheat lost weight, while steers grazing triticale gained 0.20 kghd-1d-1. Based on the 3-year average animal gains valued at $1.32 kg-1, mean net return ($ ha-1 yr-1) was $62.15 for triticale and $22.55 for wheat. Since these grazed cover crops provide ecosystem services in addition to forage, grazing could be viewed as a mechanism for recovering costs and adds additional value to the system. Based on this 3-year grazing trial, triticale was superior to wheat and likely will provide the most stable beef yearling performance across years with variable weather for the western Cornbelt USA.

Critical review of the impact of cover crops on soil properties

Grasses as well as leguminous and non-leguminous broadleaves are the major categories of commonly grown cover crops worldwide.This review focuses on the contribution of cover crops to soil properties.The review first considers the single and mixed cover crops and shows that grass species are desirable for their decay and ability to provide substantial soil cover,broadleaf species are used for their quick decomposition and capacity of releasing residues into the soil,while the leguminous species are used for their ability to fix atmospheric nitrogen.Secondly,the impacts of cover crops on soil health are reviewed.Integrating cover crops into conventional cropping systems may reduce soil bulk density,improve soil structure and hydraulic properties to facilitate increased water infiltration and storage.Crop residue additions from cover crops may enhance soil organic C and N accretion as well as increase availability of P,K,Ca,Fe and Mg in some soil types under certain climatic conditions.Further,cover crops may provide a better condition for microbial activity,abundance,and diversity.Finally,the review shows that through proper management,cover crops may be utilized as an essential component of soil conservation practices for enhanced soil health.Still,further investigation is necessary to determine cover crop effects in additional cropping systems and climatic zones as well as the long-term effects of cover crops on soil properties,subsequent crop yield,and overall cropping system profitability.This review is an important source of information for crop growers,crop management institutions,universities,and crop consultants for sustainable agricultural production.

Modelling the impacts of cover crop management strategies on the water use,carbon exchange and yield of olive orchards

Cover crops have long been proposed as an alternative soil management for minimizing erosion rates in olive stands while providing additional ecosystem services.However,the trade-off between these benefits and the competition for water with the trees makes the definition of optimal management practices a challenging task in semiarid climates.This work presents an improved version of OliveCan,a process-based simulation model of olive orchards that now can simulate the main impacts of cover crops on the water and carbon balances of olive orchards.Albeit simple in its formulation,the new model components were developed to deal with different cover crop management strategies.Examples are presented for simulation runs of a traditional olive orchard in the conditions of southern Spain,evaluating the effects of different widths for the strip occupied by the cover crop(Fcc)and two contrasting mowing dates.Results revealed that high Fccresulted in lower olive yields,but only when mowing was applied at the end of spring.In this regard,late mowing and high Fccwas associated with lower soil water content from spring to summer,coinciding with olive flowering and the earlier stages of fruit growth.Fccwas also negatively correlated with surface runoff irrespective of the mowing date.On the other hand,net ecosystem productivity(NEP)was substantially affected by both Fccand mowing date.Further simulations under future climate scenarios comparing the same management alternatives are also presented,showing substantial yield reductions by the end of the century and minor or negligible changes in NEP and seasonal runoff.

Applying plant-based irrigation scheduling to assess water use efficiency of cotton following a high-biomass rye cover crop

Background:This study addressed the potential of combining a high biomass rye winter cover crop with predawn leaf water potential(ΨPD)irrigation thresholds to increase agricultural water use efficiency(WUE)in cotton.To this end,a study was conducted near Tifton,Georgia under a manually-controlled,variable-rate lateral irrigation system using a Scholander pressure chamber approach to measure leaf water potential and impose varying irrigation scheduling treatments during the growing season.ΨPDthresholds were-0.4 MPa(T1),-0.5 MPa(T2),and-0.7 MPa(T3).A winter rye cover crop or conventional tillage were utilized for T1-T3 as well.Results:Reductions in irrigation of up to 10%were noted in this study for the driest threshold(-0.7 MPa)with no reduction in lint yield relative to the-0.4 MPa and-0.5 MPa thresholds.Drier conditions during flowering(2014)limited plant growth and node production,hastened cutout,and decreased yield and WUE relative to 2015.Conclusions:We conclude thatΨPDirrigation thresholds between-0.5 MPa and-0.7 MPa appear to be viable for use in aΨPDscheduling system with adequate yield and WUE for cotton production in the southeastern U.S.Rye cover positively impacted water potential at certain points throughout the growing season but not yield or WUE indicating the potential for rye cover crops to improve water use efficiency should be tested under longer-term production scenarios.

Cover Crop Effects on Near-Surface Soil Aggregate Stability in the Southern Mississippi Valley Loess (MLRA 134)

The use of cover crops (CC) during the agricultural fallow period has been shown to help alleviate soil compaction and provide stabilizing effects against soil erosion. These benefits are particularly important as many of the silty, loess-derived soils of the major land resource area (MLRA) 134, the Southern Mississippi Valley Loess, have large erosion potentials. This study evaluated the effects of CC and no-cover crop (NCC) treatments on a selection of silt-loam soils in MLRA 134. Treatments were implemented during Fall 2018 and Fall 2019 and consisted of a range of CC species. Soil samples from the top 10 cm were collected to evaluate a suite of soil properties. Soil texture, pH, soil organic matter, and Mehlich-3 extractable Mg, Na, and Ca were unaffected (P > 0.05) by CC treatment. Total water-stable aggregate concentration was unaffected (P > 0.05) by CC treatment and soil depth (i.e., 0 - 5 and 5 - 10 cm). Soil bulk density was greater (P •cm−3) than under CC treatment (1.24 g•cm−3). Water-stable aggregate concentration was unaffected (P > 0.05) by CC treatment and soil depth, but was 21.5 times greater (P •g−1) than in the > 4-mm (0.05 g•g−1) size class. Study results indicate that, even among sites with large variability, CC can have consistent, short-term, positive effects on soil properties, but a long-term commitment to continuous, annual cover crops is necessary for the full realization of potential benefits.

Non-leguminous winter cover crop and nitrogen rate in relation to double rice grain yield and nitrogen uptake in Dongting Lake Plain, Hunan Province, China

Annual ryegrass(Lolium multiflorum Lam.), a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year(2009–2011) field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass(RG) as a winter cover crop and winter fallow(WF) without weed. Subplots were three N treatments for each rice season: 0(N_0), 100(N_(100)) and 200 kg N ha–1(N_(200)). In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice(0.4–1.7 t ha–1 for grain yield and 4.6–20.3 kg ha–1 for N uptake) and double rice(0.6–2.0 t ha–1 for grain yield and 6.3–27.0 kg ha–1 for N uptake) when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N_(100) and N_(200) plots than in N_0 plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.

Bulk Density in Jack Bean’s Development Grown in Cerrado Oxisol

The use of cover plants promotes the recycling of nutrients and the increase in organic mass, and minimizes the effects of erosion. The objective was to evaluate the effect of bulk density in the development of jack bean (Canavalia ensiformis) in Cerrado Oxisol. The experiment was conducted in a greenhouse at the Federal University of Mato Grosso, Rondonópolis-MT, in the period from June to September 2013. Oxisol was used from a Cerrado reserve area, collected at 0 - 0.20 m depth. The experimental design was completely randomized, corresponding to bulk density levels (1.0, 1.2, 1.4, 1.6 and 1.8 Mg&middotm-3), and five replications. The experimental plot consisted of three PVC rings (polyvinyl chloride) with 150 mm internal diameter, 300 mm total height, where the upper and lower rings of pots were filled with 1.0 Mg&middotm-3 density soil and intermediaries according to bulk density treatments. The results were submitted to variance analysis and, when significant, to regression analysis, both with a 5% probability, using SISVAR software. At 60 days after germination, number of leaves, stem diameter, plant height, dry mass of leaves, stem dry mass, dry mass of roots, dry mass of nodules, number of nodules and chlorophyll index (SPAD index) were evaluated. The increase in bulk density negatively influences the development of jack bean, showing little efficiency as a decompacting plant in Cerrado Oxisol.

Response of Underseeded Red Clover(Trifolium pratense L.)to Winter Wheat(Triticum aestivum L.)Herbicides as Affected by Application Timing

Underseeding red clover in winter wheat is a beneficial agronomic practice. Still, many growers tend to forgo this approach. One reason is that herbicides used on winter wheat may injure underseeded red clover, reducing its biomass and the subsequent benefits it provides. Therefore, the effect of winter wheat herbicides on underseeded red clover needs to be evaluated. The objectives of this research were to assess the crop tolerance of underseeded red clover to ten winter wheat herbicides used in Ontario, Canada and determine if red clover tolerance differed when the herbicides were applied at various winter wheat growth stages. Experiments were conducted in 2009 and 2010 at four different Ontario locations. Each herbicide treatment was either applied at an early, normal or late timing. Overall, red clover was not affected by herbicides applied at the early timing. The likelihood of herbicides causing injury and reducing biomass of underseeded red clover increased when they were applied at the more advanced winter wheat growth stages. If timing is a constraint, the three herbicides bromoxynil/MCPA, tralkoxydim, and fenoxaprop-pethyl are the safest to use on red clover underseeded to winter wheat. The remaining herbicides 2,4-D, dicamba/MCPA/mecoprop, dichlorprop/2,4-D, thifensulfuron/ tribenuron + MCPA, fluroxypyr + MCPA, pyrasulfotole/bromoxynil, and prosulfuron + bromoxynil are more injurious, with the last two being the most harmful. By having identified the least damaging herbicides on underseeded red clover in winter wheat and the optimal timing for herbicide application, growers are more likely to adopt this beneficial agronomic practice, save on fertilizer costs and improve soil quality.

No-till is challenged:Complementary management is crucial to improve its environmental benefits under a changing climate

Tillage is the most common agricultural practice dating back to the origin of agriculture.In recent decades,no-tillage(NT)has been introduced to improve soil and water quality.However,changes in soil properties resulting from long-term NT can increase losses of dissolved phosphorus,nitrate and some classes of pesticides,and NT effect on nitrous oxide(N_(2)O)emission remains controversial.Complementary management that enhances the overall environmental benefits of NT is therefore crucial.By incorporating cover crops,nutrient cycling and nutrient use efficiency in NT fields could be improved given the nutrient supplying capacity of some cover crops.Cover crops could also offset the need for occasional tillage of NT cropland,an operation whose effect is only temporary in reducing,for example,soil compaction associated with NT management.When used in combination with NT,cover crop termination methods,using agrochemicals,should be carefully considered to prevent further jeopardy to water quality.Compared to herbicides,the use of roller crimping could potentially result in production cost saving while minimizing soil disturbance and export of agrochemicals.Future research should focus on various combinations of cover crop traits(e.g.,decomposition rate)and management(e.g.,timing of cover crop termination)that account for site-and cash crop-specific requirements.

Development of an Internet of Things (IoT) System for Measuring Agricultural Runoff Quantity and Quality

Runoff is an important component of the water balance of agricultural fields. Accurate measurement or estimation of agricultural runoff is important due to its potential impact on water quantity and quality. Since runoff from agricultural fields is sporadic and is often associated with irrigation and/or intense rainfall events, manually measuring runoff and collecting water samples for water quality analysis during runoff events is inconvenient and impractical. In the fall of 2017, a field site was selected at the Clemson University Edisto Research and Education Center with the objective of developing, constructing, and testing an Internet of things (IoT) flume system to automatically measure runoff and collect water samples. In 2018, an automatic IoT system was developed and installed consisting of six stainless steel H-flumes (22.9-cm), which measured runoff from six adjacent research plots under two different cultural regimes (cover crop and no cover crop). An electronic eTape sensor was installed in the flume and used to measure the water level or the flume’s head. Open-source electronic (Arduino) devices and a cloud-based platform were then used to create a wireless sensor network and IoT system to automatically record the amount of runoff (hydrograph) coming from each section, collect water samples and transmit the data to a Cloud server (Thingspeak.com) where the data can be viewed remotely in real-time. The IoT flume system has been operating successfully and reliably for more than two years.

Effects of Direct Sowing under Mulch-Based Cropping System (DMC) on Cotton and Maize Yield and Chemical Characteristics of Ferruginous Soil (Lixisoil) in the South Sudan Area of Burkina Faso

To better understand the effects of direct sowing under mulch-based cropping system (DMC) in Burkina Faso’s cotton production systems, randomized blocks of Fisher experimental design were implemented at Farako-Ba research station from 2010 to 2019. The study was conducted on lixisoil to evaluate DMC effects on biomass production, crops yields and soil chemical properties in a maize and cotton rotation system associated with cover crop. Conventional tillage and direct seeding without cover crop were compared to DMC under B. ruziziensis (GERM. & EVRARD), DMC under B. ruziziensis + M. cochinchinensis mulch and DMC under C. juncea (L.) mulch used in association with maize. Biomass production, crop yields and soil chemistry were evaluated. Results showed that over 10 years, no-till with or without a cover crop provided cotton seed and maize yields that were statistically equivalent to the tillage commonly practiced by farmers. Cover crop has allowed increasing the biomass production compared to Conventional Tillage and Direct Seeding. Maize yield has not varied significantly with the cover crop. After 10 years of maize and cotton rotation, the improvement raised from +27% to +38% for organic matter and from +15% to +29% for nitrogen with DMC including legumes such as M. cochinchinensis and C. juncea compared to Conventional Tillage on 0 - 5 cm depth. No significant differences were found on soil pH like P2O5 and K2O content. Although DMC with C. juncea used as cover crop did not provide the best biomass production, it contributes to increase nitrogen and organic matter and presents better mineral balances in 10 years of rotation. The 5 - 10 cm and 10 - 20 cm were little influenced by DMC systems.

Intercropping effect on root growth and nitrogen uptake at different nitrogen levels

Aims Intercropping legumes and non-legumes may affect the root growth of both components in the mixture,and the non-legume is known to be strongly favored by increasing nitrogen(N)supply.the knowledge of how root systems affect the growth of the individual species is useful for understanding the interactions in intercrops as well as for planning cover cropping strategies.the aim of this work was(i)to determine if different levels of N in the topsoil influence root depth(rD)and intensity of barley and vetch as sole crops or as an inter-cropped mixture and(ii)to test if the choice of a mixture or the N availability in the topsoil will influence the N uptake by deep roots.Methods In this study,we combined rhizotron studies with root extraction and species identification by microscopy with studies of growth,N uptake and 15N uptake from deeper soil layers,for studying the root interactions of root growth and N foraging for barley(Hordeum vul-gare l.)and vetch(Vicia sativa l.),frequently grown in mixtures as cover crops.N was added at 0(N0),50(N1)and 150(N2)kg N ha−1.the roots discrimination relying on the anatomical and morphologi-cal differences observed between dicots and monocots proved to be a reliable method providing valuable data for the analysis.Important Findingsthe intercrop and the barley attained slightly higher root intensity(rI)and rD than the vetch,with values around 150 crosses m−1 and 1.4 m,respectively,compared to 50 crosses m−1 and 0.9 m for the vetch.at deep soil layers,intercropping showed slightly larger rI values compared to the sole-cropped barley.the barley and the intercropping had larger root length density(r D)values(200-600 m m−3)than the vetch(25-130)at 0.8-1.2 m depth.the topsoil N supply did not show a clear effect on the rI,rD or r D;however,increasing topsoil N favored the proliferation of vetch roots in the intercropping at deep soil layers,with the barley:vetch root ratio ranging from 25 at N0 to 5 at N2.the N uptake of the barley was enhanced in the intercropping at the expense of the vetch(from~100 mg plant−1 to 200).the intercropped barley roots took up more labeled nitrogen(0.6 mg 15N plant−1)than the sole-cropped barley roots(0.3 mg 15N plant−1)from deep layers.

In-depth analysis of soil management and farmers’perceptions of related risks in two olive grove areas in southern Spain

This manuscript presents a questionnaire-based study aimed to provide a detailed analysis on the different soil management carried out by olive farmers in two representative olive-growing areas in southern Spain(Cordoba and Estepa),their perceptions on cover crop use and the possible influence of the different types of farms and farmers’typologies on these perceptions.Our results show a relatively large variability of soil management,with fourteen options,as a result of a combination of different alternatives for bare soil and cover crops with the use or not of pruning residues,but with a great similarity between both areas.The results indicate a high adoption of soil conservation measures in the two study areas,with 63%of farmers using cover crops and 80%a mulch of pruning residues,higher than that reported in previous studies in Southern Spain,and a trend of lower use of these techniques by less experienced and younger farmers.This high penetration of soil conservation measures resulted in a significant reduction of soil erosion risk,as indicated by the relatively low values for the cover and management factor(C)of RUSLE,also calculated and presented in this study,but also the possibility of focusing further efforts on fanners with less experience.Our results indicate the persistence of a minor,but relevant,percentage of farmers using bare soil management(37%)and no mulching(20%),with a moderate concern on the impact of soil erosion on soil degradation and provision of ecosystem services.This suggests the need to concentrate efforts also on this cluster of farmers to enhance the success of what seems to be a remarkable expansion of the use of soil conservation measures in recent decades in Southern Spain,but also in similar areas in the Mediterranean basin.

No-till and conservation agriculture in the United States:An example from the David Brandt farm,Carroll,Ohio

No-till(NT)farming(conservation agriculture)began in the US in the 1960s.The state of Ohio has a university research location that began no-till research in 1962.A few innovative Ohio farmers,including NT pioneers David Brandt and Bill Richards,were early adopters of the new conservation practice.Initially,no-till was most successful on sloping,well drained soils,then with improvements to the system,including cover crops,it became more widely adopted on all soil types.David Brandt was an enthusiastic learner and teacher of no-till practices,working with chemical company representatives and Cooperative Extension Specialists to demonstrate the system.David Brandt’s cooperation with Ohio State University researchers continues to provide a valuable site for studying the long term changes in soil health and ecosystem services.Results showed that total microbial biomass as one of the soil biological health indicators significantly increased with an associated decrease in carbon(C)loss under NT compared with conventional tilled soil(CT).Under NT,there was significantly higher total C and total N compared to CT.Active C,as a composite measure of soil health,significantly increased with NT.When cover crops,especially cover crop cocktail mixes,were used,NT substantially improved soil health.Long-term NT with cover crop cocktail mixes significantly increased the soil aggregate stability,compared with CT.The overall rate of C sequestration by NT suggested that the soils on the Brandt farm act as a consistent sink of atmospheric CO2 although this tends to level off after about 20 years.The Brandt farm showed that crop yields are increased under long-term NT with cover crops mixes.Results suggested that starting with a cover crop when switching from CT to NT,is more likely to ensure success and to maintain economic crop yields.Another early adopter,Bill Richards,from Circleville,Ohio,also became a national leader and promoter of no-till farming.He served as head of the United States Department of Agriculture’s Natural Resources Conservation Service in the early 1990s and instituted a program that led to rapid expansion of no-till.He advises that farmers who follow conservation agriculture principles need to be more proactive,from local level to national levels,to influence policy decisions that can lead to robust improvement in soil health.

No-till systems on the Chequen Farm in Chile:A success story in bringing practice and science together

No-till cropping systems provide an opportunity to protect the soil from erosion,while contemporaneously maintaining high yields and contributing to global food security.The historical aspects and the remarkable development of no-till systems on the Chequen Farm in Chile are reviewed.The adoption of no-till over the last 40 years has been a major turning point in reducing the devastating effects of soil erosion and a model for the evolution of sustainable crop production in highly erodible terrain in other parts of the world.The process of adoption of no-till systems in severely eroded foothills of Chile is described,as well as the environmental benefits and the sustainability of the system.The practical aspects of these developments are supported by scientific literature where appropriate,illustrating the value and coincident knowledge gained when combining analogue observations and information with scientific principles.