Yield Of Cereal Crops Research Articles

Susceptibility of the bird cherry‐oat aphid, Rhopalosiphum padi (Hemiptera: Aphididae), to four insecticides

AbstractThe bird‐cherry oat aphid (Rhopalosiphum padi) is a global pest, attacking most cereal crops including barley, wheat, oats and triticale. The aphids cause yield losses through direct feeding damage and the transmission of plant viruses. In Australia, feeding injury can reduce cereal yields by 6%, with the damage caused by aphid‐vectored viruses reducing the yield of cereal crops by up to 30%. Aphid control in these crops is achieved almost exclusively with insecticides, and there is growing concern surrounding insecticide resistance evolution in multiple aphid species. In this study, nine field populations of R. padi were collected from localities representing the major grain growing regions of Australia. Toxicity data against four insecticides (dimethoate, alpha‐cypermethrin, pirimicarb and imidacloprid) was generated for each aphid population. This revealed little differences in population responses for three of these insecticides. For alpha‐cypermethrin, a widely used insecticide in Australia, there were significant differences between several populations. These data will be important for future monitoring of insecticide responses of R. padi and highlight the impending pest management challenges growers could encounter in Australia.

A light-regulated gene, TaLWD1L-A, affects flowering time in transgenic wheat (Triticum aestivum L.)

Flowering time is an important agronomic trait that greatly influences plant architecture and grain yield in cereal crops. The present study identified a light-regulated gene, TaLWD1L-A, from hexaploid wheat that encodes a WD40 domain-containing protein. TaLWD1L-A was localized in the nucleus. Phenotypic analysis demonstrated that TaLWD1L-A overexpression in transgenic wheat led to an obvious early flowering phenotype. Upregulation of the floral activator gene TaFT1 caused the early flowering phenotype in transgenic wheat plants. TaLWD1L-A also affected the expression of circadian clock genes, including TaTOC1, TaLHY, TaPRR59, TaPRR73 and TaPRR95, and indirectly regulated the expression of the TaFT1 in transgenic plants by affecting the expression of vernalization-related genes TaVRN1 and TaVRN2 and photoperiod-related genes TaPpd-1 and TaGI. The early flowering phenotype in TaLWD1L-A-overexpressing transgenic lines led to a relatively shorter phenotype and yield reduction. Our results revealed that TaLWD1L-A affected the expression of circadian clock-related genes and played an important role in wheat flowering regulation by influencing the expression of genes related to vernalization and photoperiod pathways.

Local-Scale Cereal Yield Forecasting in Italy: Lessons from Different Statistical Models and Spatial Aggregations

Statistical, data-driven methods are considered good alternatives to process-based models for the sub-national monitoring of cereal crop yields, since they can flexibly handle large datasets and can be calibrated simultaneously to different areas. Here, we assess the influence of several characteristics on the ability of these methods to forecast cereal yields at the local scale. We look at two diverse agro-climatic Italian regions and analyze the most relevant types of cereal crops produced (wheat, barley, maize and rice). Models of different complexity levels are built for all species by considering six meteorological and remote sensing indicators as candidate predictive variables. Yield data at three different spatial aggregation scales were retrieved from a comprehensive, farm-level dataset over the period 2001–2015. Overall, our results suggest the better predictability of summer crops compared to winter crops, irrespective of the model considered, reflecting a more intricate relationship among winter cereals, their physiology and weather patterns. At higher spatial resolutions, more sophisticated modelling techniques resting on feature selection from multiple indicators outperformed more parsimonious linear models. These gains, however, vanished as data were further aggregated spatially, with the predictive ability of all competing models converging at the agricultural district and province levels. Feature-selection models tended to elicit more satellite-based than meteorological indicators, with a preference for temperature indicators in summer crops, whereas variables describing the water content of the soil/plant were more often selected in winter crops. The selected features were, in general, equally distributed along the plant growing cycle.

Variation in zinc concentration of sweetcorn kernels reflects source-sink dynamics influenced by kernel number.

Grain yield and mineral nutrient concentration in cereal crops are usually inversely correlated, undermining biofortification efforts. Here, sink size, expressed as kernel number per cob, was manipulated by controlling the time when the silks of sweetcorn (Zea mays) cv. Hybrix 5 and var. HiZeax 103146 were exposed to pollen. Twelve other varieties were manually pollinated to achieve the maximum potential kernel number per cob, and kernel Zn concentration was correlated with kernel number and kernel mass. As kernel number increased, kernel Zn concentration decreased, with the decrease occurring to similar extents in the embryo tissue and the rest of the kernel. However, total kernel Zn accumulated per cob increased with increasing kernel number, as the small decreases in individual kernel Zn concentration were more than offset by increases in kernel number. When both kernel number and mass were considered, 90% of the variation in kernel Zn concentration was accounted for. Differential distribution of assimilates and Zn to sweetcorn cobs led to significant decreases in kernel Zn concentration with increasing kernel number. This suggests there will be challenges to achieving high kernel Zn concentrations in modern high-yielding sweetcorn varieties unless genotypes with higher Zn translocation rates into kernels can be identified.

Quantifying Plant-Borne Carbon Assimilation by Root-Associating Bacteria

Herbaspirillum seropedicae is a rhizobacteria that occupies a specialized ecological niche in agriculture. As an endophyte and prolific grass root colonizer it has the potential to promote plant growth, enhancing crop yield in many cereal crops. While the mechanisms for plant growth promotion are controversial, the one irrefutable fact is these microorganisms rely heavily on plant-borne carbon as their main energy source in support of their biological functions. Unfortunately, the tools and technology enabling researchers to trace carbon exchange between plants and the microorganisms associating with them has been limiting. Here, we demonstrate that radioactive 11CO2 administered to intact maize leaves with translocation of 11C-photosynthates to roots can provide a ‘traceable’ source of carbon whose assimilation by microbial organisms can be quantified with enormous sensitivity. Fluorescence root imaging of RAM10, a green fluorescent protein (GFP) reporting strain of H. seropedicae, was used to identify regions of high microbial colonization. Microbes were mechanically removed from these regions via sonication in saline solution and extracts were subjected to fluorescence measurement and gamma counting to correlate carbon-11 atoms with numbers of colony forming units. The method has potential to translate to other microorganisms provided they possess an optical reporting trait.

Factors driving cereal response to fertilizer microdosing in sub‐Saharan Africa: A meta‐analysis

AbstractFertilizer microdosing (FM) is being promoted in sub‐Saharan Africa (SSA) to boost crop productivity on smallholder farms. However, yield response variability is a barrier to adoption. We conducted a meta‐analysis to analyze the variability in cereal crop yield response to FM and to determine the main factors associated with this variability. Thirty publications pertaining to millet [Pennisetum glaucum (L.) R. Br.], sorghum (Sorghum bicolor L. Moench) or maize (Zea mays L.) were assessed. Factors analyzed were crop type, rainfall, soil texture, type and rate of fertilizer, and complementary practices. On average, FM improved millet, sorghum and maize crop yields by 68%. Yield response tended to increase with increasing rainfall and the largest yield gains were observed in medium‐textured soils (81%), as compared to light (61%) and heavy‐textured soils (30%). The combined application of N and P performed better than either element alone. Crop response tended to increase with increasing rates of N. In the case of P, this was true only on light textured‐soils. On medium‐textured soils, the response appeared independent of the rate of P. There was a synergetic effect of water conservation measures on the performance of FM, while combining FM with organic matter (OM) amendments decreased its performance. Results highlighted major trends in cereal crop response to FM that could be used to prioritize target areas. However, these may require additional, site‐specific field experiments, especially for factors for which little data is currently available.

Current state of wheat insects entomofauna in Dnepropetrovsk, Zaporizhia and Poltava regions

Cereals are the basis of world crop production. In Ukraine, winter wheat crop plays a rolea strategic agricultural product. The basis of food security and the formation of the national export potential depend on this crop species. Wheat has a steadydemand on the internal and foreign markets. In the structure of crops, it occupies about 6 million hectares, which is more than 22% of all cultivated areas and almost 42% of grain crops. Like most other crops, cereals serve as food supply for a wide range of insect phytophages. Conventionally, the entire fauna of endangeredspecies can be divided into multiphages, oligophages and monophages. Cereal plants are damaged by insects during the entire growing season, from germination to harvesting. There are more than 230 species of wheat insects. Territory of the steppe zone of Ukraineamounted 17 most common and criticallyendangeredspecies on. The degree of harmfulness of each species in different vegetation periods is not the same. The goal of the paper was to reveal a current state of the most common endangeredspecies (wheat phytophages) within Dnepropetrovsk, Poltava and Zaporizhia Oblasts, and to assess a degree of their harmfulness (according to literature data). Harmful insects were accounted using conventional manual sampling method. The accounting was carried out on plots of 50 × 50 cm (0.25 m2), staggered evenly over an entire field, using a frame placed onto the plants randomly. All wheat stems inside the frame were shaken to a ground surface, and the number of harmful insects was counted. At the same time, the upper layer of soil (0–25 cm) was visually inspectedfor the presence of insect larvae and imagos. 16 samples were collectedon each field. The average number of each insect species per 1 m2 of wheat crops was calculated. As a result of 50 fields survey in Dnepropetrovsk, Zaporizhia and Poltava Oblast, a list of the most common endangeredspecies (wheat phytophages) in the steppe and forest-steppe zones was created. It includes 17 species belonging to 7 families from three orders. The most recorded representatives of Coleoptera order were 12 species, four species from Hemiptera order and one from Thysanoptera. On average, three species of wheat phytophages belong to each of the families; the largest number of endangeredspecies is represented by Scarabaeidae family. Among the identified phytophages, the most common were Harpalus rufipes (De Geer, 1774) 88% of infected fields, Zabrus tenebrioides (Goeze, 1777) 78% and Anisoplia austriaca (Herbst, 1783) 72%. Specimenof endangeredspecies as Eurygaster integriceps (Puton, 1881) were found on 34 fields, Haplothrips tritici (Kurdjumov, 1912) on 22 fields, Oulema lichenis (Heyden, 1879) on 21 fields, and Aelia acuminata (Linnaeus, 1758) on 18 fields. A brief description of each of 17 endangeredspecies was presented, taking into account their harmfulness in different periods of wheat vegetation. The degree of harmfulness of each species in different vegetation periods is not a same. A distinction is made between the early period, spring and the second half of the growing season. Early vegetation period is from the seedling emergence to the period of grass tillering. During this period, an impact of harmful insects is particularly dangerous, and a damage they cause can lead to a death of plants over large areas. The species most dangerous for wheat at this time are Harpalus rufipes and Zabrus tenebrioides. It is difficult to establish a clear distinction between the impact of endangeredspecies on plants during different periods of vegetation. With a beginning of spring vegetation, Oulema lichenis, Phyllotreta vittula and Chaetocnema aridula and Tropinota hirta are added to the above-mentioned species. Harmfulness during this period consists will be represented by leaf blade damage. The middle of vegetation coincides with an ear formation and grain filling phases. The most active endangeredwheat species during this period are considered to be Haplothrips tritici, Opatrum sabulosum, Pedinus femoralis and Blaps lethifera. The quality indicators of a cereal crop yield are reduced by Eurygaster integriceps and E. maura, Aelia acuminata and A. rostrata. Before the harvest the grain is damaged by various Scarabaeidae, in particular Anisoplia austriaca, A. agricola , A. segetum. As a result of controlling the number and species composition of endangeredwheat species, it is necessary to adapt the application of integrated methods of wheat protection to the soil and climatic conditions of the steppe and forest-steppe zones of Ukraine.

Senescence‐related translocation of nonstructural carbohydrate in rice leaf sheaths under different nitrogen supply

AbstractThe translocation of nonstructural carbohydrates (NSC) from leaf sheaths to filling grains after anthesis contributed greatly to the grain yield of cereal crops. In this study, the effect of nitrogen (N) supply levels on the accumulation and translocation of NSC in leaf sheath tissues and its relationship with the initiation and progression of leaf senescence during grain filling was investigated using two rice (Oryza sativa L.) genotypes, namely, premature flag leaf senescence mutant (psf) and its wild‐type. Three N treatment levels were used to examine N‐supply induced alteration in the activities of several key enzymes involved in NSC translocation and N assimilation in different leaf sheaths. The results show that the NSC translocation rate in leaf sheaths under low nitrogen (LN) treatment was significantly higher than those under normal nitrogen (NN) and high nitrogen (HN) treatments. However, the positive effect of LN on the NSC translocation in leaf sheath was closely associated with its negative effect on grain yield, due to accelerated leaf senescence and shortened leaf longevity. Comparatively, the upper‐positional sheath had a lower NSC amount and higher NSC translocation rate than the lower‐leaf sheaths after heading. High N suppressed sucrose‐phosphate synthase (SPS) activity in leaf sheaths, but enhanced the activity of key enzymes involving in N assimilation in leaf sheaths. The upper sheath had higher activity of sucrose‐metabolizing enzymes and lower activity of N‐assimilating enzymes. Hence, the upper‐leaf sheath had a relatively weak N assimilation and stronger NSC translocation than the lower‐leaf sheaths.

The Rice Basic Helix-Loop-Helix 79 (OsbHLH079) Determines Leaf Angle and Grain Shape.

Changes in plant architecture, such as leaf size, leaf shape, leaf angle, plant height, and floral organs, have been major factors in improving the yield of cereal crops. Moreover, changes in grain size and weight can also increase yield. Therefore, screens for additional factors affecting plant architecture and grain morphology may enable additional improvements in yield. Among the basic Helix-Loop-Helix (bHLH) transcription factors in rice (Oryza sativa), we found an enhancer-trap T-DNA insertion mutant of OsbHLH079 (termed osbhlh079-D). The osbhlh079-D mutant showed a wide leaf angle phenotype and produced long grains, similar to the phenotypes of mutants with increased brassinosteroid (BR) levels or enhanced BR signaling. Reverse transcription-quantitative PCR analysis showed that BR signaling-associated genes are largely upregulated in osbhlh079-D, but BR biosynthesis-associated genes are not upregulated, compared with its parental japonica cultivar ‘Dongjin’. Consistent with this, osbhlh079-D was hypersensitive to BR treatment. Scanning electron microscopy revealed that the expansion of cell size in the adaxial side of the lamina joint was responsible for the increase in leaf angle in osbhlh079-D. The expression of cell-elongation-associated genes encoding expansins and xyloglucan endotransglycosylases/hydrolases increased in the lamina joints of leaves in osbhlh079-D. The regulatory function of OsbHLH079 was further confirmed by analyzing 35S::OsbHLH079 overexpression and 35S::RNAi-OsbHLH079 gene silencing lines. The 35S::OsbHLH079 plants showed similar phenotypes to osbhlh079-D, and the 35S::RNAi-OsbHLH079 plants displayed opposite phenotypes to osbhlh079-D. Taking these observations together, we propose that OsbHLH079 functions as a positive regulator of BR signaling in rice.

The role of climate in the trend and variability of Ethiopia's cereal crop yields

Food security has been and will continue to be a major challenge in Ethiopia. The country's smallholder, rainfed agriculture renders its food production system extremely vulnerable to climate variability and extremes. In this study, we investigate the impact of past climate variability and change on the yields of five major cereal crops in Ethiopia—barley, maize, millet, sorghum, and wheat—during the period 1979–2014 using the Decision Support System for Agrotechnology Transfer (DSSAT) crop model. The model is calibrated at both the site and agroecological-zone scales. At the sites studied, the model results suggest that climate in the past four decades may have contributed to an increasing trend in maize yield, a decreasing trend in wheat yield, and no clear trend in the yields of barley and millet; cereal crop yield is positively correlated with growing season solar radiation and temperature, but negatively correlated with growing season precipitation. For modeled cereal crops across the nation during the study period, yield in western Ethiopia is positively correlated with solar radiation and day time temperature; in the eastern and southeastern Ethiopia where water is a limiting factor for growth, yield is positively correlated with precipitation but negatively correlated with solar radiation and both day time and night time temperature. The national average of simulated yields of most crops (except maize) showed an overall decreasing (although not statistically significant) trend induced by past climate variability and changes. Over a large portion of the highly productive areas where there is a negative correlation between yield and temperature, yield is simulated to have significantly decreased over the past four decades, an indication of adverse climate impact in the past and potential food security concern in the future.

Potential of China’s Agricultural Resources

The calculation of the agricultural potential of China, based on the production of grains, oilseeds (inputs are arable and irrigation areas, fertilizers) and meat (inputs are grains, oilseeds, and oilseeds derivatives (meal) production), according to FAO and USDA statistics. Based on the analysis of the relationships of these parameters, a mathematical model is developed (a system of equations of multiple regression). Growth in yield of cereal crops up to 6.1 t/ha, oilseeds crop yield grow to 2.7 t/ha, the proportion of grain sent to livestock feed up to 60%, the share of irrigated land up to 60% are the main input parameters. In this case potential production of food products, in particular, grain crops and meat, is potentially sufficient for the self-supply of the population of China of 1,600 million people. An acute problem for China will remain to provide the population with meat products, which will require the import of oilseed meal. This scientific and methodological toolbox makes it possible to obtain an objective quantitative assessment of the potential regional population

Intrapopulation Antagonism Can Reduce the Growth and Aggressiveness of the Wheat Head Blight Pathogen Fusarium graminearum.

Fusarium graminearum is a causal agent of Fusarium head blight (FHB), a disease that reduces yield and quality of cereal crops and contaminates grain with mycotoxins that pose health risks to humans and livestock. Interpopulation antagonistic interactions between isolates that produce different trichothecene mycotoxins can reduce FHB in wheat, but it is not known if interactions between isolates with a shared population identity that produce the same trichothecenes have a similar effect. Using isolates from the predominant F. graminearum populations in North America (NA1 and NA2), we examined intrapopulation interactions by comparing growth, disease progression, and toxin production of individual isolates with multi-isolate mixes. In vitro, mycelial growth was significantly greater when most NA1 and NA2 isolates were cultured individually versus when cultured as a mixture of isolates from the same population. In susceptible wheat Norm, FHB generally progressed faster in heads inoculated with an individual isolate versus a multi-isolate mixture, but the antagonistic effect of intrapopulation interactions was more pronounced for NA1 than NA2 isolates. By contrast, in moderately resistant wheat Alsen, mixtures of isolates from either population caused obvious reductions in FHB development. Mycotoxin contamination was not consistently affected by intrapopulation interactions and varied depending on the interacting isolates from either population. Our results indicate that antagonistic intrapopulation interactions can influence FHB in controlled environmental conditions. Understanding if the regional composition of pathogen populations similarly influences FHB in the field could improve disease forecasting and management practices.

Rice-Wheat cropping system under changing climate Scenario: A review

Climate change directly or indirectly influences all economics aspects, but agriculture is among the sectors which are most sensitive and inherently vulnerable to climate. The impacts of increased temperature from global warming and changes in rainfall patterns resulting from climate change are expected to reduce agricultural production and put further pressure on marginal land. Climate change and especially increase in ambient temperatures will reduce the yields of major cereal crops especially Rice-wheat. Hence, to achieve our goals of food security, we need to emphasize the use and production of food crops that can withstand the on-going changes to the climate, especially in the arid and semi-arid regions around the globe that are at a greater risk of food insecurity. There are key factors that significantly impact to mitigate stress conditions of the climate, i.e. short duration crop, value added weather services, genotype with higher per day yield potential, weather linked agricultural insurance etc.

Insight into the Role of Epigenetic Processes in Abiotic and Biotic Stress Response in Wheat and Barley.

Environmental stresses such as salinity, drought, heat, freezing, heavy metal and even pathogen infections seriously threaten the growth and yield of important cereal crops including wheat and barley. There is growing evidence indicating that plants employ sophisticated epigenetic mechanisms to fine-tune their responses to environmental stresses. Here, we provide an overview of recent developments in understanding the epigenetic processes and elements—such as DNA methylation, histone modification, chromatin remodeling, and non-coding RNAs—involved in plant responses to abiotic and biotic stresses in wheat and barley. Potentials of exploiting epigenetic variation for the improvement of wheat and barley are discussed.

Arbuscular mycorrhizal fungi affect the concentration and distribution of nutrients in the grain differently in barley compared with wheat

Societal Impact StatementCereal crops such as wheat and barley provide key nutritional elements to the human diet. However, the distribution of nutrients within the cereal grain itself is critically important, as nutrients can be lost during the grain milling process. Mycorrhizal fungi can take up nutrients from the soil and deliver them to plants, and consequently, grain nutrient content can be modified by inoculation of the soil with mycorrhizal fungi. Here we show at the microscopic level how mycorrhizal fungi modify the concentration and distribution of nutrients within wheat and barley grain, and consider the impact of this for human nutrition.Summary The concentration and distribution of nutrients in cereal grains are critically important for human nutrition. Mycorrhizal fungi affect the yield and nutrition of cereal crops, but there has been little focus on the effects on the grain, particularly at the microscopic level. Although arbuscular mycorrhizal fungi (AMF) can modify grain nutrient concentrations relative to mock‐inoculated plants, it is not known whether this contributes to modifications to the distribution of nutrients within the grain. Barley and bread wheat plants were grown to maturity with or without AMF (Rhizophagus irregularis) inoculation in soil amended with 20 mg added zinc kg−1. The resulting grain from matured plants was dried, fixed and sectioned to the root primordia level, then subjected to laser ablation ICP‐MS to analyse the distribution and concentration of 12 elements. Elemental concentration and localisation in the grain samples was highly influenced by plant species, and for some elements, AMF inoculation. Heavy metals (zinc, iron, manganese, copper, cobalt and nickel) were the most highly influenced by AMF inoculation, particularly in wheat; macronutrients including phosphorus, magnesium, potassium and sulphur were also affected by AMF, particularly in barley. Elemental concentrations, particularly of macronutrients, tended to be greater in mycorrhizal barley grain than non‐mycorrhizal, but the reverse was observed in wheat grain. Mycorrhizal plants of both species had reduced accumulation of manganese, nickel and cobalt in the grain.

Localized Floods, Poverty and Food Security: Empirical Evidence from Rural Pakistan

National level floods affect large sections of the population, and in turn, receive attention from the government and international agencies. Localized natural disasters, including localized floods, do not get the attention of the government and policymakers because their impact is felt within limited geographical areas, despite the fact that these disasters severely affect the livelihood of rural communities. This study examines the impact of localized floods on the livelihood of farmers in Pakistan using a cross-sectional data set collected from 812 households. The empirical results show that localized floods severely affect rural livelihoods, and affected households have lowered cereal crop yields, less income, and reduced food security levels. Farmers adopt a number of strategies, including crop and livestock insurance, bund-making, land-leveling, and tree planting, to combat the impact of localized floods. Among all these mitigating strategies, the tree plantation is ranked as the best mitigating strategy followed by crop and livestock insurance, land leveling, and bund making, respectively. Education, wealth, access to non-governmental organizations (NGOs), extension services, and infrastructure, influence the adoption of measures to mitigate the effect of flood risks. National policy on localized flood risks needs to strengthen local institutions to provide support to families and extension services to train farmers to mitigate the impact of localized floods.

The Role and Contribution of Plant Breeding and Plant Biotechnology to Sustainable Agriculture in Africa


 
 
 Africa’s economy is driven by agriculture, a sector that constitutes 32% of the continent’s GDP. The ongoing Agricultural Transformation Agenda (ATA) in Africa hinges on a system change (from subsistence farming to agribusiness) approach that explores high productivity to strengthen the African economy. During the “Green Revolution” period, increased global yields of cereal crops were achieved through the interactions of breeding and agronomy. However, in the face of current challenges, such as climate change and need for new market niches, there is an increasing exigency to explore modern plant breeding (including biotechnology) to develop new varieties with the capacity for high yields in reduced chemical-input systems and with the genetic diversity needed to maintain yield stability in Africa ́s fluctuating climatic conditions. Biotechnology has significantly shortened the time required for the development of new cultivars, varieties and hybrids. Modern breeding tools include Double Haploid technology, marker assisted breeding, genomics, genetic engineering and genome editing. It is these tools that help accelerate the development of market responsive varieties needed for sustainable agriculture in Africa that will be highlighted.
 KEY WORDS: TECHNOLOGY, CROP IMPROVEMENT, GENETICS, MODERN BREEDING TOOLS.
 
 

Rural-urban connectivity and agricultural land management across the Global South

Research on how urbanization affects rural agriculture has typically focused on loss of farmland due to urban expansion. However, more distal pathways that could link urbanization to rural agriculture, including enhanced connectivity through rural-urban migration and market access, remain poorly understood. Here, we assess whether greater rural-urban connectivity is associated with changes in agricultural land management across the Global South. Such associations are complex, and thus difficult to measure at this scale. We therefore take a two-step approach to investigate these relationships. First, using a multivariate clustering approach, we define a series of rural-urban connectivity typologies from existing spatial data on land use, demographics, rural market access, and rural population change (as a proxy for outmigration). We examine the variation in key agricultural outcome variables (mean cereal crop yields, % of attainable yields met, and cropping frequency) within the typologies, which shows that greater overall connectivity (market access and population change) is associated with higher cereal yields, yield attainment, and cropping frequency. Second, building on these clustering results, we develop hypotheses about the relationship between rural-urban connectivity and agricultural land use intensity. We then use propensity score matching to test these hypotheses by comparing locations with similar sociodemographic and land use characteristics. When controlling for gross domestic product (GDP) per capita, agricultural land, and population density, rural locations with relatively high market access, negative population change, and greater built-up area have significantly higher mean nitrogen application rates, irrigated areas, and cereal yields across the Global South. Results vary by region, but greater rural-urban connectivity and urban extents are generally associated with higher overall agricultural inputs and yields, particularly in Asia. However, we find little support for a relationship between connectivity and either % attainable yields met or field size. Our findings stress the need to better understand the mechanisms that link urbanization processes and agricultural management at different spatiotemporal scales.

Estimation of crop angle of inclination for lodged wheat using multi-sensor SAR data

Lodging - the bending of crop stems - reduces the quantity and quality of cereal crop yields. Early quantification of crop lodging is important to prevent further losses and to facilitate harvesting operations. Crop angle of inclination (CAI) is a quantitative measure of the lodging stage and a component of lodging severity/score. CAI is an important structural parameter for lodged crops and very few studies have investigated its estimation using satellite-based remote sensing. In this study, the performance of Sentinel-1 and multi-incidence angle (FQ8-27° and FQ21-41°) RADARSAT-2 data were investigated for estimating CAI. Temporal crop biophysical/structural parameters (CAI and crop height) and meteorological data (rainfall and wind speed) were collected throughout May 1-June 30, 2018 in a very large commercial farm located in Jolanda di Savoia, Ferrara, Italy. Field data were grouped into different crop lodging stages (non-lodged/healthy (H), moderate lodging (ML), severe lodging (SL) and very severe lodging (VSL)) based on CAI. Quantitative relationships were established between field-measured CAI values and the RS-derived metrics for Sentinel-1 and RADARSAT-2 timeseries using support vector regression (SVR) models. The RADARSAT-2 FQ8 model performed most robustly with a R2CV (cross-validated R2) of 0.87 and a RMSECV (cross-validated RMSE) of 8.89° while the performance of the Sentinel-1 and RADARSAT-2 FQ21 models were comparable with an RMSECV of 11.35° and 11.63° respectively. Low incidence angle data were particularly sensitive to high CAI values (VSL) while high incidence angle data were useful for predicting lower CAI (ML and SL). While the RADARSAT-2 FQ-8 model outperformed the other two, the Sentinel-1 model still explained 78% of the CAI variability in the study site, which is important in the context of operational crop lodging stage assessment. This is the first study to demonstrate the utility of SAR remote sensing data for estimating CAI as a measure of the lodging stage and a component of lodging severity.

Pros and cons of no-till technology in a long-term field experiment on sod-podzolic soil

In a ten-year field experiment the technologies of conventional tillage (Plowing) and resource- and soil-saving treatment (No-till and Mini-till) were compared. The pros and cons of the No-tillage in the condition of temperate humid zone on the sod-podzolic soil are shown. The cons are: significant increase of soil density, lower crop biomass, higher weed infestation, an increase of pesticides application. The pros are increased soil moisture storage capacity, potential stability of cereal crop yield and economic benefits on grain production.