Nanotechnology has shown promising potential to promote sustainable agriculture. This article reviews the recent developments on applications of nanotechnology in agriculture including crop ...production and protection with emphasis on nanofertilizers, nanopesticides, nanobiosensors and nano-enabled remediation strategies for contaminated soils. Nanomaterials play an important role regarding the fate, mobility and toxicity of soil pollutants and are essential part of different biotic and abiotic remediation strategies. Efficiency and fate of nanomaterials is strongly dictated by their properties and interactions with soil constituents which is also critically discussed in this review. Investigations into the remediation applications and fate of nanoparticles in soil remain scarce and are mostly limited to laboratory studies. Once entered in the soil system, nanomaterials may affect the soil quality and plant growth which is discussed in context of their effects on nutrient release in target soils, soil biota, soil organic matter and plant morphological and physiological responses. The mechanisms involved in uptake and translocation of nanomaterials within plants and associated defense mechanisms have also been discussed. Future research directions have been identified to promote the research into sustainable development of nano-enabled agriculture.
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•Nanotechnology could promote sustainable agriculture.•Different roles of nanotechnology in agriculture are illustrated.•Comprehensive evaluation of its impacts on soil, plant and environment.•Perspectives on future challenges and opportunities in nano-enabled agriculture.
Climate change, increasing populations, competing demands on land for production of biofuels and declining soil quality are challenging global food security. Finding sustainable solutions requires ...bold new approaches and integration of knowledge from diverse fields, such as materials science and informatics. The convergence of precision agriculture, in which farmers respond in real time to changes in crop growth with nanotechnology and artificial intelligence, offers exciting opportunities for sustainable food production. Coupling existing models for nutrient cycling and crop productivity with nanoinformatics approaches to optimize targeting, uptake, delivery, nutrient capture and long-term impacts on soil microbial communities will enable design of nanoscale agrochemicals that combine optimal safety and functionality profiles.
Drawing on a harmonized longitudinal dataset covering more than 55,000 smallholder farms in six African countries, we analyze changes in crop productivity from 2008 to 2019. Because smallholder ...farmers represent a significant fraction of the world's poorest people, agricultural productivity in this context matters for poverty reduction and for the broader achievement of the UN Sustainable Development Goals. Our analysis measures productivity trends for nationally representative samples of smallholder crop farmers, using detailed data on agricultural inputs and outputs which we integrate with detailed data on local weather and environmental conditions. In spite of government commitments and international efforts to strengthen African agriculture, we find no evidence that smallholder crop productivity improved over this 12-y period. Our preferred statistical specification of total factor productivity (TFP) suggests an overall decline in productivity of -3.5% per year. Various other models we test also find declining productivity in the overall sample, and none of them finds productivity growth. However, the different countries in our sample experienced varying trends, with some instances of growth in some regions. The results suggest that major challenges remain for agricultural development in sub-Saharan Africa. They complement previous analyses that relied primarily on aggregate national statistics to measure agricultural productivity, rather than detailed microdata.
The superior agronomic and human nutritional properties of grain legumes (pulses) make them an ideal foundation for future sustainable agriculture. Legume‐based farming is particularly important in ...Africa, where small‐scale agricultural systems dominate the food production landscape. Legumes provide an inexpensive source of protein and nutrients to African households as well as natural fertilization for the soil. Although the consumption of traditionally grown legumes has started to decline, the production of soybeans (Glycine max Merr.) is spreading fast, especially across southern Africa. Predictions of future land‐use allocation and production show that the soybean is poised to dominate future production across Africa. Land use models project an expansion of harvest area, whereas crop models project possible yield increases. Moreover, a seed change in farming strategy is underway. This is being driven largely by the combined cash crop value of products such as oils and the high nutritional benefits of soybean as an animal feed. Intensification of soybean production has the potential to reduce the dependence of Africa on soybean imports. However, a successful “soybean bonanza” across Africa necessitates an intensive research, development, extension, and policy agenda to ensure that soybean genetic improvements and production technology meet future demands for sustainable production.
Soybean is fast becoming an increasingly attractive cash crop in Africa. We have examined current and future legume production in Sub‐Saharan Africa using a modelling approach based on available FAO data to provide projections for 2050. These data predict a large expansion in African soybean production. The resultant great potential for the amelioration of poverty, hunger, and malnutrition will be a major driver for farmers and producers to overcome the significant challenges that might otherwise impede soybean production in Africa.
Nitrate is an essential nutrient and signaling molecule for plant growth. Plants sense intracellular nitrate to adjust their metabolic and growth responses. Here we identify the primary nitrate ...sensor in plants. We found that mutation of all seven
Arabidopsis
NIN-like protein (NLP) transcription factors abolished plants’ primary nitrate responses and developmental programs. Analyses of NIN-NLP7 chimeras and nitrate binding revealed that NLP7 is derepressed upon nitrate perception via its amino terminus. A genetically encoded fluorescent split biosensor, mCitrine-NLP7, enabled visualization of single-cell nitrate dynamics in planta. The nitrate sensor domain of NLP7 resembles the bacterial nitrate sensor NreA. Substitutions of conserved residues in the ligand-binding pocket impaired the ability of nitrate-triggered NLP7 to control transcription, transport, metabolism, development, and biomass. We propose that NLP7 represents a nitrate sensor in land plants.
Transcription-activating nitrate sensor
Plants depend on nitrogen, responding with changes in growth and metabolism when nitrogen supplies change. Indeed, nitrogen fertilizer underlies a good deal of agricultural crop productivity. Studying a family of seven similar genes, Liu
et al
. identified the nitrate sensor in the small mustard plant
Arabidopsis thaliana
. The protein’s nitrate-binding pocket resembles that found in bacteria nitrate sensors. Conformation change upon nitrate binding allows the protein to then function as a transcriptional activator, triggering the plant’s responses to nitrogen availability. —PJH
A single bifunctional protein links nitrate sensing to changes in transcription in the small mustard plant
Arabidopsis thaliana
.
Biochar application to croplands has been proposed as a potential strategy to decrease losses of soil‐reactive nitrogen (N) to the air and water. However, the extent and spatial variability of ...biochar function at the global level are still unclear. Using Random Forest regression modelling of machine learning based on data compiled from the literature, we mapped the impacts of different biochar types (derived from wood, straw, or manure), and their interactions with biochar application rates, soil properties, and environmental factors, on soil N losses (NH3 volatilization, N2O emissions, and N leaching) and crop productivity. The results show that a suitable distribution of biochar across global croplands (i.e., one application of <40 t ha−1 wood biochar for poorly buffered soils, such as those characterized by soil pH<5, organic carbon<1%, or clay>30%; and one application of <80 t ha−1 wood biochar, <40 t ha−1 straw biochar, or <10 t ha−1 manure biochar for other soils) could achieve an increase in global crop yields by 222–766 Tg yr−1 (4%–16% increase), a mitigation of cropland N2O emissions by 0.19–0.88 Tg N yr−1 (6%–30% decrease), a decline of cropland N leaching by 3.9–9.2 Tg N yr−1 (12%–29% decrease), but also a fluctuation of cropland NH3 volatilization by −1.9–4.7 Tg N yr−1 (−12%–31% change). The decreased sum of the three major reactive N losses amount to 1.7–9.4 Tg N yr−1, which corresponds to 3%–14% of the global cropland total N loss. Biochar generally has a larger potential for decreasing soil N losses but with less benefits to crop production in temperate regions than in tropical regions.
Biochar is expected as a potential strategy for cropland N conservation. Uncertainties exist, however, regarding the extent and spatial variability of biochar function at the global level. Using Random Forest regression modelling of machine learning, this study mapped the impacts of different biochar types, and their interactions with biochar application rates, soil properties and environmental factors, on soil N losses (NH3 volatilization, N2O emissions, and N leaching) and crop productivity. Results show that a suitable biochar management has the potential to achieve a decrease in 3%–14% in global cropland N losses, with an increase in 4%–16% in global crop production.
The globally recognized need to advance more sustainable agriculture and food systems has motivated the emergence of transdisciplinary solutions, which include methodologies that utilize the ...properties of materials at the nanoscale to address extensive and inefficient resource use. Despite the promising prospects of these nanoscale materials, the potential for large-scale applications directly to the environment and to crops necessitates precautionary measures to avoid unintended consequences. Further, the effects of using engineered nanomaterials (ENMs) in agricultural practices cascade throughout their life cycle and include effects from upstream-embodied resources and emissions from ENM production as well as their potential downstream environmental implications. Building on decades-long research in ENM synthesis, biological and environmental interactions, fate, transport and transformation, there is the opportunity to inform the sustainable design of nano-enabled agrochemicals. Here we perform a screening-level analysis that considers the system-wide benefits and costs for opportunities in which ENMs can advance the sustainability of crop-based agriculture. These include their on-farm use as (1) soil amendments to offset nitrogen fertilizer inputs, (2) seed coatings to increase germination rates and (3) foliar sprays to enhance yields. In each analysis, the nano-enabled alternatives are compared against the current practice on the basis of performance and embodied energy. In addition to identifying the ENM compositions and application approaches with the greatest potential to sustainably advance crop production, we present a holistic, prospective, systems-based approach that promotes emerging alternatives that have net performance and environmental benefits.
Productivity growth in smallholder agriculture is an important driver of rural economic development and poverty reduction. However, smallholder farmers often have limited access to information, which ...can be a serious constraint for increasing productivity. One potential mechanism to reduce information constraints is the public agricultural extension service, but its effectiveness has often been low in the past. Digital technologies could enhance the effectiveness of extension by reducing outreach costs and helping to better tailor the information to farmers' individual needs and conditions. Using primary data from India, this study analyses the association between digital extension services and smallholder agricultural performance. The digital extension services that some of the farmers use provide personalized information on the types of crops to grow, the types and quantities of inputs to use, and other methods of cultivation. Problems of selection bias in the impact evaluation are reduced through propensity score matching (PSM) combined with estimates of farmers' willingness to pay for digital extension. Results show that use of personalized digital extension services is positively and significantly associated with input intensity, production diversity, crop productivity, and crop income.
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