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Abstract Meteorological conditions affect the dynamics of nitrogen (N) by oat crops. Fuzzy logic allows the development of simulation models involving N management and the non-linearity of meteorological conditions. The objective of this study was to identify the most sustainable N management for oat crops considering N rates applied at sowing and as top-dressing with different timing. Potential variables were selected for the development of a rule base for fuzzy modeling and simulate grain yield for N managements considering the non-linearity of meteorological conditions. The experiment was carried out in Augusto Pestana, RS, Brazil, from 2015 to 2017. A randomized block design with four replications was used, in a 4×3 factorial arrangement, consisted of four N rates applied at sowing (0, 10, 30 and 60 kg/ha), using total N top-dressing rates of 70 kg/ha for the soybean-oat and 100 kg/ha for the maize-oat, applied at three timings (10, 30, and 60 days after emergence). The most sustainable N managements for oat crops were under absence of N and application 10 kg/ha of N at sowing, with the remainder applied as top-dressing at 10 and 30 days after emergence. The N application timing, mean air temperature, and rainfall depth are potential variables for the development of a rule base for fuzzy modeling, and efficient in simulating oat grain yield.

Rotational cropping is an important and effective agricultural management practice that significantly contributes to crop yields, plant health, and soil structure. Microorganisms invariably accompany crop growth and play a vital role in facilitating plant nutrient uptake, disease resistance, and adaptation to environmental stressors. Given the essentiality of microorganisms in the soil ecosystem, exploring the contribution of soil microbial communities to the rotational cropping system is of significant reference value for improving the rotational cropping system. Although numerous studies have investigated the differences in microbial communities in various crop rotation systems, considering the factors such as the growth stage of wheat, climate, soil fertility, and human activities that exert a significant impact on soil microorganisms, it is imperative to study the effects of different crop rotation systems on soil microbial communities at various growth stages of wheat under controlled experimental conditions. Based on a 12-year long-term rotational cropping platform, we analyzed the composition and structure of bacterial and fungal communities in the rhizosphere of wheat under three crop rotation systems at four growth stages: wheat-maize, wheat-soybean, and wheat-cotton, and constructed a co-occurrence network to identify potential key functional microorganisms. The results showed that both the rotational cropping system and the growth stage of wheat had significant effects on the microbial communities in the long-term rotational cropping system, while the effects of crop rotation systems (R2=0.140) were stronger than growth stage (R2=0.108). And the differences in microbial communities had a certain cumulative effect on the growth and development of wheat. In addition, the rhizosphere microbial co-occurrence network of the wheat-cotton rotational cropping system had 26 key functional microorganisms, much more than those in the other two systems. However, it is worth noting that the key microorganisms in the wheat corn rotation system have a stronger promoting effect on wheat growth. Two of the key functional microorganisms, Niabella_Hub9 and Dokdonella_Hub24, had a significant promoting effect on wheat yield. This study improves the understanding and recognition of the functions and roles of microorganisms in different crop rotation systems, providing a basis for rational utilization and optimization of crop rotation systems. • Rotation systems and growth stages notably affect rhizosphere microbial community. • Rotation systems significantly influence the function of microbial communities. • Wheat cotton rotation co-occurrence network has the most hubs but lowest stability. • Key microbes in wheat maize rotation notably correlated with indicators of wheat. [ABSTRACT FROM AUTHOR]

Introducing legumes to crop rotations could contribute toward healthy and sustainable diet transitions, but the current evidence base is fragmented across studies that evaluate specific aspects of sustainability and nutrition in isolation. Few previous studies have accounted for interactions among crops, or the aggregate nutritional output of rotations, to benchmark the efficiency of modified cropping sequences. We applied life cycle assessment to compare the environmental efficiency of ten rotations across three European climatic zones in terms of delivery of human and livestock nutrition. The introduction of grain legumes into conventional cereal and oilseed rotations delivered human nutrition at lower environmental cost for most of the 16 impact categories studied. In Scotland, the introduction of a legume crop into the typical rotation reduced external nitrogen requirements by almost half to achieve the same human nutrition potential. In terms of livestock nutrition, legume-modified rotations also delivered more digestible protein at lower environmental cost compared with conventional rotations. However, legume-modified rotations delivered less metabolisable energy for livestock per hectare-year in two out of the three zones, and at intermediate environmental cost for one zone. Our results show that choice of functional unit has an important influence on the apparent efficiency of different crop rotations, and highlight a need for more research to develop functional units representing multiple nutritional attributes of crops for livestock feed. Nonetheless, results point to an important role for increased legume cultivation in Europe to contribute to the farm and diet sustainability goals of the European Union's Farm to Fork strategy.

[Display omitted] • The response of bacterial community to rotation difference was higher than fungi. • Garlic-maize rotation increased the connection density of bacterial network. • Garlic-maize rotation decreased fungal network connectivity. • The decreasing SOC increased the bacterial diversity and abundance. • Garlic -maize rotation decreased C and P limitation, and increased N limitation. The ecological environment and function of farmland soil are strongly affected by crops. However, there is still a lack of understanding of how the soil microbial environment responds to crop changes in rotation systems. Therefore, we studied wheat–maize (W–M) and garlic–maize (G–M) crop rotation systems to explore the responses in terms of soil nutrients and the microbial community to different tillage systems. The results showed that the W–M cropping system was continuously limited by phosphorus nutrition, and the G–M cropping system was alternately affected by nitrogen and phosphorus nutrition due to the different nutrient requirements of crops. The bacterial communities were significantly affected by the cropping systems and crop types, whereas the fungal communities were only affected by the crop types. Compared with W–M, G–M increased the abundances of Nitrospirae, Bacteroidetes, and Rokubacteria in the bacterial community, and decreased the abundance of Basidiomycota in the fungal community, as well as increasing the nodes and links between bacterial communities but weakening the links between fungal communities. Compared with W-M, G-M decreases the contents of soil organic carbon and total nitrogen, increases the diversity and abundance of bacteria, and decreases the diversity of fungi, thereby reducing extracellular enzyme C/N and N/P, and increasing the activity ratio of C/P, ultimately reduces C and P limitations and increases N limitations. Differences in crop types result in greater changes in soil bacteria than fungi in crop rotation systems. Our study provides more insights into the relationship between soil nutrient limitation and microenvironment in rotation systems. [ABSTRACT FROM AUTHOR]

This study explored the influence of different crop rotations and fertilization methods on the nitrogen and phosphorus runoff loss⁃ es in Erhai Lake basin. Field plot experiments were conducted to investigate the crop yields and characteristics of nitrogen and phosphorus runoff losses under seven different rotation systems: Garlic-corn, barley-rice, oilseed rape-rice, broad bean-tobacco, garlic-tobacco, broad bean-rice, and garlic-rice, combined with three fertilization methods: Fast-release fertilizer (CF), slow-release bulk blending fertilizer （BB）, and no fertilizer (CK). Compared with CF, application of BB reduced the amount of nitrogen and phosphorus fertilizer by 9.85%~ 47.49% and 10.81%~63.33%, respectively, and there were obvious yield increases: 19.69% for rice in the barley-rice rotation, 16.99% for broad beans in the broad bean-rice rotation, 24.32% for garlic in the garlic-rice rotation, and 35.79% for oilseed rape in the oilseed raperice rotation. Under the seven rotation systems, the total amounts of nitrogen and phosphorus runoff losses in BB treatments were lower by 10.72%~28.80% and 17.13%~47.87%, respectively, than those in the CF treatments. Higher amounts of fertilizer applied to flue-cured to⁃ bacco resulted in increased runoff losses of nitrogen and phosphorus of 5 907.00 g·hm-2 and 821.25 g·hm-2, respectively. The oilseed raperice rotation resulted in high runoff loss of phosphorus（1 045.77 g·hm-2）. Our results indicated that BB fertilizers specifically tailored for targeted crops and soils could effectively reduce the nitrogen and phosphorus runoff losses. Broad bean-rice is a good rotation system for decreasing non-point pollution from nitrogen and phosphorus in Erhai Lake basin. [ABSTRACT FROM AUTHOR]

The Huang-Huai-Hai Plain in China relies heavily on the winter wheat-summer maize rotation for grain production. However, this cropping system faces challenges regarding its sustainability due to significant environmental costs. This study aims to evaluate the nitrogen footprint of different cropping systems, compare their economic benefits, and identify alternative summer crops that can optimize system yield, economic advantages, and environmental impact. A three-year field experiment was conducted to compare the economic and environmental impacts of three cropping systems: winter wheat-summer maize (W-M), winter wheat-summer soybean (W-S), and winter wheat-sweet potato (W-SP). The experiment involved assessing yield, inputs, and outputs, and conducting a comprehensive nitrogen footprint analysis for each system. Over the three experimental years, the W-S system showed the highest yield improvement for winter wheat. The W-SP system had the highest annual maize equivalent yield and total income but incurred the highest total annual cost compared to the other two systems. However, the W-SP system demonstrated the highest annual average economic profit performance, nearly double that of the other two systems. The nitrogen footprint analysis revealed that both the W-S and W-SP systems reduced reactive nitrogen emissions compared to the W-M system. Notably, the W-S system managed to reduce the nitrogen footprint by 34%. The average nitrogen footprint emissions scores for W-M, W-S, and W-SP systems were 2.1, 2.3, and 3.5, respectively. Among the three systems, the W-SP system achieved the highest economic benefits but also had the greatest negative environmental impact. The W-S system demonstrated a significant reduction in reactive nitrogen loss while maintaining productivity, indicating its potential for mitigating negative environmental impacts. Our three-year field study highlights the advantages of the W-S system in reducing the nitrogen footprint and its potential contribution to sustainable agricultural development in the Huang-Huai-Hai Plain. [Display omitted] • Nitrogen footprints (NF) in different cropping systems were evaluated. • Shifting summer maize to soybean obtained higher yields and economic benefits. • Introducing sweet potato got the highest income but paid environmental cost most. • The soybean-based system could maintain system yield and reduce NF by 34.06%. [ABSTRACT FROM AUTHOR]

In three years rotation systems each field divided to two parts and 1st part cultivated with onion and potato and second part kept fallow. In 2nd year onion cultivated on potato and vice versa and fallow plots went under potato planting. In the 3rd year, onion cultivated on onion and potato planted on potato and onion. So fallow-onion, fallow-potato, onion-onion, potato-onion, onion-potato and potato-potato rotation systems were studied. Results showed that potato-onion rotation increased significantly bulb yield by producing jumbo bulbs. Tuber yield in fallow-potato was high because of more coarse seed tubers. In onion-potato system, tubers were tiny and big tubers were less but jumbo. Second year fallow-potato seed and little tubers were more so their sizes become tiny. But in potato-potato fewer yields obtained because of three sizes less number and size. Potato increased soil organic carbon (OC) percentage. Following onion decreased OC and another potato increased OC again sharply. OC changes in fallow year plots showed minimum change but in second year planting potato increased OC more than onion. Fallow-potato-potato system increased OC from second year end, but potato-onion-potato system showed decrease after increase and onion-onion-onion increase OC constantly.

Conservation agriculture management practices (e.g., cover crops and residue retention) have been widely promoted to improve soil quality and environmental sustainability. However, little is known about the long-term interactive effects of cover crops and residue retention on yield of the cash crops and environmental outcomes in dryland cropping systems under climate change. We used the pre-validated APSIM model, driven by statistically downscaled daily climate data from 27 Global Climate Models (GCMs) under two Shared Socioeconomic Pathways (SSP245 and SSP585), to assess the combined influences of cowpea cover crops and three residue retention levels on soil water balance, soil organic carbon (SOC), nitrogen (N) dynamics, crop yield and gross margin across six crop rotation systems during the historical period (1985–2020), near future (2021–2056), and far future (2057–2092) in southeast Australia. Our results showed that, on average, cover crops decreased soil moisture on the day of sowing the succeeding cash crop (by 22%), but led to greater SOC stock (21%), reduced N loss through leaching (71%), and enhanced N uptake and yield of cereals, but decreased N uptake and yield of field pea. The effects of cover crops on yield and gross margin became more positive in the far future under both SSPs, which may be attributed to the SOC increase and greater N availability in the long term. These benefits were more evident under residue removal due to the partly compensatory effects from cover crop residues. Furthermore, cover crops were profitable in the wetter parts of the study region (east), but reduced gross margin in the drier west due to depletion of soil water reserves for the next cash crop. We conclude that particularly where residues are removed, the long-term adoption of cowpea cover crops could be a potential practice to sustain crop productivity with environmental co-benefits under climate change in the wetter parts of the dryland cropping region of southeast Australia. • Cover crops increase SOC, N availability, and cash crop yields except for field pea. • Benefits to yield increase under climate change but decrease with residue retention. • Cover crops are profitable in the wetter area but not in the drier part of the study region. • Long-term use of cover crops may achieve co-benefits for production and environment. [ABSTRACT FROM AUTHOR]

In this paper we study embeddings of the Fano plane as a bipartite graph. We classify all possible embeddings especially focusing on those with non-trivial automorphism group. We study them in terms of rotation systems, isomorphism classes and chirality. We construct quotients and show how to obtain information about face structure and genus of the covering embedding. As a by-product of the classification we determine the genus polynomial of the Fano plane. [ABSTRACT FROM AUTHOR]

This work presents the development of a methodology that, through the use of the coordinate transformation method, identifies the ideal modal parameters that should be used during the modal balancing process as well as allows eliminating the computational modes generated during the rotor response diagram extraction process. There is currently a wide variety of methods for structures that allow extracting limited modal parameters, such as: previous knowledge of the number of modes, adjustment of computational or spurious modes, close mode identification problems, and others. However, localizing the phase angle in rotation systems in any angular position and through complex coupling of the vibration modes does not ensure that the methods developed for structures conserve the same performance during the adjustment process. As regards the line of investigation into modal balancing, a method is proposed that allows ensuring that the modes found are real modes of the system and that through direction tracking where a single vibration mode is excited, the optimum extraction position of the modal parameters used in the balancing process can be determined. The proposed methodology was developed using a linear model and was applied in a field turbogenerator to identify the vibration modes present in the response diagrams. [ABSTRACT FROM AUTHOR]

In this paper, we suggest an algorithm to enhance the accuracy of sensor measurements representing camera parameters. The process proposed is based solely on a pair of wide baseline (or sparse view) images. We use the so-called JUDOCA operator to extract junctions. This operator produces junctions in terms of locations as well as orientations. Such an information is used to estimate an affine transformation matrix, which is used to guide a variance normalized correlation process that produces a set of possible matches. The fundamental matrix can be easily estimated using the so-called RANSAC scheme. Consequently, the essential matrix can be derived given the available calibration matrix. The essential matrix is then decomposed using Singular Value Decomposition. In addition to a translation vector, this decomposition results in a rotation matrix with accurate rotation angles involved. Mathematical derivation is done to extract angles from the rotation matrix and express them in terms of different rotation systems.

Many sustainable agronomical practices can be adopted to contain environmental risks of crop production and, at the same time, sustain yield and quality. In this framework, the aim of this research was to study the effects of continuous cropping (CC) and crop rotation, tillage and fertilization strategies on durum wheat (Triticum durum Desf.) production. The responses of soil properties were further investigated. The research was carried out from 1998 to 2006 in two two-year rotations repeated two times and in a continuous cropping. The wheat yield and total nitrogen (N) uptake mean value were significantly higher in rotation (by 9.7 and 21.5%, respectively) than in CC. Moreover, the broad bean-wheat rotation significantly increased wheat performance, in particular yield (+35.2 and 47.9% in conventional and in minimum tillage, respectively) compared to sugar beet-wheat rotation. The minimum tillage increased total organic carbon compared to the conventional one and this enhancement was observed both in CC and rotation (+11.6 and 10.6%, respectively). The reduced tillage also increased total N in both cropping systems and mineral N (+25.4%) in rotation. On the whole, the findings of this research provide an opportunity to identify best cultivation strategies to improve wheat performance in rainfed farming systems. [ABSTRACT FROM AUTHOR]

We show that, if $\mathrm{P}\not=\mathrm{NP}$, there is a constant c>1 such that there is no c-approximation algorithm for the crossing number, even when restricted to 3-regular graphs. [ABSTRACT FROM AUTHOR]

Historians and economists have been unaware of environmental constraints and they have considered the low yield per hectare of the main cereals to be an indication of the relative backwardness of Southern Spanish agriculture. This paper proposes a methodology of analysis that integrates environmental and economic variables to explain the differences in crop productivity between Southern Spain and northern Europe in the 19th century. Here, the relative backwardness will be explained not only by deficiencies in productivity, capital investment or diffusion of new technology, but principally by the comparative ecological disadvantages that areas such as Andalusia had in comparison with Northern Europe, if an agricultural growth based on cereals was to be chosen. [Copyright &y& Elsevier]