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In response to potential denial environments such as canyons, gullies, islands, and cities where users are located, traditional Telemetry, Tracking, and Command (TT&C) systems can still maintain core requirements such as availability, reliability, and sustainability in the face of complex electromagnetic environments and non-line-of-sight environments that may cause service degradation or even failure. This paper presents a single-station emergency solution that integrates communication and TT&C (IC&T) functions based on radar chaff cloud technology. Firstly, a suitable selection of frequency bands and modulation methods is provided for the emergency IC&T system to ensure compatibility with existing communication and TT&C systems while catering to the future needs of IC&T. Subsequently, theoretical analyses are conducted on the communication link transmission loss, data transmission, code tracking accuracy, and anti-multipath model of the emergency IC&T system based on the chosen frequency band and modulation mode. This paper proposes a dual-way asynchronous precision ranging and time synchronization (DWAPR&TS) system employing dual one-way ranging (DOWR) measurement, a dual-way asynchronous incoherent Doppler velocity measurement (DWAIDVM) system, and a single baseline angle measurement system. Next, we analyze the physical characteristics of the radar chaff and establish a dynamic model of spherical chaff cloud clusters based on free diffusion. Additionally, we provide the optimal strategy for deploying chaff cloud. Finally, the emergency IC&T application based on the radar chaff cloud relay is simulated, and the results show that for severe interference, taking drones as an example, under a measurement baseline of 100 km, the emergency IC&T solution proposed in this paper can achieve an accuracy range of approximately 100 m, a velocity accuracy of 0.1 m/s, and an angle accuracy of 0.1°. In comparison with existing TT&C system solutions, the proposed system possesses unique and potential advantages that the others do not have. It can serve as an emergency IC&T reference solution in denial environments, offering significant value for both civilian and military applications.

HWSC systems that target weed seed production during harvest have been in use in Australian crop production systems for over 30 years. Until recently, though, grower adoption of these systems has been relatively low. It is now apparent with the introduction of a range of new weed seed targeting systems that there is renewed grower interest in the use of this approach to weed control. With the aim of determining the current adoption and use of HWSC systems, 600 crop producers from throughout Australia's cropping regions were interviewed on their adoption and use of these systems. This survey established that 43% of Australian growers are now routinely using HWSC to target weed seed production during grain harvest. The adoption of narrow-windrow burning (30%) was considerably greater than the other currently available techniques of chaff tramlining (7%), chaff carts (3%), bale-direct system (3%), and the Harrington Seed Destructor (HSD) (<1%). When growers were asked about their future use of these systems 82% indicated that they would be using some form of HWSC within five years. Grower preferences for future HWSC use were primarily for either narrow-windrow burning (42%) or the HSD (29%). This very high level of current and potential HWSC adoption signifies that HWSC is now considered an established weed control practice by Australian growers.

The widespread evolution of multiple herbicide resistance in the most serious annual weeds infesting Australian cropping fields has forced the development of alternative, non-chemical weed control strategies, especially new techniques at grain harvest. Harvest weed seed control (HWSC) systems target weed seed during commercial grain harvest operations and act to minimize fresh seed inputs to the seedbank. These systems exploit two key biological weaknesses of targeted annual weed species: seed retention at maturity and a short-lived seedbank. HWSC systems, including chaff carts, narrow windrow burning, bale direct, and the Harrington Seed Destructor, target the weed seed bearing chaff material during commercial grain harvest. The destruction of these weed seeds at or after grain harvest facilitates weed seedbank decline, and when combined with conventional herbicide use, can drive weed populations to very low levels. Very low weed populations are key to sustainability of weed control practices. Here we introduce HWSC as a new paradigm for global agriculture and discuss how these techniques have aided Australian grain cropping and their potential utility in global agriculture. La ampliamente diseminada evolución de resistencia a múltiples herbicidas en las malezas anuales más serias infestando los sistemas de cultivos australianos ha forzado el desarrollo de estrategias de control de malezas alternativas, especialmente nuevas técnicas al momento de la cosecha de granos. Los sistemas de control de semillas de malezas en cosecha (HWSC) se enfocan en las semillas de malezas durante las operaciones de cosecha comercial de granos y actúan para minimizar el suministro de semillas frescas al banco de semillas. Estos sistemas explotan dos debilidades biológicas clave de las especies de malezas anuales de interés: retención de semilla al momento de la madurez y un banco de semillas de corta vida. Los sistemas HWSC, incluyendo las carretas de descarga de grano, la quema de líneas angostas de residuos después de la cosecha, el embalado directo, y el Destructor de Semilla Harrington, se enfocan en los residuos de cosecha que contienen semillas de maleza durante la cosecha comercial de grano. La destrucción de estas semillas de malezas durante o después de la cosecha del grano facilitan la reducción del banco de semillas de malezas, y cuando se combinan con el uso convencional de herbicidas, pueden llevar las poblaciones de malezas a niveles muy bajos. Tener poblaciones muy bajas de malezas es clave para la sostenibilidad de las prácticas de control de malezas. Aquí, nosotros introducimos HWSC como un nuevo paradigma para la agricultura global y discutimos como estas técnicas han ayudado a la producción australiana de granos y su utilidad potencial en la agricultura global.

Chaff jamming is a widely used passive interference method. A chaff cloud diffusion model for the widespread chaff cloud was presented. The high-density chaff cloud aerodynamic model can rapidly predict the chaff elements’ time-varying spatial orientation, location, and overall spatial distribution. Basing on these pieces of information, the radar cross section (RCS) for the single chaff fibre can be obtained based on the method of moments (MoM). For high-density chaff clouds, the attenuation and shielding effects on the signal must be considered. This paper proposed a voxel splitting method in rotated coordinates, dividing the chaff cloud into rectangular cells with one side perpendicular to the direction of radar entry. The varied polarized RCS features of the chaff cloud were simulated and analysed on this foundation. By dividing the chaff cloud into dynamic voxels and considering the uneven density distribution of the chaff cloud and the signal attenuation in each segment caused by the continuous fluctuating shape, fine-grained simulations of the chaff cloud radar echoes can be performed.

Phosphorus (P) fertilisers have long been applied to sandy soils in south-western Australia to enhance agricultural production. However, significant P leaching is experienced which decreases P availability to crops. The aim of this study was to determine if biochar could be used as a soil amendment to decrease P leaching and increase P uptake by wheat plants. A lysimeter study was designed where two types of biochar, derived either from chicken manure (CM) or wheat chaff (WC) at 0, 1 and 2 % ( w / w ) and three P fertiliser rates at 0, 25 and 50 kg/ha, were applied to a loamy sand soil where wheat ( Triticum aestivum L. var. Wyalkatchem) was grown under glasshouse conditions. Leaching events were conducted over a period of 8 weeks at two weekly intervals. Leachate volume was less in the biochar-amended soil compared to non-amended soil. Biochar increased plant shoot P uptake but also P leaching, which was attributed to P derived from both the applied fertiliser and the biochar. Biochar also increased available P and microbial biomass P in soil, although the extent of increase with WC biochar was less pronounced than for that with CM biochar. Biochar application increased mycorrhizal colonisation in wheat roots which was higher (up to 70 %) at the P application rate of 25 kg/ha but declined with P application rate of 50 kg/ha (to 35 %). Increase in soil pH and mycorrhizal colonisation from biochar application might be contributing to the increase in plant P uptake and shoot growth. However, biochar was not a mitigation strategy to decrease P leaching on these sandy soils.

Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of chaff material containing weed seed into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the chaff environment is unfavorable for weed seed survival. The chaff row environment effect on weed seed survival was examined in field studies, and chaff response studies determined the influence of increasing amounts of chaff on weed seedling emergence. The objectives of these studies were to determine the influences of (1) chaff lines on the summer–autumn seed survival of selected weed species and (2) chaff type and amount on rigid ryegrass seedling emergence. There was frequently no difference (P > 0.05) in seed survival of four weed species (rigid ryegrass, wild oat, annual sowthistle, and turnip weed) when seeds were placed beneath or beside chaff lines. In one instance, wild oat seed survival was increased (P < 0.05) when seed were placed beneath compared to beside a chaff line. The pot studies determined that increasing amounts of chaff consistently resulted in decreasing numbers of rigid ryegrass seedlings emerging through chaff material. The suppression of emergence broadly followed a linear relationship in which there was approximately a 2.0% reduction in emergence with every 1,000 kg ha–1 increase in chaff material. This relationship was consistent across wheat, barley, canola, and lupin chaff types, indicating that the physical presence of the chaff was more important than chaff type. These studies suggested that chaff lines may not affect the survival over summer–autumn of the contained weed seeds but that the subsequent emergence of weed seedlings will be restricted by high amounts of chaff (>40,000 kg ha–1). Nomenclature: Annual sowthistle; Sonchus oleraceus L.; rigid ryegrass; Lolium rigidum Gaud.; turnip weed; Rapistrum rugosum (L.) All.; wild oat Avena fatua L.; barley; Hordeum vulgare L.; canola; Brassica napus L.; lupin; Lupinus angustifolius L.; wheat; Triticum aestivum L.

Chaff jamming is one of the common countermeasures in electronic warfare against radio fuze. Currently, there is no unified and effective evaluation criterion and method for the anti-chaff jamming capability of radio fuze. An evaluation method for the anti-chaff jamming performance of radio fuze during the missile-target encounter trajectory phase is proposed. A dynamic echo model of chaff clouds was established. The echo signals of the chaff cloud and the target were calculated and the fuze actuation were simulated and analyzed. The results show that this evaluation method can effectively assess the anti-chaff jamming performance of typical radio fuze.

Wild oat is a significant weed of cropping systems in the Canadian Prairies. Wild oat resistance to herbicides has increased interest in the use of nonchemical management strategies. Harvest weed seed control techniques such as impact mills or chaff collection have been of interest in Prairie crops, with wild oat identified as a key target. To evaluate the effects of crop rotation maturity, harvest management, and harvest weed seed control on wild oat, a study was conducted from 2016 to 2018 at four locations in the Canadian Prairies. Two-year crop rotations with either early, normal, or late-maturing crops were implemented before barley was seeded across all rotations in the final year. In addition, a second factor of harvest management (swathing or straight cut) was included in the study. Chaff collection was used in this study to quantify wild oat seeds that were targetable by harvest weed seed control techniques. The hypothesis was that earlier maturing crops would result in increased wild oat capture at harvest and, therefore, lower wild oat populations. Wild oat density and wild oat biomass were lowest in the early maturing rotations. In addition, wild oat exhibited lower biomass in swathed crops than straight-cut crops. Wild oat seedbank levels reflected a similar trend with the lowest densities occurring in early maturing rotation, then the normal maturity rotation, and the late maturing rotation, which had the highest seedbank densities. Wild oat densities increased in all crop rotations; however, only harvest weed seed control and crop rotation were implemented as control measures. Wild oat numbers in the chaff were not reflective of the earliness of harvest. Crop yields suggest that competitive winter wheat stands contributed to the success of the early maturing rotations compared to other treatments. Early maturing rotations resulted in reduced wild oat populations, likely through a combination of crop competitiveness and rotational diversity, and harvest weed seed control management effects from earlier maturing crops.

Recent studies have broadened our knowledge regarding the origins of agriculture in southwest Asia by highlighting the multiregional and protracted nature of plant domestication. However, there have been few archaeobotanical data to examine whether the early adoption of wild cereal cultivation and the subsequent appearance of domesticated-type cereals occurred in parallel across southwest Asia, or if chronological differences existed between regions. The evaluation of the available archaeobotanical evidence indicates that during Pre-Pottery Neolithic A (PPNA) cultivation of wild cereal species was common in regions such as the southern-central Levant and the Upper Euphrates area, but the plant-based subsistence in the eastern Fertile Crescent (southeast Turkey, Iran, and Iraq) focused on the exploitation of plants such as legumes, goatgrass, fruits, and nuts. Around 10.7–10.2 ka Cal BP (early Pre-Pottery Neolithic B), the predominant exploitation of cereals continued in the southern-central Levant and is correlated with the appearance of significant proportions (∼30%) of domesticated-type cereal chaff in the archaeobotanical record. In the eastern Fertile Crescent exploitation of legumes, fruits, nuts, and grasses continued, and in the Euphrates legumes predominated. In these two regions domesticated-type cereal chaff (>10%) is not identified until themiddle and late Pre-Pottery Neolithic B (10.2–8.3 ka Cal BP). We propose that the cultivation of wild and domesticated cereals developed at different times across southwest Asia and was conditioned by the regionally diverse plant-based subsistence strategies adopted by Pre-Pottery Neolithic groups.