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Cereal crops play a critical role in global food security, but their productivity is increasingly threatened by climate change. This study evaluates the feasibility of using PlanetScope satellite imagery and a UAV equipped with the MicaSense RedEdge multispectral imaging sensor in monitoring winter wheat under various fertilizer treatments in a Mediterranean climate. Eleven fertilizer treatments, including organic-mineral fertilizer (OMF) pellets, were tested. The results show that conventional inorganic fertilization provided the highest yield (8618 kg ha⁻1), while yields from OMF showed a comparable performance to traditional fertilizers, indicating their potential for sustainable agriculture. PlanetScope data demonstrated moderate accuracy in predicting canopy cover (R2 = 0.68), crop yield (R2 = 0.54), and grain quality parameters such as protein content (R2 = 0.49), starch (R2 = 0.56), and hectoliter weight (R2 = 0.51). However, its coarser resolution limited its ability to capture finer treatment-induced variability. MicaSense, despite its higher spatial resolution, performed poorly in predicting crop components, with R2 values below 0.35 for yield and protein content. This study highlights the complementary use of remote sensing technologies to optimize wheat management and support climate-resilient agriculture through the integration of sustainable fertilization strategies. [ABSTRACT FROM AUTHOR]

The Biomass Proxy is a new cloud-free vegetation monitoring product that offers timely and analysis-ready data indicative of above-ground crop biomass dynamics at 10m spatial resolution. The Biomass Proxy links the consistent and continuous temporal signal of the Sentinel-1 Cross Ratio (CR), a vegetation index derived from Synthetic Aperture Radar backscatter, with the spatial information of the Sentinel-2 Normalized Difference Vegetation Index (NDVI), a vegetation index derived from optical observations. A global scaling relationship between CR and NDVI forms the basis of a novel fusion methodology based on static and dynamic combinations of temporal and spatial responses of CR and NDVI at field level. The fusion process is used to mitigate the impact on product quality of low satellite revisit periods due to acquisition design or persistent cloud coverage, and to respond to rapid changes in a timely manner to detect environmental and management events. The resulting Biomass Proxy provides time series that are continuous, unhindered by clouds, and produced uniformly across all geographical regions and crops. The Biomass Proxy offers opportunities including improved crop growth monitoring, event detection, and phenology stage detection. [ABSTRACT FROM AUTHOR]

In the context of increasing environmental change, monitoring crop conditions throughout the growing season is critical for agricultural management, risk mitigation and early assessment of food, feed, fuel and fiber production. Satellite Earth observations can provide frequent and spatially continuous measures of cropping systems to support informed agricultural decisions. However, current analysis-ready satellite data are based on optical observational systems that do not provide land surface information under cloudy conditions, and therefore cannot ensure a continuous and operational monitoring of dynamic systems such as crops. To fill this gap, Planet developed the Biomass Proxy product which provides a timely and analysis-ready relative measure of the above-ground crop biomass daily at 10 m spatial resolution. Based on Earth observations from Sentinel-1 and Sentinel-2 constellations, the Biomass Proxy is a cloud-free vegetation monitoring product for agricultural management at scales varying from the intra-field to the national scale. The objective of this study was to quantify the sensitivity of Planet's Biomass Proxy to crop biomass dynamics and yield. Field data representative of various agricultural systems and climates from the University of Nebraska-Lincoln and Michigan State University were used to characterize the relationships between the Biomass Proxy and the biomass of corn, winter wheat and soybean fields. Results demonstrated the sensitivity of the Biomass Proxy to changes in crop fresh biomass throughout the growing season, and the potential of the product to detect rapid changes in plant growth due to agricultural practices or environmental stresses, such as nitrogen or water deficiencies. The Biomass Proxy was highly correlated with the plant fresh biomass (R2 > 0.9 for corn) allowing for near real-time monitoring of crop growth and management decisions such as irrigation water, fertilizer and fungicide applications depending on the crop. Using regressions, the Biomass Proxy was able to explain 80 % of the yield variance of agricultural fields one to two months before harvest, allowing marketing and logistic decisions to be made with a better knowledge of the crop status. The Biomass Proxy is a unique satellite-based product used to characterize the various components of agricultural ecosystems, early detect crop growth anomalies, or assess crop yield. The Biomass Proxy provides real time information on crop conditions and environmental threats, helping mitigate risks by supporting agricultural decisions. • Planet's Biomass Proxy is a cloud-free vegetation monitoring product for agriculture. • The Biomass Proxy is a satellite-based relative measure of crop biomass. • It can early detect crop growth anomalies due to water shortage. • It explained 80 % of corn yield in Nebraska 8 weeks before harvest. [ABSTRACT FROM AUTHOR]