Global Assimilation of Remotely Sensed Leaf Area Index: The Impact of Updating More State Variables Within a Land Surface Model

As vegetation regulates water, carbon, and energy cycles from the local to the global scale, its accurate representation in land surface models is crucial. The assimilation of satellite-based vegetation observations in a land surface model has the potential to improve the estimation of global carbon and energy cycles, which in turn can enhance our ability to monitor and forecast extreme hydroclimatic events, ecosystem dynamics, and crop production. This work proposes the assimilation of a remotely sensed vegetation product (Leaf Area Index, LAI) within the Noah Multi-Parameterization land surface model using an Ensemble Kalman Filter technique. The impact of updating leaf mass along with LAI is also investigated. Results show that assimilating LAI data improves the estimation of transpiration and net ecosystem exchange, which is further enhanced by also updating the leaf mass. Specifically, transpiration anomaly correlation coefficients improve in about 77 and 66% of the global land area thanks to the assimilation of leaf area index with and without updating leaf mass, respectively. Random errors in transpiration are also reduced, with an improvement of the unbiased root mean square error in 70% (74%) of the total area without the update of leaf mass (with the update of leaf mass). Similarly, net ecosystem exchange anomaly correlation coefficients improve from 52 to 75% and random errors improve from 49 to 62% of the total pixels after the update of leaf mass. Better performances for both transpiration and net ecosystem exchange are observed across croplands, but the largest improvement is shown over forests and woodland. The global scope of this work makes it particularly important in data poor regions (e.g., Africa, South Asia), where ground observations are sparse or not available altogether but where an accurate estimation of carbon and energy variables can be critical to improve ecosystem and crop management.

The effects of different compositions of growth media on the development of microplants of the Solnechny potato variety

The results of studying the effect of nutrient media of various compositions on the growth of improved micro-plants of potatoes of the Solnechny variety grown under laboratory conditions in vitro are presented. Six compositions of the nutrient medium were studied: standard Murashige-Skuga medium modified for micropropagation (considered as a control), modified Murashige-Skuga medium with a reduced content of mineral components (up to 1/2 and up to 1/3), modified Murashige-Skuga medium with an increased content of agar-agar (10 g/l), modified Murashige-Skuga medium with a reduced content of agar-agar (4 g/l), Murashige-Skuga medium modified with the addition of 3 mg/L giberrellinic acid and 1 mg/L indoliacetic acid. The following parameters of cultivated plants were taken into account: plant length, root presence, number of internodes, total plant mass, leaf mass, root mass, leaf plate surface area. The use of modified nutrient media with a reduced content of mineral components led to an increase in plant length (by 28-30%), stem mass (by 25%) due to leaf mass (by 18%) and stem mass (by 31%) and the total surface area of leaf plates (by 12%). In the variant using a medium with 1/3 mineral components an increase in the mass of the root system was observed (by 20%). When growing plants on a modified nutrient medium with a high content of agar-agar, a decrease in the length of plants (by 6%), a decrease in the mass of the scion (by 12%) due to a decrease in the mass of the stem (by 15%) was observed. Plants grown on a modified nutrient medium with a reduced content of agar-agar were distinguished by a larger mass of the root system (by 10%), scion (by 17%) (due to an increase in leaf mass (by 27%), as well as the total surface area of leaf plates (by 22%). When growth regulators (giberrellin and indoliacetic acid) were added to the modified nutrient medium, a significant increase in plant height (by 70%), a decrease in the mass of the root system (by 50%) and leaves (by 46%), and an increase in the mass of the stem (by 23%) were observed. The total leaf surface area was 28% lower than the control values. For accelerated micropropagation of improved potato plants of the Solnechny variety and preparation of plants for transplanting to aerohydroponic systems in order to produce mini-tubers, the following modified nutrient media are optimal options: with a reduced number of mineral components (1/2 and 1/3) and with a reduced content of agar-agar.

Formation of biometric indicators of sugar beet hybrids of domestic breeding

Purpose. Find out the features of biometric indicators formation in sugar beet hybrids of domestic breeding. Methods. Field, laboratory. Results. According to the results of the research, it was determined that in early August, the maximum weight of roots (840 g) was in hybrid ‘ITsB 0904’. Good indicators were observed in hybrids ‘Umanskyi Ch S97’, ‘Soniachnyi’ and ‘Anichka’, 770, 780, and 800 g at the average group indicator of 730 g. It was investigated that the hybrid ‘Maksym’ (15.1%) and ‘Etiud’ (14.9%) were the best in terms of sugar accumulation in roots. Sugar content at the level of 14.8 % was observed in hybrids ‘Umanskyi ChS 97’, ‘Ramzes’, ‘Konstanta’, ‘Soniachnyi’ and ‘Verkhnia’ at the average group value of 14.5%. Conclusions. It is important to continue the study of the dynamics of root and leaf mass formation together with the process of sugar accumulation in roots in terms of establishing individual efficiency of hybrids and developing recommendations for the fullest realization of their potential in production conditions.

Significance of varieties in technology of growing parsley

In order to obtain a significant level of parsley yield in the Right-Bank Forest-Steppe of Ukraine, it is necessary to select varieties in accordance with soil and climatic conditions of cultivation. The comparative estimation of productivity of grades of parsley of sheet foreign selection in the specified conditions is carried out. The results of phenological observations of plant development, their biometric parameters depending on the genetic features are presented. The possibility of growing the studied varieties of leaf parsley of foreign selection in the conditions of the Right-Bank Forest-Steppe of Ukraine has been established. From the presence of mass shoots to the last harvest, the studied varieties had a growing season of 128–155 days. The first harvest was carried out 61–74 days after the mass germination. Aromatic and Vega varieties proved to be faster growing. The leaf mass of Orpheus and Fest was slightly slower. Vega and Orpheus plants had the lowest height – 23.6 cm and 25.4 cm, respectively. The next to increase the height of the leaf rosette was the Fest variety, whose plants reached 33.9 cm. The plants of the Pione variety were 35.1 cm high. The highest plant height in the experiment was Argon and Aromatnaya – 36.2 cm and 36.4 cm, respectively. Vega and Orpheus plants had the lowest productivity – 114 g and 160 g, respectively. The next variety as the productivity of the plant increased was the variety Argon with an index of 195 g. The plants of the control variety Aromatnaya had a productivity of 227 g. The plants of the varieties Fest and Pione had the highest productivity – 253 g and 255 g, respectively. The total yield of parsley leaf mass in the experiment averaged 5.01–10.20 kg/m2. Vega was the lowest and Fest and Pione the lowest.

Optimized Estimation of Leaf Mass per Area with a 3D Matrix of Vegetation Indices

Leaf mass per area (LMA) is a key plant functional trait closely related to leaf biomass. Estimating LMA in fresh leaves remains challenging due to its masked absorption by leaf water in the short-wave infrared region of reflectance. Vegetation indices (VIs) are popular variables used to estimate LMA. However, their physical foundations are not clear and the generalization ability is limited by the training data. In this study, we proposed a hybrid approach by establishing a three-dimensional (3D) VI matrix for LMA estimation. The relationship between LMA and VIs was constructed using PROSPECT-D model simulations. The three-VI space constituting a 3D matrix was divided into cubical cells and LMA values were assigned to each cell. Then, the 3D matrix retrieves LMA through the three VIs calculated from observations. Two 3D matrices with different VIs were established and validated using a second synthetic dataset, and two comprehensive experimental datasets containing more than 1400 samples of 49 plant species. We found that both 3D matrices allowed good assessments of LMA (R2 = 0.76 and 0.78, RMSE = 0.0016 g/cm2 and 0.0017 g/cm2, respectively for the pooled datasets), and their results were superior to the corresponding single Vis, 2D matrices, and two machine learning methods established with the same VI combinations.

Forest Leaf Mass per Area (LMA) through the Eye of Optical Remote Sensing: A Review and Future Outlook

Quantitative remote sensing of leaf traits offers an opportunity to track biodiversity changes from space. Augmenting field measurement of leaf traits with remote sensing provides a pathway for monitoring essential biodiversity variables (EBVs) over space and time. Detailed information on key leaf traits such as leaf mass per area (LMA) is critical for understanding ecosystem structure and functioning, and subsequently the provision of ecosystem services. Although studies on remote sensing of LMA and related constituents have been conducted for over three decades, a comprehensive review of remote sensing of LMA—a key driver of leaf and canopy reflectance—has been lacking. This paper reviews the current state and potential approaches, in addition to the challenges associated with LMA estimation/retrieval in forest ecosystems. The physiology and environmental factors that influence the spatial and temporal variation of LMA are presented. The scope of scaling LMA using remote sensing systems at various scales, i.e., near ground (in situ), airborne, and spaceborne platforms is reviewed and discussed. The review explores the advantages and disadvantages of LMA modelling techniques from these platforms. Finally, the research gaps and perspectives for future research are presented. Our review reveals that although progress has been made, scaling LMA to regional and global scales remains a challenge. In addition to seasonal tracking, three-dimensional modeling of LMA is still in its infancy. Over the past decade, the remote sensing scientific community has made efforts to separate LMA constituents in physical modelling at the leaf level. However, upscaling these leaf models to canopy level in forest ecosystems remains untested. We identified future opportunities involving the synergy of multiple sensors, and investigated the utility of hybrid models, particularly at the canopy and landscape levels.

Impact of Modeling Abstractions When Estimating Leaf Mass per Area and Equivalent Water Thickness Over Sparse Forests Using a Hybrid Method

Equivalent water thickness (EWT) and leaf mass per area (LMA) are important indicators of plant processes, such as photosynthetic and potential growth rates and health status, and are also important variables for fire risk assessment. Retrieving these traits through remote sensing is challenging and often requires calibration with in situ measurements to provide acceptable results. However, calibration data cannot be expected to be available at the operational level when estimating EWT and LMA over large regions. In this study, we assessed the ability of a hybrid retrieval method, consisting of training a random forest regressor (RFR) over the outputs of the discrete anisotropic radiative transfer (DART) model, to yield accurate EWT and LMA estimates depending on the scene modeling within DART and the spectral interval considered. We show that canopy abstractions mostly affect crown reflectance over the 0.75–1.3 μm range. It was observed that excluding these wavelengths when training the RFR resulted in the abstraction level having no effect on the subsequent LMA estimates (RMSE of 0.0019 g/cm2 for both the detailed and abstract models), and EWT estimates were not affected by the level of abstraction. Over AVIRIS-Next Generation images, we showed that the hybrid method trained with a simplified scene obtained accuracies (RMSE of 0.0029 and 0.0028 g/cm2 for LMA and EWT) consistent with what had been obtained from the test dataset of the calibration phase (RMSE of 0.0031 and 0.0032 g/cm2 for LMA and EWT), and the result yielded spatially coherent maps. The results demonstrate that, provided an appropriate spectral domain is used, the uncertainties inherent to the abstract modeling of tree crowns within an RTM do not significantly affect EWT and LMA accuracy estimates when tree crowns can be identified in the images.

Influence of integrated crop-livestock-forest on morphological composition and nutritional value of Marandu palisadegrass under continuous grazing

This study characterizes the changes in leaf mass, morphological composition and nutritional value of leaf blades of palisadegrass (Urochloa brizantha cv. Marandu) under continuous grazing in the first year of implementation of pasture and after second year of the eucalyptus planting in an Integrated Crop-Livestock System and Integrated Crop-Livestock-Forest, which were tested in the four seasons. The experimental design was in random blocks, with three treatments: Crop-Livestock System (ICL) and Integrated Crop-Livestock-Forest with two eucalyptus tree densities (ICLF-1L, 196 eucalyptus trees ha-1 and ICLF-3L, 448 eucalyptus trees ha-1) and four replicates. Sixty castrated Nellore cattle with initial weight of 235.43 ± 25.46 kg and mean age of 16 ± 2.81 months were used during the growing phase under continuous grazing. The agronomic variables were: total dry mass of forage, leaves, stem and dead material; leaf: stem and live: senescent material ratios; and accumulation rate. The leaf: stem and live: senescent material relation did not obtain any difference between the evaluated systems. Dry matter, crude protein, fiber fractions and digestibility of leaf blades were evaluated. Dry mass of the forage (6775 kg ha-1), stem (2175 kg ha-1), senescent material (3175 kg ha-1) and dry matter content (28.6%) were greater in the ICL, whereas crude protein (11.3%) was greater in the ICLFs. On the other hand, accumulation rate and dry mass of leaf blades did not change between systems. Thus, until the first year of grazing, tree systems have advantages, because the forage production (accumulation rate) and leaf mass are similar to those of plants in full sun, besides showing higher nutritional value.