scholarly journals Global quantification of the bidirectional dependency between soil moisture and vegetation productivity

Author(s):  
Wenmin Zhang ◽  
Fangli Wei ◽  
Stéphanie Horion ◽  
Rasmus Fensholt ◽  
Matthias Forkel ◽  
...  
2021 ◽  
Author(s):  
Wantong Li ◽  
Matthias Forkel ◽  
Mirco Migliavacca ◽  
Markus Reichstein ◽  
Sophia Walther ◽  
...  

<p>Terrestrial vegetation couples the global water, energy and carbon exchange between the atmosphere and the land surface. Thereby, vegetation productivity is determined by a multitude of energy- and water-related variables. While the emergent sensitivity of productivity to these variables has been inferred from Earth observations, its temporal evolution during the last decades is unclear, as well as potential changes in response to trends in hydro-climatic conditions. In this study, we analyze the changing sensitivity of global vegetation productivity to hydro-climate conditions by using satellite-observed vegetation indices (i.e. NDVI) at the monthly timescale from 1982–2015. Further, we repeat the analysis with simulated leaf area index and gross primary productivity from the TRENDY vegetation models, and contrast the findings with the observation-based results. We train a random forest model to predict anomalies of productivity from a comprehensive set of hydro-meteorological variables (temperature, solar radiation, vapor pressure deficit, surface and root-zone soil moisture and precipitation), and to infer the sensitivity to each of these variables. By training models from temporal independent subsets of the data we detect the evolution of sensitivity across time. Results based on observations show that vegetation sensitivity to energy- and water-related variables has significantly changed in many regions across the globe. In particular we find decreased (increased) sensitivity to temperature in very warm (cold) regions. Thereby, the magnitude of the sensitivity tends to differ between the early and late growing seasons. Likewise, we find changing sensitivity to root-zone soil moisture with increases predominantly in the early growing season and decreases in the late growing season. For better understanding the mechanisms behind the sensitivity changes, we analyse land-cover changes, hydro-climatic trends, and abrupt disturbances (e.g. drought, heatwave events or fires could result in breaking points of sensitivity evolution in the local interpretation). In summary, this study sheds light on how and where vegetation productivity changes its response to the drivers under climate change, which can help to understand possibly resulting changes in spatial and temporal patterns of land carbon uptake.</p>


2021 ◽  
Author(s):  
Josephin Kroll ◽  
Jasper Denissen ◽  
Wantong Li ◽  
René Orth

<p>Vegetation productivity is generally governed by water and energy availability. In arid regions, it is usually water-controlled (i.e. soil moisture), whereas in humid regions it is mainly influenced by energy variables (i.e. incoming radiation). Shifts within or even between these regimes might result from hydro-meteorological extremes. For example, during droughts vegetation might become water-limited even in typically energy-controlled regions. In this context, the aim of our analysis is to detect the difference between the controls of average and extreme vegetation productivity.</p><p>For this purpose, we use global satellite-based Sun-Induced Chlorophyll Fluorescence (SIF) data as a proxy for vegetation productivity alongside several hydro-meteorological variables. We select the three largest positive and negative monthly SIF anomalies from 2007 – 2015 and determine the hydro-meteorological variable with the largest corresponding standardized anomaly, which is considered to represent the main driver of the respective vegetation extreme.</p><p>We aggregate the results across grid cells of similar climate conditions. By contrasting main controls and their importance on vegetation productivity during extreme and general conditions, we find that water control in arid regions and energy control in humid regions are overall consistent in both conditions, while the importance of deep root-zone soil moisture is significantly increased in arid regions. Then, we identify regions where transitions between water and energy-control occur and further assess to which extent such regime transitions amplify vegetation productivity anomalies and/or impact their recovery.</p><p>This study contributes to a better understanding of vegetation productivity extremes, which may change with changing future patterns of temperature and precipitation, with subsequent feedbacks on the climate system and implications on food security.</p>


2019 ◽  
Vol 5 (1) ◽  
pp. 97-106
Author(s):  
Rudi Budi Agung ◽  
Muhammad Nur ◽  
Didi Sukayadi

The Indonesian country which is famous for its tropical climate has now experienced a shift in two seasons (dry season and rainy season). This has an impact on cropping and harvesting systems among farmers. In large scale this is very influential considering that farmers in Indonesia are stilldependent on rainfall which results in soil moisture. Some types of plants that are very dependent on soil moisture will greatly require rainfall or water for growth and development. Through this research, researchers tried to make a prototype application for watering plants using ATMEGA328 microcontroller based soil moisture sensor. Development of application systems using the prototype method as a simple method which is the first step and can be developed again for large scale. The working principle of this prototype is simply that when soil moisture reaches a certainthreshold (above 56%) then the system will work by activating the watering system, if it is below 56% the system does not work or in other words soil moisture is considered sufficient for certain plant needs.


SIGMA TEKNIKA ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 81
Author(s):  
Muhammad Irsyam

ABSTRAK           Faktor yang menentukan kegagalan pertumbuhan suatu tanaman hampir dipengaruhi oleh teknik atau cara penyiraman tanaman yang salah. Hal ini disebabkan oleh teknik penyiraman yang dilakukan secara manual sehingga tidak semua tanaman mendapatkan asupan air yang merata untuk menghidari tanaman menjadi layu. Faktor lain yang menyebabkan kegagalan pertumbuhan tanaman adalah kelembaban tanah.          Oleh karena itu, untuk mengurangi permasalahan tersebut dirancanglah “Sistem Otomasi Penyiraman Tanaman Berbasis Telegram”. Adapun sistem ini meliputi penyiraman tanaman secara otomatis berdasarkan kadar kelembaban tanah dengan sistem pemberitahuan atau notifikasi yang akan dikirimkan kepada petani dengan menggunakan aplikasi smart phone Telegram.          Sistem ini telah mampu mengontrol penyiraman sesuai dengan kondisi yang diinginkan. Dengan adanya sistem otomasi penyiraman tanaman berbasis telegram maka dapat meningkatkan efesiensi dan efektivitas petani sehingga kualitas tanaman dapat terjaga dengan baik.Kata kunci -- Penyiraman Tanaman, Penyiraman Secara Otomatis, Telegram.ABSTRACT                Factors that determine the failure of a plant's growth of almost are influenced by incorrect cropping techniques or methods. This is caused by the technique of watering is done manually so that not all plants get a uniform water intake to avoid crops withered. Another factor that causes plant growth failure is soil moisture.          Therefore, to reduce the problem was designed "Telegram Based Water Planting Automation System". The system includes automatic watering of plants based on moisture level of the soil with a notification or notification system that will be sent to farmers using Telegram smart phone applications.          This system has been able to control the watering according to the desired conditions. With the telegraph-based plant watering plant automation system can improve the efficiency and effectiveness of farmers so that the quality of the plant can be maintained properly. Keywords -- Watering Plants, Watering Automatically, Telegram.  


Author(s):  
N.A. Thomson

In a four year grazing trial with dairy cows the application of 5000 kg lime/ ha (applied in two applications of 2500 kg/ha in winter of the first two years) significantly increased annual pasture production in two of the four years and dairy production in one year. In three of the four years lime significantly increased pasture growth over summer/autumn with concurrent increases in milk production. In the last year of the trial lime had little effect on pasture growth but a relatively large increase in milkfat production resulted. A higher incidence of grass staggers was recorded on the limed farmlets in spring for each of the four years. In the second spring immediately following the second application of lime significant depressions in both pasture and plasma magnesium levels were recorded. By the third spring differences in plasma magnesium levels were negligible but small depressions in herbage magnesium resulting from lime continued to the end of the trial. Lime significantly raised soil pH, Ca and Mg levels but had no effect on either soil K or P. As pH levels of the unlimed paddocks were low (5.2-5.4) in each autumn and soil moisture levels were increased by liming, these factors may suggest possible causes for the seasonality of the pasture response to lime


2016 ◽  
Vol 27 (3-4) ◽  
pp. 55-69
Author(s):  
M. A. Listopadsky

With gradient analysis investigated the role of soil moisture in the formation of the modern population of birds in the reserve forest plantations. Soil moisture was divided into seven grades. For this purpose used grass cover and the coefficient of local moistening. His proposed PhD L. P. Travleev. This method allows knowing the degree of influence of soil moisture at the birds. We analyzed birds species composition, population, placement in space and power of influence factors (soil moisture). Investigations were carried out on the territory of the Biosphere Reserve «Askania Nova». We studied the birds which live in the reserve at the end of the summer, autumn and winter. This happened from 2006 to 2013 years. Specially was studied as permanently specific form of birds is found in a particular humidity. The degree of coupling was studied using the amount of information that transmits to the local bird humidification. For 68 species of birds are the options of the population density, coefficient koligatsii and data communication with the seven variants of soil moisture. For all kinds of set information «price» of each option dampening that contributes to the formation of a particular community of birds. Thus, the defined contribution to the formation of soil moisture forest bird communities. Species representation and density gradient within the test moisture is not in direct linear relationship from moisture and ranges from 11 (very coldly) to 50 species (moist soil). The density of the community varies from 0,5 birds / hectare (very dry) to 269 birds / hectare (fresh soil). The strongest link between the information and the formation of moisture gradient structure avifauna is typical in a fresh soil – bird on the edge, and wet – forest representatives. These types of humidification function is performed starting in the formation of two major blocks dendrophilous community. The steppe birds give way to forest representatives when the soil slightly moist. The main conclusion of our study includes the following: than wetter the soil the more species of birds lives in the forest; some graduation humidity are the most important for separate species of birds; it is very important for birds, there are places where one can drink water. Further invasive alien species can occur where the soil is moist. Forest with dry soil is already fully occupied by birds.


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