scholarly journals A Sentinel-2 Image-Based Irrigation Advisory Service: Cases for Tea Plantations

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1305
Author(s):  
Yi-Ping Wang ◽  
Chien-Teh Chen ◽  
Yao-Chuan Tsai ◽  
Yuan Shen

In this study, we aim to develop an inexpensive site-specific irrigation advisory service for resolving disadvantages related to using immobile soil moisture sensors and to the differences in irrigation needs of different tea plantations affected by variabilities in cultivars, plant ages, soil heterogeneity, and management practices. In the paper, we present methodologies to retrieve two biophysical variables, surface soil water content and canopy water content of tea trees from Sentinel-2 (S2) (European Space Agency, Paris, France) images and consider their association with crop water availability status to be used for making decisions to send an alert level. Precipitation records are used as auxiliary information to assist in determining or modifying the alert level. Once the site-specific alert level for each target plantation is determined, it is sent to the corresponding farmer through text messaging. All the processes that make up the service, from downloading an S2 image from the web to alert level text messaging, are automated and can be completed before 7:30 a.m. the next day after an S2 image was taken. Therefore, the service is operated cyclically, and corresponds to the five-day revisit period of S2, but one day behind the S2 image acquisition date. However, it should be noted that the amount of irrigation water required for each site-specific plantation has not yet been estimated because of the complexities involved. Instead, a single irrigation rate (300 t ha−1) per irrigation event is recommended. The service is now available to over 20 tea plantations in the Mingjian Township, the largest tea producing region in Taiwan, free of charge since September 2020. This operational application is expected to save expenditures on buying irrigation water and induce deeper root systems by decreasing the frequency of insufficient irrigation commonly employed by local farmers.

2020 ◽  
Vol 63 (5) ◽  
pp. 1549-1558
Author(s):  
Daran R. Rudnick ◽  
Matt Stockton ◽  
Saleh Taghvaeian ◽  
Jason Warren ◽  
Michael D. Dukes ◽  
...  

HIGHLIGHTSUniversity extension has been playing a larger role, serving a larger number of irrigated farms.Extension programs in irrigation water management (IWM) have been transitioning away from lectures and field tours as the primary means of knowledge transfer.New IWM programs focus on experiential learning, development of practitioner networks, and industry participation.Abstract. Promotion and adoption of irrigation water management (IWM) technology, tools, and best management practices are important as water availability concerns are addressed. Traditional extension programs have relied on lecture presentations, field tours, fact sheets, and on-station demonstrations to promote IWM practices and tools. However, these platforms tend not to provide the experience and opportunity for growers to identify and become comfortable with innovative solutions, such as new technology. To address these challenges and to appeal to an ever-changing client base, innovative and locally relevant extension and outreach programs have been devised to engage and educate growers. This article describes some of these programs that extend beyond previous traditional programs to connect growers with IWM. Keywords: Demonstrations, Experiential learning, Grower competition, Outreach, Practitioner networks.


2019 ◽  
Vol 50 (4) ◽  
pp. 198-207
Author(s):  
Ioannis Gravalos ◽  
Avgoustinos Avgousti ◽  
Theodoros Gialamas ◽  
Nikolaos Alfieris ◽  
Georgios Paschalidis

Water supply limits and continued population growth have intensified the search for measures to conserve water in urban gardening and agriculture. The efficiency of water use is depended on performance of the irrigation technologies and management practices. In this study, a robotic irrigation system was developed that consists of a moving bridge manipulator and a sensor-based platform. The manipulator constructed is partly using open-source components and software, and is easily reconfigurable and extendable. In combination to the sensor-based platform this custommade manipulator has the potential to monitor the soil water content (SWC) in real time. The irrigation robotic system was tested in an experimental soil tank. The total surface of the soil tank was divided by a raster into 18 equal quadrants. The water management for maintaining water content in the soil tank within tolerable lower limit (refill point) was based on three irrigation treatments: i) quadrants whose SWC is below the refill point are irrigated; ii) quadrants are irrigated only when the daily mean SWC of the tank is below the refill point and only for those whose actual SWC is lower than that limit; and iii) quadrants are irrigated every two days with constant amount of water. A comparison of the results of the three irrigation treatments showed that the second treatment gave less irrigation events and less applied water. Finally, we could conclude that the performance of the fabricated robotic system is appropriate and it could play an important role in achieving sustainable irrigation into urban food systems.


Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 264 ◽  
Author(s):  
Mohammad Hossein Mohammadi ◽  
Mahnaz Khataar

We developed a numerical model to predict soil salinity from knowledge of evapotranspiration rate, crop salt tolerance, irrigation water salinity, and soil hydraulic properties. Using the model, we introduced a new weighting function to express the limitation imposed by salinity on plant available water estimated by the integral water capacity concept. Lower and critical limits of soil water uptake by plants were also defined. We further analysed the sensitivity of model results to underlying parameters using characteristics given for corn, cowpea, and barley in the literature and two clay and sandy loam soils obtained from databases. Results showed that, between two irrigation events, soil salinity increased nonlinearly with decreasing soil water content especially when evapotranspiration and soil drainage rate were high. The salinity weighting function depended greatly on the plant sensitivity to salinity and irrigation water salinity. This research confirmed that both critical and lower limits (in terms of water content) of soil water uptake by plants increased with evapotranspiration rate and irrigation water salinity. Since the presented approach is based on a physical concept and well-known plant parameters, soil hydraulic characteristics, irrigation water salinity, and meteorological conditions, it may be useful in spatio-temporal modelling of soil water quality and quantity and prediction of crop yield.


Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 186
Author(s):  
Carson Roberts ◽  
Drew M. Gholson ◽  
Nicolas Quintana-Ashwell ◽  
Gurpreet Kaur ◽  
Gurbir Singh ◽  
...  

The Mississippi River Valley Alluvial Aquifer (MRVAA) is being depleted, and practices that improve water stewardship have been developed to reduce drawdown. This study assesses how Mississippi Delta producers changed their perceptions of these practices over time. The analysis employs data from two surveys carried-out in 2012 and 2014 of all Mississippi permittees who held an agricultural well permit drawing from the MRVAA. Focusing on water-saving practices, this study found that producer perception of the usability of flowmeters improved over time. About 80% and 90% more producers growing corn and soybeans, respectively, felt that computerized hole selection was highly efficient. In 2014, 38% of corn and 35% of soybean producers believed that shortened furrow length was a highly efficient practice—up from 21% in corn and 24% in soybean producers in 2012. Approval of irrigation automation, moisture probes, and other irrigation technology rose from 75%of producers in 2012 to 88% by 2014. Favorability toward water-saving practices increased overall between the survey years.


2021 ◽  
Vol 23 (2) ◽  
pp. 182-196
Author(s):  
L. Puri ◽  
I. Nuberg ◽  
B. Ostendorf ◽  
E. Cedamon

Operational plans are a key element in community forestry in Nepal. However, the relevance of these plans to forest user groups (FUGs) is under scrutiny. This study investigates the usefulness of operational plans against the backdrop of knowledge, capacity and management practices of FUGs. Data were collected from 13 operational plans, 16 group discussions involving forestry professionals, and 218 household interviews in two villages of Lamjung district in Nepal. Whereas operational plans should specifically reflect site specific objectives and activities of forest management, the survey revealed identical objectives across the community forests. Current operational plans are technically complex, poorly linked to the place-based context of livelihood needs and less useful to the FUGs to inform and enhance forest management. This study proposes to differentiate community forests according to their production potentials, and revise the operational plans by shortening the elements that have little or no relevance to the FUGs.


2021 ◽  
Author(s):  
Alba Canet-Marti ◽  
Angela Morales-Santos ◽  
Reinhard Nolz ◽  
Günter Langergraber ◽  
Christine Stumpp

<p>Sustainable agriculture should be based on management practices that improve resource usage efficiency and minimize harmful impacts on the environment while maintaining and stabilizing crop production. Both tillage and irrigation can have a great influence on hydrological processes within agroecosystems. However, it remains difficult to directly assess the effect of practices on water fluxes which has been mainly indirectly quantified by complex numerical modelling methods in the past. Therefore, the objective of the study was to use a space for time concept and measure oxygen and hydrogen isotopes (δ<sup>18</sup>O, δ<sup>2</sup>H) in the pore water of soil profiles as well as moisture contents for quantifying the soil water balance and fluxes. Covering all combinations, soil profiles and isotope analysis was performed for 16 sites planted with winter wheat and managed with different tillage (conventional tillage (CT), reduced tillage (RT), minimal tillage (MT), and no-tillage (NT)) and irrigation systems (hose reel boom irrigation with nozzles (BI), sprinkler irrigation (SI), drip irrigation (DI) and no irrigation (NI)). The results indicated that the more intense the tillage, the lower the water content. Among the irrigation systems, DI had the highest average water content. Tracing the minimum in the isotopic composition of the pores water within the depth profiles showed a deeper percolation of water in the CT fields, which indicates higher water flow velocity. Considering both water content and differences in water flow velocities resulted in water fluxes ranging from 90 to 151 mm yr<sup>-1</sup>. The losses due to evapotranspiration varied between 57 and 80%. The resulting evapotranspiration within tillage and irrigation variants decreased in the order RT>CT≈MT>NT, and SI>BI>DI>NI. Thus, the method revealed that the lower water content in CT fields is a consequence of deeper water infiltration. Moreover, irrigation water contributed mostly to evapotranspiration, and drip irrigation showed the lowest evapotranspiration losses among irrigation systems. This study demonstrated that water stable isotopes can be used as indicators and are a promising method to quantify water fluxes in agricultural fields with great potential for evaluating management practices.</p>


Author(s):  
Erol H. Cakmak

Irrigated agriculture in Turkey currently consumes 75 percent of the total water consumption, which corresponds to about 30 percent of the renewable water supply. Unfavorable future global climate and economic conditions will increase the stress in the water sector. The operation and maintenance (O&M) of almost all large surface irrigation schemes developed by the state has been transferred to irrigation associations governed by the farmers. The purpose of this paper is to provide an overview of irrigation management practices and an evaluation of irrigation water pricing after the transfer using price data at the association level since 1999. Results indicate that both irrigation water charges and collection rates increased following the transfer. However, the recuperation of investment costs for irrigation development from the users has remained minimal. The price of the irrigation water continued to be on per hectare basis, and farmers using pumping water face 2.5 times higher water charge per hectare then the gravity water users. The uptake of more efficient water application technology accompanied by pricing mechanisms reflecting scarcity value of water will certainly ease the adjustment burden of the irrigation sector in the future.


Author(s):  
Erol H. Cakmak

Irrigated agriculture in Turkey currently consumes 75 percent of the total water consumption, which corresponds to about 30 percent of the renewable water supply. Unfavorable future global climate and economic conditions will increase the stress in the water sector. The operation and maintenance (O&M) of almost all large surface irrigation schemes developed by the state has been transferred to irrigation associations governed by the farmers. The purpose of this paper is to provide an overview of irrigation management practices and an evaluation of irrigation water pricing after the transfer using price data at the association level since 1999. Results indicate that both irrigation water charges and collection rates increased following the transfer. However, the recuperation of investment costs for irrigation development from the users has remained minimal. The price of the irrigation water continued to be on per hectare basis, and farmers using pumping water face 2.5 times higher water charge per hectare then the gravity water users. The uptake of more efficient water application technology accompanied by pricing mechanisms reflecting scarcity value of water will certainly ease the adjustment burden of the irrigation sector in the future.


2020 ◽  
Vol 12 (11) ◽  
pp. 1804 ◽  
Author(s):  
Nicolas Lamquin ◽  
Sébastien Clerc ◽  
Ludovic Bourg ◽  
Craig Donlon

Copernicus is a European system for monitoring the Earth in support of European policy. It includes the Sentinel-3 satellite mission which provides reliable and up-to-date measurements of the ocean, atmosphere, cryosphere, and land. To fulfil mission requirements, two Sentinel-3 satellites are required on-orbit at the same time to meet revisit and coverage requirements in support of Copernicus Services. The inter-unit consistency is critical for the mission as more S3 platforms are planned in the future. A few weeks after its launch in April 2018, the Sentinel-3B satellite was manoeuvred into a tandem configuration with its operational twin Sentinel-3A already in orbit. Both satellites were flown only thirty seconds apart on the same orbit ground track to optimise cross-comparisons. This tandem phase lasted from early June to mid October 2018 and was followed by a short drift phase during which the Sentinel-3B satellite was progressively moved to a specific orbit phasing of 140° separation from the sentinel-3A satellite. In this paper, an output of the European Space Agency (ESA) Sentinel-3 Tandem for Climate study (S3TC), we provide a full methodology for the homogenisation and harmonisation of the two Ocean and Land Colour Instruments (OLCI) based on the tandem phase. Homogenisation adjusts for unavoidable slight spatial and spectral differences between the two sensors and provide a basis for the comparison of the radiometry. Persistent radiometric biases of 1–2% across the OLCI spectrum are found with very high confidence. Harmonisation then consists of adjusting one instrument on the other based on these findings. Validation of the approach shows that such harmonisation then procures an excellent radiometric alignment. Performed on L1 calibrated radiances, the benefits of harmonisation are fully appreciated on Level 2 products as reported in a companion paper. Whereas our methodology aligns one sensor to behave radiometrically as the other, discussions consider the choice of the reference to be used within the operational framework. Further exploitation of the measurements indeed provides evidence of the need to perform flat-fielding on both payloads, prior to any harmonisation. Such flat-fielding notably removes inter-camera differences in the harmonisation coefficients. We conclude on the extreme usefulness of performing a tandem phase for the OLCI mission continuity as well as for any optical mission to which the methodology presented in this paper applies (e.g., Sentinel-2). To maintain the climate record, it is highly recommended that the future Sentinel-3C and Sentinel-3D satellites perform tandem flights when injected into the Sentinel-3 time series.


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