Crop irrigation uses more than 70% of the world's water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be ...accomplished by cultivating more water-efficient crop species and/or through the application of efficient irrigation systems, which includes the implementation of a suitable method for precise scheduling. At the farm level, irrigation is generally scheduled based on the grower's experience or on the determination of soil water balance (weather-based method). An alternative approach entails the measurement of soil water status. Expensive and sophisticated root zone sensors (RZS), such as neutron probes, are available for the use of soil and plant scientists, while cheap and practical devices are needed for irrigation management in commercial crops. The paper illustrates the main features of RZS' (for both soil moisture and salinity) marketed for the irrigation industry and discusses how such sensors may be integrated in a wireless network for computer-controlled irrigation and used for innovative irrigation strategies, such as deficit or dual-water irrigation. The paper also consider the main results of recent or current research works conducted by the authors in Tuscany (Italy) on the irrigation management of container-grown ornamental plants, which is an important agricultural sector in Italy.
Container hardy ornamental nursery stocks are generally grown with considerable applications of water and agrochemicals, resulting in an important pollution. These crops are often over-irrigated ...because of inaccurate scheduling, which is generally based on growers’ experience. The design of an efficient irrigation management system is therefore crucial to improve profitability and sustainability of production. Reclaimed municipal or industrial wastewater is a source of irrigation water alternative to fresh water; generally, reclaimed wastewater has a high salt content and its use can induce salinity stress in sensitive crops, such as many ornamental species.
In this work, a prototype of fertigation controller was designed for the management of container hardy ornamental nursery stocks irrigated with different water sources, including saline water. The prototype could schedule irrigation, alternatively, as a time clock system, or using a soil moisture dielectric sensor, or by a crop evapotranspiration (ET) model. In addition, the prototype could monitor the salinity in the root zone using either a dielectric sensor capable of measuring both substrate moisture and bulk electrical conductivity (EC), or a probe measuring the EC of the water draining from the containers. Excessive salinization of the containers irrigated with saline water was automatically prevented by the adoption of a series of measures: irrigation with fresh water or a mixture of fresh water and saline water; increase of irrigation dose; reduction of fertilizer concentration in the nutrient solution delivered to the crop. The system was tested in a series of experiments conducted in Pistoia (Italy) between 2008 and 2010 with two ornamental species: Photinia × fraseri Dress and Prunus laurocerasus L. When irrigation with fresh water was scheduled with the dielectric sensor or the ET model, seasonal water use and the loss of both N and P were reduced by 17% to 84% compared with the timer-controlled irrigation. The control of saline water irrigation using either the dielectric sensor or the EC probe mitigated the salinity-induced growth inhibition in both species; however, it did not prevent the occurrence of leaf damages (leaf scorch) on Prunus plants, which were unmarketable at the end of growing season. In contrast, in the more salt-tolerant Photinia plants, the use of the prototype resulted in a fresh water saving of 51% to 73% and all plants were classified in the top market quality category.
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•A controller was designed to irrigate container crops with fresh or saline water.•Substrate salinization was prevented using different sensors and control strategies.•The prototype reduced fresh water use by 17%–84% compared to standard system.•The prototype also decreased the loss of nitrogen and phosphorus by 53%–84%.
The objective of this study was to design and test a prototype fertigation controller for the management of container ornamental nursery stocks irrigated with different water sources, including saline water or reclaimed municipal/industrial wastewater. The prototype could schedule irrigation in various ways, i.e. as a time clock, or by means of a soil moisture dielectric sensor, or using a crop evapotranspiration (ET) model. The prototype also monitored the salinity in the root zone using a dielectric sensor that measured both substrate moisture and electrical conductivity (EC), or a probe measuring the EC of the water draining out of the containers. Excessive substrate salinization of the containers irrigated with saline water (containing 10 mM of sodium chloride) was prevented by the automated adoption of a series of measures: irrigation with fresh water or a mixture of fresh water and saline water; progressive increase of irrigation dose for each event, and progressive reduction of fertilizer concentration in the nutrient solution delivered to the crop. The system was tested in three experiments conducted in Pistoia (Italy) between 2008 and 2010 with two ornamental species: Photinia × fraseri Dress (a salt-medium tolerant species) and Prunus laurocerasus L. (a salt-sensitive species). When irrigation with fresh water was controlled with a dielectric sensor or an ET model, total irrigation water use and the loss of both N and P were reduced by 17% to 84% compared with the time-controlled irrigation. The sensor-based control of saline water irrigation reduced the salinity effects on dry matter accumulation in both species; however, it did not prevent the occurrence of leaf damages (leaf scorch) on Prunus plants, which were unmarketable by the end of growing season. On the contrary, no leaf damages were visible on Photinia plants irrigated with saline and/or fresh water, such that all were classified in the top quality market category. The controller developed in this work could be used in commercial nurseries to improve profitability and sustainability of container hardy ornamental nursery stock production.
In Europe, one of the major production centres for hardy ornamental nursery stocks is located around the town of Pistoia in Tuscany, Italy. The map refers to 2004, when nearly 1500 nurseries were in ...operation on about 4600ha. Since then, nursery industry has expanded steadily with an increasing application of container cultivation, which currently covers around 1000ha. Annual water consumption of the whole nursery industry is estimated to be around 12millionm3, which approximates the urban water consumption of Pistoia. Due to over-irrigation, huge quantities of water are being used in nurseries, in particular for container crops that consume 75–80% of the total water demand of HONS industry. Inaccurate scheduling is the main cause of excessive irrigation. Growers generally estimate crop water needs based on personal experience and use simple timers for automated irrigation. The asterisk on the map indicates the Experimental Station for Nursery Crops (Ce.Spe.Vi.), where the irrigation study was conducted. Compared with traditional timer, substrate water status and evapotranspiration irrigation scheduling reduced considerably both water use (−21% to −40%) and nutrient emission (−39% to −74%) in heterogeneous container nursery crops, with no significant effects on plant growth and quality.
•Different irrigation treatments were compared in heterogeneous nursery crops.•Irrigation was controlled using timer, soil moisture probe or crop model.•Water use and nutrient emission were reduced using plant-driven control methods.•Irrigation scheduling did not affect plant growth and quality.
A study was conducted to determine the effects of implementing different irrigation scheduling methods on heterogeneous container hardy ornamental nursery stocks. Four ornamental shrub species were grown in the same irrigation sector during the summer of four consecutive years (2007–2010): Forsythia×intermedia, Photinia×fraseri, Prunus laurocerasus L. and Viburnum tinus L. Automated drip irrigation based on either substrate water status (SW) or calculated crop evapotranspiration (ET; MODEL) was compared with “typical” timer-controlled irrigation (TIMER). In TIMER treatment, containers were irrigated based on grower management. In SW treatment, irrigation was controlled either by a water-filled tensiometer (2007) or by a dielectric soil moisture sensor (2008–2010) placed in one pot with a Prunus plant, the species with intermediate water need as found in preliminary work. In MODEL treatment, irrigation was controlled on the basis of the species with the greatest ET. Crop ET was calculated multiplying reference ET (ET0) by a species-specific crop coefficient (KC), which in turn was estimated from plant height. In all treatments, pre-irrigation substrate water deficit was lower than the plant available water in the container. Compared with TIMER treatment, SW and MODEL irrigation scheduling reduced considerably both water use (−21% to −40%) and nutrient emission (−39% to −74%) with no significant effect on plant growth and quality. Water saving resulted from a reduction of irrigation frequency and leaching fraction (water leached/water applied). Wireless sensor network technology and near/remote monitoring techniques can facilitate the application of plant-driven irrigation scheduling in commercial nurseries, where generally hundreds of plant taxa are cultivated in many independent irrigation sectors.
Uncontrolled and unsustainable urban sprawl are altering the Earth’s surface at unprecedented rates. This research explores the potential of active remote sensors for mapping urban areas, for ...monitoring urban expansion processes and for depicting landscape pattern dynamics in a metropolis of South America. Based on multi-temporal urban cover maps of Cordoba, Argentina, purposely derived from COSMO-SkyMed SAR data by urban extraction algorithms, we quantified urban surface increase and described urbanization processes that occurred during 2010–2021 in sectors with different degrees of soil sealing. We extracted urban extent in four time-steps using an Urban EXTent extraction (UEXT) algorithm and quantified urban expansion, identifying newly built areas on 2.5 ha cells. For these cells, we computed urban cover and a set of landscape pattern indices (PIs), and by projecting them in a composition vs. configuration Cartesian space we performed a trajectory analysis. SAR-based urban extraction and cover change proved to be very accurate. Overall accuracy and Cohen’s Kappa statistic evidenced very high values, always above 91.58% and 0.82, respectively, for urban extraction, and also above 90.50% and 0.72 concerning the accuracy of urban expansion. Cordoba’s urban surface significantly increased (≈900 ha in 10 years) following three main spatial processes in different city sectors (e.g., edge-expansion and outlying on peri-urban areas, and infill inside the ring road), which may have contrasting effects on the sustainability of the metropolitan area. Trajectory analysis highlighted non-linear relations between the urban cover and the PIs. Areas with very low and low urban intensity underwent a steep rise of both urban cover and PI values (e.g., urban patch dimension, complexity and number), depicting urban edge-expansion and outlying processes. In the areas with medium and high urban intensity the increase in patch dimension, along with the decrease in patch number and complexity, evidence the coalescence of urban areas that incorporate in the urban fabric the remnants of non-built up zones and fill the few residual green spaces. The proposed SAR mapping procedure coupled with landscape analysis proved to be useful to detect and depict different moments of urban expansion and, pending more tests on other cities and geographical conditions, it could be postulated among the RS indicators to monitor the achievement of the Sustainable Development Goals established by the United Nations.
•SDM is an effective tool for predicting plant invasions.•An integrative PAB approach to explain Acacia saligna distribution in Sardinia.•Combined action of propagule pressure, abiotic, biotic ...factors promotes the invasion.•iSDM largely benefits from the use of high resolution and dedicated thematic layers.•iSDM is an effective tool for decision-making to prevent the invasion risk.
The present study aimed to investigate the role of propagule pressure (P), abiotic (A), and biotic (B) factors (collectively indicated as PAB) on the suitability of the Mediterranean island of Sardinia (Italy) to be invaded by the tree Acacia saligna, recently included in the list of invasive alien species of European Union concern.
To this aim, a binomial Generalized Linear Model was applied for disentangling the relationship between 432 A. saligna occurrence records and 10 thematic layers, at high-resolution (10 x10 m), used as proxies for the 3 categories of PAB variables. The 432 occurrence records of A. saligna were periodically monitored (period 2000–2018) to check the persistence of the populations and their invasive status. The predictive power of the model was evaluated by computing the mean of the AUC scores, through cross-fold validation. The model adequately described how the PAB factors influence the presence of A. saligna which is mainly shaped by abiotic factors such as topography, and biotic factors such as the presence of woody dune vegetation, and to a lesser extent by other predictors. The projection of the model to the whole island clearly shows that suitability varies at the landscape level due to the variation of the PAB across the territory. The probability of A. saligna occurrence near the coast is higher in sand dunes. In the internal areas of the island it occurs close to the roads and urban areas. This study and the tested methodology could represent a suitable tool to prioritize areas for the monitoring of A. saligna to meet the requirements of the Regulation (EU) No. 1143/2014 on Invasive Alien Species (the IAS Regulation).
Novel approaches and algorithms to estimate crop physiological processes from Earth Observation (EO) data are essential to develop more sustainable management practices in agricultural systems. ...Within this context, this paper presents the results of different research activities carried out within the ESA-MOST Dragon 4 programme. The paper encompasses two research avenues: (a) the retrieval of biophysical variables of crops and yield prediction; and (b) food security related to different crop management strategies. Concerning the retrieval of variables, results show that LAI, derived by radiative transfer model (RTM) inversion, when assimilated into a crop growth model (i.e., SAFY) provides a way to assess yields with a higher accuracy with respect to open loop model runs: 1.14 t·ha−1 vs 4.42 t·ha−1 RMSE for assimilation and open loop, respectively. Concerning food security, results show that different pathogens could be detected by remote sensing satellite data. A k coefficient higher than 0.84 was achieved for yellow rust, thus assuring a monitoring accuracy, and for the diseased samples k was higher than 0.87. Concerning permanent crops, neural network (NN) algorithms allow classification of the Pseudomonas syringae pathogen on kiwi orchards with an overall accuracy higher than 91%.
Monitoring city boundaries and extents is a mandatory task so as to achieve the 11 th Goal of sustainable development agenda 2030. This work aims at exploring the potential of the SAR dataset ...recorder by the SIASGE constellation for mapping urban areas and their extent. In particular, urban maps have been produced by applying the Urban EXTent algorithm to Very High Resolution (VHR) Cosmo-SkyMed first generation (CSK and CSG, respectively) in X-band and SAOCOM (SAO) data in L-band. Urban extractions based on multi-temporal SAR data and based on a single date have also been compared. SAR-based urban maps have been finally analyzed against existing land cover maps produced by multi-spectral data. All three SAR derived maps presented high accuracy, with CSG being the best one, and CSK and SAO slightly less performant. Urban maps derived from multitemporal SAR information presented higher accuracy than those based on a single date and, at the same time, resulted coherent with land cover maps produced by traditional multispectral data classification. The VHR CSG and CSK, with high computational efforts, well support urban extent mapping at very fine local scale, while SAO data provide a good support for mapping urban areas at a regional or country scale.
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