Scheduling a deficit irrigation strategy from leaf turgor measurements: impact on water status, gas exchange and oil yield

2018 ◽  
pp. 267-272
Author(s):  
C.M. Padilla-Díaz ◽  
C.M. Rodriguez-Dominguez ◽  
A. Perez-Martin ◽  
A. Montero ◽  
J.M. García ◽  
...  
2018 ◽  
Vol 202 ◽  
pp. 241-252 ◽  
Author(s):  
C.M. Padilla-Díaz ◽  
C.M. Rodriguez-Dominguez ◽  
V. Hernandez-Santana ◽  
A. Perez-Martin ◽  
R.D.M. Fernandes ◽  
...  

Horticulturae ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 8 ◽  
Author(s):  
Riccardo Lo Bianco

Predicting apple yield in relation to tree water use is important for irrigation planning and evaluation. The aim of the present study was to identify measurable variables related to tree water use that could predict final fruit yield of apple trees under different strategies of deficit irrigation. Adult ‘Gala’ and ‘Fuji’ apple trees were exposed to conventional irrigation (CI), delivering 100% of crop evapotranspiration; partial root zone drying (PRD), delivering 50% of CI water only on one alternated side of the root-zone; and continuous deficit irrigation (CDI), delivering 50% of CI water on both sides of the root-zone. Integrals of soil (SWDint) and leaf (LWSDint) water deficit along with growth and stomatal conductance (Gsint) were calculated across each season and used to estimate total conductance (GStree) and transpiration (Trtree) per tree, transpiration efficiency on a fruit (GRfruit/Tr) or tree (GRtrunk/Tr) growth basis, and transpiration productivity (Yield/Trtree). ‘Fuji’ trees had higher Yield/Trtree, but had lower GRtrunk/Tr and similar GRfruit/Tr compared to ‘Gala’ trees. In ‘Fuji’, CDI reduced yield, trunk growth, leaf hydration, and gas exchange, while in ‘Gala’, it did not reduce yield and gas exchange. In ‘Fuji’, a linear combination of GRtrunk/Tr, GRfruit/Tr, and Gstree contributed to predicting yield, with GRfruit/Tr explaining nearly 78% of the model variability. In ‘Gala’, a linear combination of LWSDint and Gstree contributed to predicting yield, with Gstree explaining over 79% of the model variability. These results indicate that measuring tree water status or water use may help predict final apple yields only in those cultivars like ‘Gala’ that cannot limit dehydration by closing stomates because of carbon starvation. In more vigorous cultivars like ‘Fuji’, transpiration efficiency based on fruit growth can be a powerful predictor of final yields.


2020 ◽  
Vol 12 (15) ◽  
pp. 2359
Author(s):  
Víctor Blanco ◽  
Pedro José Blaya-Ros ◽  
Cristina Castillo ◽  
Fulgencio Soto-Vallés ◽  
Roque Torres-Sánchez ◽  
...  

The present work aims to assess the usefulness of five vegetation indices (VI) derived from multispectral UAS imagery to capture the effects of deficit irrigation on the canopy structure of sweet cherry trees (Prunus avium L.) in southeastern Spain. Three irrigation treatments were assayed, a control treatment and two regulated deficit irrigation treatments. Four airborne flights were carried out during two consecutive seasons; to compare the results of the remote sensing VI, the conventional and continuous water status indicators commonly used to manage sweet cherry tree irrigation were measured, including midday stem water potential (Ψs) and maximum daily shrinkage (MDS). Simple regression between individual VIs and Ψs or MDS found stronger relationships in postharvest than in preharvest. Thus, the normalized difference vegetation index (NDVI), resulted in the strongest relationship with Ψs (r2 = 0.67) and MDS (r2 = 0.45), followed by the normalized difference red edge (NDRE). The sensitivity analysis identified the optimal soil adjusted vegetation index (OSAVI) as the VI with the highest coefficient of variation in postharvest and the difference vegetation index (DVI) in preharvest. A new index is proposed, the transformed red range vegetation index (TRRVI), which was the only VI able to statistically identify a slight water deficit applied in preharvest. The combination of the VIs studied was used in two machine learning models, decision tree and artificial neural networks, to estimate the extra labor needed for harvesting and the sweet cherry yield.


2015 ◽  
Vol 158 ◽  
pp. 69-81 ◽  
Author(s):  
Alberto Samperio ◽  
María José Moñino ◽  
Antonio Vivas ◽  
Fernando Blanco-Cipollone ◽  
Abelardo García Martín ◽  
...  

2018 ◽  
Vol 45 (8) ◽  
pp. 865 ◽  
Author(s):  
Amanda P. De Souza ◽  
Adriana Grandis ◽  
Bruna C. Arenque-Musa ◽  
Marcos S. Buckeridge

Photosynthesis and growth are dependent on environmental conditions and plant developmental stages. However, it is still not clear how the environment and development influence the diurnal dynamics of nonstructural carbohydrates production and how they affect growth. This is particularly the case of C4 plants such as sugarcane (Saccharum spp.). Aiming to understand the dynamics of leaf gas exchange and nonstructural carbohydrates accumulation in different organs during diurnal cycles across the developmental stages, we evaluated these parameters in sugarcane plants in a 12-month field experiment. Our results show that during the first 3 months of development, light and vapour pressure deficit (VPD) were the primary drivers of photosynthesis, stomatal conductance and growth. After 6 months, in addition to light and VPD, drought, carbohydrate accumulation and the mechanisms possibly associated with water status maintenance were also likely to play a role in gas exchange and growth regulation. Carbohydrates vary throughout the day in all organs until Month 9, consistent with their use for growth during the night. At 12 months, sucrose is accumulated in all organs and starch had accumulated in leaves without any diurnal variation. Understanding of how photosynthesis and the dynamics of carbohydrates are controlled might lead to strategies that could increase sugarcane’s biomass production.


Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1315
Author(s):  
Xun Bo Zhou ◽  
Guo Yun Wang ◽  
Li Yang ◽  
Hai Yan Wu

Low water availability coupled with poor planting method has posed a great challenge to winter wheat (Triticum aestivum L.) productivity. To improve productivity and water use efficiency (WUE) under deficit irrigation, an effective water-saving technology that is characterized by three planting modes has been developed (uniform with 30-cm row spacing (U), double-double row spacing of 5 cm (DD), and furrow-ridge row spacing of alternated 20 cm and 40 cm (F)) combined with three irrigation regimes (50 mm water each at growth stage 34 (GS34) and GS48 (W1), and 100 mm water at GS48 (W2), or 100 mm each water at GS34 and GS48 (W3)). Results showed that DD increased yield by 9.7% and WUE by 12.6% due to higher soil water status and less soil water depletion and evapotranspiration compared with U. Although the soil water status, soil water depletion, evapotranspiration, and yield increased with increasing irrigation amount, more soil water depletion and evapotranspiration resulted in low WUE. The deficit irrigation was beneficial for improving WUE as W1 had significantly increased yield by 5.4% and WUE by 7.1% compared with W2. Yield and evapotranspiration showed a quadratic dynamic equation indicating that yield increased with increasing evapotranspiration. Considering WUE and relatively higher yield under deficit water, W1 combined with DD is suggested to be a good management strategy to be applied in winter wheat of water-scarce regions.


2017 ◽  
Vol 21 (7) ◽  
pp. 3507-3524 ◽  
Author(s):  
Abebe D. Chukalla ◽  
Maarten S. Krol ◽  
Arjen Y. Hoekstra

Abstract. Reducing the water footprint (WF) of the process of growing irrigated crops is an indispensable element in water management, particularly in water-scarce areas. To achieve this, information on marginal cost curves (MCCs) that rank management packages according to their cost-effectiveness to reduce the WF need to support the decision making. MCCs enable the estimation of the cost associated with a certain WF reduction target, e.g. towards a given WF permit (expressed in m3  ha−1 per season) or to a certain WF benchmark (expressed in m3  t−1 of crop). This paper aims to develop MCCs for WF reduction for a range of selected cases. AquaCrop, a soil-water-balance and crop-growth model, is used to estimate the effect of different management packages on evapotranspiration and crop yield and thus the WF of crop production. A management package is defined as a specific combination of management practices: irrigation technique (furrow, sprinkler, drip or subsurface drip); irrigation strategy (full or deficit irrigation); and mulching practice (no, organic or synthetic mulching). The annual average cost for each management package is estimated as the annualized capital cost plus the annual costs of maintenance and operations (i.e. costs of water, energy and labour). Different cases are considered, including three crops (maize, tomato and potato); four types of environment (humid in UK, sub-humid in Italy, semi-arid in Spain and arid in Israel); three hydrologic years (wet, normal and dry years) and three soil types (loam, silty clay loam and sandy loam). For each crop, alternative WF reduction pathways were developed, after which the most cost-effective pathway was selected to develop the MCC for WF reduction. When aiming at WF reduction one can best improve the irrigation strategy first, next the mulching practice and finally the irrigation technique. Moving from a full to deficit irrigation strategy is found to be a no-regret measure: it reduces the WF by reducing water consumption at negligible yield reduction while reducing the cost for irrigation water and the associated costs for energy and labour. Next, moving from no to organic mulching has a high cost-effectiveness, reducing the WF significantly at low cost. Finally, changing from sprinkler or furrow to drip or subsurface drip irrigation reduces the WF, but at a significant cost.


2011 ◽  
Vol 38 (5) ◽  
pp. 372 ◽  
Author(s):  
Gregorio Egea ◽  
Ian C. Dodd ◽  
María M. González-Real ◽  
Rafael Domingo ◽  
Alain Baille

To determine whether partial rootzone drying (PRD) optimised leaf gas exchange and soil–plant water relations in almond (Prunus dulcis (Mill.) D.A. Webb) compared with regulated deficit irrigation (RDI), a 2 year trial was conducted on field-grown trees in a semiarid climate. Five irrigation treatments were established: full irrigation (FI) where the trees were irrigated at 100% of the standard crop evapotranspiration (ETc); three PRD treatments (PRD70, PRD50 and PRD30) that applied 70, 50 and 30% ETc, respectively; and a commercially practiced RDI treatment that applied 50% ETc during the kernel-filling stage and 100% ETc during the remainder of the growth season. Measurements of volumetric soil moisture content in the soil profile (0–100 cm), predawn leaf water potential (Ψpd), midday stem water potential (Ψms), midday leaf gas exchange and trunk diameter fluctuations (TDF) were made during two growing seasons. The diurnal patterns of leaf gas exchange and stem water potential (Ψs) were appraised during the kernel-filling stage in all irrigation regimes. When tree water relations were assessed at solar noon, PRD did not show differences in either leaf gas exchange or tree water status compared with RDI. At similar average soil moisture status (adjudged by similar Ψpd), PRD50 trees had higher water status than RDI trees in the afternoon, as confirmed by Ψs and TDF. Although irrigation placement showed no effects on diurnal stomatal regulation, diurnal leaf net photosynthesis (Al) was substantially less limited in PRD50 than in RDI trees, indicating that PRD improved leaf-level water use efficiency.


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