scholarly journals Peach Tree Response to Single and Combined Regulated Deficit Irrigation Regimes under Shallow Soils

2003 ◽  
Vol 128 (3) ◽  
pp. 432-440 ◽  
Author(s):  
Joan Girona ◽  
Mercè Mata ◽  
Amadeu Arbonès ◽  
Simó Alegre ◽  
Josep Rufat ◽  
...  

Productive and vegetative tree responses were analyzed during 3 consecutive years in peach [Prunus persica (L.) Batsch cv. Sudanell] plots subjected to three regulated deficit irrigation (RDI) strategies plus a control irrigation treatment. A postharvest RDI treatment (RDI-P) was irrigated at 0.35 of control after harvest. A Stage II RDI treatment (RDI-SII) was irrigated at 0.5 of control during the lag phase of the fruit growth curve. The third treatment (RDI-SII-P) applied RDI during Stage II at 0.5 of control and postharvest at 0.35 of control. The control treatment, like RDI-P and RDI-SII-P when not receiving RDI, was irrigated at 100% of a water budget irrigation scheduling in 1994 and 1996, full crop years, and 80% of the budget in 1995, an off year with a very small crop. A carry-over effect of deficit irrigation was highly significant in all parameters measured during the third year of the experiment. The general effect of water stress during Stage II did not affect return bloom and fruit set, whereas water stress during postharvest apparently reduced both parameters. As a consequence, fruit counts and fruit load manifested marked differences between treatments, which were also correlated to changes in fruit size. The RDI-II, which had the highest fruit yield, also had the smallest fruit size, whereas RDI-P manifested the lowest yield and largest fruit size. Vegetative growth (shoot elongation and trunk cross sectional area) was significantly reduced during the first 2 years of the experiment in accordance with the amount of the irrigation reduction. However, in 1996 growth was strongly governed by fruit load. The use of RDI-SII-P represented an intermediate cropping effect between the opposite bearing behavior of RDI-SII and RDI-P, while not expecting distinctive fruit yield or size reductions and offering remarkable water savings of 22% of the control applied water.

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2316
Author(s):  
Yang Wu ◽  
Zhi Zhao ◽  
Feng Zhao ◽  
Xiaolei Cheng ◽  
Pingping Zhao ◽  
...  

A field experiment was conducted to evaluate the effects of regulated deficit irrigation (RDI) on the fine root redistribution of mature pear trees in 2009 and 2010. The experiment consisted of four RDI treatments: MRDI-1 and SRDI-1, in which the trees received irrigation replacing 60% and 40% of pan evaporation (Ep) during Stage 1 (cell division stage), and MRDI-1+2 and SRDI-1+2, in which the trees received irrigation replacing 60% and 40% of Ep during Stage 1+2 (cell division and slow shoot growth stage). All the RDI-treated trees received irrigation replacing 80% of Ep (full irrigation) in other stages, and the control trees were fully irrigated during the whole growth season. The results showed that the fine root length density (RLD) of mature pear trees was reduced by water stress. The resumption of full irrigation boosted fine root growth. The RLD of the SRDI-1-treated trees in the irrigated zones recovered in early July, they maintained water and nutrient absorption during the fruit enlargement stage, and the final fruit yield was significantly improved. The RLD of trees in the irrigated zones with MRDI-1 and MRDI-1+2 recovered in July and September, respectively, but there were no significant differences in fruit yield between the MRDI-1, MRDI-1+2, and the control. This indicates that the fruit yield was not negatively or positively impacted by the redistribution of moderate water stress applied during either Stage 1 or Stage 1+2.


EDIS ◽  
2017 ◽  
Vol 2017 (5) ◽  
Author(s):  
Davie Mayeso Kadyampakeni ◽  
Kelly T. Morgan ◽  
Mongi Zekri ◽  
Rhuanito Ferrarezi ◽  
Arnold Schumann ◽  
...  

Water is a limiting factor in Florida citrus production during the majority of the year because of the low water holding capacity of sandy soils resulting from low clay and the non-uniform distribution of the rainfall. In Florida, the major portion of rainfall comes in June through September. However, rainfall is scarce during the dry period from February through May, which coincides with the critical stages of bloom, leaf expansion, fruit set, and fruit enlargement. Irrigation is practiced to provide water when rainfall is not sufficient or timely to meet water needs. Proper irrigation scheduling is the application of water to crops only when needed and only in the amounts needed; that is, determining when to irrigate and how much water to apply. With proper irrigation scheduling, yield will not be limited by water stress. With citrus greening (HLB), irrigation scheduling is becoming more important and critical and growers cannot afford water stress or water excess. Any degree of water stress or imbalance can produce a deleterious change in physiological activity of growth and production of citrus trees.  The number of fruit, fruit size, and tree canopy are reduced and premature fruit drop is increased with water stress.  Extension growth in shoots and roots and leaf expansion are all negatively impacted by water stress. Other benefits of proper irrigation scheduling include reduced loss of nutrients from leaching as a result of excess water applications and reduced pollution of groundwater or surface waters from the leaching of nutrients. Recent studies have shown that for HLB-affected trees, irrigation frequency should increase and irrigation amounts should decrease to minimize water stress from drought stress or water excess, while ensuring optimal water availability in the rootzone at all times.


2010 ◽  
Vol 67 (2) ◽  
pp. 164-169 ◽  
Author(s):  
Thomas Sotiropoulos ◽  
Dimitrios Kalfountzos ◽  
Ioannis Aleksiou ◽  
Spyros Kotsopoulos ◽  
Nikolaos Koutinas

Regulated deficit irrigation (RDI) involves inducing water stress during specific fruit growth phases by irrigating at less than full evapotranspiration. The objectives of this research were to study the effects of RDI perfomed at stage II of fruit growth and postharvest, on productivity of clingstone peaches, fruit quality as well as photosynthetic rate and midday leaf water potential. The research was conducted in a commercial clingstone peach (Prunus persica L. Batch cv. A-37) orchard in Greece. Trees were irrigated by means of microsprinklers and their frequency was determined using local meteorological station data and the FAO 56 Pennman-Monteith method. Photosynthetic rate was measured by a portable infrared gas analyzer. Midday leaf water potential was measured by the pressure chamber technique. During the years 2005 and 2006, the treatment RDII with irrigation applied at growth stage II of the peach tree did not affect productivity, fresh and dry mass of fruits. RDII reduced preharvest fruit drop in comparison to the control. RDII as well as the combined treatment RDII plus RDIP with irrigation applied at postharvest, at both years reduced shoot length of the vigorous shoots inside the canopy. RDII in comparison to the control increased the soluble solids content of the fruits and the ratio soluble solids/acidity. However it did not affect fruit acidity and fruit firmness. RDII as well as RDII plus RDIP in 2006 increased 'double' fruits and fruits with open cavity in comparison to the control and RDIP. Water savings were considerable and associated with the climatic conditions of each year.


2007 ◽  
Vol 47 (1) ◽  
pp. 71 ◽  
Author(s):  
R. J. Hutton ◽  
J. J. Landsberg ◽  
B. G. Sutton

This paper addresses the question of whether a citrus crop has the same need for water at all stages of development or whether it is possible to withhold water at times when the crop is less sensitive to water stress, thus, reducing total water use and improving water use efficiency while still maintaining yield. To answer this question water applied by irrigation was reduced by up to 33% relative to standard full irrigation by extending the intervals between applications from 3 to 17 days during fruit growth stages II and III in the annual growth cycle. As expected, the longer intervals resulted in greater depletion in soil moisture and significant water stress developed as soil water deficits approached the lower limits of plant available water. Stressed trees exhibited mean pre-dawn water potential (ψl) values of –0.93 MPa and midday ψl values decreased to between –2.0 and –2.5 MPa. Periodic soil water deficits in late summer and autumn reduced shoot growth, but fruit yield was unaffected, and there was no evidence of reduced canopy size. Water use efficiency (mass of fruit produced per unit water applied) improved, but fruit growth was extremely sensitive to moisture stress and extended irrigation intervals in summer and autumn reduced fruit size. Fruit juice quality was also affected, as there was an increase in both total soluble solids and juice acidity, but the practical consequences of these were limited because there were only small changes to the sugar : acid ratios. This work has demonstrated that deficient irrigation during summer can be used to manipulate growth and reduce water use, but at the risk of a marginal reduction in fruit size.


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