Application Of Regulated Deficit Irrigation Research Articles

Yield, fruit quality and water use efficiency of tomato for processing under regulated deficit irrigation: A meta-analysis

Tomato is one of the most widely grown vegetables in the world because of special nutritive value of its fruit. Regulated deficit irrigation (RDI) is widely applied in tomato production due to the water shortage. A lot of studies demonstrated that certain degree of deficit irrigation decreased the tomato yield but improved the fruit quality. The purpose of this paper is to use a meta-analysis to: 1) estimate the effect of RDI on processing tomato yield, water use efficiency and fruit quality; 2) identify soil texture, growth stage and deficit severity that benefit yield and increase water use efficiency compared to full irrigation. We analyzed 25 research articles with 561 experimental groups and 145 control groups. Overall, RDI decreased processing tomato yield with mean difference of 18.61 t ha-1, increased water use efficiency with mean difference of 2.33 kg m-3, and improved fruit quality. The yield decreased with mean difference of 19.79 t ha-1 in loamy soil and 14.26 t ha-1 in non-loamy soil. The soil texture had no significant effects on yield and water use efficiency under severe RDI. Application of RDI at the first stage is recommended because of no significant yield loss and significant increase of water use efficiency. RDI can improve processing tomato total soluble solids and Vitamin C. Moreover, both of them were increased more when RDI was applied at the third stage than at previous two stages. Our findings can be helpful on how to use RDI correctly to balance the processing tomato yield, water conservation and fruit quality.

Quality attributes of pistachio nuts as affected by rootstock and deficit irrigation.

In this work, the influence of two regulated deficit irrigation (RDI) treatments and three different rootstocks on the quality of pistachios was evaluated by analyzing different parameters: morphological analysis, physicochemical analysis and sensory analysis. The results obtained in terms of the choice of rootstock revealed that Pistacia atlantica had increased production yields, nut weight, mineral content, higher intensities of characteristic sensory attributes and a higher degree of consumer satisfaction, than the other rootstocks studied. Moreover, the results established that the application of RDI on pistachio cultivation had no significant influence on production yield, weight, size, colour, water activity or mineral composition. Furthermore, T1 treatment (stem water potential < -1.3 MPa) resulted in higher intensities of characteristic sensory attributes and a greater level of satisfaction among international consumers. These results confirm that the application of deficit irrigation (T1) contributes to an increase in overall product quality. Furthermore, Pistacia atlantica rootstock provided better yield and quality than the other rootstocks studied.

Fruit yield and root system distribution of 'Tommy Atkins' mango under different irrigation regimes

This study aimed to evaluate the fruit yield and the distribution of 'Tommy Atkins' mango root system under different irrigation regimes in the semiarid region of Bahia. The experimental design was completely randomized with five treatments and three replicates: 1 - Irrigation supplying 100% of ETc in phases I, II and III; 2 - Regulated deficit irrigation (RDI) supplying 50% of ETc in phase I (beginning of flowering to early fruit growth); 3 - RDI supplying 50% ETc in phase II (start of expansion until the beginning of physiological maturity); 4 - RDI supplying 50% ETc in phase III (physiological mature fruits); 5 - No irrigation during all three phases. The regulated deficit irrigation supplying 50% of the ETc during phase I and II provided larger root length density of 'Tommy Atkins' mango. Regardless of management strategy, the roots were developed in all evaluated soil volume and the highest density is concentrated from 0.50 to 1.50 m distance from the trunk and in 0.20 to 0.90 m depth in the soil, that suggests this region to be the best place for fertilizer application as well for soil water sensor placement. The application of RDI during fruit set does not influence either root distribution or production. Root system and crop production is significantly reduced under no irrigation conditions.

Response of peach trees to regulated deficit irrigation during stage 2 of fruit development and summer pruning

Regulated deficit irrigation (RDI) during stage 2 of fruit development and summer pruning (watersprout removal, WSR) can be used to control excessive vegetative growth in high-density peach orchards. The dynamics of tree-light interception after the application of RDI (no irrigation during stage 2) and WSR in summer were evaluated during two consecutive years. RDI and WSR treatments produced similar reductions in the percentage of light intercepted by the tree at the end of the 2-year experiment. However, it was not possible to produce the same seasonal dynamics in the percentage of light intercepted by the tree using the RDI and the WSR techniques; RDI trees showed a gradual reduction in the amount of light intercepted as the productive cycle progressed, while WSR trees showed an immediate reduction in the amount of light intercepted. Moreover, the mechanisms responsible for vegetative growth reduction were different in the RDI and the WSR techniques. The RDI technique was associated with reductions in tree water status and decreases in gravimetric soil water (theta g) and fruit growth capacity. RDI may have reduced theta g below the threshold required for optimum fruit growth, whereas WSR reduced water consumption, improved water status and therefore could have benefited fruit growth. Therefore, RDI and WSR greatly differ when the mechanisms responsible for vegetative growth reduction are taken into consideration.