Water deficit on the growth and yield of irrigated soybean in the Brazilian Cerrado region

ABSTRACT The increase in disputes over water use in the Brazilian Cerrado has demanded improvements in irrigation management and increase in water use productivity. In this context, deficit irrigation is an interesting management strategy, as it enables water savings without significant losses of yield. The present study aimed to evaluate the phenology and yield of a soybean cultivar subjected to different soil moisture contents. The experimental design used was randomized blocks with five treatments and four replicates. In each treatment, an irrigation strategy was applied based on the available water in the soil (AW). The T1 treatment was performed by applying from 80 to 100% AW; in T2 treatment, the allowed variation was from 60 to 80% AW; in T3 treatment, it was from 40 to 60% AW; in T4, from 20 to 40% AW; and in T5, from 0 to 20% AW. It was verified that, in winter and summer, even without the need to reduce water withdrawal, it is recommended to apply from 60 to 80% of the available water in the soil for soybean crop, without decreasing yield. In situations of water restriction, it is possible to have yield of around 55 and 70% in winter and summer, respectively, for the condition from 20 to 40% of the available water in the soil.

Effects of Regulated Deficit Irrigation and Early Cluster Thinning on Production and Quality Parameters in a Vineyard cv. Tempranillo Under Semi-Arid Conditions in Southwestern Spain

The efficient use of water in the vineyard requires knowledge of the crop’s response to irrigation in terms of production and quality and the interaction of the same with the environmental conditions. In this work, the behavior of a trellis system vineyard in cv. Tempranillo, located in the south-west of Spain, was analyzed for three years in relation to different irrigation strategies based on crop evapotranspiration (ETc), and with two levels of crop load established by early cluster thinning. The response of the vineyard to the same irrigation strategy varied depending on the characteristics of the year. The vineyard’s biomass production increased in a linear trend as annual water status improved. However, during pre-veraison, the water status had a more significant impact on the harvest by affecting bud fertility. The increase in individual cluster weight only partially compensated the loss of yield caused by cluster thinning. The year’s characteristics highly conditioned the response to the irrigation treatment and, together with cluster thinning, modified the characteristics of the musts, although the response was varied.

EFFECT OF DEFICIT IRRIGATION ON QUALITY INDICATORS OF APRICOT FRUITS AFTER HARVESTING AND STORAGE

Trees irrigation is one of the major activities because the fruit production is proportional to water use. The current decrease of water resources leads to the urgent need to adopt a strategy which could be applied to efficiently utilize water without affecting the growth, yield and fruit quality. Therefore, deficit irrigation is an alternative. The crop studied was apricot, 'Orizont' cultivar, 13 years old, grafted on the 'Constanta 14' rootstock. The planting distance was 4 m between the rows and 5 m between trees on the row. The split-plot experiment described here is monofactorial with irrigation strategy having three graduations. The irrigation regime consists of a fully irrigated treatment (b1, non-stressed) according to the irrigation needs (100% of ETc = ETo x Kc), a deficit irrigation treatment (b2) irrigated with half the amount of water in b1 (50% of ETc), and a control, non-irrigated treatment (b3). These plots comprised three adjacent fruit tree rows, with the central row containing five trees for measurements and observations. This research aims to study the effects of deficit irrigation on some quality indicators of apricot fruits after harvest and storage. Fruits in the b3 treatment were much firmer, followed by the fruits from the b2 treatment. The study suggests that moderate deficit irrigation can be profitable for enhancing key fruit quality characteristics.