Effect of foliar application of N and humic acids on growth and yield of durum wheat

Abstract

-The aim of this study was to monitor the effect of foliar application of humic acid on plant growth, photosynthetic metabolism and grain quality of durum wheat grown in a Mediterranean-type climate. Four fertilization treatments were applied: a non-fertilized control, a crop fertilized with foliar application of humic acid, a crop fertilized with mineral N on soil at sowing, tillering and stem elongation, and a crop fertilized with foliar application of N (ammonium-nitrate solution). Aboveground plant mass accumulation was measured throughout two growing seasons, and grain quality parameters were tested at harvest time. Gas exchange, leaf protein content and Rubisco activity were monitored at different stages of plant development. Differences between years were often relevant due to weather conditions. The foliar application of humic acid caused a transitional production of plant dry mass with respect to unfertilized control and split soil N application. This effect was also evident for grain yield, spike fertility and grain protein content during the two years of the study. Humic acid never affected photosynthesis or stomatal conductance, while Rubisco activity and leaf protein content showed intermediate responses between unfertilized control and split soil N application. We conclude that humic acid had limited promoting effects on plant growth, grain yield and quality, and photosynthetic metabolism of durum wheat crops grown in a typical Mediterranean-type agro-ecosystem of southern Italy, with respect to split soil N application.humic acid / durum wheat / gas exchange / nitrogen / protein / Rubisco / grain quality

The Effect of Sulfur-Containing Humic Acid on Yield and Nutrient Uptake in Olive Fruit

“…Research shows that humic acid stimulates photosynthesizing activity in plants through increasing the activity of rubisco enzyme [33]. Given the critical role of plant hormones, especially cytokinin, in the fixation and increase of chlorophyll [34] and quasi-hormonal compounds (cytokinin) of humic matter [7] [8], the loss of chlorophyll content in plants treated with humic acid in the present study is inconsistent with other studies that show higher chlorophyll content under humic acid application.…”

Effects of the times of application of a soil humic acid on berry quality of table grape (Vitis vinifera L.) cv Italia

“…Few researches deal with foliar applications of HAs in the open field, in species such as strawberry (Neri et al, 2002), rice (Tejada and González, 2004) and durum wheat (Delfine et al, 2005). Applications of HAs to fruit species are very scarcely reported in the literature and some investigations have been conducted in olive (Fernández-Escobar et al, 1996), lemon (Sánchez-Sánchez et al, 2002) and apple (Neilsen et al, 2005).…”

Desempenho do abacaxizeiro 'Vitória' em resposta à aplicação de ácidos húmicos durante a aclimatação

“…Os ácidos húmicos (AH), formados por agregados moleculares heterogêneos e estabilizados por pontes de hidrogênio e interações hidrofóbicas (Piccolo, 2001), favorecem o desenvolvimento do sistema radicular Rodda et al, 2006;Zandonadi et al, 2007), o acúmulo de nutrientes (Vaughan & Malcolm, 1985;Chen & Avaid, 1990;Chen et al, 2004) e a biossíntese de clorofilas (Ferrara & Brunetti, 2008). Para culturas como arroz (Tejada & Gonzalez, 2004), trigo (Delfine et al, 2005) e videira (Ferrara & Brunetti, 2008), tem sido relatada a promoção de crescimento pela aplicação foliar de AH. Em abacaxizeiro, o uso de AH poderia ser uma estratégia viável na aclimatação de plantas propagadas in vitro, pois poderia promover maior crescimento, resultando em redução no longo tempo necessário para a transferência das plantas para o cultivo em campo.…”