Effect of N Fertigation Rates and Humic Acid on The Productivity of Crisphead Lettuce (Lactuca sativa L.) Grown in Sandy Soil

Abstract

Lettuce is a slow-growing plant, which often accumulates 70:80% of it is head biomass and N uptake just during the last three to five weeks before the harvest. As well, add humic acid (HA) with N fertilizers is helping reduce the loss of N via leaching, especially in sandy soil. Therefore, the doses of N fertilizer and HA preferably add them in harmony with the requirements of different lettuce growth stages. This investigation aimed to study effect of three N fertigation rates; 50, 100 and 150 kg ha -1 and four rates of humic acid (HA); control, 400, 800 and 1600 mg l -1 as well as their interaction on the growth, head characters and mineral uptake (N, P and K) of crisphead lettuce. The results showed that lettuce plants receiving N fertigation rate up to 150 kg ha -1 were achieved the highest fresh and dry weight of outer leaves and head as well as total yield ha -1 . Furthermore, the total chlorophyll content, T.S.S. and mineral uptake were improved with increase N fertigation rate up to 150 kg ha ), fresh and dry weight of outer leaves and head and N, P and K uptake as well as chlorophyll content and T.S.S. Whereas, the ratio of outer leaves: head as the dry weight base was a significant increase with an increase in HA rate up to 1600 mg l -1 . Generally, the results showed that lettuce plants receiving N fertigation up rate 150 kg ha -1 + 800 mg l -1 HA achieved the highest mean values of fresh and dry weight of outer leaves and head as well as total yield ha -1 and chlorophyll content of crisphead lettuce plants.

Biostimulant Substances for Sustainable Agriculture: Origin, Operating Mechanisms and Effects on Cucurbits, Leafy Greens, and Nightshade Vegetables Species

“…Similar results were obtained in two other lettuce studies by Mirdad and Kiran [164,165], who both tested combinations of fertilization and HSs applications. The former author tested soil applications of Has at varying rates (30 through 90 L ha −1 ), which were evaluated at two different nitrogen fertilization levels representing non fertilized and optimally fertilized.…”

Humic acid and boron treatment to mitigate salt stress on the melon plant

“…However, under salt stress conditions the potassium absorption is markedly reduced due to the competitive effect with sodium, where plants absorb Na ions more than necessity, resulting in malnutrition status in plants grown under these conditions (Kusvuran et al 2007). These results are in consonance with the finding of Khaled (2011) for N, K, and Na in corn, Asri et al (2015) for N, K, and TSS in tomato, Ahmad et al (2016) for N and K in canola, Mirdad (2016) for N, K and TSS in lettuce, Kahraman (2017) for K and Ca in cowpea, as well as, humic acid increases the contents of N and K, and decreases sodium content of bean plant under saline conditions (Aydin et al, 2012). The positive effect of humic acid on plants may be due to improving chemical, physical and biological properties of the soil, elements chelation and pH adjustment (Karakurt et al, 2009), thus the low soil pH may affect plant growth indirectly, at the low soil pH the availability of many elements increases while the other nutrients such as calcium were limited (Yan et al 1992).…”

The tolerance of oil palm (Elaeis guineensis) seedlings to Al stress is enhanced by citric acid and natural peat water

“…Application of 200 ppm peat water elevated the rate of photosynthesis, as well as content of chlorophyll a, chlorophyll b, and carotenoid. According to Panda et al (2009), Al stress could reduce the content of chlorophyll, but giving exogenous compounds such as citric acid (Hu et al 2016;Song et al 2018) and humic acid (Mirdad, 2016) enabled seedlings to alleviate chlorophyll damage, thus improved the photosynthesis rate. Chotimah et al (2007) explained that peat water contains 0.104% humic acid.…”