Influences of nitrogen fertilizer application rates on radish yield, nutrition quality, and nitrogen recovery efficiency

Abstract

Radishes (Raphanus sativus L.) were grown in plastic pots in a screenhouse to investigate the influences of nitrogen fertilizer application rates (NFAR) on yield, nitrate content, nitrate reductase activity (NR), nutrition quality, and nitrogen recovery efficiency (NRE) at commercial mature stage. Five N-rate treatments, 0.644, 0.819, 0.995, 1.170, and 1.346 g$pot -1 , were set up in the screenhouse pot experiments, and nitrogen fertilizer (unlabeled N and 15 N-labeled fertilizer) was applied as basal dressing and topdressing, respectively. The results indicated that the fresh and dry weight yields of radish increased with the increase of NFAR at the range of 0.099 to 0.180 g N$kg -1 soil, decreased at 0.207 g N$kg -1 soil, and accordingly there was a significant quadratic relationship between the fresh and dry weight yields of radish and the NFAR. At the high addition of urea-N fertilizer, the nitrate content accumulated in the fleshy roots and leaves due to the decline in NR activity. From 0.644 to 0.819 g N$pot -1 NR increased most rapidly, the highest NR activity occurred at 0.819 g N$pot -1 , and the lowest NR activity happened at 1.346 g N$pot -1 . Soluble sugar and ascorbic acid initially increased to the highest value and then decreased, and, contrarily, crude fiber rapidly decreased with the increase of NFAR. Total N uptake (TNU), N derived from fertilizer (N dff ), and N derived from soil (N dfs ) in radish increased, except that N dfs relatively and slightly decreased at the rate of 0.207 g N$kg -1 soil. The ratio of N dff to TNU increased, but the ratio of N dfs to TNU as well as NRE of N fertilizer decreased with the increase of NFAR. Therefore, the appropriate NFAR should be preferably recommended for improving the yields and nutrition qualities of radish and NRE of N fertilizer.

Effect of N Management on Root Yield and N Uptake of Radishes in Southern China

“…The highest growth of plant in radish was recorded at the highest N rates (Srinivas and Naik, 1990). Liao et al (2009) revealed there were significantly positive and linear relationships between total N uptake and the fresh weight and dry weight of radish. Similar findings were also reported by Zhang et al (2013) and Pan et al (2012) for field grown rice, who found crop yield was affected not only by the rate but also by the time of N application.…”

Impact of Vermicompost as Component of Growing Medium on Phytomass Formation of Radish (Raphanus Sativus L.)

“…The negative correlation between the mineral nitrogen in the growing substrate and the content of vitamin C in vegetables, or the positive correlation between the content N an in soil and the content of nitrates in vegetables is well-known (Citak & Sonmez 2010;Čekey et al 2011;Lošák et al 2016). Liao et al (2009) claims that small application doses of nitrogen can result in the increase of vitamin C content in radish roots and leaves.…”

Role of nitrogen and magnesium for growth, yield and nutritional quality of radish

“…Vegetables are important agricultural products indispensable to people's lives, and the vegetable industry is an important industry related to the national economy and people's livelihood ( Sahu, 2004 ). Radish ( Raphanus sativus L.) is a root vegetable whose taproot is enlarged to form fleshy root as the edible organ widely cultivated around the globe, and is a nutritionally well-balanced vegetable in existence ( Liao et al, 2009 ). Carbohydrate, protein, crude fiber and vitamin C are the nutritious constituents of radish ( Bakhsh et al, 2006 ), broadly used as core plant, green sprouts and flabby leaves ( Alam et al, 2010 ).…”