Azza Ebid

Nitrogen Uptake by Radish, Spinach and Chingensai from Composted Tea Leaves, Coffee Waste and Kitchen Garbage

A pot experiment was conducted to determine the effects of the application of composted tea leaves (TC), coffee waste (CC), and kitchen garbage (KC) on the nitrogen and nitrate accumulated in radish (Raphanus sativus L. cv. ‘radicula pers’), Chingensai (Brassica campestris L. cv. ‘Choyo No. 2’), and spinach (Spinacia oleracea L. cv. ‘Ban chu paruku’) as compared with the effect of inorganic 15N labeled fertilizer (IN) application. The compost was applied at the rate of 24 g kg−1 soil, corresponding to about 250 to 300 kg N ha−1; the A value method was used to estimate nitrogen uptake. Dry matter production was significantly higher in the IN and TC treatments than in the KC and CC treatments for all the species and tissue. Of the composts used, TC was most effective in increasing N uptake and N content in the vegetables. The composts derived N recovery as a percentage of total N uptake varied with plant species, 50.8%-62.9% in radish root, 35.3%-60.4% in radish leaf, 29.9%-48.2% in spinach leaf, and 31.3%-54.8% in Chingensai leaf. The N-use efficiencies of IN, TC, CC, and KC were 6.3%, 6.3%, 5.3%, and 6.6% in radish root; 13.6%, 9.7%, 8.4%, and 6.7% in radish leaf; 22.4%, 14.4%, 3.6%, and 5.8% in spinach leaf; and 61.2%, 39.5%, 25.5%, and 21.5% in Chingensai leaf, respectively. Nitrate accumulation in edible portions was highest in plants provided with IN as compared with those grown with composts, and nitrate content in radish root was markedly higher than that in the leaf. It is observed that the fate of compost derived N differed noticeably with vegetable species, plant part, and compost source.

Controlled release of phosphorous fertilizer bound to carboxymethyl starch-g-polyacrylamide and maintaining a hydration level for the plant

A controlled release fertilizer system based on phosphate bound-carboxymethyl starch-graft-polyacrylamide (P-CMS-g-PAM) has been prepared in order to deliver the phosphate fertilizer to the plant at a constant rate thereby. This system aims to increase fertilizer phosphorus use efficiency (FPUE) and maintain a hydration level for the plant at the same time. Two types of starch phosphate monoesters were prepared using mono-ammonium (MAP) and di-ammonium phosphate (DAP). First, starch was converted to carboxymethyl starch and then was phosphorylated with mono-ammonium dihydrogen phosphate and di-ammonium dihydrogen phosphate. After phosphorylation, the samples were grafted with acrylamide in the presence of methylene bisacrylamide as a crosslinking agent. The prepared systems of P-CMS-g-PAM were differently characterized by Fourier transformer infrared (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and phosphorous analysis. The swelling behavior was investigated. The kinetics of grafting reaction were also studied. The release behavior of phosphate bound was studied at pH 7 and 25 °C. The mechanism of the phosphate release from P-CMS-g-PAM was examined using the Korsmeyer-Peppas model.

Combined Effects of Soil Water Regimes and Rice Straw Incorporation into the Soil on 15N, P, K Uptake, Rice Yield and Selected Soil Properties

Understanding the effects of water regimes on nutri ent uptake of rice plants, especially by different organic fertilizers is crit ical to improve long-term rice productivity. In a greenhouse experiment, the effec ts of soil water management and incorporation of rice straw into the soil on nutrie nt uptake, soil properties and rice productivity were studied in a clay soil. The treat ment included two levels of soil water regimes (continuous submergence and alternative alternate submergencedrying) and four rice straw levels (0, 5, 10 and 15 t ha ). Results showed that, soil pH decreased slightly with increasing rate of rice str aw application in both continuous submergence and alternatesubmergence-drying alternative submergence -drying . Soil Eh values were correlated to rice straw application levels. Alternatesubmergencedrying Alternative submergence -drying in rice plant for some period of time significantly increased rice growth parameters and rice yield. Nitrogen in rice plant was derived mostly from fertilizer (higher N dff) values in continuous submergenceand alternative submergence-drying. The highest N atom% values in plant were observed at panicle initiation stage under both wat er regimes. .Most of N uptake by rice plant was from the soil (averaged 53%). The up take of P, K and Zn nutrients were wasgreater in continuous submergence than in alternatesubmergencedrying alternative submergence -drying.