Influence of different moisture regimes and n-fertilization on electrochemical changes and some nutrients in the leachate solution during growing period of rice plants

Abstract

A pot experiment was conducted in the greenhouse of NRC, Dokki, Giza, Egypt, using clay loam soil to study the effect of different moisture regimes (M1, M2 and M3) and fertilizer treatment(F0, F1, F2, F3, and F4) on electrochemical change and concentration of some nutrients in the leachate solution during growing period of rice plant (variety Sakha 102). The important results could be summarized in the follows: PH values showed the highest decreases under all the fertilizer treatments when the moisture regime of M1 was used followed by M2 and M3 in descending order. Furthermore, pH values showed higher decreases when the fertilizer treatment of F3 was used followed by F4, F2, F1 and F0 in decreasing order. Under all soil moisture regimes and fertilizer treatment Eh values sharply decreased during the 12 days after starting (DAS), then they decreased to the lowest values at 24 DAS. The soil moisture regimes decreased Eh values in soil solution during the growth period of rice plants. The highest decreases were obtained under soil moisture of M1 followed by M2 and M3 in descending order. The greatest decreases of Eh values were obtained by using the fertilizer treatment of F3 followed by F4, F2, F1 and F0 in descending order. Results showed that , P, K+, Fe++ and Mn++ concentrations in soil solution were higher in the early stages of rice plans and reached a peak at 24 days after staring (DAS), then the concentrations of all the studied nutrients gradually decreased with increasing the growth period. Inorganic N-fertilizer treatments (F1 and F2) gave higher nutrients concentrations under all soil moisture regimes as compared with N-organic fertilizer treatment alone (F4). Combination of organic and inorganic fertilizer (F3) gave the higher nutrients concentration in the leachate solutions followed by fertilizer treatments of F2, F1, F4 and F0 in decreasing order. The highest values of , P, K+, Fe++ and Mn++ concentrations were obtained at 24 days after starting (DAS) by using the fertilizer treatment of F3 under soil moisture regime of M1 (F3 M1¬) followed by F3M2 and F3M3 in decreasing order, while the lowest values were obtained at 72DAS under soil moisture regime of M3 and unfertilized treatment F0 (M3F0).