Hanaa, A. Zein El-Abdeen and Khaled, Y. Farroh( 2019). Preparation and Characterization of Nano Organic Soil Conditioners and It's Effected on Sandy Soil Properties and Wheat ProductivityNature and Science 2019;17(2 )
Abstract: Development of technologies that improve food productivity without any adverse impact on the ecosystem is the need of hour. In this context, development of controlled delivery systems for slow and sustained release of agrochemicals or soil conditioners crucial. So, the major advantages of chitosan include its ability to function as a protective reservoir for the active ingredients, protecting the ingredients from the surrounding environment while they are in the chitosan domain, and then controlling their release, in the sandy soil systems'. Also, productivity and study chitosan nanoparticle either alone or in composite with humic acids as soil conditioners were taken in consideration. Production of the chitosan nanoparticle (CS NPs) and chitosan-humic acids nanocomposite (CS-HA nanocomposite) were carried out and using X-ray diffractometer (XRD), Dynamic Light Scattering (DLS) Analysis and transmission electron microscope (TEM) for characterization. Obtained results concluded that the X-ray diffract gram of CS NPs and CS-HA nanocomposite shows a broad peak at around 2=28° where the structure of nanochitosan after crosslinking with tripolyphosphate it shows a decrease in crystallinity of chitosan while CS-HA NPs shows the less intense peak and less crystalline entity. Nanoparticles prepared by gelation method showed a mean size of 20.5 and 37.3 nm as well as mean positive charge of 42 and 22.5 mV for CS NPs and CS-HA nanocomposite respectively, when analyzed by Malvern zeta–sizer. Also, TEM micrograph of the CS NPs and CS-HA nanocomposite showed that the CS nanoparticles have nearly spherical shape, smooth surface and size range of about 17 nm and the cross-linking between chitosan and humic acids was about 36 nm. To study these materials as soil conditioners, a field experiment was carried out during the two successive winter seasons of 2016/2017 and 2017/2018 at the experimental station of the Agriculture Research Center in Ismailia region (Ismailia Governorate), Egypt cultivated with wheat (Triticum aestivum L., cv Giza 168). The treatments were arranged in a split plot design with three replicates. The main plot included five treatments, control (recommended NPK), humic acids (HA), chitosan (CS)), chitosan nanoparticles (CS NPs) and chitosan- humic nanocomposite (CS-HA nanocomposte) while the sub-plot areas included their concentrations (C1, C2 and C3) according to type of soil conditioners. In general, results show that mean values of the soil treated with CTS-HA nanocomposite at concentration C3 was enhanced their total porosity (TP) and moisture content which represented in field capacity (FC), wilting point (WP) and available water (AW). An opposite trend was obtained with soil bulk density where it decreased with increased treatment concentrations in all treatments applied as compared to control. Furthermore, the applied of nano organic soil conditioners were decreased soil reaction (pH) as compared to control and such decreased was proportional to treatment concentrations. On the other hand, both electrical conductivity (EC) and organic matter (OM) were increased significantly with all treatments and concentrations applied as compared to control. The maximum increased was obtained with CS-HA nanocomposite as compared to other normal forms of organic soil conditioners. The same trend was observed with available N and P content in soil. In addition, results revealed that all mean values of wheat growth parameters (biological yield, grain, straw and 1000 grain) were generally increased significantly in all treatments applied as compared to control. The magnitude increases in yield production was observed with chitosan-humic nanocomposite more than unique application of chitosan and humic acid. Such increase reach to (38.1% and 37.9%) for yield, (52.8% and 78.7%) for grain, (20 % and 26.7%) for straw and (62.9% and 59.1%) for 1000 grain in two successive seasons, respectively. Also, mean values of growth parameters were increased by increasing application rates. Finally, from above mention results we can be concluded that the usage of nano organic soil conditioners were more effective than other normal forms which led to improved soil physical and chemical properties along with wheat productivity.
Keywords: (Characterization; XRD; DLS; TEM, organic soil conditioners, chitosan, humic acids, nanocomposite, sandy soil, wheat plant.)
