A Study On The Development And Application Of Foliar Fertilizers With High Efficiency Of Iron Use

Iron (Fe) deficiency is a common nutritional disorder in crops in China, especially in calcareous soils of North China. It not only limits crop growth, development and quality, but also indirectly affects human health. Iron-spraying is one of the most effective way to control Fe deficiency. However, low technology, inefficiency and high price of most ferric fertilizers are major barriers to the treatment of iron deficiency. So the study was conducted to obtain effective, low price and environmental-safe spraying organic iron fertilizers, which have the function of improving yields, quality and absorption of iron nutrition. Then, an experiment was conducted to see the effect of such organic iron fertilizers by spraying them on peanut and rape. The findings show that organic iron fertilizers have increased biomass and improved soil quality and also have had a function on the iron chlorosis restoration. The results are as follows:(1) The pot experiment was conducted and significant correlations of quadratic curve were found between the spraying concentrations of bioactive substances (sorbitol, mannitol, xylitol, sodium gluconate, glycine, glutamate and seaweed extract) and the biomass, nutrient uptake and quality of rape were all improved. The yields, quality and nutrient uptake of rape were improved by spraying appropriate concentration of bioactive substances. It was found that the optimal application rates of sorbitol, sodium gluconate and glycine were150～300mg/kg,600-1200mg/kg,120～250mg/kg.(2) The effects of the combined application of sodium gluconate, sorbitol, glycine, seaweed extract and ferrous sulfate on the growth, quality and absorption of iron of rape by spraying were studied. The results show that the yield and quality of rape were improved, the activity iron contents and SPAD values increased significantly and iron nutrient use efficiency was improved by combined application of bioactive substances and ferrous sulfate, compared with spraying ferrous sulfate (Fe) only. The contents of active iron and SPAD values of rape of sodium gluconate and ferrous sulfate combined application were increased respectively by7.57%and32.75%. The spraying of glycine and ferrous sulfate fertilizer could remarkedly improve Vc and soluble sugar contents of rape, which were increased by14.70%and21.49%, respectively, the nitrate content was decreased by47.80%.(3) The effects of different temperatures and pH values on iron content of compounded systems were studied. The results showed that the temperatures had more effect on iron contents of compounded systems than initial pH values. The compounded system which formed by iron and bioactive substances (glycine and sodium gluconate) were stability and had high iron content when the reaction temperatures were range from50to60degrees celsius and pH were range from5to6. Foliar fertilizer products (organic iron fertilizer Ⅰ, Ⅱ and Ⅲ) could be developed by adding auxiliaries such as surface active agents, which were consistent with standard of water-soluble trace minerals fertilizers (NY1428-2010).(4) The study showed that spraying organic iron fertilizer Ⅰ, Ⅱ and Ⅲ could promote the growth of peanut, in addition to promoting iron absorption of plants. The optimal iron concentrations of organic iron fertilizers by spraying were50～100mg/L. Compared with fertilizer of ferrous sulfate, the biomass of peanut were increased by82～99%,34～100%,40～56%, The active iron contents in young leaves were increased by27%,22～49%and106～185%, the uptake contents of iron were increased by17～54%,11～55%,4.5～35%by spraying organic iron fertilizer Ⅰ,Ⅱ Ⅲ, respectively, Organic iron fertilizers had a function on the iron chlorosis correction.The fertilizer efficiency of organic iron fertilizerl, Ⅱ were better than Ⅲ.(5) The results showed that organic iron fertilizers by spraying not only enhanced the growth and contents of iron nutrient, but also improved the quality of rape. Compared with ferrous sulfate, the yields of rape were increased by18.11%,21.78%, the contents of iron nutrition were increased by24.69%and53.63%, the contents of Vc were enhanced by0.43%and8.59%, the soluble sugar contents were improved by0.44%and21.49%by spraying organic iron fertilizer Ⅰ and Ⅱ, respectively; Compared with Hefeng iron, the yields and the active iron content of rape were improved by2.74%and5.94%;22.61%and16.22%respectively by spraying organic iron fertilizer Ⅰ and Ⅱ; While the effects of organic iron Ⅱ on rape were better than organic iron Ⅰ.