Effects of Applying Humic Acid and DMPP Compound Fertilizer on the Growth of Maize

[Objectives] The aim was to study the effects of humic acid and DMPP on the growth of maize and explore the appropriate added concentration to provide basis for industrial production. [Methods]The pot experiment was used to study the effects of adding different concentrations of humic acid,DMPP and their compound on the growth of maize. [Results] Both humic acid and DMPP could increase plant height,stem diameter,SPAD and biomass of maize. The effect of adding 10 kg of humic acid per t was better than that adding 5 kg,and biomass increased by 5. 4% and 3. 3% compared with CK. The effect of adding 1 kg of DMPP was better than that adding 0. 5 kg,and biomass increased by 5. 7% and 2. 7% compared with CK. The compound application of the 2 improved the fertilizer efficiency. The best treatment was 5‰ humic acid ＋ 1 ‰ DMPP,which could increase plant height,stem diameter,SPAD,and dry weight by 8. 1%,12. 3%,10. 6%,and 10. 7%,respectively,and it also had lower economic costs compared with the compounding application of 10‰ humic acid ＋ 1‰ DMPP.[Conclusions]The 5‰ humic acid ＋ 1 ‰ DMPP compound fertilizer formula was more suitable for application in maize production.

Effect of Nitrogen Topdressing on Growth and Yield of Garlic

With Cangshan garlic and early bolting garlic as experimental materials,this paper studies the effect of nitrogen topdressing on the garlic growth and yield of garlic stems and garlic bulbs. The results show that under the same amount of nitrogen,applying ammonium phosphor nitrate can better promote the growth of garlic than applying urea and ammonium chloride; both ammonium chloride and ammonium phosphor nitrate can effectively improve the yield of garlic stems and garlic bulbs,especially for ammonium phosphor nitrate; through economic benefit analysis,applying ammonium chloride and ammonium phosphor nitrate can produce greater economic benefits than applying urea,and especially ammonium phosphor nitrate increases the economic benefits of Cangshan garlic and early bolting garlic by 5490 yuan and 6690 yuan per ha,respectively.

Theoretical Study on the Effects of Spatial Structure of P Complexation Sites on the Soil Phosphorus Activation in Leonardite Humic Acid Complexes

Humic acid is an important active component in soil environment. The spatial structures of P complexation sites in humic acid complexes play an important role in soil phosphorus activation and fertilizer efficiency. To explore the effects of spatial structure, the three different coordination modes of iron-carboxyl in models were calculated by the ONIOM method available in the Gaussian09 package. The(U)B3LYP hybrid density functional was employed to optimize the configuration for the QM region, and the UFF force field was used to calculate for the MM region. The results show that the different spatial structures influence the soil phosphorus activation by affecting the electronic structure, Gibbs free energy and interaction energy of the models. And the effects are as follows: the unidentate structure model ~6P-Fe-MHA-UD, the bidentate chelating structure model ~6P-Fe-MHA-BD>the bidentate bridging structure model ~5P-Fe-MHA-BD-BG. It can be known that, the fertilizer efficiency can be improved through increasing the proportion of the unidentate structure and the bidentate chelating structure in production engineering. The research provides a theoretical basis for further optimization of the production of humic acid phosphate fertilizer.

CRITICAL PROCESSES AND MAJOR FACTORS THAT DRIVE NITROGEN TRANSPORT FROM FARMLAND TO SURFACE WATER BODIES

Agricultural non-point source pollution is increasingly an important issue affecting surface water quality.Currently,the majority of the studies on nitrogen loss have focused on the agricultural field scale,however,the response of surface water quality at the watershed scale into the nitrogen loss at the field scale is poorly understood.The present study systematically reviewed the critical processes and major factors that nitrogen transport from farm fields to surface water bodies.The critical processes of farmland nitrogen entering surface water bodies involve the processes of nitrogen transport from farmland to ditches and the transformation processes of nitrogen during migration in ditches/rivers.Nitrogen transport from farmland to ditches is one of the prerequisites and critical processes for farmland nitrogen transport to surface water bodies.The transformation of nitrogen forms in ditches/rivers is an intermediate process in the migration of nitrogen from farmland to surface water bodies.Nitrogen loss from farmland is related to soil storage and exogenous inputs.Therefore,nitrogen input management should not only consider the current input,but also the contribution of soil storage due to the historical surpluses.Ditches/rivers have a strong retention capacity for nitrogen,which will significantly affect the process of farmland nitrogen entering surface water bodies.The factors affecting nitrogen transformation in river/ditches can be placed in four categories:(1)factors affecting hydraulic retention time,(2)factors affecting contact area,(3)factors affecting biological activity,and(4)forms and amount of nitrogen loading to river/ditches.Ditch systems are more biologically(including plants and microbes)active than rivers with biological factors having a greater influence on nitrogen transformation.When developing pollution prevention and control strategies,ecological ditches can be constructed to increase biological activity and reduce the amount of surplus nitrogen entering the water body.The present research should be valuable for the evaluation of environment impacts of nitrogen loss and the non-point source pollution control.