| [Object] Fertilization is an important measure to increase crop production. With the increase of population, the demand for food and agricultural products has increased, and the new fertilizer has been paid more and more attention. The influences of multielement compound fertilizer and humic acid-urea on soil nutrients content, enzyme activity, and cotton growth and nutrient absorption were investigated in a drip-irrigated cotton field. Cotton yield and economic benefit were also evaluated in this study. The objective of this research is to provide the reference for new fertilizer application in drip irrigation cotton field. [Methods] A field experiment was conducted at an ecology garden of Tianye at Shihezi, Xinjiang province from 2014 to 2015. Exp. 1: Three basal application rates of multielement compound fertilizer were set as 300, 450, and 600 kg/hm2(noted as F300, F450, and F600, respectively). In addition, the treatment of traditional chemical fertilizer basal application was set as control(CK1). Exp. 2: Seven treatments were(1) No N fertilizer,(2) No N fertilizer topdressing,(3) Urea application 270 kg N/hm2,(4) Humic acid-ureaⅠapplication 180 kg N/hm2 and(5) 270 kg N/hm2,(6) Humic acid-ureaⅡapplication 180 kg N/hm2 and(7) 270 kg N/hm2(noted as N0, CK2, U-270, UI-180, UI-270, UII-180, and UII-270, respectively). Exp. 3: Three fertilization modes were set as(1) No N fertilizer,(2) Traditional chemical fertilizer basal application + Humic acid-ureaⅠfertigation,(3) Multielement compound fertilizer basal application + Urea fertigation,(4) Multielement compound fertilizer basal application + Humic acid-ureaⅠfertigation(noted as N0, C+UHA, F+U, and F+UHA, respectively). [Results](1) Application of multielement compound fertilizer significantly increased the activity of soil urease, but under the fertilizer dosage of 600 kg/hm2 showed inhibitory effect of urease. Alkaline phosphatase activity and soil microbial biomass C increased significantly with multielement compound fertilizer dosage rising. Multielement compound fertilizer applied had less significant effect on sucrase, cellulose enzyme activity and microbial biomass N.(2) The dry matter weight and yield of cotton had no significant difference with control in the F300 treatment. Application of multielement compound fertilizer significantly increased nutrient absorption and yield, this increased cotton yield by 18% in the F450 treatment and by 20% in the F600 treatment. But the processing ratio decreased obviously with the increase of applying multielement compound fertilizer in the F600 treatment. Therefore, the appropriate basal application rate of multielement compound fertilizer was 450 kg/hm2 for this study.(3) Under the condition of no topdressing nitrogen(N0 and CK2), the soil NO3--N content always remain at low levels during the cotton growth. The soil NO3--N content significantly increased after the topdressing nitrogen, the UI-270 treatment with the highest content of soil NO3--N, followed by the UII-270 and U-270. The soil NO3--N content significantly reduces in the UI-180 UII-180 treatment.(4) The common urea and humic acid-urea application significantly increased dry matter weight, nutrient absorption and yield of cotton. The UI-270 treatment with the highest dry matter weight, N, P, K uptake and cotton yield. This increased cotton yield by 17% in the humic acid urea type I treatment, cotton yields were significantly higher in the UI-270 treatment than in the U-270 treatment by 17%. Therefore, the appropriate topdressing rate of humic acid-urea was 270 kg/hm2 for this study.(5) The F+UHA treatment significantly increased dry matter accumulation and N, P, K uptake. The cotton yields were significantly higher in the F+UHA treatment than in the C+UHA treatment by 26% and 17% in the F+U treatment.[Conclusion]The multielement compound fertilizer application significantly increased the activity of soil urease and alkaline phosphatase. It can increased N, P, and K uptake by cotton, thus increased cotton yield. The humic acid-urea significantly increased the soil nitrogen level. Compared with urea, the application of humic acid-urea I significantly increased cotton N, P, K uptake, yield and fertilizer use efficiency under the same rate of fertilization. The multielement compound fertilizer combining humic acid-urea I significantly increased cotton growth and nutrient absorption, thus increased cotton yield. |
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