| Phosphorus（P）is an essential nutrient element for vegetable growth.Application of phosphorus fertilizer can increase soil available phosphorus content,vegetable phosphorus accumulation,vegetable yield as well as improve vegetable quality.However,in the process of vegetable production in the facility,in order to pursue high yield and high benefit,the amount of phosphorus applied in the facility garden soil far exceeds the requirements of vegetable production,which will give rise to the problem of excessive soil phosphorus surplus and low use rate of phosphorus fertilizer due to the fixation of phosphorus fertilizer after being applied into the soil,and it will cause the potential environmental and water pollution risks.In this paper,the effects of different planting years,planting patterns and agronomic measures on soil nutrients contents were investigated in Hexian,the Vegetable Town,and the optimum phosphorous fertilizer dose was designed based on the field investigation results.A field experiment was carried out in Hexian to explore the effects of phosphorus fertilizer reduction and different new type of phosphorus fertilizer application on cucumber yield,quality and phosphorus fertilizer use efficiency under the drip irrigation condition.The main results are as follows:（1）The results of the survey showed that there was a significant positive correlation between soil nutrient content and planting years.The soil p H of the protected garden was much lower than that of the open garden.The soil p H decreased by 0.18～1.18 and0.06～0.92 in the 0～20 cm and 20～40 cm layers of the protected garden in different planting years,respectively.The soil salinization degree was higher in the cultivated garden with 20 years of cultivation,and the electrical conductivity value was 0.91 d S·m-1,which was 1118%and 492%higher than that of the farmland with food crops and the open garden with 20 years of cultivation,respectively.The soil nutrient content in the protected garden was higher than that in the open garden.The soil organic matter content in the 0～20cm and 20～40 cm of the protected garden was 18.62～28.89 g·kg-1 and 13.03-19.33 g·kg-1,respectively,with an average of 24.19 and 15.75 g·kg-1.37.5%and 10.4%higher than the mean of open garden,respectively.The total nitrogen content in the topsoil of the facility garden was 1.41～1.76 g·kg-1,with an average of 1.57 g·kg-1,and the total nitrogen content in the open garden had no significant change.Available P was mainly accumulated in the surface soil.The content of available P in 0～20 cm soil in different planting years ranged from 53.44 to 299.22 mg·kg-1,with an average of 153.82 mg·kg-1.The average content of available P in 20 years was 299.22 mg·kg-1.Compared with open garden and farmland,57.9%and 872.3%higher;The longer the planting years,the higher the content of soil available K in different deep facilities,but the open garden had no significant change.（2）The results of phosphorus fertilizer reduction experiment showed that the less the amount of phosphorus fertilizer,the lower the soil available phosphorus content.The available P content in 0～20 cm soil was 179.27,261.59,231.77,229.56 and 230.04mg·kg-1,respectively,when p fertilizer was not applied,formula fertilizer was applied,and P fertilizer was reduced by 10%,30%and 50%in cucumber seedling pulling stage.Phosphorus accumulation in cucumber plants was 10.15,14.13,13.52,18.25 and 13.94kg·hm-2,respectively.Compared with the control treatment,the phosphorus accumulation was the highest(7.17 kg·hm-2),the phosphorus contribution rate（178.7%）,agricultural efficiency（388.7%）,partial productivity（75.4%）and absorption efficiency（162.9%）when the phosphorus application rate was reduced by 30%.Cucumber yield（22.8%）and yield/input ratio（25.1%）were significantly increased.Comprehensive analysis showed that under the condition of water and fertilizer integration,the appropriate amount of P fertilizer could significantly improve the phosphorus accumulation,the use rate of P fertilizer,the yield and the ratio of production to input of cucumber.（3）Field experiment of greenhouse cucumber was conducted with six treatments including:（1）no phosphate fertilizer（CK）;（2）diammonium phosphate（DAP）;（3）microbial agent combined with application of diammonium phosphate（MA-DAP）;（4）loss-controlled diammonium phosphate（LC-DAP）;（5）zinc humic acid diammonium phosphate（ZHA-DAP）;（6）Alginic acid diammonium phosphate（AA-DAP）.【Result】Compared with DAP treatment,soil available P content in MA-DAP,LC-DAP and ZHA-DAP treatments increased by 6.14%,5.06%and 18.63%;phosphorus accumulation in cucumber plants increased by 1.80%,11.88%and 2.78%,cucumber yield increased by2.93%,18.29%and 16.59%,the ratio of production to investment increased by 1.60%,10.78%and 9.78%,the contribution rate of phosphate fertilizer increased by 13.20%,127.25%and 119.04%,agronomic use efficiency increased by 15.91%,170.45%and154.55%,partial productivity increased by 1.71%,18.29%and 16.59%,And the absorption and use efficiency increased by 37.27%,59.69%and 38.03%,respectively.Among which,LC-DAP treatment had the highest level.Compared with DAP treatment,the soluble sugar content in cucumber fruit of MA-DAP,LC-DAP and AA-DAP increased by 0.47%,18.07%and 11.61%,and the vitamin C content increased by 3.19%,12.13%and 1.23%,respectively.Among which,LC-DAP treatment had the highest contents. |
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