Effect Of Surface Dual Coverage On Rhizosphere Environmental Factors And Growth Of Greenhouse Cucumber

The cucumber was selected to study different cover of combination of plastic film and maize straw on soil surface in greenhouse. Data of environmental factors of rhizosphere soil microorganisms, nutrients and growth of cucumber were measured to explore the best treatment and internal mechanism. The more rational amount of fertilization and irrigation water was explored in the condition of cover of plastic film and maize straw. The results were as follows:1. The different treatments of surface cover improved rhizosphere soil microbial quantity and some nutrient content, reduced evapotranspiration and soil moisture density, increased soil crumb structure, promote root growth of underground and plant growth of aboveground, and ultimately improved the yield and quality of cucumber. Compared with the cover of single straw or mulching, the different thickness of corn stover plused mulch covering improved the most of indicators of plants growth, fruit quality and yield, reduced evaporation of soil moisture, bulk density, conductivity, improved organic matter content of rhizosphere soil of0-20cm and20-40cm depth in early fruiting, and promoted total K content of rhizosphere soil of0-20cm depth, compared to single mulching, straw mulch improved the content of organic matter, nitrogen, phosphorus, and potassium of rhizosphere soil of0-40cm depth. But the treatment of mulching is better than single straw mulch for improving the soil temperature, rhizosphere actinomycetes, reducing evaporation and promoting the indicators of growth of cucumber.2. For treatments of different thickness of corn stover plused film, thickness of3cm and5cm straw covered film were better than thickness of1cm straw covered film and promoted indicators of plant growth, fruit quality, and yield. And the treatments both reduced soil moisture evaporation and conductivity value, improved surface CO2concentration, crumb structure, rhizosphere cellulolytic bacteria, nitrogen-fixing bacteria, organic matter, total N, P content of soil of0-20cm depth, and increased organic matter, total N, nitrogen content of soil of20-40cm depth. There had not significant difference for promoting the growth and development, environmental factors of rhizosphere soil nutrients and microorganism between the two treatments of3cm and5cm thickness of corn stover plused film. Considered fully, the treatment of3cm straw covered film was the best and had greater value in the production practice. 3. Compared with CK, DJ2treatment of3cm straw covered film significantly reduced soil moisture evaporation and density of0-20cm depth, and increased the proportion of soil aggregate structure. In the early fruiting, DJ2treatment significantly increased content of organic matter67.85%, total N27.33%, total P27.16%, total K7.89%, nitrogen46.77%, available P66.90%, available K43.89%of rhizosphere soil of20-40cm depth. In the later fruiting, DJ2treatment increased rhizosphere soil bacteria count82.78%, cellulolytic bacteria count10.98%, congtent of organic matter20.83%, total P22.83%, total K5.16%and nitrogen5.53%, and reduced fungi count33.50%of rhizosphere soil of0-20cm depth, and improved content of organic matter15.43%, nitrogen6.09%, available K4.55%.of rhizosphere soil of20-40cm depth. In the later fruiting, DJ2treatment also significantly increased plant height34.84%, stem diameter8.27%, leaf area27.42%, Pn1.25%, Gs24.43%, Ci5.82%, Tr39.42%, root factor73.24%, root diameter20.43%, total root length55.73%, total root surface area54.46%, total root volume70.37%, fruit soluble sugar content7.78%, soluble protein content54.90%, Vc content33.31%, ratio of fruit dry weight to fresh weight9.80%, commodities melon rate14.23%, plant dry weight21.91%, number of fruiting plant30.92%, plant yield39.16%, total yield14.77%.4. In the condition of3cm straw and mulching, the tset of different fertilizer was studied to find that, compared with traditional fertilizer, reducing amount of chemical fertilizer within a certain range did not significantly reduced yield and quality of greenhouse cucumber but promoted some indicators of growth, soil enzyme activity, microbial quantify, and significant increased fruit P and K content which were benefit to improve fruit quality. Consolidated all aspects, the effect of treatment2(N:68kg/hm2, P2O5:30kg/hm, K2O:90kg/hm) was more obvious. Compared with CK, treatment2did not decrease the plant yield and total yield but decreased significantly12.98%for fruit nitrate content. In the peak of fruiting, treatment2significantly increased stem diameter8.66%, leaf number15.67%, Pn18.96%, Gs13.59%,Tr21.53%, shoot ratio24.02%, total root surface area9.83%, total root volume16.10%, improved rhizosphere bacteria count50.41%, nitrogen-fixing bacteria count24.07%, actinomycetes count25.50%, cellulose-decomposing bacteria count23.22%, catalase activity14.00%, urease activity13.91%, invertase activity30.20%while reduced significantly fungi count.5. In the condition of3cm straw and mulching, the tset of different amount of ertilizer irrigation water was studied to find that the effect of treatment2(Amount of irrigation water every time was258m3/hm2. Irrigation times was12from planting to end of harvest) was more obvious, compared with CK, and saved40%water resources. Compared with CK, treatment2had little difference in yield and quality, and significantly increased root factors12.87%, shoot ratio21.65%, total root surface area14.40%, total root volume19.31%, non-rhizosphere soil total K24.09%, catalase activity13.58%, invertase activity17.21%, count of rhizosphere bacteria53.78%, nitrogen-fixing bacteria30.17%, actinomycetes51.43%, cellulolytic bacteria45.98%, fungi165.87%.6. Integrated correlation and factor analysis, the results showed that the surface dual coverage of mulch and straw significantly increased the rhizosphere soil organic matter, nitrogen, phosphorus and potassium content, therefore, promotde count of rhizosphere soil bacteria, nitrogen-fixing bacteria, cellulose-decomposing bacteria, and actinomycetes. The coverage improved of the surface soil temperature and effectively controled moisture evaporation. All these factors promoted root growth of cucumber and affect leaf net photosynthesis, and ultimately promoted yield and quality of cucumber. Firstly factors affecting the growth of greenhouse cucumber were index of root growth, count of rhizosphere soil bacteria and organic matter content. Secondly factors were rhizosphere soil nitrogen content, count of nitrogen-fixing bacteria and fungi, and available P and K content.