优化施肥处理下设施菜地土壤容重与孔隙度的变化

土壤容重与孔隙度影响土壤养分的有效性及作物生长，与耕作、施肥、灌溉等农业管理措施密切相关。为了研究设施农业条件下土壤环境质量的变化，探索较优施肥模式。以寿光种植番茄的大棚土壤为对象，以不施化肥和有机肥的土壤为对照，研究优化施肥条件下土壤容重、孔隙度与土壤呼吸强度的变化。结果表明：与对照相比，优化施肥处理在一定程度上改善了土壤容重和孔隙状况，可减少土壤容重3.73%~14.93%，增加土壤总孔度的4.18%~15.79%，平均毛管孔度和非毛管孔度分别增加了8.07%与8.94%。根区与非根区的土壤呼吸强度比对照分别增强了23.4%~34.6%和9.6%~106.9%。其中，以有机肥8 t/hm2和秸秆4 t/hm2混匀撒施、生长期追施氮150 kg/hm2的处理变化最为明显，可在生产实践中推荐运用。试验还表明，根区土壤的平均呼吸强度为62.91 mg/kg?d，约为非根区34.45 mg/kg?d的1.8倍。土壤呼吸强度均与土壤容重和土壤总孔度呈抛物线型变化关系，当土壤容重约为1.25 g/cm3和总孔度约为53%时，土壤具有较强的呼吸作用强度。

Soil Bulk Density and Porosity in Greenhouse Vegetables Field under the Optimized Fertilization Treatment

Soil bulk density and porosity influence the bioavailability of soil nutrient and crop growth, and are closely related to the cultivation, fertilization, irrigation and other agricultural management measures. In order to research soil environmental quality and explore the optimal fertilization mode under Greenhouse field conditions, soil bulk density, porosity and soil respiration intensity were studied under the optimized fertilization conditions, with the soil of no chemical fertilizer and manure for control in Shouguang Greenhouse vegetables field planting tomato, and the results showed that, compared with the control, the optimized fertilization treatments improved the soil bulk density and porosity conditions in a certain extent. Such measures reduced the soil bulk density by 3.73% to 14.93% and increased the soil total porosity by 4.18% to 15.79%. In the meantime, the average capillary porosity and the non capillary porosity increased by 8.07% and 8.94%, respectively. Soil respiration intensity enhanced by 23.4% to 34.6% in the root zone and by 9.6% to 106.9% in the non root zone compared with the control. Among them, the treatment with 8 t/hm2 of manure and4 t/hm2 of straw blending broadcast, and topdressing 150 kg/hm2 of nitrogen in the growth period got the most obvious effect and should be recommended to apply in the production practice. The results also showed that the average soil respiration intensity in root zone was 62.91 mg/（kg· d） with about 1.8 times of 34.45 mg/（kg · d） in the non-root zone. Soil respiration intensity was parabolic relationship to soil bulk density and soil total porosity. When the soil bulk density was about 1.25 g/cm3 and total porosity was about 53%, the soil would have higher respiration intensity.