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Straw returning is one of the important measures for improving soil fertility. It is unclear, however, whether the regulation function of soil on nitrogen (N) cycle after fertilization is sustainable and the relationship between the regulation function and the amount of straw returned to the field. In this study, a 3-year straw returning field trial was set up in a field had been carried out straw returning of all the havested straw for nine years. The amount of straw returned was 100%, 67%, 33% and 0 of the average annual straw yield (7500 kg·hm秸秆还田是土壤培肥的重要措施之一,但培肥后土壤对氮素循环的调控功能是否具有可持续性以及与后续秸秆还田数量的关系尚不清楚。本研究对黑土旱地农田进行9年培肥处理后,设置了连续3年秸秆还田处理,秸秆还田量分别为年均秸秆产量(7500 kg·hm

Excessive fertilization easily leads to the degradation of greenhouse vegetable fields, therefore rational fertilizations are important to maintain the production and sustainable development of vegetable. In this study, two fertilization treatments (optimized fertilization and conventional fertilization, noted as OF and CF, respectively) under continuous tomato-pepper cropping were arranged to investigate soil physicochemical properties, abundance and trophic groups of nematode and vegetable yield. The results showed that OF could maintain soil pH at the relatively higher level and increase the yield of tomato and pepper by 9.0% and 6.9% compared to CF treatment. In contrast to CF, OF increased nematode quantity and the relative abundance of bacterivores, but decreased the relative abundance of fungivores and plant-parasites, more obviously in the growth season of tomato. No obvious differences in plant parasite index, diversity, and richness were observed between CF and OF treatments across all sampling stages of tomato and pepper. Nematode channel ratio ranged from 0.39 to 0.64 in CF treatment, which was significantly lower than that in OF treatment (0.67-0.84), suggesting that the decomposition of food network was dominated by fungi in CF treatment but by bacteria in OF treatment. Based on soil physicochemical properties, nematode groups and vegetable yield, we concluded that optimized fertilization could not only increase vegetable growth but also improve soil ecological environment.高强度利用下设施蔬菜地的施肥过量问题导致了土壤质量的严重退化,合理施肥是维持蔬菜地生产力和可持续发展的重要措施.本研究比较了常规施肥和优化施肥两种施肥方式下连续种植番茄和辣椒后土壤理化性质、线虫群落及蔬菜产量的差异.结果表明: 优化施肥处理土壤pH显著高于常规施肥处理,且番茄和辣椒产量分别提高了9.0%和6.9%.与常规施肥相比,优化施肥提高了土壤线虫数量和食细菌线虫的相对多度,但降低了食真菌线虫和植食性线虫的相对多度.两季蔬菜种植过程中,不同施肥处理土壤寄生线虫成熟指数、多样性指数和丰富度指数无显著差异.优化施肥土壤线虫通路比值(0.67～0.84)显著高于常规施肥(0.39～0.64),前者土壤食物网的分解途径以细菌为主,而后者则为真菌控制.综合土壤理化性质、线虫数量和群落及蔬菜产量指标,优化施肥措施能够在促进蔬菜生长的同时,显著改善土壤生态环境.

Banana Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (FOC) is a worldwide soil-borne disease that causes serious economic losses every year. Effective ways of preventing the disease are still not available. In this study, biological soil disinfestation (BSD) with incorporation of various organic matters under flooding conditions combined with plastic mulching was applied to suppress FOC and prevent banana Fusarium wilt disease. The biological properties of the soil during the BSD process were investigated using quantitative real-time PCR and denaturing gradient gel electrophoresis. The results showed that the values of soil redox potential significantly decreased by >800 mV in the treatments that incorporated rice straw and bagasse under flooding conditions compared with untreated soil. The lowest soil pH (5.36) and a significant decline in the FOC population to 2.79 % of untreated soil were obtained in flooded soil with the highest amount of rice straw. Incorporation of bagasse, pig manure, and lime also significantly decreased the populations of FOC, but were less effective than rice straw. Application of rice straw under flooding conditions significantly increased soil bacterial diversity, and the increased bacteria were considered to have an antagonistic effect on FOC. In 2013 field experiment, a wilt disease control efficiency of 82.3 % was obtained in flooded soil incorporated with 0.5 % (w/w) rice straw compared with untreated soil, and the control efficiency of BSD was further confirmed in 2014 field experiment. These results indicated that BSD can reduce FOC populations in soil, ameliorate soil microbial communities, and reduce the occurrence of banana Fusarium wilt disease.

In this study, we investigated the effects of two strains of probiotic bacteria (Bacillus megaterium BM and Bacillus amyloliquefaciens BA) combined with chemical fertilizers and vermicompost on the soil property, the yield and quality of tomato. The results showed that under the same nutrient level, vermicompost significantly increased the yield, soluble sugar and protein contents of fruit, the soil pH and available phosphorus when compared with chemical fertilizers. Vermicompost combined with probiotics not only increased the tomato yield, soluble sugar, protein and vitamin C contents, sugar/acid ratio of fruit, and reduced the organic acid and nitrate nitrogen contents of fruit, also increased the soil pH and nitrate nitrogen content, and reduced soil electric conductivity when compared with vermicompost treatment. This improved efficiency was better than that by chemical fertilizers combined with probiotics. For BA and BM applied with chemical fertilizers or vermicompost, both stains had no significant effect on tomato quality. When co-applied with vermicompost, BA and BM showed significant difference in tomato yield. High soil available phosphorus content was determined when BM was combined with chemical fertilizers, while high soil available potassium content was obtained when BA was combined with vermicompost. Our results suggested that probiotics and vermicompost could be used as alternatives of chemical fertilizers in tomato production and soil fertility improvement.

High application rate of chemical fertilizers and unreasonable rotation in facility vegetable cultivation can easily induce the occurrence of soil acidification, salinization, and serious soil-borne diseases, while to quickly and effectively remediate the degraded facility vegetable soil can considerably increase vegetable yield and farmers' income. In this paper, a degraded facility vegetable soil was amended with 0, 3.75, 7.50, and 11.3 t C x hm(-2) of air-dried alfalfa and flooded for 31 days to establish a strong reductive environment, with the variations of soil physical and chemical properties and the cucumber yield studied. Under the reductive condition, soil Eh dropped quickly below 0 mV, accumulated soil NO3(-) was effectively eliminated, soil pH was significantly raised, and soil EC was lowered, being more evident in higher alfalfa input treatments. After treated with the strong reductive approach, the cucumber yield in the facility vegetable field reached 53.3-57.9 t x hm(-2), being significantly higher than that in un-treated facility vegetable field in last growth season (10.8 t x hm(-2)). It was suggested that strong reductive approach could effectively remediate the degraded facility vegetable soil in a short term.

Applying large amount of nitrogen fertilizer into vegetable field can induce soil NO(3-)-N accumulation, while rapidly removing the accumulated NO(3-)-N can improve vegetable soil quality and extend its service duration. In this study, a vegetable soil containing 360 mg N x kg(-1) was amended with 0, 2500, 5000, and 7500 kg C x hm(-2) of ryegrass (noted as CK, C2500, C5000, and C7500), respectively, and incubated in a thermostat at 30 degrees C for 240 h under flooding condition, aimed to investigate the effects of organic material amendment on vegetable soil nitrate concentration and nitrogenous gases emission. By the end of the incubation, the soil NO(3-)-N concentration in CK was still up to 310 mg N x kg(-1). Ryegrass amendment could remove the accumulated NO(3-)-N effectively. In treatments C2500, C5000, and C7500, the duration for the soil NO(3-)-N concentration dropped below 10 mg N x kg(-1) was 240 h, 48 h, and 24 h, respectively. After the amendment of ryegrass, soil pH increased significantly, and soil EC decreased, with the increment and decrement increased with increasing amendment amount of ryegrass. The cumulative emissions of soil N2O and N2 in ryegrass amendment treatments amounted to 270-378 mg N x kg(-1), and the N2O/N2 ratio ranged from 0.6 to 1.5. Incorporating with ryegrass under flooding condition could rapidly remove the accumulated NO(3-)-N in vegetable soil, but the high N2O emission during this process should be attached importance to.