摘要:在水环境敏感区域以有机生产代替常规集约化农业，对保护生态环境、提高水库水质和保障居民饮用水安全具有重要意义。实际生产中，如果为追求产量盲目施用有机肥会增加氮磷径流流失风险。为在保障产量的前提下减少氮磷流失，本研究于昆明松华坝水库集水区，以不施肥（CK）和常规施用化肥（CF）为对照，在有机生产方式下设置不同类型有机肥[牛粪（DMC）、鸡粪（CMC）以及二者与豆饼的混合有机肥（HH）]及用量（与CF处理等氮素投入100%、80%和60%）的有机肥施用模式，共计11个处理（CK、CF、0.6DMC、0.8DMC、DMC、0.6CMC、0.8CMC、CMC、0.6HH、0.8HH、HH），分析其对土壤径流氮磷流失阻控效果和作物产量的影响。研究结果表明，在有机种植方式下，施用有机肥可使施肥初期（0~25 d）总氮径流浓度比常规施化肥降低26.3%~73.9%，生育期总氮累积浓度降低32.8%~67.0%。单施牛粪和鸡粪导致径流水总磷浓度比CF提高49.1%和12.3%，施用混合有机肥或减氮施用牛粪和鸡粪总磷浓度则比CF处理降低15.8%~52.5%。氮素投入水平和施肥类型对径流水氮磷浓度、土壤硝态氮和速效磷含量有显著影响。等氮素投入下不同肥料类型的径流水总氮浓度为化肥>牛粪>混合有机肥>鸡粪，总磷浓度为牛粪>鸡粪>混合有机肥>化肥；土壤硝态氮含量为化肥>牛粪、鸡粪>混合有机肥，速效磷含量为鸡粪>牛粪>混合有机肥>化肥。以60%氮素水平施用有机肥对径流水氮磷累积浓度和土壤硝态氮含量削减效果最佳，但土壤速效磷仍有累积风险。混合有机肥处理的青花菜产量最高，而单施牛粪或鸡粪存在减产风险。综合来看，与常规施用化肥相比，60%氮素投入加牛粪、鸡粪和豆饼混合有机肥的施肥模式可在产量提高16.7%的前提下，使径流水总氮、硝态氮、氨态氮浓度分别降低66.5%（18.94 mg·L-1）、67.2%（11.11 mg·L-1）和66.2%（6.57 mg·L-1），总磷降低52.5%（0.5 mg·L-1），可作为推荐施肥类型和用量在松华坝流域有机蔬菜生产进行推广。
关键词:环水/
有机农业/
施肥管理/
径流/
氮磷流失/
蔬菜产量
Abstract:Runoff of nitrogen and phosphorus from farmland is an critical source of river and lake pollution. Organic farming in watersheds could be beneficial for the environment and water quality compared to conventional farming. However, overuse of organic fertilizer can also lead to an increased risk of phosphorus loss. The aim of this study was to analyze the effects of different organic fertilizer application patterns on vegetable yield and nitrogen and phosphorus runoff losses. A field experiment was conducted by building runoff pounds in a vegetable plot in the Songhua Dam watershed, a representative plateau lake in Yunnan Province. Chemical fertilization was the control treatment (CF), and the effects of different organic fertilizer application patterns of cow manure (DMC), chicken manure (CMC), and mixed fertilization of cow manure, chicken manure, and soybean cake (HH) were compared at fertilization rates of 100%, 80%, and 60% of the N input of CF. The vegetable production and nitrogen and phosphorus runoff losses were compared. The dynamic change in total nitrogen (TN) runoff concentration showed that the initial phase (0-25 d) after fertilization was an important period to take preventive and control measures for nitrogen runoff caused by chemical fertilizer application. The results showed that the cumulative concentration of TN in the runoff with organic fertilizer application was significantly lower (26.3%-73.9%) than in the CF treatment after 25 days of fertilization. During the growth stage, the reduction in cumulative concentrations of TN in the runoff was 32.8%-67.0% under organic fertilizer application compared with CF. The cumulative concentration of total phosphorus (TP) in the runoff increased by 49.1% and 12.3% with the DMC and CMC treatments, respectively, but decreased by 15.8%-52.5% under the other organic fertilization treatments. Variance analysis indicated that the nitrogen input levels and the organic fertilzer types could significantly affected the concentration of TN, ammonium, nitrate, and TP in the runoff, and they also had significant interactions with the ammonium nitrogen and TP concentrations. Under 100% N input, the impact of fertilization patterns on TN in the runoff was as follows: CF > DMC > HH > CMC. TP in the runoff was as follows: DMC > CMC > HH > CF. Soil nitrate and available phosphorus were CF > DMC ≈ CMC > HH and CMC > DMC > HH > CF, respectively. Under 60% N input, the reduction of TN and TP in the runoff was significantly greater than 80% and 100% N inputs. The content of soil available phosphorus increased under the organic fertilization treatments compared with CF. Compared with CF and the other types of organic fertilizer, HH significantly increased the yield and quality of broccoli (Brassica oleracea), while the yield of DMC and CMC tended to decrease. On the presumption that broccoli yield increased by 16.7%, the 0.6 HH combination could significantly reduce TN, nitrate, ammonium, and TP in the runoff by 66.5% (18.94 mg·L-1), 67.2% (11.11 mg·L-1), 66.2% (6.57 mg·L-1), and 52.5% (0.5 mg·L-1), respectively, and could be used as the recommended fertilization system to promote organic vegetable production and to reduce nitrogen and phosphorus runoff losses in the Songhua Dam watershed. The results presented here provide reference and technical support for water quality protection through organic agriculture in China.
Key words:Watershed/
Organic farming/
Fertilization pattern/
Runoff/
Nitrogen and phosphorus loss/
Vegetable yield
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