农田生态系统养分吸收与养分平衡是影响系统生产力和环境质量的关键因素之一。本研究通过分析玉米田养鹅和常规玉米种植生产方式下玉米植株与籽粒的养分分配状况，以及系统中养分的输入和输出状况，对比评价各处理下养分的吸收和利用效率以及养分盈余和亏缺状态。结果表明，玉米田养鹅处理下玉米籽粒和秸秆的氮（N）、磷（P）和钾（K）含量与对照相比无显著差异；玉米田养鹅处理各养分的吸收量与产量的相关性大小依次为P＞K＞N，其中P和K养分与产量的相关性显著（p＜0.05）；对照为P＞N＞K，其中P和N养分与产量的相关性显著（p＜0.05）；玉米田养鹅处理和对照的N、P2O5和K2O养分收获指数、吸收效率和利用效率之间均无明显差异；不同处理均存在较低的养分投入和较高的养分产出的情况，系统养分失衡，尤其是N和K元素在产出后严重亏缺，与玉米田养鹅处理相比，对照的N和K养分亏缺量分别高出39.0%和34.90%，处理间差异显著（p＜0.05），对照P素的亏缺较小，但玉米田养鹅处理P素出现少量盈余，处理间差异极显著（p＜0.01）；从经济效益来看，玉米田养鹅处理虽存在玉米减产的问题，但其经济产量损失的部分可由肉鹅的经济产出得以补偿并获得了更高的经济效益。总体而言，玉米田养鹅处理对养分吸收和利用无明显影响，养分平衡状况较好，经济效益较高。%Facing a rapidly growing population,Tibet has to improve its agricultural productivity so as to provide sufficient food. To improve agricultural production and enhance crops yields,farmers have increased the use of fertilizers. However,the Tibetan plateau environment is so sensitive and fragile that any increased usage of these chemicals may put the plateau environment at risk of agricultural non-point source pollution. How to harmonize economic benefits with ecological ones is a significant challenge to development of Tibetan agriculture. Nutrient absorption and nutrient balance of a farmland ecosystem is one of the key factors affect productivity and environmental quality of the system. Raising Geese in Corn Fields(hereinafter referred to as RGICF)is a compound production pattern based on the principle of“Agro-pastoral Integration”, a concept proposed in 2011. This conceptual farming method relies on the use of weeds and bottom leaves of the crops in the fields as feed sources to raise poultry with. To evaluate differences between the two systems of RGICF and conventional corn cultivation in nutrient absorption,nutrient balance,nutrient distribution in the plant,and nutrient input and output of the system,a field experiment was conducted at Village Zhangmai of Bayi,Tibetan Autonomous Region,in Southwest China 2013. Two treatments,RGICF and conventional corn cultivation(hereinafter referred to as CK),were laid out in the experimental field. Each treatment was designed to have three blocks or plots,and each plot covered an area of 80 m2. Logs were kept of RGICF and CK from May 2013 to May 2014 about nutrient inputs and outputs,while chemical analysis were conducted of samples of the corn for nutrient(N,P and K)concentration and distribution in stalks and grains,and samples of the soil,too,for nutrient budgeting. Results show that no significant differences were found between RGICF and CK in N,P and K concentration in corn grains and stalks. Correlation between nutrient adsorption and corn yield exhibited and order of P>K>N in RGICF and P>N>K. No significant differences were found either between RGICF and CK in nutrient harvest,adsorption efficiency and utilization efficiency of N,P and K. Nutrient budgeting of the systems revealed nutrient disbalance in the systems,particularly N and K deficits in the soil after harvest. Compared with RGICF,CK was 39.0% and 34.90% greater in N and K deficit. The differences were significant(p<0.05). However,the deficit of P was relatively small in CK, while it turned into P surplus in RGICF,showing extremely significant difference(p<0.01). In the aspect of economic benefit,though RGICF suffered certain loss(6.22%)in corn yield,the was compensated or even over-compensated by geese raising,making RGCIF much higher in economic benefit than CK of avoiding the application of herbicides,used in CK fields. In all,RGICF does not have much influence on nutrient adsorption and utilization,but improves somewhat soil nutrient balance and yields higher economic benefit. Therefore,it can be concluded that RGICF can be extrapolated as an important production pattern for sustainable agriculture in the future in Tibet.
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