【作者】 杨治平；

【导师】 陈明昌；

【作者基本信息】 山西大学 ， 生态学， 2012， 博士

【摘要】 小麦-玉米轮作系统是山西省重要的作物种植体系之一,主要分布在临汾和运城两个地区,对全省谷类作物生产的贡献率达30%。养分管理不合理尤其是氮肥过量施用是目前该区域高产区中普遍存在的问题,不仅降低养分利用效率,还造成环境方面潜在的风险。本文通过村级水平的农户调查了解了小麦-玉米轮作生产中农户施肥行为以及养分流动状况；通过在洪洞县和永济市多年多点的田间试验,采用氮素实时监控技术和磷钾恒量监控技术,建立了山西省小麦-玉米轮作体系农田养分综合管理技术,分析了氮肥施用对研究地区小麦和玉米产量与环境效应的影响；采用GIS技术,对氮、磷、钾养分进行了区域化研究,建立了区域尺度的养分管理技术体系。主要研究结果如下：1.村级水平养分流动与养分循环研究表明,村级养分投入与产出极不平衡,氮磷盈余,而钾缺少。主要原因是小麦-玉米体系氮素投入量过大,一个轮作周期氮磷钾的投入量分别为714kg/ha,137kg/ha (P2O5),42kg/ha(K2O),导致的后果是养分投入量大而利用效率低。2.田间试验结果显示,建立小麦-玉米轮作养分资源综合管理技术体系,采用其中的核心技术“氮素实时监控技术和磷钾量监控技术”推荐氮磷钾肥最佳用量,与传统的施肥处理比较,能够大幅度降低肥料用量,尤其是氮肥用量,提高产量,增加收益。在连续3年6季作物的试验周期中,氮肥总用量为862kg/ha,仅为农民传统处理的35%,作物增产6.2%,永济点平均年总收入增加1262.4元/ha,洪洞点平均每年总收入增加3065元/ha。对永济市0-120cm土体NO3--N含量动态研究发现,应用养分资源综合管理技术,由于推荐的施氮量低,向下淋洗的硝态氮没有传统处理严重。但无论是应用养分资源综合管理技术还是农户传统管理模式,一旦施肥后,表层聚集的N03--N会急剧增加,而后又慢慢减少,向土层下方淋洗。3.洪洞县农田应用养分资源综合管理技术,小麦季氮素表观损失比传统施肥减少22%,玉米季比传统施肥减少91%,小麦-玉米轮作体系比传统施肥减少56%。永济市农田由于农户传统施肥量不足,应用养分资源综合管理技术增加了施氮量,因此,氮素表观损失较农户传统施肥一个轮作周期高出64.7kgN/ha,但区别不是很大,多施的氮素主要用于产量提高。小麦-玉米轮作体系氮效率研究结果,应用养分资源综合管理技术,3茬小麦和3茬玉米的PFPN均在30kg/kg以上,而农户传统处理的PFP值只有20kg/kg左右,养分资源综合管理技术养分生产效率较农户模式提高50%左右。4.2007-2008年对氮素损失途径的定量化研究,结果显示,永济试验区以NOx形式排放损失的氮量占到施氮量的1.2%,该结果高于IPCC的确认值(1%)。而本试验条件下,氨挥发量不是很高,只占施氮量的7%,可能是本地区氮肥采用深施以及施肥后马上采用喷灌技术的原因。氨损失的程度仅为华北地区其它采用深施进行试验研究的结果的一半,其它研究中较大的损失可能是施肥量过高导致土壤铵态氮含量高的原因。本研究中,因为土壤表层的NH4+含量在10天内比较稳定,而N03含量较低,仅为施氮量的3.9%,所以土壤硝化和反硝化速率都很低,不是氮损失的主要途径,而尿素深施抑制了氨挥发,这些将有利于提高肥料的利用效率。应用箱法对N20的排放研究得出,N2O排放与农田氮用量密切相关,随施N量的增加而增加。土壤温度和湿度会影响N2O的排放。DMPP可有效抑制N2O排放,大约可以减少N2O排放量的一半,从而减少氮素损失,提高氮肥利用效率5.以永济市为例,对全市511个GPS定位土壤样本分析发现,氮磷钾养分在不同兮M尺度上存在中等程度的自相关性,目前氮磷仍然是限制作物生长的主要因素。本文同时应用克立格法对全氮、有效磷和交换性钾的空间分布进行评价分析,并进行了区域化养分管理分区,分区后全市氮素管理可以按四个等级、有效磷按一个等级、交换性钾按二个等级进行养分管理。3年的田间试验对区域化养分管理技术验证,如果推荐肥料用量被农户所采纳,小麦-玉米轮作系统产量可增加10-20%,经济收入增加1550-2610元/ha。鉴于以上研究结果,初步得出山西省小麦-玉米轮作区生产中养分管理建设性意见：1.针对小麦-玉米轮作系统养分失衡问题,提出“减氮稳磷”对策,大力提倡秸秆还田,加强钾的养分再循环,增施农家肥。2.针对小麦-玉米轮作系统氮素淋洗损失的问题,在建议减少氮素用量的同时,提出必须解决肥料的剂型和肥料形态,比如研发与小麦玉米生长需求相匹配的缓释氮肥等。3.欧美等小麦玉米生产大国的偏生产力可以达到50～60kg/kg,从我们的结果来看,PFP值还没有达到此标准,关键是籽粒产量偏低的原因。因此,产量的进一步提升是目前要解决的问题,提出养分管理研究必须与高产栽培技术相结合。4.鉴于目前我国农户生产经营规模小,土壤样品采集化验成本高的状况,区域化养分管理技术是一个可行的选择。因此,区域化养分管理或养分分区管理系统更适合中国农村实际状况,值得在县、乡、村级水平上进一步发展。在此基础上研发相应的区域化专用配方肥,实现技术的物化更有必要。更多还原

【Abstract】 Wheat-Maize (W-M) rotation is one of the important crop-growing systems in Shanxi Province. It is mainly distributed in Linfen and Yuncheng Basin, and its production accounts for30%of the total production of cereal crops in the province. Unreasonable management of nutrients, especially excessive nitrogen application is a common problem in high-yield area of the region, not only reduces the efficiency of nutrient utilization, but also causes potential environmental problems. In this paper, Village-level household survey was conducted to understand the farmer’s fertilization behavior and nutrient flows. Nutrient real-time monitoring technologies were applied in the experiments to establish the integrated nutrient management techniques (INM) of W-M rotation system in Shanxi Province. In addition, effects of nitrogen fertilizers on crop yield and environment was evaluated. Based on the above, using GIS technology, regional scale nutrient management system was established in Yongji County. The main findings are as follows:1. Nutrient flows and nutrient cycling studies showed that nutrient input and output was extremely unbalanced at the village level, specifically, nitrogen (N) and phosphorus (P) surplus, and the lack of potassium (K). It was due to the too much nitrogen inputs in W-M system. For example, the rate of N, P, and K inputs in Hongdong survey was714kg/ha.137kg/ha and42kg/ha, respectively.2. The field experiments results showed that INM could increase the crop yield and significantly reduce the amount of fertilizer, especially nitrogen fertilizer, compared with traditional fertilization management. In the3-year experiments, the total amount of nitrogen fertilizer using INM was862kg/ha, only35%of the traditional treatment. But the yield of INM was increased by6.2%, the annual profitabilty was increased by1262.4yuan/ha in Yongji trials, and3065yuan/ha in Hongdong trials. At the same time, the results about dynamic changes of soil nitrate nitrogen (NO3--N) concentration of0-120cm depth in Yongji County found that the application of INM could effectivly reduce the leaching of NO3--N, compared with the traditional treatment, due to the lower nitrogen rate. But whether the integrated nutrient management technology or farmer’s traditional management, the leaching of NO3--N would occur after fertilization.3. Apparent N losses of INM in wheat season reduced by22%than traditional fertilization management in Hongdong and91%in maize season. In Yongji County, because INM increased the nitrogen rate, apparent N losses is higher64.7kg N/ha than traditional fertilization management in W-M rotation. For the nitrogen efficiency, partial factor productivity from applied nitrogen (PFPN) is increased by50%, compared with the traditional treatment.4. In2007-2008, the studies of the pathways of nitrogen loss were implemented in Yongji. The results showed that7%of the applied N was lost by ammonia (NH3) volatilization when the urea fertilizer was deep placed using farmers’local practice, and that1.2%of the applied N was lost as nitric oxide and nitrogen dioxide (NOX). The result of NOX loss is higher than the value of IPCC (1%), whereas, NH3loss was much lower than that observed in other experiments with deep placement in the North China Plain. The greater losses in those experiments may have been due to the higher rates of fertilizer application, which resulted in higher ammoniacal N concentrations.The study on nitrous oxide (N2O) emissions using chamber method showed that the amount of nitrous oxide (N2O) emissions increased with applying nitrogen fertilizer. In addition, soil temperature and humidity also affect N2O emissions. The nitrification inhibitor DMPP (3-4-dimethyl pyrazole phosphate) can effectively inhibit N2O emissions and reduce about half of the N2O emissions rate.5. Throngh the analysis of a total of511GPS-referenced soil samples taken in Yongji County, moderate spatial dependence was found for soil total nitrogen (TN), Olsen extractable phosphorus (OLSENP) and extractable potassiue (EXTK). but at different spatial scales. Low concentrations of TN and OLSENP were found and they are likely to be the main limiting nutrients for crop growth in this county. The spatial distributions of TN. OLSENP and EXTK were estimated by using kriging interpolation. The cropped areas of the county were divided into fertilizer management categories consisting of four classes of TN, three classes of OLSENP and two classes of EXTK. In3-year field verification trials in two villages, the crop yields of the wheat-maize rotation system increased by10-20%, and farmers’cash income increased by1550-2610RMB/ha/year where regional fertilization recommendations were implemented, in comparison with traditional farmers’practices.Given the above findings, the initial comments on the nutrient management of wheat-Maize rotation in Shanxi Province are as follow:1. In view of the nutrient imbalances of wheat-maize rotation system, the strategy which reduce nitrogen rate and stabilize phosphorus rate are adviced. In additon, it is necessary that strengthen stalk return to the field and apply organic fertilizer.2. Research of release nitrogen fertilizer matching the growth of wheat and maize is necessary when we study the nitrogen feitilizer application.3. Partial factor productivity from applied nitrogen of wheat and maize in Europe and America can achieve50-60kg/kg, but it has not yet reached this standard in our country. Therefore, the further increase of the yield is the current problem to be solved, the proposed nutrient management research with the combination of high-yield cultivation techniques.4. The regionalized fertilization maps are a practical alternative to site-specific soil nutrient management approaches in areas where it is not practical, because of small farm size or other constraints, to use intensive soil sampling and chemical analyses. Hence, a regionalized nutrient management (or nutrient zone management) system is more suitable for the rural Chinese situation and should be developed at the county, town or village levels.更多还原