摘要
本研究以河北省山前平原秸秆还田条件下现有的小麦-玉米高产攻关田及培育中农田为试验对象,采用跟踪调查和作物关键生育期多层取样的研究方法,查明了现有高产粮田土壤物理化学特性的时空变异规律,明确了高产田土壤肥力与土壤质量状况,探讨了高产高效培育措施对土壤物理性状、土壤养分的影响,初步确定了作物高产,水肥高效,土壤环境友好的高产培育技术措施。为保障河北省粮食生产安全、提高水肥资源生产效率和土壤生产力提供了理论依据。得出以下主要结论:
1、高产田土体构型为“蒙金土”,保水保肥能力较强。一般生产田上下分层不明显,通体质地单一,保肥保水能力较高产田差。
2、高产田土壤有机质和活性有机质随土层的加深而递减,整个轮作季高产田有机质变化不大,活性有机质变化较大,高产田和一般生产田差异不显著。土壤速效磷钾呈规律性变化,高产田0-20 cm土层速效磷钾均显著高于一般生产田,以下两个土层高产田和一般生产田差异不显著。土壤硝态氮主要分布在0-20 cm土层,小麦季远大于玉米季,高产田小麦季大于一般生产田。
3、在冬小麦-夏玉米轮作体系中,高产田和一般生产田的氮、磷、钾素平衡都有盈余,高产田氮素和磷素的盈余量低于一般生产田,钾素盈余量高于一般生产田。高肥料投入可获得高产,但养分利用率并未提高,易出现土壤硝态氮累积。
4、高产田小麦季0-100 cm土体剖面的硝态氮累积量及迁移到土层深处的量大于一般生产田,存在较高淋溶风险。高产田土壤电导率小于土壤盐渍化临界值,尚未出现土壤盐渍化的现象。
5、待培育的辛集土壤耕层土壤容重较大,有板结趋势。土体表层的物理特性有待改善,主要依赖于耕作方式的改进和有机肥的施用。
6、四种高产培育模式,分别为:处理A(当地传统管理),处理B(现有高产田推荐管理),处理C(高肥料投入管理),处理D(水肥高效管理)。结果表明:四个处理土壤养分变化趋势基本一致。整个冬小麦季有机质变化不大,活性有机质呈规律性变化,施用了有机肥的处理C、D大于处理A、B。土壤速效磷钾整体呈下降趋势,处理C、D明显大于处理A、B。土壤硝态氮主要分布在0-40 cm土层,整个生育期呈下降趋势,硝态氮累积明显。
7、高产培育的冬小麦产量为:D>C>B>A,实现了增产目标,肥水利用效率得到了提高。
8、高产培育中,土壤剖面硝态氮变化较大,出现大量累积,成熟期表现为:C>B>D>A,但尚未存在土壤盐渍化的威胁。
高产培育试验中,处理D(水肥高效处理)显示了较高的土壤养分水平,冬小麦产量最高,达10360 kg/hm2,但其肥料投入量并非最高,说明这种培肥方式既有利于提高粮食产量,又有利于提高水肥的利用率,维持土地生产力的持续性。
This study is designed for wheat-maize high yield key project field (HF) and cultivating high yield field (CHF) under straw returning in piedmont plain of Hebei. The methods of tracking investigation and many soil layers sampling in the key crop growth stages were adopted. We have revealed the soil space and time variation change low of physical and chemical characteristics in HF, and confirmed the status of high-yield soil fertility and quality. We have studied the affects of high efficient cultivating measures to the soil physical and chemical characteristics. The cultivating high yield field (CHF) measure was confirmed which made the yield be increased, the water-fertilizer using be efficient, and soil environment be friendly. It provided reasonable evidences of improving water and fertilizer resources production efficiency and soil productivity for ensuring the safety in food production of Hebei province.
The main conclusions shows as follows,
1 The HF soil configuration as a "Mongolian gold soil”and the ability of retaining water and nutrients is stronger. The CF from top to bottom layer is not obvious, texture of a single whole body and the ability of retaining water and nutrients is weaker.
2 The content of SOM and ASOM in HF becomes lower with the soil depth going deeper. There is little difference in the content of SOM between HF and CF in the whole winter wheat and summer maize rotation. There is a notable difference in the content of ASOM in HF, while no significant difference between HF and CF. The change of soil available P and available K in both HF and CF is regular. Contrast to the CF, the HF gets a higher content of soil available P and available K in the layer 0-20 cm。But in the following 2 layers, there is significantly difference. The nitrate mainly distributes in the layer of 0-20 cm. The content of nitrate is higher in winter wheat than summer maize, there is no significant difference between HF and CF in summer maize, and HF is higher than CH in winter wheat.
3 Generally, there is a surplus of N, P, K in winter wheat and summer maize rotation of HF. Contrast to CF, HF gets a higher surplus of N and P but a lower surplus in K . The yield could be high with high fertility inputing, but fertilizer utilization efficiency of HF is not improved, and the soil NO3--N is easy to accumulate.
4 The nitrate accumulation of every growth stage in 0-100 cm soil layers of HF is more than CF, and a high leaching risk in HF. But there is no soil salinization in HF with high fertilizer input.
5 In CHF, the bulk density of plough layer is high. The physical characteristics of soil top layer should be improved, mainly relies on the improvement of tillage and the employment of organic fertilizer.
6 There are four treatments of the experiment with cultivating high yields field in Xinji, and they are treantment A (The local traditional managment), treatment B (The existing recommending managment), treatment C (The management with high fertility input) and treantment D (The management with high water-fertility efficiency). The result shows that, the soil nutrients variation of the fore treatments shows the same tendency. There is little change of SOM in winter wheat. The change of ASOM is regular. The SOM and ASOM content of C and D which was inputed with organic fertilizer are higher than A and B. Available P and K reduce, while C and D is higher than A and B. The nitrate mainly distributes in the layer of 0-40cm, reducing in whole growth period, existing obvious nitrate accumulation.
7 The winter wheat yield of CHF shows as follows: D>C>B>A, and we reach the aim of yield recrease, and the water-fertilizer efficiency is also improved.
8 There is much nitrate accumulation in 0-100 cm soil layer of CHF with big change, and the tendency is C>B>D>A. but there is no threat of soil salinization.
In the study of cultivating high yield field, the soil nutriunt of treatment D (The management with high water-fertility efficiency) is more, and the winter wheat yield is highest to 10360 kg/hm2, but the fertilizer inputing is not the most. So, this cultivating masure is good to increase the yield, improve the water-fertilizer efficiency and keep the sustainability of soil productivity.
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