中国科学院水利部水土保持研究所机构知识库

    黄土高原旱作塬区耕地面积占总面积的1/3，是西北地区重要的产粮区，也是典型的雨养农业区。农业生产面临的主要问题是降雨偏少且季节分布不均，施肥偏多但利用率低，提高水分养分利用效率是保证作物高产稳产的关键。本文选取旱作农田冬小麦和春玉米连作体系为研究对象，在陕西省长武县王东沟小流域设置的不同管理措施定位试验基础上进行田间观测试验，首先于2016-2017生长季研究了小麦地7个和玉米地6个处理收获期剖面硝态氮分布、生长季内土壤剖面水分运移状况及其对产量影响；并于2017-2018生长季分析玉米地6种处理不同时期土壤温度、水分、硝态氮淋溶累积变化和作物生长状况。研究不同管理措施对农田土壤水氮运移及作物生产的影响，以提高水肥利用效率、减小硝态氮残留和增加作物产量为目标，为选取适宜于该区可持续生产的农田管理措施提供理论依据，取得以下主要研究结果和结论：

        1.小麦地2016-2017生长季，传统翻耕配施钾肥（NPK）和添加生物炭（NPB）较传统翻耕（NP）对土壤水分补给与消耗无明显影响。NPK土壤剖面硝态氮存在累积峰，但峰值只有NP的20.2%，硝态氮主要分布在0-100 cm土层；而NPB剖面无硝态氮累积，硝态氮主要分布在0-20 cm土层，两个处理土壤硝态氮累积量在0-300 cm层较NP显著减少了66.0%和73.2%。覆膜处理较NP显著影响土壤水分补给与消耗，传统翻耕配合生育期地膜全覆盖（NPFGT）、休闲期地膜全覆盖（NPFFT）和全年地膜全覆盖（NPFWT）在0-300 cm层水分补给量较NP显著增加32.7%、43.1%和43.5%，而NPFFT水分消耗量较NP显著提高2.0倍。NPFFT和NPFWT土壤剖面硝态氮存在累积峰，但峰值只有NP的77.1%和37.8%，而NPFGT剖面无硝态氮累积。三个处理硝态氮分别主要分布在0-200、0-100和0-20 cm土层，硝态氮累积量较NP显著减少了19.2%、59.7%和78.7%。此外，NPFGT和NPFWT较NP生物量、产量和水分利用效率分别显著增加56.4%和66.3%、20.0%和18.9%及24.3%和15.2%，而NPFFT水分利用效率显著减少22.7%。

    NPFGT和NPFWT改善土壤水分条件、提高水分利用效率，增产效果显著，其中NPFGT减少硝态氮淋溶累积效果最佳；NPB和NPK虽不能改善土壤水分条件，但均可增加产量、有效减少硝态氮淋溶累积；而NPFFT不仅减产和显著降低水分利用效率，且未能缓解硝态氮氮淋溶累积。

    2.玉米地2016-2017和2017-2018生长季，土壤水分变化均经过补给、消耗和再补给的过程。第一次水分补给时期（休闲-抽雄期），水分主要在100 cm以下的深层补给，其中免耕配合地膜覆盖（NF）、秸秆覆盖（NS）和秸秆地膜二元覆盖（NSF）水分补给量较免耕（NT）平均显著增加17.1、25.3和31.6 mm。水分消耗时期（抽雄-灌浆期），水分主要在0-200 cm消耗，其中NS、NF、免耕添加生物炭（NB）和NSF水分消耗量较NT平均显著增加19.7、26.4、27.6和41.7 mm。第二次水分补给时期（灌浆-收获期），水分主要在0-100 cm层补给，其中2017-2018生长季NF和NB水分补给量较NT显著提高2.7和6.4倍，NS显著降低75.0%。NS和NB不同时期硝态氮变化主要集中在0-100和200-300 cm，两个生长季收获期硝态氮累积量较NT显著降低26.5%和45.2%，且NS均存在明显的累积峰；NSF和NF硝态氮只在0-40 cm层有明显变化，两个生长季收获期硝态氮累积量较NT显著降低62.5%和70.5%，且均无累积峰。此外，NB生物量和水分利用效率较NT两年平均显著增加18.4%和15.6%；NF和NSF生物量、产量和水分利用效率较NT平均显著增加43.4%和49.2%、43.4%和50.5%及37.2%和44.2%，且氮素吸收、LAI和降雨利用效率均较NT显著提高1.7倍。

    再者，2017-2018生长季NS较NT生育前期（0-85天）0-80 cm层土壤温度显著降低1.3-2.1 ℃；而NF较NT显著增加0.6-1.5 ℃。休闲期，NSF、NS、NF蒸散量较NT显著减少12.0、19.3和32.5 mm；而生育期，NB蒸散量较NT显著减少28.4 mm。

    结合两年玉米地试验，NS虽能改善土壤水分条件但降低土壤温度，产量无明显提高，且未能有效缓解硝态氮淋溶累积。NB、NF和NSF可提高氮素利用，但NB不能有效改善土壤水热状况，增产不显著；NF和NSF改善土壤温度、水分和作物生长条件，提高水分利用效率，增产显著。其中NSF最优，是改善旱塬玉米地水肥热状况，提高作物产量的有效措施。

    The cultivated area in the dry farming tableland area of the Loess Plateau accounts for 1/3 of the total area, which is an important grain-producing area and a typical rain-fed agricultural area in the northwestern region. The main problems faced by agricultural production are less rainfall and uneven seasonal distribution, more fertilization but low utilization rate. Therefore, water and nutrients are the keys to limiting the high and stable yield of crops. In this paper, the continuous cropping system of winter wheat and spring maize in rainfed farmland was selected as the research object. Different conservation tillage measures were set in the Loess Plateau of Wangdonggou small watershed in Changwu County, Shaanxi Province, carried out field experiment for two years. Firstly, 7 treatments were selected in wheat fields and 6 treatments were selected in maize fields to analysis soil nitrate accumulation and water transport in 2016-207. Then, the changes about soil temperature, water content, and NO₃^--N and crop development of six treatments in maize field were analyzed in 2017-2018. So that the effects of different farmland management measures on soil temperature, water, fertilizer, and crop production were studied to improve water and fertilizer use efficiency and increase crop yield, and to provide a theoretical basis for selecting farmland management measures suitable for sustainable production in the region, the main research results are as follows:

    1 In the 2016-2017 growing year, compared with conventional tillage (NP) in the wheat field, NP with potassium fertilizer (NPK) and NP with biochar (NB) had no significant effect on soil water replenishment and consumption. The NO₃^--N of NPK was concentrated in 0-100 cm, and cumulative peak accounted for only 20.2% of NP. While NB was concentrated in 0-20 cm and had no cumulative peak. And the NO₃^--N accumulation of them in 0-300 cm significantly decreased 66.0% and 73.2%. Mulching were significantly effected on soil water replenishment and consumption, the water replenishment of NP with plastic film mulching in growing period (NPFGT), plastic film mulching in fallow period (NPFFT), and plastic film mulching in the whole year (NPFWT) significantly increased 32.7%, 43.1%, and 43.5%. while the consumption of NPFFT increased significantly 2.0 times in 0-300 cm compared with NP respectively. The NO₃^--N of NPFFT, NPFWT, and NPFGT were concentrated in 0-200, 0-100, and 0-20 cm, and cumulative peak of NPFFT and NPFWT accounted for only 77.1% and 37.8% of NP, while NPFGT had no cumulative peak. And the NO₃^--N accumulation of them in 0-300 cm significantly decreased 19.2%, 59.7%, and 78.7%. In addition, the biomass, yield, and water use efficiency of NPFGT and NPFWT significantly increased 56.4% and 66.3%, 20.0% and 18.9%, and 24.3% and 15.2%, while the water use efficiency of NPFFT significantly decreased 22.7% compared with NP.

  NPFGT and NPFWT improved soil water status and significantly increased yield, and NPFGT was the best treatment to reduce the leaching and accumulation of NO₃^--N. NPB and NPK cannot improve soil water status, but they all effectively reduced the leaching and accumulation of NO₃^--N. While NPFFT not only significantly reduces water use efficiency and yield, but also fails to alleviate the leaching and accumulation of NO₃^--N.

    2 In the 2016-2017 and 2017-2018 growing year, the soil water had gone through water replenishment, consumption, and recharge. During the first water replenishment period (fallow-tasseling), soil water was mainly replenished to the deep below 100 cm. The replenishment of no-tillage with plastic film mulching (NF), straw mulching (NS), and straw-plastic film mulching (NSF)was significantly increased 17.1, 25.3, and 31.6 mm compared with no-tillage (NT). During the water consumption period (tasseling-filling), soil water was mainly consumed from 0-200 cm. The consumption of NS, NF, NT with biochar (NB), and NSF were significantly increased 19.7, 26.4, 27.6, and 41.7 mm compared with NT. During the second water replenishment period (filling-maturing), soil water was mainly replenished to the deep above 100 cm. The replenishment of NF and NB significantly increased 2.7 and 6.4 times, while NS significantly decreased 75.0% compared with NT in 2017-2018 growing year. The soil NO₃^--N transport of NS and NB were concentrated in 0-100 and 200-300 cm, which NO₃^--N accumulation were significantly decreased 26.5% and 45.2% compared with NT in maturing period, and NS had obvious cumulative peaks. While NSF and NF were concentrated in 0-40 cm, which NO₃^--N accumulation were significantly decreased 62.5% and 70.5%, and had no cumulative peaks. In addition, the biomass and water use efficiency of NB significantly increased 18.4% and 15.6% over the two years compared with NT. And the biomass, yield and water use efficiency of NF and NSF significantly increased 43.4% and 49.2%, 43.4% and 50.5%, and 37.2% and 44.2%, and nitrogen uptake, LAI, and rainfall use efficiency were significantly increased 1.7 times.

    Moreover, the soil temperature of NS was decreased 1.3-2.1 ℃ in the early growth period (0-85 day), while NF was increased 0.6- 1.5 ℃ compared with NT in 2017-2018 growing year. And the evapotranspiration of NSF, NS, and NF significantly decreased 12.0, 19.3, and 32.5 mm in fallow period compared with NT, while NB was significantly decreased 28.4 mm in growth period.

    Combined with two-year maize field experiment, NS could improve soil water condition but reduced soil temperature, yield did not increase significantly, and it could not effectively alleviate NO₃^--N leaching and accumulation. NB, NF, and NSF can improve nitrogen utilization, but NB cannot effectively improve soil water and temperature conditions, and the yield increase was not significant, while NF and NSF improved soil temperature, water and crop growth status, it significantly increased water use efficiency and yield.

目录

第一章 绪论 1

1.1 研究目的与意义 1

1.2 国内外研究现状 2

1.2.1 施肥对土壤水氮运移及作物生长的影响 2

1.2.2 免耕对土壤水氮运移及作物生长的影响 4

1.2.3 生物炭对土壤水氮运移及作物生长的影响 5

1.2.4 秸秆对土壤水氮运移及作物生长的影响 5

1.2.5 地膜对土壤水氮运移及作物生长的影响 7

第二章 研究内容与方法 9

2.1 研究目标和内容 9

2.1.1 研究目标 9

2.1.2 研究内容 9

2.2 研究方法 9

2.2.1 试验区概况 9

2.2.2 试验设计 11

2.3 试验数据计算方法 14

2.4试验数据处理与统计分析 14

2.5 试验技术路线 15

第三章 不同管理措施对黄土塬区冬小麦土壤水分和硝态氮淋溶累积的影响 17

3.1 材料与方法 18

3.1.1 试验区概况 18

3.1.2 试验处理 19

3.1.3 样品采集与测定 20

3.1.4 土壤水分最大补给深度和消耗深度确定方法 21

3.2 结果与分析 21

3.2.1 土壤剖面水分补给与消耗深度 21

3.2.2 土壤剖面水分补给量和消耗量 23

3.2.3 土壤剖面硝态氮分布 24

3.2.4 土壤剖面硝态氮累积量 25

3.2.5 作物农艺性状 26

3.3 讨论 27

3.3.1 不同管理措施对土壤硝态氮累积影响 27

3.3.2 土壤水分运动与硝态氮累积关系 29

3.4 结论 30

第四章 保护性耕作措施对黄土塬区春玉米土壤水分和硝态氮淋溶累积的影响 33

4.1 材料与方法 34

4.1.1 试验区概况 34

4.1.2 试验处理 35

4.1.3 样品采集与测定 36

4.1.4 土壤水分最大补给深度和消耗深度确定方法 37

4.2 结果与分析 37

4.2.1 土壤剖面水分补给和消耗深度 37

4.2.2 土壤剖面水分补给量和消耗量 39

4.2.3 土壤剖面硝态氮分布 40

4.2.4 土壤剖面硝态氮累积量 41

4.2.5 作物农艺性状 42

4.3 讨论 43

4.3.1 不同保护性耕作措施对土壤硝态氮累积影响 43

4.3.2 土壤水分运动与硝态氮累积关系 45

4.4 结论 47

第五章 保护性耕作措施对黄土塬区土壤温度、水分、硝态氮及春玉米产量的影响 49

5.1. 材料与方法 51

5.1.1试验区概况 51

5.1.2 试验处理 51

5.1.3 样品采集与测定 51

5.2. 结果分析 52

5.2.1 气候条件 52

5.2.2 土壤温度 53

5.2.3 土壤水分 54

5.2.4 土壤硝态氮 58

5.2.5 玉米生物量、氮素吸收与LAI 61

5.2.6 玉米产量、水分利用效率与降雨利用效率 63

5.3 讨论 63

5.3.1土壤温度 64

5.3.2土壤水分 64

5.3.3土壤硝态氮 66

5.3.4玉米生长与产量 68

5.4 结论 69

第六章 结论与展望 71

6.1 主要结论 71

6.1.1 不同管理措施对黄土塬区冬小麦和春玉米农田土壤水分和硝态氮淋溶累积影响 71

6.1.2不同保护性耕作措施对黄土塬区春玉米农田土壤温度、水分、硝态氮及春玉米生长的影响 71

6.2 研究展望 72

参考文献 75

致 谢 89

作者简介及攻读硕士期间已发表或待发表的文章 91