兰州大学机构库 >生态学院
旱地覆盖措施对玉米和甘草生产及土壤肥力的影响
Alternative TitleEFFECTS OF MULCHING MEASURES ON MAIZE AND LICORICE PRODUCTION AND SOIL FERTILITY IN THE DRYLAND
杨建军
Subtype博士
Thesis Advisor孙国钧 ; 李凤民
2023-05-30
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name理学博士
Degree Discipline生态学
Keyword旱地农业,覆盖措施 dryland agriculture 产量 mulching measures 区域分异性 yield DNDC regional differentiation 秸秆还田 DNDC 气候变化 straw returning 玉米–甘草复合系统 climate change maize–licorice complex system
Abstract

近20余年来,在黄土高原旱地农业区,垄沟覆膜玉米生产得到快速发展,从黄土高原的东南向西北,随着水热条件逐渐变差,垄沟覆膜玉米的增产效应反而逐渐加强,在半干旱偏旱地区,垄沟覆膜玉米可以增产1倍以上,这一现象的驱动机理至今尚不清楚。

甘草(Glycyrrhiza uralensis Fisch.)是黄土高原半干旱区重要的药用植物,覆盖措施能否改善甘草药材品质和产量也鲜有报道。同时,由于甘草的地上生物量较低,其根系作为药材被收获移除,造成其向土壤返还的有机物质,相对于玉米等其他作物大幅度下降,导致土壤肥力有持续降低的风险。

垄沟覆膜玉米生产力大幅度提高,为建立和提高玉米–甘草复合系统的生产效益和土壤肥力提供了重要机遇。为此开展了以下主要研究:(1)水热条件较差地区垄沟覆膜玉米增产幅度更高的驱动机理;(2)不同覆盖措施对甘草药材品质、产量和土壤肥力的影响;(3)未来气候情景下覆盖措施对甘草有效成分产量和土壤有机碳(SOC)的影响;(4)构建玉米和甘草复合系统,提高生产效益和土壤肥力的情景模拟。2019–2020年在通渭县现代农业示范基地(年均温9.1 ℃、年均降水量508 mm)、安定区干旱气象与生态环境试验基地(年均温8.1 ℃、年均降水量417 mm)和榆中县兰州大学旱地农业生态试验站(年均温6.7 ℃、年均降水量351 mm)分别布置玉米田间试验,设置垄沟覆膜(RP)和垄沟不覆膜(CK)两个处理。在榆中县兰州大学旱地农业生态试验站进行甘草田间试验,设置平作不覆盖(CK)、垄沟秸秆覆盖(SM)、垄沟地膜覆盖(RP)和平作地膜覆盖(FP)4个处理,以田间试验数据参数化的反硝化–分解(DNDC)模型为基础,结合第六阶段国际耦合模式比较计划(CMIP6)气候变化模式,预测未来气候情景下覆盖措施对甘草有效成分产量和SOC含量的影响。在上述研究基础上,对玉米–甘草复合系统进行情景模拟,分析其生产效益和土壤肥力等。主要结果如下:

(1)RP的玉米产量随年降水量和年均温的增加逐渐增加,当年降水量和年均温达到一定水平时,RP玉米产量不再增加而保持平稳,CK的产量随年降水量和年均温线性增加。RP的增产效应(RP-CK)随着年降水量和年均温的降低呈线性增大。RP处理玉米增产的原因主要是穗粒数和百粒重的增加。与水热条件较好的通渭和安定相比,水热条件较差的榆中,RP对穗粒数和百粒重的增加更为明显,RP处理两年(2019–2020)平均的玉米穗粒数在三个试验点分别比CK增加了7%、23%和28%,百粒重分别增加了35%、18%和94%,产量分别增加了22%、34%和166%。

(2)与水热条件较好的通渭和安定相比,水热条件较差的榆中,RP的增温保墒效果更加明显。在通渭、安定和榆中,与CK相比,全生育期RP的表层土壤(0–10 cm)温度分别增加了1.2、1.5和2.3 ℃,土壤湿度分别增加了9.7%、12.2%和20.7%。在V6(六叶期)之前,三试验点RP平均增温分别为2.4、2.8和3.5 ℃;V6–V12(十二叶期)时期,分别为0.9、1.5和2.8 ℃;V12–R1(吐丝期)时期,分别为0.7、0.7和1.7 ℃;R1–收获期,分别为0.7、1.0和1.2 ℃。相对重要性分析表明,在水热条件较差地区,土壤温度和水分对作物产量的贡献大于土壤养分的;而在水热条件较好地区,作物生产力受土壤养分、土壤温度和水分的共同影响,其土壤温度和水分对作物产量的贡献与土壤养分的相当。

(3)三年生甘草根有效成分产量(甘草苷和甘草酸的累积量)在SM、RP和FP处理比CK分别增加35%、36%和33%;土壤湿度比CK分别提高58%、74%和30%。RP和FP显著增加了表层土壤温度。与CK相比,SM使 0–20 cm SOC、可溶性有机碳(DOC)和土壤全氮(TN)的含量,分别显著提高了14.9%、41.4%和12.3%。

(4)与CK相比,SM显著提高了土壤微生物量碳(MBC)含量和土壤酶活性,而RP和FP对MBC和土壤酶活性并无影响;SM显著提高了土壤总呼吸(Rt)、异养呼吸(Rh)和自养呼吸(Ra),RP和FP增加了Ra和Rt,但SM、RP和FP并无影响碳排放效率(CEE)。与CK相比,SM显著增加了Rt和Rh的温度敏感性(Q10),而RP和FP 对Rt和Rh的Q10并无影响;SM、RP和FP对Ra的Q10均无显著影响。

(5)通过DNDC模型和CMIP6模拟结果表明,2021–2100年,与CK相比,SM、RP、FP和RS(秸秆翻埋还田加地膜覆盖)均能提高甘草根有效成分产量,但RP、FP和RS的产量稳定性大于SM;SM和RS的SOC呈增加趋势,而CK、RP、FP的SOC则持续降低。因此,未来气候情景下RS能够获得较高产量和稳定性,并保持SOC增长,是黄土高原半干旱区的优选甘草种植方式。

(6)通过DNDC模型模拟表明,与CK相比,RP使榆中县玉米的平均籽粒产量和秸秆生物量分别增加125%和64%。通过对统计年鉴提供的2009–2018年的数据分析表明,榆中县牲畜(牛、羊)的存栏和出栏量,估算了牲畜对玉米秸秆饲草的年最大需求量为4.3万吨。在玉米–甘草复合系统情景模拟中,去除作为牛羊饲草的玉米秸秆部分,不覆膜玉米与甘草种植面积比大于等于7:3时,才能满足榆中县甘草种植中秸秆还田的需求量。此情景中,甘草有效成分(甘草苷和甘草酸)总生产量为1002吨,甘草和玉米的总经济效益为6.7亿元。覆膜玉米与甘草种植面积比大于等于5:5时,即可满足榆中县甘草种植中秸秆还田的需求量。此情景中,甘草有效成分(甘草苷和甘草酸)总生产量为1669吨,玉米与甘草的总经济效益为11.1亿元。

(7)在覆膜玉米–甘草复合系统中,通过玉米秸秆还田扭转了甘草种植中SOC降低的负面效应,甘草农田的SOC(0–20 cm)为11.65–13.41 g·kg–1,比未秸秆还田的增加了38%–59%,并达到了增产的效果,玉米的平均籽粒产量和秸秆生物量分别为6176 kg·ha–1和7878 kg·ha–1,比未覆膜的增加了64%–125%;甘草根产量为2984–3414 kg·ha–1,有效成分产量为87–99 kg·ha–1,比未秸秆还田的增加了14%–31%。因此,黄土高原半干旱偏旱地区构建覆膜玉米–甘草复合系统,在覆膜玉米秸秆生产量及其最大需求量、经济效益和甘草生产力和土壤肥力等方面均有益,值得进一步开展试验研究和示范推广。

综上所述,在黄土高原半干旱偏旱地区,覆膜玉米增产幅度大于水热条件较好的其它地区,可为甘草生产提供足量秸秆材料,在促进甘草提高有效成分产量的同时,也增加了农田SOC含量。覆盖措施有利于提高玉米–甘草复合系统的生产力、经济效益和土壤肥力,是旱地农业高质量可持续发展的重要技术依托

Other Abstract

In the past 20 years, the maize yield of the ridge–furrow mulching system (RFMS) has developed rapidly in the dryland agricultural area of the Loess Plateau. From the southeast to the northwest of the Loess Plateau, the maize yield increase effect of RFMS has been gradually enhanced with the gradually deteriorated hydrothermal conditions. In the semi-arid and arid areas, the maize yield increase of RFMS has more than doubled. The driving mechanism of this phenomenon is still unclear.

Glycyrrhiza uralensis Fisch. is an important medicinal plant in the semi-arid region of the Loess Plateau, and it has been rarely reported whether mulching measures can improve the quality and yield of licorice. At the same time, due to the low aboveground biomass of licorice, its roots were harvested and removed as medicinal materials, resulting in a significant decline in organic matter returned to the soil compared to other crops such as maize, resulting in a risk of continuous reduction in soil fertility.

The productivity of ridged and furrow mulched maize was greatly increased, which provided an important opportunity to establish and improve the production efficiency and soil fertility of the maize–licorice complex production system. To this end, the following major studies have been carried out: (1) The driving mechanism of higher yield increase of ridge and furrow mulching maize in areas with poor hydrothermal conditions; (2) Effects of different mulching measures on quality, yield, and soil fertility of licorice; (3) Effects of mulching measures on active component yield and soil organic carbon (SOC) of licorice under future climate scenarios; (4) Scenario simulation of maize and licorice composite system to improve production efficiency and soil fertility. In 2019 and 2020, the modern agriculture demonstration base in Tongwei County, Dingxi City (average annual temperature 9.1 ℃, average annual precipitation 508 mm), and the experimental base of dry drought meteorology and ecological environment, Anding District, Dingxi City (average annual temperature 8.1 ℃, average annual precipitation 417 mm) and the dryland Agroecology Experimental Station of Lanzhou University in Yuzhong County, Lanzhou City (average annual temperature 6.7 ℃, average annual precipitation 351 mm) were used to conduct field experiments, and two treatments were set up, including ridge and furrow mulched with plastic film (RP) and ridge and furrow without film mulched (CK). Field experiments were carried out in Yuzhong (the dryland Agroecology Experimental Station of Lanzhou University) from 2019 to 2020. The field experiment contained four treatments: plat planting without mulching (CK), ridge-furrow maize straw mulching (SM), ridge-furrow plastic film mulching (RP), and plat planting with plastic film mulching (FP). A parameterized the Denitrification-Decomposition (DNDC) model combined with the Coupled Model Inter-comparison Project Phase 6 (CMIP6) climate change model was used to predict the effects of mulching measures on the licorice yield and SOC content under future climate change scenarios. Based on the above studies, the scenario simulation of maize–licorice complex production system was carried out to analyze its production benefits and soil fertility. The main results are as follows:

(1) With the increase of annual precipitation and annual temperature, the yield of maize under RP treatment increased firstly and then stabilized, while the yield of CK increased linearly with the increase of annual precipitation and annual temperature. The yield increase effect of RP increased linearly with the decrease in annual precipitation and annual temperature. The increase in kernel number per ear and 100-kernel weight was the main reason for the yield increase of maize under RP treatment. Compared with Tongwei and Anding with better hydrothermal conditions, Yuzhong with poorer hydrothermal conditions had more obvious increases in kernel number per ear and 100-kernel weight. Compared with CK, the average kernel number per ear increased by 7%, 23% and 28%, and 100-kernel weight increased by 35%, 18% and 94%, grain yield increased by 22%, 34% and 166%, respectively, in two years (2019–2020) under RP treatment.

(2) Compared with Tongwei and Anding with better hydrothermal conditions, Yuzhong with poorer hydrothermal conditions had a better effect of increasing temperature and preserving moisture by RP, which was the main reason for the increase in yield. In Tongwei, Anding and Yuzhong, compared with CK, the surface soil temperature (0–10 cm) of RP increased by 1.2, 1.5 and 2.3 ℃, and the soil moisture increased by 9.7%, 12.2% and 20.7%, respectively. Before the six-leaf stage (V6), the average RP warming was 2.4, 2.8 and 3.5 ℃, respectively. In V6–V12 (twelve–leaf stage), 0.9, 1.5 and 2.8 ℃, respectively; V12–R1 (silking stage), 0.7, 0.7 and 1.7 ℃, respectively; R1-harvest period, 0.7, 1.0 and 1.2 ℃, respectively. The relative importance analysis showed that in areas with poor hydrothermal conditions, the contribution of soil temperature and water to crop yield was greater than that of soil nutrients. In areas with better hydrothermal conditions, crop productivity was affected by soil nutrients, soil temperature and moisture, and the contribution of soil temperature and water to crop yield was comparable to that of soil nutrients.

 (3) The yield of active components (the accumulation of glycyrrhiza and glycyrrhizic acid) in SM, RP and FP increased by 35%, 36% and 33% compared with CK, respectively. Soil moisture was 58%, 74% and 30% higher than CK, respectively. RP and FP also significantly increased surface soil temperature. Compared with CK, SM significantly increased the contents of 0–20 cm SOC, soluble organic carbon (DOC) and soil total nitrogen (TN) by 14.9%, 41.4% and 12.3%, respectively.

 (4) Compared with CK, SM significantly increased soil microbial biomass carbon (MBC) content and soil enzyme activities, while RP and FP had no effect on MBC and soil enzyme activities; SM significantly increased total respiration (Rt), heterotrophic respiration (Rh) and autotrophic respiration (Ra), RP and FP increased Ra and Rt; but SM, RP and FP had no significant effect on carbon emission efficiency (CEE). Compared with CK, SM significantly increased the temperature sensitivity (Q10) of Rt and Rh, while RP and FP did not affect the Q10 of Rt and Rh. SM, RP and FP had no significant effect on Q10 of Ra.

(5) The DNDC model and CMIP6 were used to simulate the future climate change scenario. From 2021 to 2100, SM, RP, FP and RS (straw returning with plastic film mulching) could all increase the yield of licorice root, but the yield stability of active components of licorice root of RP, FP and RS was greater than that of SM. The SOC of SM and RS showed an increasing trend, while the SOC of CK, RP and FP continued to decrease. Therefore, RS could achieve higher yield and stability and maintain SOC growth under future climate conditions, which is the preferred licorice cultivation method.

  (6) DNDC model simulation showed that RP increased the average grain yield and straw biomass of maize in Yuzhong County by 125% and 64%, respectively, compared with CK. Based on the quantity of livestock (cattle, sheep) stock and released in Yuzhong County, the maximum demand for maize straw forage for livestock was estimated to be 43,000 tons. In the scenario simulation of the maize–licorice complex system, the demand for straw returning to the field in licorice planting in Yuzhong County could be satisfied only when the maize straw as forage of cattle and sheep was removed and the planting area ratio of non-mulching maize to licorice was greater than or equal to 7:3. In this scenario, the total production of bioactive components (liquiritin and glycyrrhizin) was 1,002 tons, and the total economic benefit of maize and licorice was 670 million yuan. When the planting area ratio of mulched corn to licorice is greater than or equal to 5:5, the demand for straw returning to the field in licorice planting in Yuzhong County can be satisfied. In this scenario, the total production of bioactive components (liquiritin and glycyrrhizin) was 1,669 tons, and the total economic benefit of maize and licorice was 1.11 billion yuan.

(7) In the maize–licorice complex system, maize straw return reversed the negative effect of SOC reduction in licorice planting, and the SOC (0–20 cm) in licorice fields was 11.65–13.41 g·kg–1, an increase of 38%–59% compared with non-straw returning. The average grain yield and straw biomass of maize were 6176 and 7878 kg·ha–1, respectively, which were increased by 64%–125% compared with unmulched. The yield of licorice root was 2984–3414 kg·ha–1, and the yield of the bioactive component was 87–99 kg·ha–1, which was 14%–31% higher than that of non-straw returning. Therefore, the construction of a mulched maize and licorice composite production system in the semi-arid region of the Loess Plateau was beneficial in terms of mulched maize straw production and its maximum demand, economic benefits, licorice productivity and soil fertility, and it is worth carrying out experimental demonstration and popularization.

In conclusion, the yield increase of mulched maize in the semi-arid region of the Loess Plateau was greater than that in other regions with better hydrothermal conditions, which could provide sufficient straw materials for the production of licorice, and not only promote the yield of licorice but also increase the SOC content of farmland. Mulching measures were beneficial to improve the productivity, economic benefit and soil fertility of maize–licorice complex system, which was an important technical support for the high quality and sustainable development of dryland agriculture.

Subject Area农业生态学
MOST Discipline Catalogue生态学
URL查看原文
Language中文
Other Code262010_120180904981
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/536281
Collection生态学院
Affiliation
兰州大学生态学院
Recommended Citation
GB/T 7714
杨建军. 旱地覆盖措施对玉米和甘草生产及土壤肥力的影响[D]. 兰州. 兰州大学,2023.
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