中国农业科学 ›› 2019, Vol. 52 ›› Issue (4): 661-675.doi: 10.3864/j.issn.0578-1752.2019.04.008

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

西南紫色土坡耕地农作物-耕层质量适宜性的耦合度诊断

娄义宝1,史东梅1(),金慧芳1,蒋光毅2,段腾1,江娜1   

  1. 1西南大学资源环境学院,重庆 400715
    2重庆市水土保持生态环境监测总站,重庆 401147
  • 收稿日期:2018-07-13 接受日期:2018-09-10 出版日期:2019-02-16 发布日期:2019-02-27
  • 通讯作者: 史东梅
  • 作者简介:娄义宝,E-mail: yibao93@126.com
  • 基金资助:
    国家自然科学基金(41771310);公益性行业农业科研专项(201503119-01-01)

Coupling Degree Diagnosis on Suitability Evaluation of Cultivated-Layer Quality for Slope Farmland in Purple Hilly Region of South-Western China

LOU YiBao1,SHI DongMei1(),JIN HuiFang1,JIANG GuangYi2,DUAN Teng1,JIANG Na1   

  1. 1College of Resources and Environment, Southwest University, Chongqing 400715
    2Chongqing Eco-environment Monitoring Station of Soil and Water Conservation, Chongqing 401147
  • Received:2018-07-13 Accepted:2018-09-10 Online:2019-02-16 Published:2019-02-27
  • Contact: DongMei SHI

摘要:

【目的】紫色土坡耕地是西南区农业生产重要的耕地资源,其耕层质量集中表现为侵蚀性退化严重且农作物产量低而不稳,在地块尺度上农作物产量变化较土壤质量退化具有较明显的滞后效应。论文在紫色土不同地力等级坡耕地耕层土壤质量分析基础上,定量分析紫色土坡耕地耕层质量对农作物的适宜性程度。【方法】在不同地力等级耕层质量统计分析及聚类分析基础上,对农作物-耕层适宜性的耦合度程度进行诊断分析。【结果】(1)紫色土坡耕地不同地力等级的耕层厚度为19—21 cm,有效土层厚度在21—43 cm变化,耕层厚度比较稳定但有效土层浅薄现象严重,五级坡耕地不存在心土层;五级坡耕地产量限制因素为田面坡度、有效土层厚度、耕层厚度。(2)紫色土坡耕地3种耕层类型特征明显,其中Ⅰ类耕层土壤显弱酸性(pH 6.4),阳离子交换量(21.0 cmol(+)·L -1)最大;Ⅱ类耕层田面坡度最小(11°),有效土层厚度(38 cm)和耕层厚度(22 cm)最厚,土壤速效钾含量(136.5 mg·kg -1)最多;Ⅲ类耕层有效土层厚度(28 cm)最薄,土壤显酸性(pH 4.8),阳离子交换量(9.2 cmol(+)·L -1)最小;田面坡度,有效土层厚度,土壤酸化,阳离子交换量是影响坡耕地作物产量主导因子。(3)紫色土坡耕地不同地力等级的农作物与耕层适宜性存在协调发展类和失调衰退类两种状态和同步型、滞后型、损益型、共损型4种表现,在同样地力条件下,农作物产量较耕层质量更为敏感,衰退表现更加明显;农作物-耕层耦合关系(Cd)为Ⅰ类耕层(0.4820)和Ⅱ类(0.5207)属于基本协调发展类农作物耕层同步型,农作物生长勉强适宜;Ⅲ类(0.3343)濒临失调衰退类耕层损益型,农作物生长中度不适宜。 【结论】紫色土坡耕地耕层厚度比较稳定但有效土层浅薄化现象严重,不同地力等级的农作物与耕层适宜性存在协调发展类和失调衰退类两种状态和同步型、滞后型、损益型、共损型4种表现,紫色土坡耕地改良应减小田面坡度,增加有效土层厚度,调节土壤酸碱度。研究结果可为地块尺度上紫色土坡耕地合理耕层调控及构建提供技术参数。

关键词: 坡耕地, 耕层质量, 耦合度, 合理耕层, 适宜性, 紫色土丘陵区, 西南地区

Abstract:

【Objective】As an important cultivated land resource type in southwest area, the quality of the cultivated-layer of slope farmland in purple hilly is concentrated in the phenomenon of severe erosion, low yield and unstable crop yield. The change of crop yield on the plot scale has a significant hysteresis effect compared with soil quality degradation. Based on the analysis of soil quality of sloping farmland in purple soil with different soil fertility grades, this paper quantitatively analyzed the suitability of crop quality of purple soil slope farmland to crops.【Method】The paper studied the suitability evaluation between crop growth and cultivated-layer for the different land productivity grades by the way of coupling degree model based on statistical analysis and clustering analysis. 【Result】The results showed: (1) the thickness of the cultivated-layer at different land productivity grades for purple slope farmland was from 19 to 21 cm and the effective thickness of the cultivated-layer was the range of 21-43 cm, which indicated that the thickness of cultivated-layer was stable and the thinning phenomenon of effective thickness for cultivated-layer was very serious. The limited factors of crop yield for five levels slope farmland were field slope, thickness of cultivated-layer and effective thickness of cultivated-layer. (2) the characteristics of variation of the three kinds of cultivated-layer types for purple soil slope farmland were very serious. Furthermore, soil in Type I of cultivated-layer indicated such features as weak acidic (pH 6.4) and the highest lower cation exchange capacity (20.99 cmol(+)·L -1). Soil in Type II of cultivated-layer was characteristic with smallest field slope (11.3°), the highest thickness of the effective soil layer (38cm) and thickness of cultivated-layer (22 cm), so was the soil available potassium (136.50 mg·kg -1). Soil in Type III showed such characteristics as the thinnest effective soil thickness (28 cm), acidic soil (pH 4.8) and the smallest cation exchange capacity (9.19 cmol(+)·L -1). The dominant factors affecting the crop yield of purple soil slope farmland included field slope, effective soil thickness, soil acidification and cation exchange capacity. (3) the suitability status of crop and cultivated-layer for the different land productivity grades existed two states, including coordinated development stage and maladjustment decay stage, and four types, which were synchro type, lag type, profit and loss type and common loss type. Crop was more sensitive than quality of cultivated-layer for the coupling coordination degrees under the same land productivity grades of slope farmland, which signified the more yield decrease. Crop-cultivated layer coupling coordination degrees (Cd) for Type I (0.4820) and Type II (0.5207) belonged to the basic coordination development stage and the lag type for crop - cultivated layer, which caused the crop growth was barely suitable. Meanwhile, Crop-cultivated layer coupling coordination degrees (Cd) for Type III (0.3343) was in mild dysregulation stage and profit and loss type, which meant the quality of cultivated-layer for crop growth was moderate unsuitable. 【Conclusion】 The thickness of cultivated-layer was stable and the thinning phenomenon of effective thickness for cultivated-layer was very serious. The suitability status of crop and cultivated-layer for the different land productivity grades existed two states, including coordinated development stage and maladjustment decay stage, and four types, including synchro type, lag type, profit and loss type and common loss type. Slope farmland improvement in purple soil should reduce the slope of the field, increase the thickness of effective soil layer, and adjust the soil pH. These results could provide some useful parameters for suitability diagnosis, regulation and construction of the cultivated-layer of purple soil slope farmland at plots level.

Key words: slope farmland, quality of cultivated-layer, coupling degree, reasonable cultivated-layer configuration, suitability, purple hilly area, South-Western China