灌溉方式对石灰性褐土团聚体分布特征、稳定性及养分含量的影响

Effects of irrigation methods on distribution characteristics, stability and nutrient contents of calcareous brown soil aggregates

  • 摘要: 为探明不同灌溉方式对石灰性褐土团聚体分布特征、稳定性及养分含量的影响, 于2016—2021年在山西农业大学小麦研究所韩村试验基地开展大田定位试验。设连续微喷灌(SI)、连续滴灌(DI)、连续漫灌(FI)和第1、2、5年漫灌与第3、4年微喷灌轮换(RI) 4个处理。定位5年后, 测定土壤>0.25 mm团聚体重量百分含量(DR0.25、WR0.25)、平均重量直径(MWD)、几何平均直径(GMD)、破坏率(PAD)、分形维数(D)等土壤团聚体粒径分布、稳定性指标, 以及土壤水稳性团聚体有机碳、有效磷、速效钾含量等养分指标, 并对水稳性团聚体分布特征、稳定性及养分含量进行了相关分析。结果表明: 1)机械稳定性团聚体在0~10 cm土层SI、DI和RI处理均以0.5~1 mm为优势粒径(FI为<0.25 mm), 在10~20 cm土层DI、FI和RI处理均以>5 mm为优势粒径(SI为0.5~1 mm), 在20~50 cm土层各灌溉处理的优势粒径则均为>5 mm; 水稳性团聚体在0~50 cm土层4种灌溉处理均以<0.25 mm为优势粒径, 但FI处理的重量百分比最高。2) SI和DI处理在0~50 cm土层有效提高了WR0.25、降低了D, 且MWD、GMD总体上高于FI和RI处理, 并在30~50 cm土层显著降低了PAD, 而FI、RI处理的这些稳定性指标受土层深度影响较大。3)与其他2个处理相比, SI、DI处理在0~50 cm土层提高了土壤水稳性大团聚体(>0.25 mm)有机碳、有效磷、速效钾含量, 尤其在提高0~30 cm土层有效磷含量和30~50 cm土层速效钾含量上效果更为显著。4)相关性分析表明, 土层、WR0.25、MWD、GMD、PAD、D、水稳性大团聚体养分含量(有机碳、有效磷、速效钾)之间的相关性均达到显著(P<0.05)或极显著(P<0.01)水平。综上所述, 微喷灌、滴灌水肥一体化更有利于改善土壤结构和性状, 促进土壤大团聚体形成, 提高水稳性团聚体稳定水平及养分含量, 应值得推广应用。

     

    Abstract: A field experiment was conducted at the Hancun Experimental Base of the Wheat Research Institute, Shanxi Agricultural University, from 2016 to 2021 to explore the effects of different irrigation methods (continuous micro-sprinkler irrigation, SI; continuous drip irrigation, DI; continuous flooding irrigation, FI; and annual rotation of flooding irrigation and micro-sprinkler irrigation, RI) on the distribution characteristics, stability, and nutrients contents of calcareous brown soil aggregates. After five years of positioning, >0.25 mm aggregates weight percentage of machine-stable aggregates (DR0.25) and water-stable aggregates (WR0.25), mean weight diameter (MWD), geometric mean diameter (GMD), destruction rate (PAD), fractal dimension (D), and nutrients (organic carbon, available phosphorus, and available potassium) contents of soil water-stable aggregates were determined. In addition, the correlations among the distribution characteristics, stability, and nutrients contents of soil water-stable aggregates were analyzed. The main results were as follows: 1) In the 0–10 cm soil layer, the dominant particle sizes of mechine-stable soil aggregates of treatments SI, DI, and RI were 0.5–1 mm, that of treatment FI was <0.25 mm. In the 10–20 cm soil layer, the dominant particle sizes of mechine-stable soil aggregates of treatments DI, FI, and RI were > 5 mm, while that of treatment SI was 0.5–1 mm; that for all treatments were > 5 mm in the 20–50 cm soil layer. The dominant particle size of the water-stable aggregate of the four treatments was <0.25 mm in the 0–50 cm soil layer, but the highest percentage of weight was observed in FI. 2) SI and DI effectively increased WR0.25, reduced D, and resulted in higher MWD and GMD overall in the 0–50 cm soil layer, as well as decreased PAD in the 30–50 cm soil layer compared to FI and RI. However, the aggregates stability indices of treatments FI and RI were largely affected by the soil depth. 3) Compared to FI and RI, SI and DI resulted in higher contents of organic carbon, available phosphorus, and available potassium in soil water-stable macro-aggregates (>0.25 mm), and had obvious advantages in increasing available phosphorus content in the 0–30 cm soil layer and available potassium content in the 30–50 cm soil layer. 4) The results of the correlation analysis showed that the relationships between soil depth, WR0.25, MWD, GMD, PAD, D, and nutrients (organic carbon, available phosphorus, and available potassium) contents of soil water-stable macro-aggregates were significant (P<0.05) or extremely significant (P<0.01). Overall, SI and DI were more advantageous in improving the structure and properties of soil, promoting the formation of soil macro-aggregates, and increasing the level of stability and nutrients contents of water-stable aggregates, and should be popularized and applied.

     

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