糜子不同种植方式对土壤酶活性及养分的影响

【目的】土壤酶参与土壤中多种生化活动,是衡量土壤生产力的指标之一。本文比较分析了不同种植方式下糜子生育期间土壤酶活性的动态变化以及成熟期土壤养分含量和糜子产量,旨在探明糜子连作障碍和连作减产的产生机制,为糜子高产高效栽培提供理论依据。【方法】以西北农林科技大学农作一站小杂粮轮作连作长期定位试验为平台,设轮作(T1)、隔年种植(T2)、连作2年(T3)、连作3年(T4)4个处理,在糜子播种期、苗期、拔节期、抽穗期、灌浆期、成熟期测定0—20 cm根际土壤中过氧化氢酶、脲酶、碱性磷酸酶、蔗糖酶活性以及成熟期0—20 cm根际土壤养分含量,对同一时期不同处理间的酶活性和成熟期不同处理间土壤有机质、全氮、碱解氮、全磷、有效磷、全钾、速效钾含量以及土壤p H值进行方差分析,并分析土壤养分和酶活性以及糜子产量之间的相关性。【结果】1)土壤过氧化氢酶、脲酶、蔗糖酶活性随着连作年限的增加而降低;碱性磷酸酶在连作2年处理的活性较低。2)随着连作年限的增加土壤p H值升高,土壤速效钾严重积累,速效磷消耗较多,说明连作导致土壤盐碱化。3)过氧化氢酶、脲酶、碱性磷酸酶活性与糜子籽粒产量呈显著正相关,土壤p H值与籽粒产量呈显著负相关;蔗糖酶活性、有机质含量与产量具有一定的相关性。【结论】糜子连作改变了土壤酶活性及土壤养分含量,导致土壤腐殖化和熟化程度减慢,土壤次生盐渍化加重,土壤养分不均衡,植株生长发育受到影响,造成籽粒产量的下降。因此,在糜子生产上要进行合理的轮作倒茬,从而减缓连作障碍,实现糜子高产优质。

Influence of different cropping patterns on soil enzyme activities and yield of broomcorn millet

【Objectives】 Soil enzymes involve in a variety of biological processes in soil, their activities are one of soil quality evaluation index. In this paper, the dynamic changes of soil enzyme activities at different growing stages of broomcorn millet, soil nutrients’ contents at the maturity and the crop yields under different cropping patterns were analysed, to provide a theoretical basis for high-yield broomcorn millet. 【Methods】 A long-term experiment of minor grain crops was carried out at theFirst Station of Northwest A & F University. Broomcorn millet was planted by rotation (T1), every two years (T2), continuously two years (T3) and continuously three years (T4). Soil catalase, urease, alkaline phosphatase and invertase activities in 0-20 cm rhizosphere soil layer were measured at sowing stage, seeding stage, jointing stage, heading stage, filling stage and maturing stage, and soil nutrient contents were determined at maturing stage.Soil organic matter, total nitrogen, alkali solution nitrogen, total phosphorus, available phosphorus, total potassium, available potassium content and pH value at the maturing stage were determined.【Results】 The activities of soil catalase, urease and invertase were decreased with the elongation of the continuous-cropping year, while the polyphenol oxidase activity was reverse, and the alkaline phosphatase activity was the lowest in the second year of the continuous-cropping. With the increase of the continuous-cropping year, soil pH was increased, soil available-potassium was obviously accumulated and soil available-phosphorus was consumed much. The catalase, urease, and alkaline phosphatase activities were significantly and positively correlated with the grain yield, while soil pH is negatively correlated with the grain yield. The correlations between soil invertase, organic matter content and the yield were not significant. 【Conclusions】Thecontinuous cropping of milletaffects the activities of soil enzymes and soil nutrients’ contents,slows downthe soil humification and amelioration degree,aggravatessoil secondary salinization and soil nutrient imbalance,and decreases the grain yields as a result. So the reasonable rotation for millet is very important, for slowing the succession cropping obstacle and achieving a high yield and quality on broomcorn millet.