高寒区施肥和豆科混播水平对燕麦人工草地土壤酶活性的影响

Soil enzyme activities in alpine naked oat-artificial grassland in response to fertilizer and legume mix levels

主要探讨了燕麦人工草地土壤酶活性对燕麦品种、施肥水平和豆科混播水平的响应,为合理评价燕麦人工草地的生态效应和对土壤培肥的影响提供理论依据。采用4个燕麦品种(A1:青燕1号;A2:林纳;A3:青海444;A4:青海甜燕麦)、4个施肥水平(B1:不施任何肥料,CK0;B2:尿素75kg/hm^2+磷酸二铵150kg/hm^2,IM;B3:有机肥1500kg/hm^2,OM;B4:尿素37.5kg/hm^2+磷酸二铵75kg/hm^2+有机肥750kg/hm^2,IM+OM)和4个箭筈豌豆混播水平(C1:0kg/hm^2;C2:45kg/hm^2;C3:60kg/hm^2;C4:75kg/hm^2)的三因素四水平正交试验设计,开展三因素对燕麦人工草地土壤酶活性(脲酶、纤维素酶和转化酶)影响的比较研究。结果表明,燕麦品种、施肥水平和豆科混播水平均能显著提高土壤酶活性;高寒区0~20cm耕作层土壤脲酶、纤维素酶和转化酶活性范围分别为400~900μg/g,80~180μg/g和4~7mg/g;3个因素对土壤酶活性影响的强弱顺序为:施肥水平>品种>豆科混播水平;在3个因素的影响下,随着生育期的推进,土壤脲酶和纤维素酶活性分别呈"先增后减"、"先降后增"的变化,分别在开花期和拔节期出现单峰值,转化酶活性呈"增—降—增—降"或"降—增—降"的变化,在拔节期和抽穗期出现双峰值。土壤酶相对活性指数和土壤酶相对活性综合指数能很好地反映土壤酶的变化。选用青海444或青海甜燕麦,混播箭筈豌豆45kg/hm^2,施尿素37.5kg/hm^2、磷酸二铵75kg/hm^2和有机肥750kg/hm^2时,对提高土壤酶活性效果最佳。

To investigate the dynamics of soil enzymatic activity with regard to the combined effects of oat varie- ty and different fertilizer and legume mixtures, an orthogonality experiment has been conducted in an alpine area. The experiment consists of three factors （oat varieties, fertilizer and legume mixtures） and four levels made up of （1） four oat varieties： Arena sativa cv. Qingyan No. 1, A. sativa cv. Lena, A. sativa cv. Qinghai 444, A. sativa cv. Qinghai; （2） four fertilizer mixes： CK0, urea （75 kg/ha）＋NH4H2PO3 （150 kg/ha）, or- ganic manure （1500 kg/ha）, urea （37.5 kg/ha）＋NH4H2PO3 （75 kg/ha）＋organic manure （750 kg/ha） ; and （3） four Vicia sativa sow mixture rates： 0 kg/ha, 45 kg/ha, 60 kg/ha, 75 kg/ha. The results showed that appropriate combinations of oat variety, fertilizer mixes and legume sow rates can significantly improve soil enzymatic activities. The activities of soil urease, cellulose and invertase were respectively in the range of 400-900 μg/g, 80-180 μg/g and 4-7 mg/g in the cultivated alpine soil. Ranked from high to low, the factors that influenced soil enzymatic activities were first fertilizer mix, then variety, then legume mixture rate. Soil urease activity first increased and then decreased during the growth period, peaking at anthesis; cellulose activity first decreased and then increased, peaking at jointing stage; invertase activity had two periods of increase followed by decrease, with double peaks at the jointing and heading stages. Soil enzyme dynamics were calculated using the relative enzymes activity index and the relative enzyme activity comprehensive index. The highest soil enzymatic activities were recorded in the treatment consisting of the Qinghai 444 or Qinghai sweat oat variety mixed with 45 kg/ha V. sativa and fertilized with 37.5 kg/ha urea, 75 kg/ha NH4H2PO3 and 750 kg/ha organic manure.