复种饲料油菜对麦茬耕层土壤酶活性的影响

Effect of Triticum aestivum/feed Brassica napus multiple cropping on soil enzymatic activities

采用大田试验方法，研究了不同种植密度与施氮量条件下，复种饲料油菜对麦茬耕层（0～15cm）土壤酶活性的影响。结果表明，麦收后复种饲料油菜能显著或极显著地提高土壤过氧化氢酶（CAT）、酸性磷酸酶（APHA）、纤维素酶（CEL）和脲酶（URA）的活性，与休闲熟化地（CK）比较，最大提高幅度分别为32．15％，35．61％，78．66％和127．36％。土壤酶活性的变化与复种饲料油菜的播种量和施氮量有关，随播种量的增加土壤CAT、CEL和URA活性表现为逐渐递增态势，而土壤APHA表现为先增后减，播种量为11．5kg／hm^2时，APHA活性可达0．7888mg／g。在油菜生长的苗期，土壤APHA、CEL和URA随施氮量的增加而增加，土壤CAT则随施氮量的增加先增后降，呈单峰曲线；在生长后期（收获期），低氮量有利于土壤APHA活性的增加，中氮量有利于土壤CAT和CEL活性的增加，高氮量有利于URA活性的增加。

The effect of multiple cropping of Brassica napus on soil enzymatic activities of the arable layer （0- 15 cm） in Triticum aestivum stubble was studied using different planting densities of B. napus and different amounts of nitrogen. Compared with fallow land （CK）, there was a significant increase in the activities of catalase （32. 15%）, acid phosphates （35.61%）, cellulose （78.66%）, and urease （127.36%） following multiple cropping of cropping rape after T. aestivurn harvest. Changes of soil enzymatic activities were related to the rate of seeding and the amount of nitrogen applied. Soil APHA increased first then decreased. APHA activities reached 0. 788 8 mg/g with a seeding rate of 11.5 kg/hm^2. Soil APHA, CEL and URA increased and soil CAT increased first then decreased with an increase of nitrogen applied at the seedling stage and behaved in a unimodal pattern. A low amount of nitrogen increased soil APHA activities, a medium amount increased soil CAT and CEL activities while a high amount increased URA activities.