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作 者 ：顾明华¹;区惠平¹;刘昔辉²;黄景¹;黎晓峰¹;李柳霞¹;沈方科¹;江立庚¹

期 刊 ：应用生态学报 2009年 20卷 06期 页码：1362-1368

关键词：稻；

摘 要 ：在水稻不同生育期分层采集稻田土壤剖面样品，研究不同耕作方式（常耕CT、免耕NT、稻草还田常耕CTS、稻草还田免耕NTS）、不同土层稻田土壤的氮素（N）形态及氮素转化菌特征.结果表明：在N素转化菌方面，水稻整个生育期0～5 cm土层氨化细菌的数量以NTS处理最多;0～5 cm和5～12 cm土层亚硝化细菌数量CT处理高于NT处理，12～20 cm土层则相反;NTS较CTS处理降低了0～20 cm土层的亚硝化细菌和反硝化细菌数量;在水稻拔节期和成熟期，NT处理较CT处理提高了0～5 cm土层的嫌气性固氮菌数量.在N素形态方面，水稻整个生育期NT处理碱解N和全N较集中分布在0～5 cm土层，明显高于CT处理，而5～12 cm和12～20 cm土层比CT处理低;12～20 cm土层的铵态氮和硝态氮含量NT与CT处理差异不显著，而NTS处理0～20 cm土层的铵态氮和硝态氮含量均有所提高.相关分析和多元回归分析表明，铵态氮与氨化细菌、亚硝化细菌、反硝化细菌正相关程度最高，而碱解氮与嫌气性固氮菌正相关程度最高，均达极显著水平.综合各土层氮素转化菌数量与不同形态N含量，NTS更有利于稻田氮素供应与养分积累.

Abstract:Paddy soil samples were collected in layers (0〖KG-*2〗-〖KG-*7〗5, 5〖KG-*2〗-
〖KG-*7〗12, and 12〖KG-*2〗-〖KG-*7〗20 cm) during rice growth period to invest
igate the characteristics of the N forms and N-transforming bacteria in the soi
l profile under different tillage patterns (no-tillage with straw returning, NT
S; conventional tillage with straw returning, CTS; no-tillage, NT; and conventi
onal tillage, CT). In the whole rice growth period, ammonifying bacteria in 0〖K
G-*2〗-〖KG-*7〗5 cm soil layer had the highest number under NTS, and nitrosobac
teria in 0〖KG-*2〗-〖KG-*7〗5 cm and 5〖KG-*2〗-〖KG-*7〗12 cm soil layers were
more abundant but in 12〖KG-*2〗-〖KG-*7〗20 cm soil layer were lesser under CT
than under NT. Nitrosobacteria and denitrobacteria in 0〖KG-*2〗-〖KG-*7〗20 cm
soil layer were lesser under NTS than under CTS. At elongating and ripening sta
ges, anaerobic N-fixing bacteria in 0〖KG-*2〗-〖KG-*7〗5 cm soil layer were mo
re abundant under NT than under CT. In the whole rice growth period, the alkali
-hydrolyzable N and total N contents in 0〖KG-*2〗-〖KG-*7〗5 cm soil layer wer
e significantly higher but in 5〖KG-*2〗-〖KG-*7〗12 cm and 12〖KG-*2〗-〖KG-*7
〗20 cm soil layers were lower under NT than under CT, and the NH4+-N and N
O3--N contents in 0〖KG-*2〗-〖KG-*7〗20 cm soil layer were higher under NT
S but in 12〖KG-*2〗-〖KG-*7〗20 cm soil layer had no significant differences be
tween NT and CT. Correlation analysis and multiple polynomial regression analysi
s further revealed that there were significant relationships between soil NH4
+-N and soil ammonifying bacteria, nitrosobacteria and denitrobacteria, and b
etween soil alkali-hydrolyzable N and soil anaerobic N-fixing bacteria. Among
the test tillage patterns, NTS could be the more desirable one for the N supply
and fertility maintenance of paddy soil.

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