秸秆还田配施化肥对土壤温度、根际微生物及酶活性的影响

以单施秸秆为对照,研究秸秆还田配施不同比例化肥对土壤温度、土壤根际微生物和酶活性的影响。结果表明:(1)在水稻不同生育期,与对照相比秸秆还田配施化肥各处理在8:00和20:00均提高了土壤温度,而在14:00降低了土壤温度。从地温日较差分析可知,秸秆还田配施化肥处理的整日地温变化幅度低于对照,且差异显著。此外随着土层深度的增加,秸秆还田配施化肥处理与对照间的差距逐渐减少,调温作用逐渐减弱。(2)秸秆还田配施化肥各处理能够增加根际土壤总细菌、放线菌、真菌、氨氧化细菌、好气性自生固氮菌、亚硝酸细菌、磷细菌和好气性纤维素分解菌的数量,但普遍区组间差异不显著。除了秸秆还田配施低量NP处理(SNP1,秸秆3 000 kg hm-2+N 150 kg hm-2+P2O575 kg hm-2)以外,秸秆还田配施化肥各处理的过氧化氢酶、脲酶、转化酶活性均高于对照,但区组间均未达到显著差异。因此,秸秆还田配施化肥能合理调节土壤温度,显著提高土壤微生物的数量与活性,有利于土壤生态环境的改善,其中秸秆还田配施NPK处理(SNPK1,秸秆3 000 kg hm-2+N 150 kg hm-2+P2O575 kg hm-2+K2O 37.5 kg hm-2;SNPK2,秸秆3 000 kg hm-2+N 225 kg hm-2+P2O5112.5 kg hm-2+K2O 56.3 kg hm-2)效果最为显著。

Effects of straw incorporation plus chemical fertilizer on soil temperature, root micro-organisms and enzyme activities

In order to explore effects of straw incorporation plus application of chemical fertilizer varying in NPK ratio on soil temperature and moisture conservation and soil-root biological properties, a field experiment was conducted. Results show that the treatments of straw incorporation plus application of chemical fertilizer varying in ratio raised soil temperature at 8:00 and 20:00 and lowered at 14:00 in all the growing periods, compared with the control. Analysis of soil temperature shows that the range of its daily variation was narrower in the treatments than in the control and the difference was significant. However, the difference was getting less significant with the increasing soil depth, which means that the soil temperature regulating effect of the treatments was declining gradually. Besides, the treatments significantly increased the populations of bacteria, actinomyces, fungi, ammonia-oxidizing bacteria, aerobic authigenic nitrogen-fixing bacteria, nitrite bacteria, phosphorus bacteria and aerobic cellulose decomposing bacteria, but generally the difference between the treatments in the effect was not significant. All the treatments, except Treatment SNP₁ (3 000 kg hm^-2 crushed straw 150 kg hm^-2N 75 kg hm^-2 P₂O₅), were higher than the control in activity of catalase, urease and invertase, but the differences were not very significant. The findings demonstrate that straw incorporation plus application of chemical fertilizer, though varying in ratio, may reasonably regulate, increase the population and activity of soil microbes and help improve the soil eco-environment. Among the treatments, Treatment SNPK₁ (3 000 kg hm^-2 straw 150 kg hm^-2 N 75 kg hm^-2 P₂O₅ 37.5 kg hm^-2 K₂O) and Treatment SNPK₂ (3 000 kg hm^-2 straw 225 kg hm^-2N 112.5kg hm^-2 P₂O₅ 56.3 kg hm^-2K₂O) are the most significant in this effect.