STUDIES ON SOIL MICROBIAL CHARATERISTICS AND DISTRTOUHON OF SOIL WATER AND SALT UNDER DRIP IRRIGATION

本文以北疆滴灌和常规灌溉土壤为研究对象，在棉花生育期定期分层采取土样，测定土壤水分、盐分含量，微生物、氨化细菌和硝化细菌数量和土壤呼吸强度，对滴灌与常规灌溉棉田土壤水分、盐分和微生物的季节变化规律及其它们之间的相互关系进行了研究。主要结论如下：试验结果表明，不同滴灌年限土壤含水量主要受灌水量的影响，表现为：滴灌水量相近的1年和3年，土壤各时期的含水量也相近。滴灌6年的灌水量较大，因此在各个时期都是较高的；盐分和水分在季节上有明显的正相关关系。在生长季节结束后，滴灌1年和3年的土壤盐分没有明显的增加；对于连续6年滴灌重盐碱土壤，（采用了加大滴灌量的措施，但仍小于常规灌的灌量），0-60cm的土层盐分有明显的积累现象，说明在盐碱较重的土地上实施滴灌技术时应慎用，并有必要进一步探讨。土壤微生物细菌、真菌、放线菌数量有明显的季节变化。细菌数量在5月出现最大值；放线菌在7月出现峰值；真菌在5月和7月数量差异不大，但高于其它季节。滴灌期内，滴灌土壤的微生物总量高于常规灌土壤。氨化细菌和硝化细菌：氨化细菌与硝化细菌的最大值均出现在7月，这与棉花旺盛生长吸肥期相一致；氨化细菌和盐分显著负相关，表明盐分对土壤生产力的危害，也表现在对土壤中有益微生物的危害上；滴灌1年和3年土壤分别高于常规灌。硝化细菌总体表现为，滴灌土壤的数量要高于常规灌土壤。呼吸强度：呼吸强度在季节上呈明显的单峰变化：7月出现最大值。滴灌6年重盐碱，土壤的呼吸强度在各个季节中都是最低的。滴灌土壤的呼吸强度高于常规灌土壤。The two sorts of soil under flood irrigation and drip irrigation in North Xinjiang were sampled, to study the seasonal changes of the moisture ,the salt and the microorganisms of soil and the relationship between these indices, the soil in different layers being sampled in cotton growth stage and the contents of soil water and salt ,the amount of microorganisms and ammonifier and nitrobacteria and intensity of soil respiration determined at regular interval times. The main results as follows: The consequence of examinations showed that the contents of water was positively correlated with soil moisture. After irrigation, there were significant salt accumulation in Q-60cm soil layer in six-year drip irrigation soil and flood irrigation soil , while there was no significant accumulation of soil salt under one-year and three-year drip irrigation. The amount of three main microbe bacteria, fungi and antinomies obviously varied with plant growth stage. The amount of bacteria reached the peak in May, and that of antinomies reached at the top in July during the year. The amounts of fungi in May and July had no obvious difference, but they were higher than those of other months. During the period of drip irrigation, the total quantity of soil microbe under different drip irrigation-year varied irregularly. The total quantity of soil microbe under drip irrigation was higher than that of flood inigation soil The amounts of ammonifier and nltrobacteria reached at the peak in July, and ammonifier was significant negatively correlated with the content of soil salt The amount of ammonifies in six-year drip irrigation soil was lest, and the quantity of ammonifier under one-year and three-year drip irrigation was higher than that of flood irrigation soil During the period of drip irrigation, The quantity of nitrobacteria was higher than that of flood irrigation. The intensity of soil respiration significantly showed a single-peak curve with time, and reached at the top in My during the year. The intensity of soil respiration of six-year drip irrigation soil was lowest in different reason- During the period of drip irrigation, the intensity of soil respiration of drip irrigation soil (six-year drip irrigation excepted) are higher than that of flood irrigation soil