蓄水单坑灌施条件下不同土温和水温对土壤水氮运移规律的影响

发布时间：2018-03-14 16:25

本文选题：蓄水单坑灌施　切入点：水氮运移　出处：《太原理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：温度对作物的生长、发育和土壤质地的形成有着重要的影响，它是农业生产中进行耕作、灌溉和施肥的一个重要影响因素。在一定的范围内，随着土壤温度的升高，作物的生长发育速度加快；在其它条件满足时，灌溉水温过低，会抑制作物根系对土壤水分和养分的吸收利用。蓄水坑灌法是一种新型的节水灌溉方法，可有效解决干旱和起到保持水土的作用。温度是控制土壤微生物活性的一个关键因素。温度的变化会影响土壤中氮素的分布，而氮素对作物生长起着重要作用，土壤中氮素的积累有助于提高土壤肥力，促进作物经济产量的提高。为了明确不同土壤温度和灌溉水温对土壤水氮运移规律的影响，以及设计合理的灌溉制度，本文通过室内土箱模型试验与理论分析相结合的方法，研究了在蓄水单坑灌施条件下不同土壤温度(20，25，30℃)和不同灌溉水温(15，20℃)，所对应单坑灌水量(7l)在灌后不同时间(1，5，，10，15d)对土壤水氮运移规律的影响。主要结论为: ⑴蓄水单坑灌施条件下不同温度对土壤水分运移规律的影响，主要包括:①随着入渗时间的延长，蓄水坑土体湿润范围不断扩大，土壤含水率在空间分布上表现为先增大后减小的趋势。②灌溉水温一定时，土壤温度越高，水分在蓄水坑土体内的运移范围越大，含水率越小；土壤温度一定时，灌溉水温越高，水分在蓄水坑土体内的运移范围越大，土壤水分在湿润体内分布越均匀。③不同土壤温度和灌溉水温条件下的湿润锋动态差别不大，土壤含水率空间分布规律基本一致。 ⑵蓄水单坑灌施不同土壤温度(20，25，30℃)条件下氮素运移的规律，主要表现为:①土壤铵态氮含量在垂向分布上随着时间的延长，表现为先增大后减小的趋势。在20—30℃范围内，随着土壤温度的升高，铵态氮含量达到最大值的时间逐渐缩短。土壤铵态氮含量在水平方向上，随着径向距离的增大表现为逐渐减小的趋势。②不同土壤温度条件下的硝态氮含量随着时间的推移而逐渐增大，在灌后15天土壤硝态氮浓度到达最大值。在20—30℃范围内，随着土壤温度的升高，硝态氮含量增幅加快。 ⑶蓄水单坑灌施不同灌溉水温(15，20℃)条件下土壤氮素运移的规律，主要表现有：①土壤铵态氮含量在垂向分布上，随着时间的延长表现为先增加后减小的趋势，灌溉水温20℃时所对应的铵态氮峰值要大于15℃下铵态氮峰值；土壤铵态氮含量随着径向距离的不断增大而逐渐减小。②土壤硝态氮含量在垂向分布上呈现出中间低两边高的特点，随着时间的不断延长，土壤硝态氮含量逐渐增大；土壤硝态氮含量随着径向距离的不断增大而逐渐增大，在土体湿润锋的边缘处，硝态氮含量达到最大值。在15—20℃范围内，随着灌溉水温的升高，土壤硝态氮浓度增大。 ⑷铵态氮在蓄水坑土体内的运移方式主要以扩散作用为主，大部分土壤铵态氮集中在湿润体内部；硝态氮在蓄水坑土体内的运移方式以对流作用为主，大部分土壤硝态氮集中在土体湿润锋边缘处。
[Abstract]:Temperature on the growth of crops, have important influence to the formation and development of soil texture, it is agricultural production in farming, an important factor for irrigation and fertilization. In a certain range, with the increase of soil temperature, the growth rate of crops increases; in other conditions, irrigation water temperature is too low that would inhibit the crop root on soil water and nutrient absorption and utilization.
Water storage pit irrigation is a new water-saving irrigation method, which can effectively solve the problem of drought and plays the role of soil and water conservation. The temperature is a key factor in controlling soil microbial activity. The temperature change will affect the distribution of nitrogen in the soil, and nitrogen fertilizer on crop growth plays an important role in the accumulation of soil nitrogen help to improve soil fertility, promote economic crop yield increasing. In order to understand the effect of different soil temperature and irrigation water temperature regulation of soil water and nitrogen transport, and design a reasonable irrigation system, through the combined method of indoor model test and theoretical analysis of soil box, in the study of the irrigation and fertilization under different soil water temperature single pit (20,25,30 C) and different irrigation water temperature (15,20 C), which corresponds to single pit irrigation (7L) at different times after irrigation (1,5,10,15d) Regulation of soil water and nitrogen transport.
The main conclusions are as follows:
The effects of different temperature on irrigation, soil moisture movement under the condition of application of single water storage pit mainly includes: 1. With the extension of the infiltration time, water storage pit soil moist expanding the scope of soil moisture distribution in space is first increased and then decreased. The irrigation water temperature for a period of time, the higher the temperature of soil and the water movement in the range of water storage pit soil body increases, water content is small; the soil temperature, irrigation water temperature is high, the water movement in the range of water storage pit soil body increases, soil moisture in the moist body distribution is more uniform. The dynamic wetting front little difference in different soil temperature and irrigation water temperature conditions the soil moisture content, spatial distribution is basically the same.
The single water storage pit irrigation under different soil temperature (20,25,30 DEG C) nitrogen migration conditions, mainly as follows: the ammonium nitrogen content in soil in the vertical distribution with time, the performance of the first increased and then decreased. At 20 - 30 Deg. C, with the increase of soil temperature, ammonium nitrogen content reached the maximum time decreases. The ammonium nitrogen content of soil in the horizontal direction, with the increase of the radial distance is gradually decreased. The nitrate nitrogen content in different soil temperature gradually increased with the passage of time, the maximum value at 15 days of soil nitrate nitrogen concentration of irrigation after 20 - 30. In the temperature range, with the increase of soil temperature, increase the content of nitrate nitrogen was accelerated.
The single water storage pit irrigation of different irrigation water temperature (15,20 DEG C) soil nitrogen migration conditions, mainly as follows: ammonium nitrogen content in soil in the vertical distribution, with the extension of time was first increased and then decreased, the ammonium nitrogen peak corresponding to irrigation water temperature at 20 degrees higher than the ammonium nitrogen peak of 15 DEG C; ammonium nitrogen content in soil decreased gradually with increasing radial distance. The soil nitrate nitrogen content in the vertical distribution showed the characteristics of high middle low on both sides, with time, soil nitrate content increased gradually; the nitrate nitrogen content in soil and with the gradual increase of increasing radial distance, on the edge of soil wetting front, the nitrate nitrogen content reached the maximum value. In 15 - 20 DEG C, with the increase of irrigation water temperature, the concentration of nitrate nitrogen in soil increased.
The ammonium nitrogen in the migration of water storage pit soil body mainly diffusion effect, most of the soil ammonium nitrogen concentration in the moist volume; nitrate nitrogen dominated by convection in the migration of water storage pit soil body, most soil nitrate nitrogen concentration in the soil wetting front edge.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152

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