不同有机肥对采煤塌陷区土壤氮素矿化动态特征研究

为揭示不同有机肥对煤矿复垦土壤氮素矿化特性的影响,以山西省孝义市水峪煤矿采煤塌陷复垦土壤为研究对象,采用室内好气培养法,研究在40%含水量和30℃培养条件下,施用3种有机肥(鸡粪、猪粪、牛粪)后在0~161天的氮素矿化动态特征,以明确不同有机肥对该矿区复垦土壤氮素矿化特征,从而预估不同有机肥的供氮特性,为合理施用有机肥进行低产农田的培肥改造提供科学依据。结果表明:(1)各处理0~14天铵态氮含量均随培养时间的延长迅速下降,与培养时间呈极显著负相关关系(P<0.01),14~161天土壤铵态氮含量维持在较低水平,培养结束时,各处理铵态氮含量均低于1.31mg/kg。(2)各处理土壤硝态氮含量、累积量及矿质氮累积量变化均呈近似的“S”形曲线递增,表现为0~56天缓慢增加,56~84天迅速增加,84天至培养结束(161天)其含量基本不变。培养结束时不同处理间硝态氮含量、累积量及矿质氮累积量整体上均表现为鸡粪>猪粪>牛粪>空白,且鸡粪较猪粪和牛粪处理间存在显著差异,猪粪和牛粪较空白处理间存在显著差异(P<0.05)。(3)不同施肥处理出现氮素净矿化的时间点不同,其中鸡粪处理在第14天时最早出现净矿化现象,而猪粪和牛粪在培养28天后才出现明显的氮素净矿化。(4)不同施肥处理在培养的不同阶段硝态氮和矿质氮累积速率不同,但整体趋势一致,表现为培养0~84天各处理土壤累积矿化波动较大,56~84天达到峰值,培养84~161天各处理矿化速率平稳下降。总体来看,有机肥的施入能有效促进煤矿复垦土壤氮素矿化,从而提高土壤氮素有效性。其中,施鸡粪较猪粪和牛粪对提高矿区复垦土壤有效氮效果更好。4种处理的氮素矿化效果总体表现为鸡粪>猪粪>牛粪>空白。

Dynamic Characteristics of Soil Nitrogen Mineralization in Mining Subsidence Area with Different Organic Fertilizers

In order to reveal the effects of different organic fertilizers on nitrogen mineralization characteristics in a coal mining reclamation soil,a pot experiment was conducted by using a subsidence reclamation soil,which collected from Shuiyu Coal Mining in Xiaoyi City,Shanxi Province.The nitrogen mineralization dynamic characteristics of 0~161 days after application of three organic fertilizers(chicken manure,pig manure,cattle manure)were studied by indoor aerobic incubation method under 40%water content and 30℃incubation conditions.The nitrogen supply characteristics of different organic fertilizers in the reclaimed soil of the mining area could be predicted,which could provide a scientific basis for the rational application of organic fertilizers for the fertility improvement of low-yield farmland.The results showed:(1)The dynamic trend of NH4+—N content in each treatment was basically same.The NH4+—N contents decreased rapidly with incubation time at 0~14 days,which were significantly negative correlation with the incubation time(P<0.01).The NH4+—N contents remained at the low level at 14~161 days.At the end of incubation,the content of NH4+—N in each treatment was lower than 1.31 mg/kg.(2)The dynamic trend of soil NO3-—N content,NO3-—N accumulation amount and mineral nitrogen accumulation showed an increased S-shaped curve in the whole incubation period,which slowly increased at 0~56 days,quickly increased at 56~84 days,and basically unchanged at 84~161 days.At the end of incubation(161 days),the NO3-—N content,NO3-—N accumulation amount and mineral nitrogen accumulation varied among different treatments,with a sequence of chicken manure>pig manure>cattle manure>CK,and chicken manure treatment was significantly higher than pig manure treatment and cattle manure treatment,meanwhile pig manure treatment and cattle manure treatment were significantly higher than CK(P<0.05).(3)The time of nitrogen net mineralization in different fertilization treatments was different.The net mineralization of chicken manure occurred at 14 days,while the net mineralization of pig manure and cattle manure occurred after 28 days.(4)Although the accumulation rates of NO3-—N and mineral nitrogen of different fertilization treatments at different periods of incubation were different,their trends were totally consistent,which showed that the soil mineralization rate fluctuated greatly at 0~84 days,peaked at 56~84 days,decreased steadily at 84~161 days.In a word,the application of organic fertilizer could effectively promote the nitrogen mineralization of reclaimed soil in coal mines,thereby improved soil nitrogen availability.Among three organic fertilizers,the application of chicken manure was better than pig manure and cattle manure in improving the available nitrogen in the reclaimed soil in the mining area.The effects of nitrogen mineralization varied with four treatments,with a sequence of chicken manure>pig manure>cattle manure>CK.