The use of swine manure as a source of plant nutrients is one alternative to synthetic fertilizers. However, conventional manure application with >90% water and a low C:N ratio results in soil C loss to the atmosphere. Our hypothesis was to use biochar as a manure nutrient stabilizer that would slowly release nutrients to plants upon biochar-swine manure mixture application to soil. The objectives were to evaluate the impact of biochar-treated swine manure on soil total C, N, and plant-available macro- and micronutrients in greenhouse-cultivated corn (Zea mays L.) and soybean (Glycine max (L.) Merr.). Neutral pH red oak (RO), highly alkaline autothermal corn stover (HAP), and mild acidic Fe-treated autothermal corn stover (HAPE) biomass were pyrolyzed to prepare biochars. Each biochar was surface-applied to swine manure at a 1:4 (biochar wt/manure wt) ratio to generate mixtures of manure and respective biochars (MRO, MHAP, and MHAPE). Conventional manure (M) control and manure-biochar mixtures were then applied to the soil at a recommended rate. Corn and soybean were grown under these controls and treatments (S, M, MRO, MHAP, and MHAPE) to evaluate the manure-biochar impact on soil quality, plant biomass yield, and nutrient uptake. Soil organic matter significantly (<0.05) increased in all manure-biochar treatments; however, no change in soil pH or total N was observed under any treatment. No difference in soil ammonium between treatments was identified. There was a significant decrease in soil Mehlich3 (M3) P and KCl extractable soil NO₃⁻ for all manure-biochar treatments compared to the conventional M. However, the plant biomass nutrient concentrations were not significantly different from control manure. Moreover, an increasing trend of plant total N and decreasing trend of P in the plant under all biochar-manure treatments than the controls were noted. This observation suggests that the presence of biochar is capable of influencing the soil N and P in such a way as not to lose those nutrients at the early growth stages of the plant. In general, no statistical difference in corn or soybean biomass yield and plant nutrient uptake for N, P, and K was observed. Interestingly, manure-biochar application to soil significantly diluted the M3 extractable soil Cu and Zn concentrations. The results attribute that manure-biochar has the potential to be a better soil amendment than conventional manure application to the soil.

中文翻译：

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比较生物炭-猪粪混合物与常规粪肥对土壤养分利用率和植物吸收的影响-温室研究

使用猪粪作为植物养分的来源是合成肥料的一种替代选择。然而，常规的施肥方法是用水> 90％且C：N比率低，会导致土壤C向大气的损失。我们的假设是将生物炭用作肥料的养分稳定剂，当将生物炭-猪粪便混合物施用到土壤中时，它将缓慢地向植物释放养分。目的是评估生物炭处理过的猪粪肥对温室栽培玉米（Zea mays L.）和大豆（Glycine max）中土壤总碳，氮以及植物可用的常量和微量营养素的影响。（L.）Merr。）。将中性pH红橡树（RO），高碱性自热玉米秸秆（HAP）和温和的铁处理过的酸性Fe自热玉米秸秆（HAPE）生物质进行热解，以制备生物炭。将每种生物炭以1：4（生物炭重量/粪肥重量）的比例表面施用于猪粪，以产生粪肥和相应生物炭（MRO，MHAP和MHAPE）的混合物。然后以推荐的比例将常规肥料（M）控制和肥料-生物炭混合物施用到土壤中。在这些控制和处理（S，M，MRO，MHAP和MHAPE）的控制下种植玉米和大豆，以评估粪便生物炭对土壤质量，植物生物量产量和养分吸收的影响。在所有肥料-生物炭处理中，土壤有机质均显着增加（<0.05）；但是，在任何处理下均未观察到土壤pH或总氮的变化。没有发现处理之间土壤铵的差异。土壤Mehlich3（M3）P和KCl可提取土壤NO含量显着降低₃ ^-与常规施肥相比，所有粪便-生物炭处理的肥料。但是，植物生物量养分浓度与对照粪便没有显着差异。此外，与对照相比，在所有生物炭处理下，植物总氮的增加趋势和磷的下降趋势均得到了观察。该观察结果表明，生物炭的存在能够以不损失植物早期生长阶段那些养分的方式影响土壤中的氮和磷。通常，对于N，P和K，玉米或大豆生物量产量和植物养分吸收没有统计学差异。有趣的是，向土壤中施用粪便生物炭显着稀释了M3可提取土壤中的铜和锌的浓度。