有機栽培における施用有機質堆肥の窒素と炭素の作物吸収,土壌残存、揮散等の動態解析

近年来，人们重新认识到动物粪便对农业生态系统的重要意义，并以^<13>C和^<15>N标记的粪便进行氮动力学研究，以掌握动物粪便的最佳施用方法。通过这些研究揭示了不同作物对动物粪便氮的吸收比例。生产^<13>C和^<15>N标签肥料。用（^<15>NH_4）_2SO_4和K^<15>NO_3（各约10原子% ^< 15>n）和^< 13>co_2在玻璃棚内栽培^<13>C和^<15>N标记凹玉米。收获后，用焦料粉碎机将玉米粉碎，青贮2个月左右作为牛饲料。饲喂^<15> n标记牛粪的奶牛（体重约150 kg），每天收集2天，每天收集^<13>C和^<15> n标记牛粪，连续收集d。添加水和木屑后，牛粪水分和碳氮比分别达到65%和40%左右。将0.5kg左右的材料放入聚苯乙烯泡沫箱中，在50℃下堆肥3个月。有时混合肥料促进堆肥，在堆肥过程中，待肥料干燥后再加水。结果，获得了^<13> c和^<15> n标记的肥料堆肥。堆肥中1 ~ 2%的^<13>C和^<15>N被水稻植株直接吸收，10 ~ 13%的^<13>C被玉米植株直接吸收。

Recently, animal manure was rediscovered as being significant to agricultural ecosystems, and the nitrogen kinetics have been studied with ^<13>C and ^<15>N labelled manure to grasp the optimum methods of animal manure appolication. The uptake ratios of nitrogen derived from animal manures on various crops were revealed through those studies.Production of ^<13>C and ^<15>N labelled manure.^<13>C and ^<15>N-labelled dent corn was cultivated in glass house by applying (^<15>NH_4)_2SO_4 and K^<15>NO_3 (about 10 atom% ^<15>N each) and ^<13>CO_2. After harvesting, dent corn was broken into pieces with a cokefodder crusher and silaged for about 2 moths as cow feed.A cow (about 150 kg weight) was fed with ^<15>N-labelled cattle feces was collected daily for 2 dags, and ^<13>C and ^<15>N-labelled were collected daily for days. By addition of water and sawdust to them, moisture and C/N ratio of those cattle feces became about 65% and 40, respectively. About 0.5kg of the materials were composted in a styrofoam box at 50℃ for 3 months.The manure was sometimes mixed to promote the composting, and water was added when the manure was dried up during the composting period. As a result, ^<13>C-and ^<15>N-labelled manure composts were obtained. From 1 to 2% of the ^<13>C and ^<15>N in the compost were absorbed directly by rice plant and from 10 to 13 of the ^<13>C in the compost were absorbed directly by dent corn plant.