Whitford W G, Steinberger Y, MacKay W, Parker L W, Freckman D, Wallwork J A, Weems D
Biology Department, New Mexico State University, Box 3AF, 8803, Las Cruces, NM, USA.
Oecologia. 1986 Mar;68(4):512-515. doi: 10.1007/BF00378764.
We tested the hypotheses that rates of decomposition in a desert should be higher following single large rain events of 25 mm than evenly spaced 6 mm events and that supplemental rainfall should result in higher populations of soil biota. There were no significant differences in mass losses of creosotebush, Larrea tridentata, leaf litter on plots receiving water supplementation and no added water. On some sampling dates, there were higher mass losses in the 6 mm·week treatment. Weekly rainfall produced higher coefficients of variation in mass losses than the other rainfall regimes. A single event pulse compared with weekly pulses of rainfall during the normal "dry" period resulted in no differences in mass losses. Microarthropods and nematodes exhibited numerical responses to supplemental rainfall but the litter microflora did not. These studies provide direct experimental evidence that the conventional wisdom linking decomposition to rainfall in deserts is wrong. The studies also suggest that the effects of litter fauna on surface litter decomposition are minimal; therefore, future studies should focus on activites of the microflora.
在沙漠中，25毫米的单次大雨过后的分解速率应高于间隔均匀的6毫米降雨事件，且补充降雨应导致土壤生物群落数量增加。在接受补水和未补水的地块上，三齿拉瑞阿（Larrea tridentata）叶片凋落物的质量损失没有显著差异。在某些采样日期，6毫米·周处理下的质量损失更高。与其他降雨模式相比，每周降雨导致质量损失的变异系数更高。在正常“干旱”期，单次降雨脉冲与每周降雨脉冲相比，质量损失没有差异。微型节肢动物和线虫对补充降雨表现出数量响应，但凋落物微生物群落没有。这些研究提供了直接的实验证据，表明将沙漠中的分解与降雨联系起来的传统观念是错误的。研究还表明，凋落物动物群对地表凋落物分解的影响很小；因此，未来的研究应关注微生物群落的活动。
