摘要
以肥际为切入点,通过土柱培养试验,研究了磷酸二氢铵（MAP）在石灰性潮土肥际的转化及肥料磷的迁移。结果表明,MAP施肥31 d后,约90%进入土壤,肥料磷的迁移距离达57 mm。无机磷形态分级结果表明,进入土壤的肥料磷仍保持较高的有效性。其中,以Ca8-P和Ca2-P增幅较大,其次为水溶态（WE-P）、Al-P和Fe-P,O-P仅有少量增加,而土壤Ca10-P没有明显变化。肥际（0-2 mm）新增含磷矿物中,Ca8-P所占比例显著增加,其它形态磷的比例则相应减少。空间上,WE-P与Al-P相似,在56 mm内显著增加,且随距施肥点距离的增加整体呈线性下降。Ca2-P亦于56 mm内显著增加,但包括0-14 mm的快速下降和随后缓慢线性下降两个阶段,并在0-14 mm内相对富集。Ca8-P分布与Ca2-P相似,但表现为集中在6 mm内快速下降。Fe-P在56 mm内显著增加,但在13 mm处含量最高,并在26 mm内相对集中形成,26 mm后缓慢线性下降。O-P仅在30 mm内略有形成。MAP施肥后,进入土壤的肥料磷相对集中,其中,约20%分布于0-2 mm内,6mm内磷的增加量即达土壤磷总增量的50%左右。MAP施肥引起土壤pH显著下降,对土壤碳酸盐及铁铝矿物溶解作用较为显著,特别是0~2 mm内碳酸盐被完全分解,6 mm内土壤碳酸盐含量显著降低。CaCO3溶解释放的Ca^2＋是导致进入土壤中的水溶性磷转化固定的主要因素,而土壤难溶性铁铝矿物溶解释放出的Fe^3＋、Al^3＋离子对水溶性磷的固定也有一定贡献。MAP对土壤难溶性铁的活化作用显著,明显提高了土壤铁的有效性。
In order to investigate the importance of reaction in fertisphere （the soil zone immediately surrounds fertilizer and characterizes with intense reactions） on phytoavailability of phosphorus （P） fertilizer, the transformation and the distribution of fertilizer -P with monoammonium phosphate （MAP） application in a calcareous fluvo - aquic soil, which obtained from Henan China, were studied using slice sectioning by 31 days incubation with soil columns. Statistical analysis showed fertilizer - P lind been moving for 57 mm. Fractionation studies showed that fertilizer- P moved into the soil columns major presented as Ca2 - P and Cas - P, then water- extracted P （WE - P）, A1 - P, and Fe- P, there was only shght increment ofO - P, whereas, there was no significant change of Ca10 - P. The proportions of new - increased P form were, 14.2%, 34.7%, 35.6%, 9.6%, 4.2% and 1.5% for water- extracted P （WE - P）, Ca2 - P, Cas - P, A1 - P, Fe - P and O - P, respectively. However, in the fertisphere （0 - 2 mm）, the proportion of new - formed Cas - P significantly increased, with the deceasing of other P forms. Furthermore, the distributions of WE - P and A1 - P were linearly dechned with the increasing distance from P fertilizer application site. The distribution of Ca2 - P characterized with two stages, they first declined down sharply （0 - 14 mm）, and then slowly they linearly reduced down to original levels of bulk soil. The distribution of Cas - P also characterized with two stages, but they sharply declined down in 6 mm. There was a peak at 13 mm in the distribution curve of Fe - P, and Fe - P major existed in 26 mm, then hnearly it declined down. However, O - P only formed and major presented in 30 mm, and the total amount of new - formed O - P could be negligible. The fertilizer- P moving into soil major presented in fertisphere, it was about 20% presented in 0 - 2 mm, whereas, the ratio was about 50% in 6 mm. MAP significantly reduced the soil pH, and drastically destroyed soil CaCO3 in fertisphere. The Ca^2 ＋ released by CaCO3 dissolution could fix half of fertilizer - P that moved into soil, whereas, the Fe^3 ＋ and A13 ＋ released from the decomposition of soil minerals also plaied an important role on P fixation. Furthermore, MAP application significantly enhanced availabihty of soil Fe.
出处
《中国土壤与肥料》
CAS
CSCD
北大核心
2008年第6期5-10,共6页
Soil and Fertilizer Sciences in China
基金
国家“973”项目(2007CB109301)
国家自然科学基金项目(30671202)资助
关键词
潮土
磷酸一铵
肥际
磷分级
磷迁移
fluvo- aquic soil
MAP
fertisphere
P fractionation
P mobihty
