四川省不同区域水稻氮肥施用效果研究

2005—2009年,在四川省不同区域布置水稻氮肥田间试验,通过研究施氮对水稻生长的影响,拟明确氮素吸收特征和氮肥利用效率,为不同区域水稻推荐施氮提供理论依据。结果表明,施用氮肥能明显提高水稻产量,成都平原区、川中丘陵区、盆周山区和川西南山地区的增产率分别为22.4%、33.7%、38.9%和33.1%。不同区域间由于地形、气候、土壤肥力等差异较大,水稻对氮素的吸收利用存在一定的差异,施用氮肥可使百千克籽粒吸氮量提高0.19 kg,当吸氮量为281.8 kg hm-2时,川西南山地区水稻产量可达10.0 t hm-2。氮肥吸收利用率以成都平原区最低(32.2%),盆周山区最高(36.7%),不同区域农学效率平均变幅为11.5~14.4 kg kg-1。地形差异是影响四川省不同区域水稻氮肥施用效果的主要因素,因此根据区域的地形差异合理调整氮肥用量是提高水稻氮肥利用率的有效途径。

Effects of nitrogen fertilization on rice in different regions of Sichuan Province

A total of 292 field experiments were laid out and conducted in different regions of Sichuan Province during the period of 2005-2009 to study effect of nitrogen (N) fertilization on rice relative to region, and further to specify features of the crop absorbing N and to lay down scientific basis for recommendation of N fertilization for rice. Results show that N application significantly increased rice yield by 22.4% in the Chengdu Plain (CP), by 33.7% in the hilly region of Central Sichuan (HCS), by 38.9% in the mountainous areas around the Sichuan basin (MAS) and by 33.1% in the mountainous area of Southwest Sichuan (MSWS), which shows that yield response of rice to N application varied with the region due to sharp differences between the regions in landform, climate and soil fertility, and hence in N absorption and utilization rate of the crop. N application increased N absorption per 100 kg grain by 0.19 kg. When N absorption of the crop reached 281.8 kg hm^-2, yield of the crop could be as high as 10.0 t hm^-2 in MSWS. In terms of average N recovery rate (REN) CP was the lowest (32.2%) and MAS the highest (36.7%). Agronomic efficiencies (AEN) of the regions varied from 11.5 to 14.4 kg kg^-1. Difference in landform between the regions is the major factor explaining the difference between the crops in different regions in N recovery rate. The findings of the study suggest that rational recommendation of N fertilization rate in light of landform of a region should be an effective way to improve N use efficiency of rice cultivation in Sichuan Province.