酸性硫酸盐土壤上直接施用磷矿粉对水稻生长的影响

1998-2001年在已垦和未垦酸性硫酸盐土壤上连续进行6造磷矿粉肥效试验，4种磷矿粉分别为摩洛哥的CALINE和BRUT磷矿粉，阿尔及利亚磷矿粉，2种速效磷肥分别为过磷酸钙（SSP）和三料过磷酸钙（TSP）。头3造磷肥在水稻移栽前施。从2000年起，每小区平均分成2个小裂区，其中裂区Ⅰ继续按以前用量每造均施，裂区Ⅱ则将后4造肥料1次施用。连续3a的试验结果表明：在未垦地上，施用磷矿粉有促进水稻分蘖和增加穗数的作用，并表现出显的增产效果，4种磷矿粉与SSP之间未表现持续显性差异；在已垦地上，各处理间无显差异，比较磷肥的累积与残留效应，也未表现显差异。累积效应中磷矿粉的RAE值最小相当于TSP的58.2%，在酸性硫酸盐土壤上以磷矿粉作为一种有效的磷肥是切实可行的。虽然缺磷是制约水稻生长的一个关键因素，但在此类土壤上单施矿粉还远不能达到常规产量，因而还存在其他限制因子。

Effect of Direct Application of Phosphate Rocks on the Growth of Rice on Acid Sulphate Soils in Guangdong Province, China

Acid sulphate soil is characterized with low pH,low phosphorus availability and excessive salt accumulation.Rational application of fertilizer,especially P,and water management improves the productivity of this soil.In this study,rice field trials were arranged with four phosph ate rocks (PRs)from Morocco(CALCINE and BRUT),Algeria,and China(Kunyang,Yunnan)respectively,and one local single superphosphate(SSP)and local triple superphosphat e(TSP).The trials were arranged in both reclaimed and un-reclaimed fields from1998to2001.The phosphates were applied to the soils each cropping season before rice transplanting during the first three seasons.From the year2000on,the plots were split into two subplots with one applied with phosphate at a former rate every season and the other with phosphate once at a rate for four season Results from the consecutive3years indicate that all PRs could increase rice grain yield signi fica nt ly in the un-reclaimed field but not significantly in the reclaimed field.PRs showe d posit ive effect on tiller numbers and panicle numbers in the un-reclaimed field.No sign ificant difference was continuously observed among phosphate rock sources.When the cum ul ativ e an d residual effects(split and single P application)were compared,no significant diffe re nce was observe d between the two application methods.RAE values indicate that all PRs were at le ast58.2%as effective as TSP when cumulative effect of PR was considered.It is feasible and practical to use PRs as a substitute of available P fertilizers on acid sulphate soils.P deficiency is a crucial limiting factor for rice growth,but there are more other factors limiting rice growth on this type of soil.