施用石灰对红壤旱地土壤酸度和油菜产量的影响

EFFECT OF LIMING ON SOIL ACIDITY AND SEED YIELD OF RAPESEED(BRSSICA NAPUS L.) CROWN ON RED SOIL UPLAND

在施石灰石粉的长期定位试验中，种植了５季油菜．结果表明：（１）施用石灰使土壤ｐＨ升高和交换性铝含量下降，其降酸作用与石灰施用量呈正相关．亩施２５０、５００、７５０及１０００ｋｇ石灰石粉的降酸作用分别可维持２、６、７及１０年．（２）施用石灰显著增加了每株荚数而提高油菜籽产量，增产幅度为１９．７％－２．９．６％．过量施用石灰并未引起油菜产量的降低．（３）施用石灰能显著抑制菌核病（连作二年）和田间杂草。（４）施用石灰使土壤ｐＨ＞５．８，交换性铝含量＜０．７ｍｅ／１００ｇ，油菜可获得较高产量。

The results of 3 10 year-long term limestone experiment which planted five crops of rapeseed showed: (1)Application of limestone increased soil pH and decreased exchangeable Al,the effect of reducing acidity was positively correlated with the rates of limestone; (2)The residual effect of Limestone with 3. 75,7. 50, 11. 25 and 15.00 t/ha was 2, 6,7,and 10 years,respectively; (3)Liming significantly increased seed yield of rapeseed by 19.7%-29.6% through the increase in the number of pods per plant;(4)Liming controlled sclerotinia rot (Sclerotinia scletirum) and field weeds;(5)To obstaine an optiunm yield of rapeseed grown on a red soil, soil pH should be raised to higher than 5.8 and exchangeable Al should be reduced to less than 0. 7 Cmol (+)/kg.