不同施肥量对甘蓝吸收水分与养分的影响

EFFECTS OF DIFFERENT FERTILIZER APPLICATION RATES ON WATER AND NUTRIENT UPTAKES IN CABBAGE

研究了甘蓝耗水量、干物质累积量、每升水干物质产出率在不同土壤水势与不同施肥量双重因素作用下的变化规律。在同一水势范围内 ,甘蓝叶、根机体养分中的N含量随施N量的加大有增高的趋势 ,而P2 O5、K2 O含量则有减少的趋势 ;甘蓝N、P、K的吸收量 ,以适量施肥(30 0kgN/hm2 )的最高、不施肥的较少、过量施肥 (12 0 0kgN/hm2 )的最少 ;养分含量中的N/P、N/K值都是随施N量的增加而提高 ,致使养分吸收失衡 ,抑制了正常生长。

The variation regularities of water consumption,accumulated dry matter amount,dry matter output rate per liter of water in cabbage plants under different soil water potentials and at different fertilizer application rates were investigated.The results are as follows.In the same range of soil water potential,with the increase of N application rate,N contents in cabbage leaves and roots tend to raise while P 2O 5 and K 2O contents tend to decrease.The amounts of absorbed N,P,K are maximum at the appropriate fertilizer application rate (300kg N/hm 2),medium at the 0 fertilizer application rate and minimum at the excessive fertilizer application rate(1200kg N/hm 2) .N/P and N/K values all rise with the increase of fertilizer application rate,which will lead to non equilibrium of nutrient uptake and inhibition of normal growth.