定位连施土粪对土壤钾素的影响

连续4年定位连施试验表明,一年一作春小麦条件下,年施入土粪150 000 kg～225 000 kg/hm2,能显著提高土壤供K量;年连施225 000 kg/ hm2土粪才能使土壤K素收支趋于平衡状态,低于此用量则是亏缺状态;按照目前生产上的正常用量75 000 kg/ hm2连施,土壤速效K减少17.5 %,若土粪用量增至2～3倍可使土壤速效K含量提高47.8 %～107.5 %,但不能保持土壤缓效K含量,4年累积减少20.4 %～25.1 %。可见,仅靠土粪是不能保持土壤K素肥力的,缓效K下降值较大。

Effects of consecutive position fertilization with dung on soil potassic content

According to experiment of consecutive position fertilization with dung for 4 years on soil, it shows that under the condition of harvesting spring wheat one time a year, the quantity of supplying potassic can be increased distinctively by fertilizing 150 000 kg/hm2 to 225 000 kg/hm2 annually. Consecutive applying annually 225 000 kg/hm2 of dung on soil can balance the output and input of soil potassic. If the quantity fertilized smaller than 225 000 kg/hm2, soil potassic is in deficit situation. According to current production, the normal consecutive fertilizing quantity is 75 000 kg/hm2, which leads soil active potassic to decrease 17.5 per cent. If the application rate of dung increases by 2 to 3 times, content of soil active potassic can improve 47.8 to 107.5 per cent, but the quantity of soil slow-release potassic can not be maintained, which reduces accumulatively 20.4 to 25.1 percent within 4 years. See from above, only depending on dung and dirt cannot maintains fertility of soil potassic, furthermore, the decrease in the content of slow potassic is more significant.