压级压价 meaning in English

lower the quality rating and press down the prices

To her great disappointment , however , the potato yield is good in stable way depending on the weather and the price is fluctuated depending on the market
然而，令她苦恼的是，收成时好时坏，马铃薯价格忽高忽低，而且还经常遭到中介商贩的压级压价。
No units purchasing agricultural products may , at the time of purchasing , beat down the grade or price of agricultural products or deduct any costs from the payment
农产品的收购单位在收购农产品时，不得压级压价，不得在支付的价款中扣缴任何费用。