自成組遷都北京，東南歲糧輸納繫於漕運，不至，則京師坐困。成化年間行改兌法，漕糧交由運軍押解，人力由民運中解放，亦提高運輸效益。朝廷為保糧石徵解順暢，發展出一套核心的督運體系，負責催押、監督，並視職司內容往來於六部間。戶部掌財稅，主稅賦徵兌；工部典山水，管運河修繕；兵部司武衛軍官，理漕糧押運，各衙司串聯，將漕務合零為整。 崇禎朝江河日下，漕運攸關軍政度支，刻不容緩，但諸多原由使漕糧未能依欽限而至，稱「遲漕」。漕艘遲滯，可歸納三項原因：首先為天寒、水淺等自然因素；再者為掛欠、土宜超載等人為因素；其次則為清兵南下、漂失之患等偶發因素。中央官員則視船隻誤遲因子提出相應對策，設法將損害降至最低。就天然因子而言可分為預防及疏解兩項：事前防範有立定期程，以合天時，漕船不凍阻；定期疏築，淺澀除去，運道則大通。事後增補則如露囤、陸運等方式，使糧石盡速收儲。 政策的施行短期間未必能洞見其結果，尤須留待時間省視其成敗枯榮。露囤便是將受天寒阻滯不得前行的漕糧積貯於水次，只須派員看守，成本較低，但乾穀易吸收地氣，朽壞子粒。彌補的方法則是設法將凍糧轉作他用，如行月糧的發放或支借為邊餉，除能消耗部分囤糧外，亦降低經冬歷春蒸燠之氣的折損。 沿途風火使徵兌糧數與實際入倉額數不符，漕軍則需賠償，即為掛欠。原有以餘米作為賠補，再佐以輕齎、䉡夫銀等項腳價的酌收，或以漕舟裝載私貨販售，皆可作為彌補之用。但餘米的侵盜或久積腐潰，路耗等費轉作朝廷正支，貨物超載船重難行，賠補機制功能漸失，使掛欠日多，漕運日遲。 崇禎二年（1629）十月天寒凍阻，漕糧囤於河干，又逢清兵入大安口，眼下之際唯有大集車畜，陸運就近收斂庇護。歲糧能保無虞，但泊於沿岸的漕艘付之一炬，影響來年春運。再者船隻行運難免遭遇風浪失事，先行打撈濕米外，漂流糧皆可免除入倉時的揚曬折耗。為防因掛欠而假借漂流，需有州官、糧道等印炤為證，再酌量陪補。 天然諸多限制已使漕運暢通困難重重，人謀的機巧又更錯綜難料，政令難以貫徹，亦無法完全杜絕貪腐。在漕務危機的處理上，政策保有適度的彈性，不至於僵化窒礙難行，並在部分俱才幹的官員調適之下，「遲漕」不至於失控，更想方設法轉遲為速，為日趨傾頹的明王朝留下一線生機。 ;The Grand Canal plays an important role in the Ming dynasty, when the capital was changed and moved to Beijing. The grain tax transportation was handed over to the army to improve the delivery efficiency. Besides, the government created an additional system of supervision to insure the grain tax to be on time. The system worked with the government branch to maintain the financial workings. The Chongzhen（崇禎） period was a chaotic times, the grain tax was indispensable for military and politics. However there were many reasons for the grain tax not arrive in the allotted time: Natural disasters, human causes and accidents. The official tried to resolve the problem and reduce the losses to a minimum. And there were two ways to settle the natural disasters: complement and prevention. The policy would not have immediate consequences in the short term, only time will tell whether it’s going to be a success. For example, when the river froze over, the grain tax will unloaded on vacant land near the bank. This way only need less soldier to watch over goods and it takes low cost. The grain put on the ground would be moisture absorption and decay. The government needed to use the grain to the other way, like be army provisions or salary. Some unexpected caused the grain tax not to cut the mustard, so the army needed to compensate. In the originally some part of the grain tax would give to the army, but it gradually turned to pay for the court. They could’t afford the expenses on the way to Beijing. There was why the grain tax transportation later and later. On the October 1629, Qing attack on the Ming Empire. But the river frozen. The grain tax put one the ground. The official commanded the army to move the grain into the granary. Therefore the grain tax survive. The grain tax ship was burned up by the Qing army. It was disastrous and affect the grain tax transportation next year. By the way, the ship sometimes drifted and shipwrecked. The army should salvage the grain at once and need the local official to prove that was an accident. Then the army could decrease the compensation. There were many natural disasters to cause the grain tax transportation later. In addition the policy was not easy to implement in the empire and the corruption couldn’t definitely remove. Some capable official had a strong capability to handle any crisis. There was a fighting chance that the Ming dynasty could keep for a while.
