by Ling Zhang
Even worse than the excessive water, the Yellow River brought about another negative impact on the local streams: heavy silt. Modern researchers have considered the eleventh century to be a period when the Yellow River carried one of its heaviest loads of silt. According to their estimates, the river carried and deposited so much sediments that it pushed the river mouth forward and Hebei's coastal line toward the ocean 333 meters each year over the course of that century.7 As a considerable portion of the silt built up new land along the ocean, a great amount of it was carried by both the Yellow's own stream and the local streams to spread and deposit over the Hebei Plain. The geographical features of the Hebei Plain certainly did not help deal with siltage. Its flat, low terrain slowed down the currents and encouraged silt to deposit. Hence, in 1110 when the river burst through its banks in southern Hebei, within merely a year, the flooding water had deposited at the rupture site a layer of sediments that stood higher than one meter.8 Hebei's local rivers became heavier and muddier, their channels narrowed, and their flows were constantly choked by silt. The Zhang River, for instance, due to the heavy siltage, became vulnerable to environmental triggers such as a heavy rainfall; it flooded more often than in the past, especially in the 1070s.9
The hydrocrats in the Song period understood that it was the excess of silt, rather than just the excess of water, that made controlling the Yellow River a nearly impossible task. They tried to tackle the problem with innovative methods, such as trying to dredge the river and remove the sediments. In the 1070s, the reformist government promoted devices like the “iron dragon-claw” (tielongzhua 鐵龍爪) and the “river-clearing harrow” (junchuanpa 浚川耙) to dig out sediments. Yet, the devices were too small and powerless to combat the massive amount of sediments and high speed of siltation.10 So the state's hydraulic projects largely had to rely on conventional solutions, like constructing extensive high dykes.
However, the dykes were fragile. They were built of wooden fascine, stone, sand, and mud, rather than the concrete or steel of modern dykes. As historical events had proven again and again, a small breach in a dyke would easily provoke a bank rupture, which would lead to a massive flood and even a shift in the river's course. In 1077, for instance, a bank rupture caused the entire Yellow River to shift southward into Henan, and terminated the river's northern course. In situations like this, not only was there a catastrophic flood, but the event also left behind an enormous deposit of sediments, both in the abandoned northern course and at the site of the bank rupture. Barely half a year after the event, the northern channel was filled up with sediments. When the state maneuvered half a million laborers to push the river's flow back to the north, the flow could no longer find its previous channel and had to carve out a new course. Similar things happened to the local streams. After the Yellow River temporarily retreated from Hebei in 1077 and released the local rivers from its control, many of the rivers could not recover their old courses, which had been ruined by the Yellow's silt. As contemporaries observed in the mid-1070s, the Small Zhang 小漳 River and the Sha River in southwestern Hebei, for instance, had already become too silted to carry water, and their courses had almost dried up.11
The fate of the Yuhe Canal is a good example to demonstrate the harm inflicted by the Yellow River's silt. Stretching nearly five hundred kilometers from the plain's southern end to its northeastern corner, the canal had functioned as the imperial state's lifeline. It linked the central plain of north China with the empire's most strategic frontier, and fed the latter with massive military supplies. As analyzed in the previous chapter, Hebei's success in obtaining supplies depended on various factors, including the availability of grain and other materials in southern parts of China, south China's willingness to share resources, and the imperial state's capacity to gather them. It certainly depended on the conditions of transportation that delivered the supplies. Without the Yuhe Canal, the state would find it difficult to ship the supplies to support its giant armies across Hebei. In 1048, the Yellow River cut through the canal and took over a part of its course. After that, the canal not only overflowed more frequently than before, but its waterbed also silted up quickly. By 1076, a stretch of fifty-five kilometers (38,000 paces) of its upper reaches in southwestern Hebei was reportedly heavily silted up.12 In southern Hebei, parts of its waterbed rose so high that boats could not pass through.13 After another decade, the majority of the canal was fully blocked by sediments, and had become “entirely useless for shipping things.”14 Having tried unsuccessfully to dredge the canal and remove its sediments with human labor, the Song government and Hebei's residents had to accept the canal's decline as irreversible. After 1128, when the Northern Song Dynasty fell and the Yellow River shifted out of Hebei, the silt-loaded Yuhe Canal was abandoned. Slowly, farmers moved near it and turned its dry waterbed into agricultural fields.15
The fall of Hebei's major water transport route seriously impeded the delivery of grain and other supplies within Hebei. As a result, grain transport had to rely primarily on more laborious and costly overland means, like draught animals and carts. We should also note that the canal's fall brought down the entire Hebei economy, and in particular caused the decline of market towns and cities along the waterway. Bereft of the benefits of water transportation, the northern capital Daming declined both economically and ecologically.16 Part of its walled city was gradually buried beneath the Yellow River's silt, and the once glamorous city lost its prosperity beginning in the late eleventh century.17 The canal itself was not repaired until two centuries later, when the Mongol's Yuan Dynasty established Beijing in the farther north as its capital, and it had to restore the canal as its main route for shipping wealth from south China.
In addition to the streams, other kinds of water, like lakes and ponds, also suffered dramatic attacks from the Yellow River and underwent phenomenal transformation.18 Take Lake Dalu 大陸 in western Hebei. The largest of the ancient lakes on the Hebei Plain, Lake Dalu had a circumference of about forty kilometers at the end of the tenth century, covering an area of 127 square kilometers.19 When the Yellow River shifted its course to western Hebei in 1108, it infiltrated the lake and caused a substantial part of the lake to silt up. As the bottom of the lake and the water level rose due to the drastic sedimentation, the water overflowed toward neighboring lowlands and joined small swamps nearby to form another small lake, as Lake Dalu itself shrank noticeably. By the early nineteenth century, this major lake in Hebei had become a small pool, and it eventually vanished in the early twentieth century.20 The environmental trauma the lake suffered from the Yellow River in the Song period paved the way for its long-term deterioration. We do not know much about other natural lakes in Hebei, but the frontier ponds that the state and Hebei's military maintained clearly underwent great transformation after 1048. As we have discussed in Chapter 5, due to the infiltration of the Yellow's muddy waters, many ponds became shallow and even dried up in the 1070s and 1080s.21 The river's inflow might also have posed similar threats to the extensive underground tunnels that Hebei's military constructed for military defense in northern Hebei.22
Over eighty years, the Yellow River forced a new landscape on Hebei with two tools, water and silt. The two phenomena they each caused – respectively, flooding and siltation – did not happen separately. Rather, they took place next to each other both in terms of space and in terms of time: sporadic pockets of dry sediments emerged in the middle of large swaths of water, or once-hidden sandy landscapes appeared soon after a flood retreated. In various locales, the human suffering from flooding in one year soon switched to an experience of drought and the dry earth in the following year. It is hard for us to visualize the entangled coexistence of the two phenomena, which seem in opposition: excessive water does not usually stand alongside excessive dryness of the land; they should remedy or counteract one another. Yet during the dramatic environmental upheavals between 1048 and 1128, they attacked Hebei hand in hand, wounding the face and the depth of the earth simultaneou
sly. In the following pages, we will discuss these two phenomena in greater detail, and explore their environmental and socio-economic implications.
8.2 Too Much Water – Soil Salinization
The excessive water in the Hebei Plain contributed to an unexpected environmental consequence, namely the salinization of Hebei's soil.23 As explained earlier, water had difficulty draining off due to Hebei's flat terrain and low elevation; it left the land soaked for long periods of time. The saline content and various minerals originally suspended in the underground water were now able to move vertically through the layers of soil. Over time, as the surface water evaporated and the underground water receded, the land dried up. But its soil was no longer the same as in the past: salt, alkalis, and other mineral materials remained inside to change the soil's chemical composition, texture, and appearance.
Before the Yellow River shifted into Hebei, parts of the region had already suffered from soil salinization. Back in the Tang Dynasty, some local officials pursued artificial irrigation, and their “excessive exploitation of water benefits” and inappropriate methods worsened the poor drainage in the region.24 The consequential soil salinization turned out to defeat the irrigation's agricultural purpose and interfered with crop cultivation. After the late tenth century, the construction of extensive ponds in northern Hebei and the maintenance of the Yuhe and other small canals together increased the volume of stagnant water on the plain. The invasion of the Yellow River only made the situation worse.
People who visited central and northern Hebei often commented on the poor quality of the soil. Except for supporting the growth of “saline grass” (yancao 鹽草), the salinized and alkalinized soil killed most plants. According to Chao Shuozhi, at the end of the eleventh century, “in places where river waters stagnate, no single inch of grass is able to grow. Instead, white alkalis spread everywhere.”25 For people who lived in such areas, farming no longer made sense.26 They had to change their livelihood, and some switched to exploiting the brine itself. Instead of farming, they extracted salt from the soil and earned a subsistence living from trading the “earthen salt.”27 Even the imperial state had to accept the unfortunate reality that it could not tax these impoverished people based on their agricultural activities. It had no choice but to permit their salt production and trade, and to tax such activities instead – a policy unique to Hebei, in contrast to the strict state monopoly on salt production and trade in other parts of China.28
Here, we must bring in Wang Anshi's reforms again. The damage to the soil and the land's failure to produce grain and taxes forced the reformist government to seek technological solutions, hoping to remedy and enrich the soil. In the 1070s and early 1080s, Wang and his fellow reformists enthusiastically advocated a “silting-field measure” (yutian fa 淤田法), which would channel the muddy waters from the Yellow River and other local rivers over arable fields. They expected the river silt to deposit there and create on the salty earth a new layer of fertile topsoil.29 This measure, which was intended to transform the harmful silt into something beneficial and economically productive, was not a new idea. It was practiced in other parts of the world and proven successful on some rivers’ flood plains, such as on the Nile in ancient Egypt. Some modern Chinese historians hold a positive opinion about the measure in eleventh-century north China and believe that it did improve the land quality, just as the Nile did to the land of ancient Egypt.30 I suggest, however, that although it is theoretically plausible, the “silting-field measure” was problematic and even harmful to much of Hebei.
First, the practicality of the measure depended on whether or not the hydraulic teams and workers could control the direction, scale, and intensity of the flood. The successful story of the ancient Egyptians had to do with the regularity and predictability of the Nile's seasonal floods. In Hebei, once a flood was triggered, it could hardly be contained or stopped; as the previous chapters have made clear, Song hydrocrats failed in most of their flood control attempts. To what extent, then, could they manage the scale of the floods for land-enriching purposes and end the flooding when the land had taken enough water? We should also note that in many places where the measure was applied during the reformist era, the land was inhabited by dense agricultural communities. Without flood-control preparation and capability, any man-made flood and consequential siltation of fields would risk inflicting great damage on existent human settlements, irrespective of whether it did any good. Indeed, in the 1070s and 1080s, Wang Anshi's critics often criticized the damage brought about by the silting-field measure.31
The second problem with the measure was, again, the issue of drainage. In agricultural terms, as agricultural historian Francesca Bray has pointed out, drainage “was more important than moisture conservation.”32 By the 1070s, Hebei already suffered from too much water; any additional water introduced by the silting-field measure would only make the burden heavier. The measure might work, but only if the water could successfully be drained off to prevent further salinization of the soil – a phenomenon modern scientists name the “secondary, derivative salinization and alkalinization (cisheng yanjianhua 次生鹽鹼化)” that is usually produced by inappropriate irrigation activities.
Let us understand this disastrous phenomenon by looking at a comparative case, which comes from Henan in the 1950s. There, newly established people's communes sought to irrigate the dry land to improve its fertility, and did so by releasing the Yellow River onto the land. The consequences were quite contrary to their intent. The floods induced massive waterlogging as well as soil salinization and alkalinization. In Henan, saline-alkaline fields increased from 2.08 million mu to 4.96 million mu between 1952 and 1962. In one leading irrigation commune, which practiced the irrigation most intensely, the salinized and alkalinized fields increased from 100 thousand mu to 280 thousand mu.33 Rather than improving land fertility, such practices caused agricultural production to drop. Even with good intentions, people's scientific ignorance caused tremendous harm to the environment and to themselves. It took Henan several decades to drain the water away and to rid the soil of its saline contents, and the hard work still continues today. Given this case, we may wonder how much harm Wang Anshi's “silting-field measure” might have inflicted. No historical records show that the Song reformists paid specific attention to drainage, so I am doubtful of the success of the measure in improving the soil quality.
The third problem with the land-enriching measure had to do with the quality of silt that the reformists expected to use to create topsoil. In the case of 1950s Henan, by 1959, the floods had relocated half a billion tons of silt from the Yellow River to the land in the communes, causing massive destruction to arable fields, waterways, and dams. Why is it that this silt did not in fact turn into fertile soil, as the communes’ people expected or as Wang Anshi had wished in the eleventh century? The answer is that there is a huge difference between silt and soil suitable for cultivation. According to soil-core analyses, the Yellow River's silt consists of large rocky debris, fine sand, and mud; only the last contains abundant organic matter and is physically and chemically able to transform into arable soil.34 The soil's maturation process – the transformation of the clayey mud and fine sand into something cultivable – is slow, and it takes place only under favorable conditions, such as certain temperature and humidity. This happens over the course of decades or centuries, not in the few years that the Song reformists and the people's communes expected. Meanwhile, in the eleventh and twelfth centuries, river overflows, bank ruptures, and floods occurred frequently. These events tore apart rocks, trees, fascines, and buildings, and threw all of these materials into the river's torrents to become parts of its silt. Hence, the Yellow River did not bring about only smooth mud and fine sand that the simple tools of medieval farmers were able to cope with. It also brought about a mixture of materials including rocks and stones that iron ploughs and hands could not process into cultivable soil. Perhaps quite in contrast to what Wang Anshi and his hydrocrats wished
to see, the new topsoil created by the soil-enriching measure was a coarse, raw earth hardly useful for agricultural practices.35
Moreover, even fine, smooth silt offers limited fertility. In the eleventh century, farmers sometimes cultivated the river's abandoned dry riverbeds, or the silted land after the retreat of a river flood, or even dangerous shores within the river's dykes, as we saw in Chapter 6. Occasionally, historical records suggest that such silted land was fertile; people strived to own it and even took lawsuits to local governments to dispute the ownership of such land.36 The state also encouraged Hebei refugees to colonize the empty land that the rivers had already silted over. Yet, does this kind of information justify the effectiveness of Wang Anshi's land-enriching measure? In the Standard History of the Song Dynasty, the fourteenth-century compilers included the following passage:
After the [Yellow River's] water recedes, sediments are a fertile glutinous soil in the summer. It then turns into a yellowish dead soil (huangmietu 黃滅土) in the early autumn; it is quite loose [in texture]. Later, it turns into a whitish dead soil (baimietu 白滅土) in the late autumn. After the first frost, it becomes sand completely.37
This rare account most likely came from some eleventh-century documents, which were available to the fourteenth-century historians but are no longer extant today. It perfectly describes the changing nature of the river's silt over seasons, as the water content in the silt evaporates and its fertility decreases. It suggests that the silt-covered land retained organic nutrients for a short period of time; it might support one or two good harvests. But as the water and organic contents filtered out, land productivity fell rather quickly as well.
