The management of limited farmable land in the rocky plateau

As for people living in the karst plateau, the land for cultivation is of great essence and consideration. That the majority of area is covered by limestone resulted in the serious shortage of land for cultivation. According to the census from Commune People's Committee, Sa Phin commune has a totality of natural area of 1595.72 ha, including 407.9 ha of farmable land (accounts for 25.5% only) and mountainous areas that is not available for cultivation. As a result, with the population of 3047 people, the average farmable land per head in Sa Phin commune is only 0.13 ha. As for Lung Hoa B village, the total area for cultivation is 106.39 ha, and the average cultivated land is 0.26 ha per head. Obviously, the difficult condition in agricultural cultivation of local people here is reflected from the data. The indigenous people have applied a number of methods to agricultural production in order to solve the problem of the cultivated land shortage in rocky plateau.

3.2.1.1. The utilization of all available land for cultivation has always been maintained as the management principle regarding the problem of limited land by villagers at Lung Hoa B.

The majority of farmable land has been exploited for cultivating maize since it is the annual primary crop. In addition, they plant fruit-trees and some vegetables in the garden. Even barren lands at roadside are also utilized to plant elephant grass for feeding livestock. The maximum utilization of cultivated land can be best observed in maize cultivation. Aside from maize fields located in valleys that are quite flat with few large rocks and a lot of soil, Lung Hoa B villagers have sustained two more categories: rocky fields (Têz poz jêz) and rock-niche fields (Têz kraor jêz). Regarding the first type named rocky fields, local people set up terrace fields with a view to utilizing the area on mountain sides with the moderate slope and plenty of soil with the help of a number of rock embankments to reduce the erosion. To build up the embankment for rocky fields, villagers firstly collected many rocks from surrounding areas or had to break the mountain for rocks sometimes. Rocks were diverse in size, but local people mainly selected ones as 20-25 cm as wide and 25-30 cm as high. Afterwards, they used a hammer and a chisel to

58 eliminate sharp edges and make rocks become flatter. The flatter edges rocks had, the more solid the embankment became. Rocks were then arranged into the embankment with the principle that big rocks would be stand at bottom to establish a solid background, and small ones are upper.

Finally, all the gaps among huge rocks were filled up and sealed with small pieces of rocks.

Noticeably, even though no agglutinative substances were applied, all rocks were firmly attached and bound together thanks to the skillful arrangement of local people. At Lung Hoa B village, normally the embankment is characterized with only one layer of rock with the thickness of nearly 20-30cm and as high as 1m due to the moderate slope of the field. For the field on higher areas with steep slopes, the embankment must be built thicker up to 40-50cm with three layers in order to better prevent erosion.

Figure 3.6. A rocky field at Lung Hoa B village (Source: Nguyen Ngoc Minh 2017) Besides, I was extremely impressed with the latter category of rock-niche field. During the time staying at Lung Hoa B village, I visited the maize fields and could not imagine how people managed to develop such a unique technique of planting maize trees into rocky niches in the mountains. There were some tiny niches with a little soil that could merely provide room for up to three maize trees. To set up a rock-niche field, local people often find niches enclosed by rock edges that could prevent strong wind, add soil to niches, and then sow maize seeds in. They

59 have to carry soil up from lower lands and add to the niche so that the maize tree can stand firm and grow. It is even believed by Hmong people in Dong Van that maize cultivated in rock niches grows better than in flat fields. Maize roots planted at smooth and flat fields would be withered and died quickly because of sunlight whilte ones planted inside rock niches was withered on day time but would be green again at night thanks to the dew and the 'sweet' of rocks.

The presence of rocky fields and rock-niche fields have asserted the very deep-rooted custom of local people to maximize all the available agricultural area. This has become a unique identity of residents living in karst.

Figure 3.7. Maize and vegetable planted in rock niches (Source: Nguyen Ngoc Minh 2016) 3.2.1.2. Intercropping and crop rotation are traditional techniques of local people at Lung Hoa B village to solve the problem of limited arable land in the karst plateau. My host family usually intensively intercrops maize as the main crop with other crops such as amaranth, pumpkin, green pea, edible canna, mustard green, and so on. After soil preparing, they start sowing the seed of maize, vegetables and beans on the field. Commonly, the process of sowing the seed requires four people who undertake different tasks. The first person sows maize seeds into the hole, then the second manures. The third person sows bean or vegetable seeds into the same maize holes, yet not into the middle but next to maize seeds, because the seed of vegetables and beans grow faster than of maize, which would have an influence on the growth of maize trees. Finally, the fourth person backfills the hole. In addition, local people also can mix

60 seeds of vegetables and beans with fertilizer and manure into the maize hole. Two or three months after sowing the seed, vegetables and beans could be harvested while maize trees continue growing.

Villagers at Lung Hoa B also rotate maize with soybean and buckwheat. On the one hand, soybean cultivation can optimize the farmable land, since soybean is planted between maize roots. One the other hand, soybean helps the land become more fertile by supplying soil with some nitrogen and organic matter. In most cases, seven or ten days after sowing maize seed, villagers plant one to two rows of spring-summer soybean between two roots of maize (the distance between maize roots is around 80cm-100cm). Spring-summer soybean can be harvested 2-3 months before harvesting maize. Commonly, villagers can cultivate two crops of soybean per year. They sow autumn-winter soybean just 1 month after spring-summer crop. After two months, when soybean plant is 5-10cm in height and requires more sunlight, local people harvest maize and cut maize stems for the sake of soybean growth and development (FAO 2015:

24). As for buckwheat, it is cultivated in small scale on some suitable lands after maize being reaped, and it can be harvested after two months. Remarkably, they almost do not cultivate any plant during the winter from October to January, so the farmable land is rested. Weeds and bush will grow and then die due to low temperatures. Before preparing soil, farmers collect dry weed to burn to get ash for next season (FAO 2015: 21-22). In general, intercropping and crop rotation are effective strategies of Hmong people residing in the karst plateau. First and foremost, this approach helps to utilize the limited arable land and offers extra agricultural products for domestic use and trading. In addition, this technique makes a contribution to maintain the soil fertility and reduce soil erosion.

61 Figure 3.8. Agricultural calendar of Hmong people at Lung Hoa B village

(Source: created by the author 2018)