Saturday 19 August 2017

Fertilizers can cause "empty fatness" in vegetables

(The Chinese version of this article was published in Lianhe Zaobao on 13 August 2017.)

Applying too much nitrogen fertilizer to vegetable crops would increase the nitrate concentration in the vegetables, causing health concern such as Blue Baby Syndrome and cancer. Actually, applying too much fertilizer to vegetable crops would cause "empty fatness" in vegetables. It is like feeding too much junk food to children, causing them to be obese.

If a farmer looks after the soil really well, natural processes will keep the soil fertile and hence there is no need to apply fertilizers, whether organic or synthetic. There is a wide range of organisms flourishing in a healthy soil, including small animals, worms, insects and microbes. In the Rhizosphere (root zone), there is a large amount of microbes helping to release the nutrients in the soil and supply them to the plants, which in return feed the microbes with its exudates (secretions through the roots, mainly sugars produced by photosynthesis).
Many legume plants (peas and beans) contain symbiotic bacteria called rhizobia within nodules in their root systems. Rhizobia fix atmospheric nitrogen into a form that plants can absorb. The high-temperature and high-pressure conditions during lightning also fix atmospheric nitrogen into nitrogen oxides, which dissolve in rainwater, forming nitrates, that are carried to the earth.

Natural fertilizers are what plants really need. 

Furthermore, the creatures in the air, on the land and in the soil such as birds, insects, small mammals, all help the cycling of nutrients in the environment. This is how the soil gets its fertility naturally. Natural fertilizers are what plants really need, not artificial fertilizers. Besides, artificial fertilizers would adversely affect the healthy structure of soil and break the natural nutrient cycles.

Creatures in and around the farm help the cycling of nutrients,
thus adding fertility to the soil.

If fertilizers (especially nitrogen) are applied too frequently or too much, the vegetables may grow faster, but they may not have the time to absorb other nutrients sufficiently. The vegetables, although bigger in size, are not healthy and more prone to diseases and pests. If we consume such vegetables, we won't be healthy too.

Vegetables that are big and look nice may not be really healthy. They may be the products of commercial farms where a lot of fertilizers are used to boost the yield. Such vegetables may not be rich in the nutrients that they should contain, especially phytonutrients, which are so important to our health.

Small natural farms in the neighbourhoods
Most of the fruits and vegetables sold in Singapore are imported from Malaysia, China and Australia. It is difficult for us, the consumers, to know for sure the farming practices used by the commercial farms in those countries.

We need to shift from the thinking that productive farms must be of industrial scale and occupy large areas of land. Land scarcity in Singapore is actually an opportunity for us to establish small, but yet productive natural farms. An UN report in 2011 predicts that small farms employing simple ecological methods will play an important role in addressing the world's food issues. These small natural farms not only produce healthy, nutritious food, but also create a conducive environment for both people and wildlife.

I hope that the leaders in Singapore, with their foresight, will seriously take this into consideration in their land use policy planning. There are unused green spaces all around Singapore. Some of these green spaces can be converted to small natural farms run by groups of people not as commercial farms, but as something similar to Food Commons, or as the next level of Community in Bloom initiatives. These small farms are not just recreational gardens where folks spend their leisure time. They should be productive farms and contribute to the food resilience of our nation, besides serving other functions such as enhancing the natural environment, education, community bonding and recreation. The planned Tengah Forest Town, which has an area of 700 hectares, has a huge potential of establishing a few larger natural farms too.

There are unused green spaces all around Singapore.

I vision Singapore to be a nation with many small natural farms in the neighbourhoods, where people come and get connected with nature, grow and share their food, and enjoy the lush, lively natural environment.

Thursday 30 March 2017

The "Terroir" concept applied to food crops
(The Chinese version of this article was published in Lianhe Zaobao on 5 March 2017.)

The French word "Terroir" refers to the set of environmental factors (soil, climate, etc.) and the farming practices employed to grow the grapes that give a wine its unique flavour and aroma.

For the same reason, the taste and flavours of vegetables are strongly related to the natural environment of the farm and the farming approach employed. Unfortunately, most vegetables available in supermarkets, and even wet markets, are rather tasteless.  These vegetables are probably grown (or rather, manufactured) in large commercial farms, which cannot afford to pay attention to "Terroir".

In Japan, a farmer called Akinori Kimura managed to grow stunningly delicious apples using "natural cultivation" method that employs neither pesticides nor fertilizers, not even organic fertilizers such as compost or manure. He points out that the key is in the soil.

In Hong Kong, about half a century ago, a farmer in a small village managed to grow a variety of Chinese cabbage which became famous because of its flavours and texture characteristic of the natural environment of the village. The variety was even given its own name "Hok Tau Pak Choi". Sadly, this variety is now extinct.  Those Hok Tau Pak Choi seeds available for sale online must be fake.

Photo credit: 江昱德 (鈴穀社會企業股份有限公司)



Soil is alive
Soil is not just a medium to physically support a growing plant. In nature, soil is alive with countless numbers of living creatures in it - microbes, insects, worms, etc. Above the soil, there are butterflies, bees, dragonflies, birds and other small animals. All this biodiversity, both in and above the soil, enhances the cycling of nutrients, and this is how soil gets its fertility.

The vitality of soil comes from soil microbes. Presence of healthy microbe communities in the soil is key to healthy plant growth. The world of soil microbes is much more complex than we can think. What we do know is that a lot of the nutrients that a plant needs come from the soil microbes through symbiotic exchange. It is obvious that a good farmer should take care to look after the natural environment both in and around the farm, including the soil. If too much fertilizer, whether organic or chemical, is applied, the communities of soil microbes will be adversely affected, leading to unhealthy plant growth and further problems such as high nitrate content and less nutritious crops.

Phytonutrients in fruits and vegetables
Besides vitamins, proteins and minerals, there is another very important group of nutrients, called phytonutrients, found in fruits and vegetables. Science estimates that there exists more that 100 thousand phytonutrients, but scientists have only studied less that one tenth of them, such as lycopene, anthocyanidin and carotene. Although phytonutrients aren't essential for keeping you alive, they help prevent disease and keep your body working properly. Among the benefits of phytonutrients are antioxidant and anti-inflammatory activities, reducing cancer and heart disease risks. Phytonutrients are diverse in nature and many are responsible for the colours and flavours of the plant foods. That's probably why nutritionists ask us to take plant foods of a variety of colours.


So, how are phytonutrients produced in plants? It is "terroir" again. The set of natural environmental factors - climate,  soil, microbes, insects and animals, provides the conditions and ingredients for a plant to produce a complete set of phytonutrients in it. Human health comes from soil health.

While it is difficult for large commercial factory farms to produce crops rich in flavours and phytonutrients,  there are examples of successful small natural farms that use natural farming methods to produce healthy and nutritious foods for the communities, and are financially sustainable too. One such farm is Le Bec Hellouin Farm in France.


Small natural farms in Singapore - an opportunity
Land scarcity in Singapore is actually an advantage in establishing small natural farms. In every district, there are already amenities and facilities like community centres, parks, hawker centres, multiple-storey carparks, clinics, post offices etc. How about farms that produce food for the residents - the next level of the already successful Community in Bloom Initiatives by NParks. Not just gardens, but small farms of 0.1 to 0.5 hectares that seriously grow food for communities while looking after the environment. In this way, consumers (residents) are close to the farms and they can see the source of their food.

The Tengah Forest Town that our government is planning has a huge potential to establish a few bigger natural farms too.

References:

香港鹤薮白 (Hok Tau Pak Choi in Hong Kong)