Thursday, 22 September 2016

Sustainable High-Tech Farms?

The word "sustainability" is very loosely used nowadays. As I am a passionate food grower, I tend to be very sensitive when I hear a farm claim that it is a sustainable farm.

Many high-tech farms claim that their farming methods are sustainable. These include those indoor farms in which the environmental factors are artificial and smartly controlled (LED, air-conditioning, etc.). To support their claim, they usually point out that they can produce higher yield and yet use less water, less land area, little or no pesticides, etc.

I judge whether a farming approach is sustainable using Nature's principles of permanence: Diversity and Law of Return

(1) Diversity
We need to have a diversity of crops, weeds, and wildlife in the farm. When you have biodiversity in your farm, you are actually managing pests. You don't need to spray poison. When you have biodiversity, you are recycling nutrients, and the soil is getting all the fertility it needs, without us having to apply fertilizers. You can get rid of the herbicides, the pesticides, the fertilizers through intensifying biodiversity.

(2) Law of Returning
We need to be giving back to Nature, giving back to soil. While we are growing food for human consumption, we must, at the same time, be feeding the living soil too. Hence farm wastes must be returned to soil as much as possible, through mulching and/or composting. We must assist Nature in recycling nutrients and materials.

So, for a farm to be truly sustainable, it has be be regenerative through observing these two Nature's principles of permanence.

Those high-tech farms, which shut Nature out, cannot be truly sustainable.

Uses of Weeds in a farm/garden

Weeds are part of the ecosystem in an organic farm. We should not aim to eradicate them. Weeds can attract insects, many of which are beneficial. Weeds can enrich the soil through the interaction of their roots and soil microbes.

My approach to weeds is that I trim and remove some of the weeds when they become overwhelming, competing for sunlight and space with my crops. I do not think that weeds can compete with crops for nutrients in the soil because if the soil is reasonably healthy, there would be more than enough nutrients for both crops and weeds. It is more the question of whether the plants are able to absorb the nutrients available in the soil. If the soil is poor in organic matter and microbes, it would be difficult for our crops to absorb the nutrients available in the soil. Simply said, organic matter and microbes in the soil help transport nutrients to the roots of the plants.

Weeds removed is a valuable resource. It is a good material for mulching. Many would dry them before using them as mulch. I often use them fresh. If the weeds regrow or if their seeds germinate, I am not too bothered. If one spends a lot of effort killing off the weeds and their seeds before using them as mulch, he/she is wasting time, because in an organic farm, there’s bound to be weeds thriving. We also should not be aiming to eradicate all the weeds.

I believe I have made a conclusive observation in these few months of growing brinjal. I use freshly cut weeds to mulch around my brinjal plants and the results are rewarding. The plants bear many flowers and fruits. I can afford to apply less fertilizers too. I think as the fresh mulch are breaking down, the nutrients and organic matter that go into the soil proliferate the microbial activities in the soil around the brinjal plants, benefiting them. The fresh mulch consists of about 70% of Cutgrass and 30% of other weeds. I consciously avoid using Creeping Spiderwort in the mulch as it is too aggressive and invasive. When we collect weeds for mulching, it will therefore be convenient to carry two buckets, one for Creeping Spiderwort (to be killed by sun-drying thoroughly), and the other for the useful weeds.

Experience in growing Roselle

I started growing crops as a volunteer in the farm of a non-profit organisation in Singapore in June 2015. Where possible, I attempt to use permaculture and natural farmning approaches there.

I'll record my experience of growing roselle in the farm:

We grew our first batch of roselle in June 2015. The seedlings were transplanted at the end of June 2015 to the plots around the aquaponics ponds. They grew well except for the few plants nearest to the (now) tool shed. These few plants were badly deprived of morning sunlight due to blockage of the plants grown by another volunteer. We had good harvest of good quality roselle calyces for two months.  Black bone powder was used by sprinkling lightly around the plants once every few weeks during flowering and fruiting periods. Composting tea was applied twice a month before flowering.

In February 2016, the second batch of roselle were grown using the seeds saved from the first batch. Seedlings were transplanted to two grow beds which received good morning sunlight. The plants grew healthily until in April 2016, when one of the roselle plants suddenly died in a day or two, with leaves drooping and turning dry and yellow. After a few days, I pulled out the whole plant, but the surrounding plants also got the same problem within a few days. I then tried to leave the dead plants on the plot, it took a longer time (10 to 20 days) to get the same problem. To me, it is highly probable that the problem had been caused by root knot nematodes in the soil. The second batch of roselle can be considered as a failure, although a few plants were able to resist the disease and produced some harvest.

Before I grow the next batch of roselle, I will grow French Marigold (Tagetes patula) in the plots. It is well known that French Marigold can effectively suppress root knot nematodes.

Believing that the second generation roselle plants were prone to root knot nematodes, and also that the quality of the calyces was not so good as the first batch,  I planted a few roselle plants (in early June 2016) from my first generation seeds in the Permaculture plot because I am afraid the the second generation seeds have been hybridized by the roselle plants of another variety growing very near my first batch.

Very near to Permaculture plot,  another volunteer is growing roselle of the other variety nearby. I therefore waited until her plants have reached maturity and bearing flowers before I planted my roselle plants from my first generation seeds, hoping that although I could not separate the two varieties by space (I do not have the authority to ask her to remove her plants),  I could at least separate them by time.