In my Sustainable Grains design I referred to the fact that I was waiting for books to arrive to allow me to continue my research into Small Scale Grain Growing. I am gradually working my way through an abundance of information, but there is plenty to be encouraged about. This includes observations of the continuous production of wheat in the same fields, with interplanted legumes, and measurements of grain yields with legume interplants as part of a formal experiment. Both of these were recorded by Sir Albert Howard in India.
Continuous Small Scale Grain Growing
The following quotes come from ‘Sir Albert Howard in India’ be LE Howard. Sorry for the small size of the text
‘In the canal colonies of the Punjab, however, wheat is grown year after year without manure, apparently without producing any diminution in the fertility of the soil. Judging from the dark green colour of the leaves and the general vegetative vigour of the crop, no nitrogenous manures are necessary. The question arises whence do the large wheat crops derive their nitrogenous manure? Apparently the answer is to be found in the leguminous weeds which thrive so luxuriantly as a bottom growth in the wheat fields of the Punjab.
‘There are three common leguminous weeds among others in the Punjab wheat fields: (1) yellow-flowered senji (Melilotus indica),(2) white- flowered senji (Melilotus alba),and (3) a creeping clover-like plant with curious curved pods (Medicago denticulata).These three plants also grow and seed freely on the banks of the water channels, and are very probably distributed by the irrigation water. In the wheat-fields they ripen their seeds and dry up by the early part of April before the wheat is cut and thus give no trouble at harvest time. At flowering time in March their roots are covered with nodules. Their general vigour shows that they are admirably adapted for bottom growth with wheat.
‘It would appear, therefore, that these weeds confer on the soil of some of the irrigated wheat lands of the Punjab all the benefits of a leguminous rotation and supply the nitrogenous manure required by the wheat crop. In this respect the wheat growers of the Punjab seem to be especially favoured by circumstances as they are able to obtain all the benefits of leguminous crops without the diminution of wheat output entailed in the usual rotations practised on wheat lands in other parts of India. No difficulty would be experienced in obtaining seeds of these leguminous plants. They grow and seed freely among the wheat, in waste places and on the banks of the water channels. Yellow-flowered senji mixed with the other two weeds is grown as a cold weather fodder crop in the Punjab and is sometimes left to ripen for seed purposes.’
This is really encouraging as it shows that it is possible to grow grains continuously in the same fields without the addition of fertilisers. A couple of points stand out however.
The passage calls the legumes ‘weeds’, suggesting that the Indian ‘Ryots’ didn’t understand their significance, yet the following links show clearly that all three are forage crops, and would provide food for their livestock
These plants are also nectar producers, and the Sweet Clovers are deep rooted, adding to their useful functions. According to the Plants for a Future database, all are edible, and can be grown in the UK, although the Burr clover may not appreciate my heavy clay soil.
The second point to note is that there are clearly other ‘weeds’ growing in these fields, not legumes, but without more detail, there is no way of deducing what parts they would play in this system.
The third point is that in India these plants set seed and died back before the wheat was harvested. If similar plants were used in a planting scheme here, the taller Sweet Clovers might hinder the harvesting of the grains, as they would be flowering at about the same time that the wheat would need to be harvested. That isn’t a problem in a small scale grain growing system, but may be on a larger scale.
There are some gaps in knowledge/potential pitfalls here. For example, it is likely that the fields were grazed by livestock between crops, recycling the ‘weeds’ into animal manure. In the Bonfils/Fukuoka wheat growing systems the straw is returned to the fields, but it is likely that the straw was fed to animals. The manure may have been returned, but might also have been burnt for fuel, with only the ash used to help maintain soil fertility. The Indian wheat was likely to have been a short season crop, whereas the Bonfils system uses Winter Wheat. The old fashioned longstraw varieties used need a period of winter cold before setting seed. A system with the type of legumes grown described by Howard might be better suited to a spring wheat, allowing an easy cut (defoliation) of the legumes prior to planting.
There is no indication of whether these legumes were left to grow undisturbed between wheat crops, or if they were killed by ploughing each year, leaving the soil seed bank to replace them after the wheat was sown. This would be really useful to know.
What is clear is that there has been a system of small scale grain growing developed that allows the ongoing growth of wheat in the same fields, over long periods, utilising legumes and other plants. With all of these legumes able to be grown in the UK, it should be possible to construct ‘guilds ‘of useful plants to grow with the grains, to replicate this.
Agricultural Legume Interplanting
Sir Albert Howard also experimented with growing a food producing legume, chickpeas, with wheat. He had observed that the Indian growers often grew grains interplanted with a legume, so he grew three rows of wheat and then a row of chickpeas, in an experiment. The growth of the outer two lines of wheat was so superior to the middle that he weighed the grains at harvest, and found that the lines adjacent to the chickpeas yielded 34% more than the inner line. (A History of Agriculture in India Vol III, Randhawa). This is corroborated by FH King, in ‘Farmers of Forty Centuries’ who observed Chinese growers growing grains and beans, two rows of grain, then a row of beans, etc. The Chinese farmer had clearly worked out the optimum configuration for themselves, without the help of scientists.
Taking Howard’s figures of 34% increase in yield, if you are replacing every third row of grain with a legume, you are losing 33% of your grain yield, from the loss of that row, but gaining a 34% increase in each of the remaining two rows. My mathematics isn’t amazing, but I understand that to mean that the extra yield from the remaining two rows will provide about 2/3 of the yield lost from the missing row, and there will be a yield of bean/legume, that wasn’t there before. This ties in with the following field bean and wheat intercropping paper, which suggests that an intercrop like this is also useful in suppressing weeds.
There is clearly evidence that a grain and legume intercrop/polyculture is possible, has been used successfully in the past, and therefore I should be able to recreate the same system, or use it as a pattern to create something new. A new pattern for Small Scale Grain Growing. All that remains to be seen is how quickly and effectively this can be done.