I grew a total of two seasons of sweet lupin. This was a protein source for my cows. I found out about sweet lupin after researching about protein sources for my dairy herd. We were already feeding soya as part of the protein mix for the cows ration. Soya in recent years has been going up in price. As dairy firms operate on very thin margins, I was looking for a way to reduce the cost of feeding the cows while still maintaining production levels.
From my research, I found out that sweet lupin is almost similar in crude protein content to soya. I then went about looking for seed. I found out that it wasn't a very popular crop grown by farmers around and thus was not readily available in the agro-vet shops. My searching for seeds led me to the agricultural research institute where I was lucky enough to get some seed. It was however expensive, in my view, compared to the seeds for other crops I was used to buying like maize and sorghum.
The staff at the agricultural research institute were kind enough to give me a pamphlet with some guiding instructions on sweet lupin farming. I came to find out that the cost of the seed was only the tip of the iceberg as regards cost of growing the crop.
In the instructions for sweet lupin farming, I was advised to do a number of things. The first was that it was recommended to use some rhizobium to inoculate the seed before planting. The rhizobium was not readily available, this was because the plant is not so common and popular among farmers around. I had to contact one of the local fertilizer companies to see if I could get some. I was given a two week waiting period while they were preparing some rhizobium for me.
Once I received the rhizobium, also before planting I was advised to also add some bio-fungicide called trianum to the field where I was to plant the sweet lupin. This was to help the plant to resist fungal diseases among them damping off and rotting. I was starting to see that sweet lupin farming would be an expensive affair. This would only be the beginning of costly affair of growing sweet lupin.
In my first trial, I underestimated how frequently the crop required preventative spraying because of fungal infections. The fungal disease I came to find out, spread pretty fast once the crop s affected. With fungal diseases in plants I came to find out that prevention is better than cure. The affected plants would begin with discolouration from green to yellowish then begin stunting in growth before eventually drying up. I found that once affected, the crop never really recovers.
The worst mistake I made was that as the crop was growing, the weeds started competing with the sweet lupin. This was because I had not done the pre-emergent herbicide before planting the seed. I thus had a “bright” idea to use a post emergent herbicide. The mistake was thinking that since sweet lupin is in the bean family, I could use a post emergent herbicide for beans. The whole crop dried up shortly after. It was painful, but a good lesson learnt. And also as the trial was done on about half an acre, the loss was not too bad.
In my second trial, I did everything right as regards the rhizobium, trianum, and proper field preparation. The crop was growing well and vigorously for the first 4 weeks. After this, I found that the fungal diseases still persisted. This was despite a spraying programme every 2 weeks with pesticide, fungicide and foliar feeding. I thus figured the fungal spray programme would have to be every week without fail. This crop of sweet lupin was very healthy and lush. The plants grew to about a height of about a meter with lots of pods. It grows like a short bushy tree.
The crop was finally ready To harvest after about 7 months. The pods are very hard and have a sharp pointed tip. Harvesting was done by hand but we had to be very careful to avoid injury. Also the pods had to be picked before getting completely dry as they explode releasing the seeds when too dry. The pods were sun-dried on a canvas before being prepared and milled and added to the cattle feed concentrates.
I found that when I used sweet lupin to directly replace soya in the dairy cows' concentrates, there was no noticeable change and milk production levels.
Would I do it again?
After growing sweet lupin and seeing what it entails to grow it, I am inclined not to try to grow it again. I think the cost of growing it is far too high from cost of seeds, to the cost of the spray programme. I would have preferred to try soya, but was advised that the altitude of the farm would not be ideal for the crop.
I also believe that other crops are better suited to my farm as protein sources for my cows. I have tried lucerne, purple vetch and desmodium all with varying success. Desmodium performs the best on my farm.