Two of the four systems are low-cost farming methods which are based on traditional and scientific knowledge on using crop residues, farm-waste, compost, Gliricidia lopping, bacterial inoculants, and herbal extracts as nutrients to nourish the soil, and as biopesticides to manage pests.

The third system is conventional agriculture which is the "control" and receives chemical input as suggested by research institutions depending on crop type. The fourth is a combination of the  first three.

According to the authors, the Green Revolution did increase yield and converted food importing countries to self-sufficient ones. However, the agronomic and other practices recommended by the Green Revolution added substantial cost to agricultural production.

Chemical inputs, the authors explain, were misused or over used, because of social norms. In this context, use of biomass as surface mulch, compost, green manure,  inter-cropping etc, not only help enhance yields and sustain soil fertility and health, but also increase activity of soil microorganisms and macrofauna.

These field experiments began in 1999 and the authors share their five years' experience in this paper. In their paper, the authors first explain what they mean by sustainable crop production. A key facet of  this system is that only the grain which is the economic yield is expected to leave the system, the stover is returned as surface mulch, if stover is required elsewhere it is compensated, also weeds that enhance crop growth are promoted. The authors feel that such a system would be relevant to small and marginal farmers, in arid and semi-arid areas of lesser developed countries.

The authors then explain the experiment and give details of the four different field trials that constitute the experiment. They also provide information on the soil type and rainfall in the region. The experiment was conducted on 1.02 hectares where 0.2 ha was used for each treatment. The authors also provide
information on the amount of inputs (chemical or natural) that each experiment received.

The study was conducted for 6 different crops - cowpea, pigeonpea, soybean, maize, sorghum and cotton. The authors discuss the intercropping that was done between these crops in each year. The results for these are provided. Further, the authors also discuss the incidence of disease and pest attacks. It was found that soil-borne
diseases like collar rot, were non existent, in the case of low-cost farming. The authors use a variety of tables to explain their experiment and tabulate their findings.

In conclusion, the authors observe that low-cost systems in this long-term experiment would probably need more labor than the conventional system. But this low-cost system, would still be relevant to the small and marginal farmer. Also some methods like use of bio-pesticides used in the low cost system, could play a role in conventional agriculture.

Download the paper here: