A two-step methodology was followed to achieve the intended objectives. In the first step, experiments were conducted on farmers’ fields to test the impact of intercrops on various insect pests of castor crop. Combinations found effective along with some other systems popular with the farmers or suggested by them were evaluated in farmers’ fields. In the second step, different LEIIPM modules were superimposed on the systems found effective and efficient in the earlier steps.
Identification of effective intercrop
Field experiments were conducted during rainy seasons of 2003, 2004 and 2005 in a randomised block design (RBD) to create crop-crop diversity systems. Eight intercrops were tested with castor as the base crop in farmers’ fields and also in the research farm of CRIDA. Ten farmers who served as replications grew each system. The villages and farmers selected represent typical Dryland farming situation. Various participatory rural appraisal (PRA) tools were used to identify the farmers and ensure their participation. The experiments were subjected to analysis of variance (ANOVA) for RBD.
Low external input IPM modules
Three low external input IPM modules were evaluated in three most effective crop diversified systems identified in the earlier step. These experiments were also taken up on-station and in farmers’ fields with the active participation of the farmers during 2005. The sequential application of various components was adopted in different ways. The low external input IPM modules were — IPM
I: Neem Seed Kernel Extract (NSKE) 5%, extract of Vitex negundo 1/10 w/w, NSKE 5% and extract of V. negundo 1/10 w/w IPM
II: Neem oil 5%, Pongamia oil 5%, Jatropha oil 5%, Neem oil 5% IPM
III: NSKE 5%, Neem oil 5%, extract of V. negundo 1/10 w/w, Pongamia oil 5% All modules included bird perches and mechanical collection of larvae by shaking of the plants. The pest population and yield data were subjected to ANOVA for two factor RBD with the IPM module as factor 1, intercrop as factor 2 and the individual farmer as replicate.
Weekly insect counts were recorded from ten randomly labelled castor plants in each plot at various stages of crop growth in the on-farm and on-station experiments. Three terminals per plant were selected. Field observations of insect pest and predator (coccinellids and spiders) populations were recorded during the cool hours of the day (7 to 9.30 am and 4 to 6 pm) as per 8 standard procedure (Pradhan, 1964). The percent parasitism by Microplitis macule Pennis was estimated by collecting 20-25 neonate larvae of semi looper from each intercropping system at fortnight intervals and mean of six observations was presented and later average of two years was given in this bulletin.
Data on microclimate variables were also recorded at weekly intervals to measure differences in microclimate among intercrop canopies. Canopy temperature (Tc) and canopy air temperature differential (CATD) were recorded from three locations in each plot, using Teletemp AG-42 Infrared Thermometer *. Relative humidity within crop canopy was determined by using Digital Psychrometer at regular intervals (Kumar et al, 1999).(*Not the recommendation of Institute) The data on the weekly observations on pest incidence, natural enemies, weather parameters etc was subjected to ANOVA as applicable (Gomez and Gomez, 1984).
The yield data were further used to construct various indices such as Competitive Ratio (CR), Aggressivity (A), Relative Crowd Coefficient (RCC), Land Equivalent Ratio (LER) against which the treatments were evaluated using standard procedure (Rao and Willey, 1980). Economic analysis was done by considering the market prices of the inputs used and farm harvest prices (FHP) of the crops concerned.
“Central Research Institute For Dryland Agriculture.” Central Research Institute For Dryland Agriculture. N.p., n.d. Web. 05 Sep. 2017 <http://www.crida.in/Bulletins/Castor.pdf>.
Central Research Institute For Dryland Agriculture.(n.d.). Retrieved from http://www.crida.in/Bulletins/Castor.pdf
- Central Institute of Dryland Agriculture