Application of systems modeling to explore options for crop intensification of sole peanut system in Anantapur region of Andhra Pradesh, India.
Background
Monocropping of peanut is practiced on Alfisols of predominant peanut belt in the Peninsular India comprising of Anantapur (0.7 m ha) and adjoining parts of Kurnool (0.25 m ha), Cuddapah (0.16 m ha) districts of Andhra Pradesh, and Kolar (0.1 m ha) district of Karnataka. Length of crop growing season that varies between 100-135 days, is constrained by low and erratic rainfall (mean annual rainfall of 567 mm and crop season rainfall of 480 mm), and low water holding capacity (44-105 mm) of the soils. Crop failure due to drought at least twice in five years is a common feature. Although monocropping of peanut is leading to the build up of pests and diseases, replacing the same with other crops is not readily acceptable to farmers of this region.
Intercropping of peanut with medium duration pigeonpea at 7:1 row ratio is recommended by NARS for Anantapur region. However, our survey in this region during 1995 on prevailing cropping systems revealed that 91% of the peanut farmers preferred to have peanut as sole crop. The two main reasons cited for non-adoption of the intercrop system are:
- Reduction in peanut yield: In the 7:1 intercrop system, pigeonpea replaces one row of peanut in every eight rows with corresponding reduction in peanut yields
- Medium duration of Pigeonpea varieties: The pigeonpea varieties currently grown are of medium duration (>160 days) and the probability of these varieties suffering from terminal stress is very high.
It is therefore hypothesized that a system involving no reduction in the yield of peanut and a short duration pigeonpea variety that escapes terminal stress is acceptable to the farmers. Hence, efforts are being made using APSIM (Agricultural Production Systems sIMulator), a cropping systems simulation model, to explore various options for a profitable peanut/pigeonpea intercrop system. The model predictions were later evaluated on farmers' fields in two villages of Anantapur region.
Simulated estimates vs. observed yields of Peanut systems:
Preliminary, long-term APSIM simulation scenarios were made on sole peanut and peanut/ short duration pigeonpea intercrop systems using the weather data of Anantapur (1962-1999). The simulations were made on three different soil profiles (30, 60, 90 cm deep) having 44, 78 and 110 mm plant available water holding capacities. Productivity of Sole peanut and peanut and pigeonpea intercrop systems under different plant densities, inputs and management practices was simulated using APSIM (ver.1.60) crop parameters for "early bunch" peanut cultivar and "short duration" pigeonpea to get preliminary information on optimum combination of these crops. Mean yields estimated in preliminary simulations are presented in table 1. The modeled results showed yield advantages due to intercropping with short duration pigeonpea when compared with sole peanut system in this region.
Table 1. APSIM simulated mean seed yields of sole peanut and peanut intercropped with short-duration pigeonpea system for different soil types. |
Soil type (Alfisols) |
Sole peanut pod yield (Kg ha -1 ) |
Peanut pod yield (kg ha -1 ) in the intercrop system |
Pigeonpea yield (kg ha -1 ) in the intercrop system |
Yield advantage (peanut equi. Kg ha -1 ) |
Shallow (~30 cm) |
694 |
606 |
215 |
200 |
Medium deep (~60 cm) |
856 |
721 |
275 |
233 |
Deep (~90 cm) |
1029 |
932 |
458 |
516 |
Trails to verify the model predictions under different management options were conducted on 24 farmers' fields during the crop season 2000/01 in Krishnamreddypally and Pampanur villages of Anantapur region. Sole peanut (TMV-2) and peanut intercropping systems with four short duration pigeonpea varieties (Manak, UPAS-120, ICP-88034, Durga) were evaluated on fields falling in the 30, 60, and 90 cm soil depth categories. A planning workshop involving farmers, scientists and extension specialists held at Agricultural Research station, Anantapur helped in designing the trials. As a result of preliminary long-term APSIM simulation scenarios, it was considered necessary to maintain peanut population around 240 thousand plants ha -1 in the intercrop system, that was as much as in sole peanut system, while the intercropped pigeonpea population would be around 90-120 thousand plants ha -1 based on soil depth. Intercropping of peanut and short duration pigeonpea were sown at 3:1 ratio at an inter-row distance of 30 cm (picture 1), as per modeled estimates.
Picture 1. Peanut intercropped with short duration pigeonpea at 3:1 ratio successfully grown on farmer's field in Anantapur district of Andhra Pradesh during 2000/01-crop season.
Based on the available nitrogen estimates from individual farmer's field, three cropping system treatments (1). Sole peanut with farmer-applied inputs, (2). Peanut intercropped with short duration pigeonpea and nitrogen application to supplement and make-up to recommend dose of nitrogen (30 kg N ha -1 ) based on soil test data, and (3). Intercrop with short duration pigeonpea and farmer-applied inputs were setup. Rainfall received during the crop season (1 st June to 31 st December) was about 509 mm in Krishnamreddypally and 436 mm in Pampanur.
Peanut harvest data collected from 24 farmers' fields have been statistically analyzed considering factors as in split-plot analysis of variance (ANOVA) for yield attributes like biomass, pod yield and plant population. Mean of biomass produced, ranged between 1929 and 2685 kg ha -1 , and mean of pod yields varied between 941 and 1313 kg ha -1 across soil depth and crop treatments. Peanut pod yield, biomass and plant population were significantly affected by cropping systems, but not by the soil depth. Intercropped short duration pigeonpea biomass and grain yield were significantly different across pigeonpea cultivars, however, contrary to initial estimates by model (table 1), soil depth had no impact. It might have happened because pigeonpea plants were able to extract water from much deeper gravely layers of these soils, while we limited soil depth, plant available soil water and root extraction up to the visible rooting depth. On-farm observation of required plant densities in the intercrop of peanut/short duration pigeonpea are in agreement with APSIM simulated estimates required to provide economic yield advantage to the farmer. However, the mean yields of the intercrops simulated by the model are lower than the observed yields of the intercrops for the crop season 2000/01.
Systems productivity and economic yield advantage of intercropping:
Peanut pod yields recorded in most of the farmers' fields are higher with sole system compared to intercrop system as the population of peanut in the intercrop was not up to the suggested plant density. However total system productivity is higher in the intercrop system in the farmers' fields, where required plant population of peanut and pigeonpea was maintained. Figure1 depicts yield of sole peanut and peanut intercrop system with Durga and ICP-88034, short duration pigeonpea cultivars. Peanut yields in sole and intercrops were mostly correlated with density of peanut population, while pigeonpea grain yields varied widely because of the damage by flower-eating blister beetles ( Mylabris pustulata ) and gram pod borer ( Helicoverpa sps ) besides lower plant population density.
Figure 1.Yield of peanut (sea green fill) and short duration pigeonpea (orange fill) in the intercrop systems as against peanut sole crop system on farmers' fields in Anantapur region of Andhra Pradesh, India during 2000-2001 rainy season.
Short duration cultivars of ICRISAT origin (Durga and ICP-88034), found farmers' preference over the other two cultivars, for better yields, bold seed type and suitable duration (125-135 days). Yield advantage was observed with 15 farmers out of 22 farmers who established intercropping treatments at 3:1 ratio. The price ratio of peanut to pigeonpea compiled from the prices of these commodities in Andhra Pradesh markets is 1:1.34. As per these prices, the gains by 10 farmers are in the range of 217 to 648 kg ha -1 of peanut yield equivalent with recommended dose of nitrogen.
Lessons from first season's field demonstrations:
Since there was a problem with pigeonpea plant establishment due to the attack by ash weevil on germinating pigeonpea plants, protective measures at that stage are critical to have optimum pigeonpea plant stand. Control measures like hand picking and destroying of flower eating blister beetles at regular intervals during flowering stage is also required. Peanut seed rate should be aimed at attaining a peanut population of around 240 thousand ha -1 in the intercrop. Peanut stem necrosis that affected sole peanut in Anantapur district (picture 2)
Picture 2. A clipping from local newspaper that reported farmers uprooting stem necrosis affected peanut crop during the crop season 2000/01 in Anantapur region.
During the crop season, had not caused significant damage to peanut in peanut/pigeonpea intercrop. Farmers agreed that intercropping system would provide minimum crop assurance in the event of total failure of peanut.
Conclusions
Intercropping of peanut with short duration pigeonpea was found to be suitable for the region as explored by APSIM simulations, in terms of utilizing the natural resources, and proved to be economically viable in majority of the farmers' field demonstrations in Anantapur district during 2000/01. Although, there is wider variability across farmers' fields, ten farmers who tested peanut/pigeonpea intercrop at 3:1 row ratio observed yield advantages ranging from 217 to 648 kg of peanut equivalent yield. These results need to be verified for one more season. Data collected from these field demonstrations indicated that there is scope for further refinement of peanut cropping systems to increase productivity and profitability.
Collaborators
Dr. D. Balaguravaiah, Dr. (Ms) Y. Padmalatha senior scientists, Agricultural Research Station (Acharya N G Ranga Agricultural University), Anantapur, Andhra Pradesh, India.
For more information please contact:
Mr.V.Nageswara Rao
Scientific Officer
and
Dr Piara Singh
Senior Scientist (Systems modeling),
ICRISAT-Patancheru 502 324.
