Drought management for sesame in Onattukara

Abstract

A microplot and a field trial were conducted at the Rice Research Station, Kayamkulam in the summer rice fallows during 1996 -97 to standardise the effective methanol dose and its time of application and to evaluate the effects of the selected dose of methanol along with varying levels of coirpith incorporation and seed hardening treatments on the performance of sesame var. Kayamkulam-I in Onattukara tract. The two experiments were laid out in completely randomised design and strip - split plot design with two and three replications respectively. The first experiment had treatments comprising of seven levels of methanol and three times of application along with an absolute control. The treatments in the second experiment included three levels each of coirpith and seed hardening treatments and four levels of methanol. The initial experiment revealed that the methanol application is well accepted by the crop. The growth characters, physiological parameters and yield attributing characters and crop duration were greatly enhanced by application of methanol dosages ranging from 20 per cent to 30 per cent concentration, during the flowering stage which is the most metabolically active stage of the crop. Thus the concentrations, 20 and 30 per cent of methanol at flowering stage was adopted in main field experiment.

In the main field, the crop responded to incorporation of coirpith, seed hardening and methanol application. The biometric characters like plant height, number of leaves and branches per plant, precarious flowering, total DMP, shoot - root ratio, root characteristics and yield attributing characters like number of capsules per plant, capsule yield were significantly augmented by the incorporation of 10 t ha-1 of coirpith soon after the harvest of second crop of rice. The above said parameters provided the maximum value with 20 per cent methanol level and seed hardening in water compared to other levels. These treatments enhanced the vegetative growth of the plants and facilitated early 'commencement of the reproductive phase thus enabling a significant reduction in crop duration by 6-7 days. The seed yield was remarkable when coirpith was incorporated at the rate of 10 t ha-1 and 20 per cent methanol spray was given to foliage at flower initiation period. The crop was favorably influenced by seed hardening in water. The uptake of N, P and K by the crop also followed improved. The relative leaf water content was highly regulated by both the coirpith levels (10 t ha-1 and 20 t ha-1) and seed hardening in water. The spraying of 20 per cent solution of methanol also recorded high leaf water content. The bulk density and soil water content were found highly depended on coil-pith levels. The application of both levels of coirpith

increased soil moisture content decreased the bulk density significantly. The values of both the parameters registered comparable effect of these levels. The biochemical analysis high proline content with treatments comprising of no coirpith. Seed hardening in water indicated high proline accumulation in plant tissues. The seed hardening in water also resulted in high content of chlorophyll in leaves. The organic carbon content of soil was greatly augmented by coirpith application, but both the levels gave comparable values. The available N, P and K contents of the soil after the experiment indicated higher nutrient status with addition of organic amendments to the soil. The outcome of economic analysis revealed that the net returns and benefit-cost ratio was maximum by incorporation of coipith at the rate of 10 t ha-1, seed hardening in water and providing foliar spray of 20 per cent methanol at flowering stage.