Evaluation of seed germination of Jatropha curcas L. under influence of soil texture modification, nutrient amendment and PGPR inoculation

Abstract

In India massive tracts of land (20.17% of total geographical area) found as wasteland accounting for about 63.85 M ha. The total degraded area in Gujarat state is 3,129 thousand ha which is about 16% of total geographical area. Wastelands are the degraded soil, the degradation of soil is due to extreme weather condition and human activities. To overcome this problem the reclamation of wasteland is one of the wise ideas. Wastelands can be reclaimed by making it suitable for plant seed germination and plantation. Due to high concentration of salt in wasteland it can only be reclaimed by halotolerant plant. As per the past researches few halotolerant plant were accepted to recover the wastelands includes Jatropha, Castor, Pongamia pinnata etc. hence the aim of this study was to make possible the Jatropha plant seed germination on wasteland by changing its texture and by applying required nutrients. The study was initiated with soil sample collection. Virgin soil and wasteland soil were selected for study. Wasteland sampling site was Pipli village under Bhavnagar district, Gujarat and virgin soil was collected from Nirma University region of Ahmedabad. Physicochemical parameters of both the soils were inspected to check the soil fertility. After determining all of the parameters it can be said that wasteland of our interest is hyper saline in nature. As the soil texture is an important characteristic of soil which affects the most to the plant growth was analysed. By using the textural triangle the wasteland was clay loam while the virgin soil was sandy loam. It is assumed and experimentally proved that wasteland soil without any amendment or modification could not support germination of Jatropha curcas. Soluble phosphate concentration was also determined of both of the soils and phosphate rich samples (TCP, RP, and SP) and then amendment percentages were decided for 200 g of system. Wasteland is degraded soils which is nutrient deficient and possess very low microbial activity. To make the wasteland nutrient rich the required nutrients were supplemented to the soil in the concentration of 50 g RP, 17.54 g TCP, 0.68 g SP, 20 mg Zn to the 200 g of soil system and was prepared different combinations. Without any nutrient supplements the soils were used as a control. After 26 days of incubation the supreme seed germination and growth was found in the combination of TCP+ZN+VS and wasteland was also proposed the seed germination of Jatropha in the combination of TCP+ZN+WL. It can be said that the nutrient 51 which has been added to soil to improve soil fertility is giving a positive effect on plat seed germination and growth parameters like shoot length, root length, leaf numbers. Soil samples were also studied with texture modification. Soil texture modification can be done by many types of organic manure. Hence the Coco coir organic manure was used to modify the soil texture, along with the best resulted nutrient supplements. Coco coir was used in the ratio of 1:4. Texture modification was affected positively on Jatropha seed germination and plant growth parameters such as root length, shoots length, leaf number. Wasteland is uncultivated and unhabituated soil due to the low microbial activity. PGPR are the microorganism which helps to improve soil fertility. Previously studied PGPR strains 10WL, 14WL, and 38WL were used to induce the potency of wasteland. Specified combinations from nutrient supplement and texture modification were used to inoculate the PGPR. Seed germination of Jatropha was affected positively by PGPR. Soil respiration activity was measured constantly throughout the study to check the fluctuation in microbial activity. From the study of evaluation of seed germination of Jatropha curcas L. under the influence of soil texture modification, nutrient supplement along with PGPR inoculation it can be concluded that Jatropha curcas L. plant can be grow on the wasteland if it gets sufficient and required nutrients and other environmental conditions with appropriate microbial activity