Impact of faba bean (Vicia faba L.) cultivation on soil microbiological activity

L. Dubova*, I. Alsiņa, A. Ruža and A. Šenberga

Latvia University of Life Sciences and Technologies, Faculty of Agriculture, Institute of Soil and Plant Sciences, Liela Street 2, LV-3001 Jelgava, Latvia
*Correspondence: laila.dubova@llu.lv

Abstract:

Faba bean (Vicia faba L.) is widely grown not only as an important protein source for food and feed, but as a component in different cropping systems to improve soil quality. Beans are grown using different soil management practices, moreover, legume seeds often are inoculated before sowing. Microorganisms, introduced in the soil as an inoculum, affect not only inoculated plants, but these microorganisms can remain in the soil for the next growing season and can also affect the subsequent crops. Seed inoculation can stimulate production of root exudates as well as change microbial diversity and structure. The aim of the present study was to estimate the soil microbiological activity in soils where faba beans were cultivated with different rhizobia inoculants obtained from collection of Latvia University of Life Sciences and Technologies. Another trial was established where faba beans were included in different crop rotations under two tillage systems. During both trials, soil microbiological activity was analysed. Soil respiration intensity was measured by changes of carbon dioxide. Soil enzymatic activity was assessed by dehydrogenase activity and fluorescein diacetate (FDA) hydrolysis intensity. The total number of bacteria, fungi and rhizobia was expressed as colony forming units (CFU) g^-1 dry soil. Soil microbiological activity depended on the cultivated crop and the crop rotation. Faba bean inoculation method had less impact on the ratio between analysed microorganism groups than on the activity of soil enzymes.

Key words:

Performance of groundnut (Arachis hypogaea Linn) under nitrogen fixing and phosphorus solubilizing microbial inoculants with different levels of cobalt in alluvial soils of eastern India

Manisha Basu¹* and P. B. S. Bhadoria¹

¹Department of Agricultural and Food Engineering, Indian Institute of Technology,Kharagpur-721 302, West Bengal, India
*Corresponding author: 1Department of Agricultural and Food Engineering,Indian Institute of Technology, Kharagpur-721 302, West Bengal, India;e-mail: basu.manisha@gmail.com; tel.: +919732654642

Abstract:

A field experiment was conducted for three years to evaluate the performance of groundnut under alluvial soil of eastern India with different types of inoculants such as Rhizobium and phosphobacterium inoculants, no inoculant, and different levels of cobalt ( 0.21 and 0.42 kg ha-1). Results indicated that Rhizobium inoculant promoted higher yield and nutrient uptake as compared to phosphobacterium. Kernel yield, averaged across three levels of cobalt, was recorded to be highest for Rhizobium inoculant, which was 16.50% and 10.72% higher over no inoculant and phosphobacterium inoculant respectively. Cobalt at the rate 0.21 kg ha-1 proved to be better as compared with other doses of cobalt and resulted in 10% higher kernel yield over no cobalt application. Among different treatment combinations, integrated application of Rhizobium + cobalt at the rate 0.21 kg ha-1 resulted in greater yield than that of other combinations, followed by phosphobacterium inoculant with the same dose of cobalt application. The yield and uptake of N, P and K by groundnut was significantly higher in the treatments receiving both inoculants and cobalt applied at 0.21 kg ha-1 than individual application of either inoculants or cobalt. The beneficial effect of application of microbial inoculants and cobalt was also reflected on the soil fertility status.

Key words:

Arachis hypogaea, cobalt, kernel yield, phosphobacterium, Rhizobium