Isolation of Drought-Tolerant Endophyte Bacteria From Local Tomato Plants.

<b>Background and Objective:</b> Exploration of drought-tolerant endophytic bacteria is significant to identify bacteria that can provide plant resistance to drought stress. This study aims to obtain the potential of endophytic bacteria to promote plant growth from tomato plants in dry land. <b>Materials and Methods:</b> Exploration of endophytic bacteria from healthy tomato plants in a dry and rocky land, Muna Regency, Indonesia. Selection of drought-tolerant endophytic bacteria using polyethylene glycol 6000. Selected isolates were tested to increase the viability of tomato seeds using a Completely Randomized Design (CRD). <b>Results:</b> There were 123 isolates of endophytic bacteria isolated from the roots and stems of local tomato plants in a dry and rocky land, Muna Regency, Indonesia. There were 39 (31.70%) isolates sensitive to drought, 55 (44.71%) isolates very sensitive to drought, 8 (6.50%) isolates tolerant to drought and 21 (17.02%) isolates very tolerant to drought. Dryness for the maximum polyethylene glycol concentration at osmotic pressure of -2.00 MPa. Inoculation of endophytic bacteria in local tomato seeds increased the viability and vigour of local tomato seeds compared to the absence of endophytic bacteria. Of the 21 isolates of drought-tolerant endophytic bacteria, there were 12 potential isolates in increasing the viability of local tomato seeds belonging to the <i>Pseudomonas</i> sp. and <i>Bacillus</i> sp. bacterial groups. <b>Conclusion:</b> <i>Pseudomonas </i>sp. and Bacillus sp. isolates identified the endophytic bacteria, which can be drought-tolerant and increase tomato seeds' viability.

Cover Crop Residue Effects on Soil and Corn Performance in Ex-Nickel Mining Soils.

<b>Background and Objective:</b> The use of cover crop residue for improving soil quality has been widely applied. Nevertheless, the effectiveness for improving ex-mining soil quality and crop performance at ex-mining soils is rarely documented. This study investigated the effect of cover crop residue on soil quality enhancement and corn production established in ex-nickel mining soils. <b>Materials and Methods:</b> An experiment comprising three treatment of cover crops residue, including <i>Eleusine indica, Centrosema pubescens</i> and <i>Calopogonium mucunoides</i>, arranged in a completely randomized design with three replications. The soil improvement process was evaluated by several parameters, such as soil acidity, soil organic carbon, total nitrogen, exchangeable potassium, exchangeable magnesium and heavy metals. On the other side, corn's growth performance was assessed using some attributes, i.e. height, diameter, total leaves, leaf area and biomass accumulation. <b>Results:</b> The results demonstrated that the cover crops residue had the potential to improve ex-nickel mining soil quality. The highest soil improvement was recorded in total nitrogen (700-800%). The treatments also showed a positive advantage to reduce heavy metals content, particularly for Fe, Mn and Zn by approximately 51.58-85.74%. No significant difference in corn growth performance was found in this study (p>0.05). However, the utilization of crop residue from <i>Calopogonium mucunoides </i>exhibited relatively higher total biomass than other treatments by around 3.08±1.99 g plant¹. <b>Conclusion:</b> Despite the treatments had no significant effect on corn performance. This study realized that cover crop residue could improve soil conditions for providing better environmental conditions for agriculture development.

Analysis of Soil Water Balance to Determine Planting Time of Crops on Dryland, Indonesia.

BACKGROUND AND OBJECTIVE: Soil water mainly derived from rainfall is an important limiting factor to increase crop production. Water balance is used to see the availability of soil water for plants at a certain time. This study aims to determine water supplies, water use and potential water loss using plant water balance and designing cropping patterns on dryland in Ranomee to subdistrict. MATERIALS AND METHODS: The analysis of soil water's availability is presented through monthly graphs from January to December in climatological terms. The data used in this analysis are the average amount of monthly rainfall and the average monthly temperature in 2016-2018 from the Meteorological, Climatological and Geophysical Agency in South Konawe Regency representing the study area, Ranomeeto subdistrict and the land area of this district. Ranomeeto Subdistrict of South Konawe has a 7 month growth period, from the 2nd November to the 2nd July. RESULTS: Analysis of the contribution of surface water to soil water content in the plant root zone shows that the Ranomeeto subdistrict of Konawe Selatan Regency has seven months-long growth period available from the second decade of November to the second decade of July. CONCLUSION: The planting time in the Ranomeeto subdistrict is in two periods of time, which is in November of decade three to February of decade three (during the rainy season) and May of decade one to July of decade one (during dry season).