India is a vast country with 329 million hectares of geographical area with agriculture still as a main occupation of 70 per cent of Indian population. Weeding is an essential operation in agriculture to prevent undesired species from growing and consuming the key resources (i.e. water, minerals, soil and sunlight) and thereby compromising crop yield. Farmers spend a large amount of time and money managing weeds. Weeds are always associated with human endeavors and because huge reductions in crop yields, increase cost of cultivation, reduce input efficiency, interfere with agricultural operations, impair quality, act as alternate hosts for several insect pests, diseases and nematodes. At a conservative estimate, an amount of Rs.100 billion is spent on weed management annually in India, in arable agriculture alone. The rotary type weeder stirs the soil more accurately, disturb the weed root and remove them from soil. In addition this helps in keeping the soil in loose condition for proper aeration. The major advantage of rotary power weeder is power being used for rotary weeder blades requires less draft and improved field performance. A portable knapsack power weeder was developed with width of cut was 25 cm and tested in chilli crop with number of blades per flange (2, 4 and 6). Operational speed, actual field capacity, field efficiency, weeding efficiency, plant damage, actual working depth of cut, fuel consumption, performance index of (2,4,6 blades per flange) was 0.43, 0.40 and 0.38 m/s, 0.029, 0.027 and 0.

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An investigation is carried out to analyze the underground water quality of 26 villages in Bapatla mandal for their quality parameters and comprehensively arriving at a single water quality index. The irrigation water samples were collected manually from the bore wells which are approximately equally distributed all over 26 villages of Bapatla mandal. The samples were analyzed using standard procedures in the laboratory (APHA, 1985). The parameters analyzed during the analysis are pH, EC, Chlorides, Calcium, Magnesium (Mg), Total Dissolved Solids (TDS), Total Hardness (TH). The final output has been given in the thematic representation of irrigation water quality attributes using SURFER 7.0 for individual as well as weighted Water Quality Index. From the investigation, it is clearly evident that the groundwater of the area needs some degree of treatment before consumption. Based on the investigations carried out, it is observed that Asodivaripalem, West Bapatla, Cheruvujamulapalem, Murukondapadu, Muthayapalem, Maruproluvaripalem and Vodarevu villages contain water quality very poor for irrigation purpose due to over salt accumulation. Necessary measures are to be taken to gain safe irrigation and drinking water to the people living in the villages. Total hardness was found to be very high in Murukondapadu, and Muthayapalem villages. Very high concentrations of chloride, calcium and magnesium were found in West Bapatla, Cheruvujamulapalem, Murukondapadu and Muthayapalem villages. The water quality is good in Jillelamudi,

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The knowledge of physical and mechanical properties of onion bulb is important for successful design of any planter. Multiplier onion is propagated through bulbs and bulbs are planted manually. Manual planting of onion bulb is highly labour intensive (80-100 man-days ha-1) due to the close plant geometry (plant to plant and row to row spacing is 10 × 15 cm) among the vegetable crops. Engineering properties of multiplier onion were determined in order to design and develop a tractor operated raised bed onion bulb planter. In multiplier onion each onion comprises of 4-5 bulbs. These bulbs were cleaned, separated into single bulbs and divided in to 9 categories manually based on their individual weight viz., <2g, 2-3 g, 3-4 g, 4-5 g, 5-6 g, 6-7 g, 7-8 g, 8-9 g, >9 g. The onion bulb had a moisture content of 80.62±0.87 %. It was observed that the properties varied for different sizes of onion grades and the grades had highly significant effect on most of the properties. The linear dimensions of onion bulbs viz., length, width, thickness for nine grades ranged from 21.21±2.60 to 32.31±3.30 mm, 13.54±1.77 to 30.95±2.91 mm and 10.91±1.40 to 22.63±2.15 mm. The geometric mean diameter, sphericity, shape index and projected area all ranged from 28.22±2.04 to 14.54±0.96 mm, 0.87±0.06 to 0.69±0.08, 1.78±0.32 to 1.22±0.14 and 5.50±0.51 to 1.55±0.30 cm2, respectively. The one hundred onion bulb weight, bulk density, true density were in the range of 1185±19.59 to 121.6±6.30 g, 793.20± 9.45 to 480.19±13.13 kg.m-3, 1086± 205.22 to 1013.6±348.85 kg.m-3, respectively. The angle of repose decreased with increase in size of onion bulbs. The interaction between sphericity, shape index and angle of repose indicated that as the size of the onion size increase angle of repose decreased.