RESPONSE OF AN IDEOTYPE OF CLUSTER ONION ( ALLIUM CEPA L . VAR . AGGREGATUM ) TO FARM AND ANIMAL WASTES

In Tamilnadu, Ariyalur district contributes a major share of cluster onion production. An ideotype popular among the growers of this locality is preferred by consumers of entire state for its size, storability and taste. Hence the present investigation was carried out the in a farmer’s field at Vennallur located in Ariyalur District during 2017. The experiment was laid out with seven treatments in randomized block design. Each treatment was replicated thrice. The treatments included three kinds of practices adopted by the farmers of the tract and four others where bulky organic manures (Vermicompost, Poultry manure) and concentrated organic manures (Neem cake and Groundnut cake) were substituted on ‘N’ equivalent basis, along with biofertilizers (Azospirillum and Phosphobacteria) and foliar spray of Panchakavya (3%). All the four treatments with organic inputs (T4 to T7) gave better results, when compared to farmer’s practice (T1 and T2). Though T3 was the best, incorporation of Poultry manure+Neem cake (T6) and Poultry manure+Groundnut cake (T7) along with Biofertilizer+Panchakavya 3 % improved the yield significantly in order.


INTRODUCTION
Cluster onion (Allium cepa L. Var.aggregatum, 2n = 2x =16, family: Alliaceae) is one among the important vegetable crops cultivated in India.In India, it is grown in an area of 8.34 lakh hectares with an annual production of 135.65 lakh tonnes [1].India ranks second in the world after China by contributing 12.30 per cent to the world production.It is semi-perishable in nature and can be transported to a long distance without much injury.India exports onion to countries like Malaysia, Russia, Kuwait, SriLanka, Singapore, Germany, Japan, Iran, Myanmar and U. K. [2].
There are many issues related to the cultivation and production of onion in India, like nutritional disorders.The continuous and imbalanced use of chemical fertilizers is adversely affecting the agricultural production [3].Organically produced crops possess better biochemical and physical quality in onion without much compromise on yield statistics [4].So the present study was designed to investigate the effect of organic manures on the growth and yield of aggregate onion.

MATERIALS AND METHODS
A field experiment entitled "Response of an ideotype of cluster onion (Allium cepa L. Var.aggregatum) to farm and animal remains" was conducted in a farmer's field at Venanallur located in Ariyalur District during the year 2017.
Twenty randomly selected plants in each plot were tagged for recording observations on growth and yield parameters such as plant height, number of leaves per plant, number of root plant, root length plant, number of bulblets/clump, bulb diameter, yield (kg/plot), yield (t/ha).These parameters where recorded at harvest (ie) during 90 DAP.The observations recorded were statistically analysed [5] and results are presented in table 1.

RESULTS AND DISCUSSION
All treatments exhibited significant differences among themselves.Treatments T4 to T7 with organic inputs gave better results when compared to farmer's practice (T1 and T2).Organic manure in the improvement of soil fertility and productivity, acknowledged for generations would have helped in the plant metabolic activity through the supply of important nutrients besides micronutrients in promoting the vigorous growth.The organic manures derived from biological sources like FYM, Vermicompost, Poultry manure, Oil cakes, Panchakavya are thus effective in enriching the soil and supporting the activities of microbes [6].
Further, results reveal that incorporation of Poultry manure+Neem cake (T6) and Poultry manure+Groundnut cake (T7) along with Biofertilizer+Panchakavya 3 % improved the yield significantly in order, though T3 was the best.The highest yield obtained by incorporating poultry litter collaborates with the previous findings [7].Treatments T4 and T5 produced yield which were significantly on par.The improvement in number of leaves, plant height, bulb diameter in the respective treatments might be due to the availability of vital macro and micronutrients in Vermicompost.Shobha and Pappiah [8] also were of opinion that application of Vermicompost is very effective in yield improvement of onion.
Though T3 was best due to the quick release of nutrients from the optimum level of chemical fertilizers; the study can be concluded stating that growth and yield of cluster onion in the tried ideotype of Ariyalur District can be significantly improved due to incorporation of Poultry manure (0.6 t/ha), Neem cake (0.57 t/ha)+Azospirillum and Phosphobacteria each @ 2 kg/ha+Panchakavya (3%).Repeated usage of such inputs over a few years would establish the merits of using organic nutrients in terms of sustainability; since the yield differences between T6 and T 3 amounts to less than 5 per cent.