Rotation of Onion and Potato and it's Effect on Yield and Soil Organic Matter

In three years rotation systems each field divided to two parts and 1st part cultivated with onion and potato and second part kept fallow. In 2nd year onion cultivated on potato and vice versa and fallow plots went under potato planting. In the 3rd year, onion cultivated on onion and potato planted on potato and onion. So fallow-onion, fallow-potato, onion-onion, potato-onion, onion-potato and potato-potato rotation systems were studied. Results showed that potato-onion rotation increased significantly bulb yield by producing jumbo bulbs. Tuber yield in fallow-potato was high because of more coarse seed tubers. In onion-potato system, tubers were tiny and big tubers were less but jumbo. Second year fallow-potato seed and little tubers were more so their sizes become tiny. But in potato-potato fewer yields obtained because of three sizes less number and size. Potato increased soil organic carbon (OC) percentage. Following onion decreased OC and another potato increased OC again sharply. OC changes in fallow year plots showed minimum change but in second year planting potato increased OC more than onion. Fallow-potato-potato system increased OC from second year end, but potato-onion-potato system showed decrease after increase and onion-onion-onion increase OC constantly.