Relationship between growth and yield of toria (Brassica rapa var napus) with thermal indices under residue management and sowing practices in hill ecosystem of north-eastern India
2012
Saha, R | Ghosh, P K
The interdependence of growth and yield of toria [Brassica rapa (L) Thell. emend. Metzger var napus L.; syn B. campestris L. ssp oleifera (Metzger) Sinsk. var toria] with thermal indices under various residue management treatments was evaluated under hilly agro-ecosystem of Meghalaya. Field experiments were conducted in toria crop during 2006–08 with two types of tillage practices (conventional and conservation tillage), three dates of sowing (early, mid and late October) and four residue management treatments, viz. Control (no residue);M0, maize stalk cover (MSC); M1, MSC + locally available weed, Ambrossia sp. @ 10 tonnes/ha; M2 and MSC + farmyard manure (FYM) @ 10 tonnes/ha; M3. The thermal indices, viz. accumulated growing degree days (GDD), heat-use efficiency (HUE) were computed for seed yield as well as total dry matter of toria and simultaneously regression equations between yield parameters and thermal indices were developed. Irrespective of tillage treatments, accumulated GDD was 22% higher in early sowing as compared to late sowing and contributed to lowest toria seed yield in early-sown condition. The highest HUE of 9.77 and 8.44 kg/ha/°C day for dry matter and 1.45 and 1.52 kg/ha/°C day for seed yield was recorded in M2 under conventional and conservation tillage practices, respectively. Significant linear relationships were observed between seed yield and total dry matter with heat-use efficiency. Therefore, mid and late October sowing with MSC + Ambrossia sp. @ 10 tonnes/ha; M2 was most efficient for getting better toria seed yield under hilly terrain condition of north- east India.
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