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ThesisItem Open Access Concurrent growing of green manure crops in dry and wet seeded rice(Department of Agronomy, College of Horticulture, Vellanikkara, 2008) Anitha, S; KAU; Jose, MathewAn investigation entitled ‘Concurrent growing of green manure crops in dry and wet seeded rice’ was conducted at Agricultural Research Station, Mannuthy to develop a comprehensive technology package for the system of concurrent growing of green manure crops in direct seeded rice. The investigation consisted of four experiments viz., Experiment Ia - Concurrent growing of green manure crops in dry seeded rice, Experiment Ib - Residual effect of concurrent growing of green manure crops in dry seeded rice, Experiment IIa - Concurrent growing of daincha in wet seeded rice and Experiment IIb - Residual effect of concurrent growing of daincha in wet seeded rice. The experiment on concurrent growing of green manure crops in dry seeded rice consisted of two green manure crops (horse gram and cowpea), three methods of incorporation (Incorporation by cono weeder, desiccation by 2,4 - D spray @1.0 kg ha-1 and allowing for self decomposition) and two levels of nitrogen (100 and 75% of recommended N) and a control without green manure crops . Among the two green manure crops, cowpea was the best in supplying the required quantity of green matter with 25 per cent savings of N fertilizer and a substantial reduction in weed incidence. All the three methods of incorporation were found to be equally effective. Hence in places where there is a difficulty in self decomposition, cowpea can be effectively incorporated by conoweeder or by spraying 2, 4-D. The cowpea variety used in this study was a short duration bush type variety facilitating additional pod yield from cowpea before it was incorporated. Concurrent growing of cowpea along with dry seeded rice is a viable system as it resulted in increased productivity, profitability and sustainability dry seeded rice. In the experiment to study the residual effect of concurrent growing of green manure crops in dry seeded rice, the main plots of dry seeded rice crop during the 1st crop season were divided into two sub plots and applied 100 and 75 per cent N to the subplots. The results revealed that concurrent growing of green manure crops were effective in increasing the yield and sustaining soil fertility status compared to pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. But there was no savings of N fertilizer to the succeeding transplanted rice crop as the highest yield of succeeding rice was achieved only when it received 100 per cent of the recommended N. The profitability of the rice- rice cropping system was the highest with concurrent growing of cowpea in dry seeded rice. The experiment on concurrent growing of daincha in wet seeded rice consisted of two stages of incorporation of daincha (20 DAS and 30DAS), three methods of incorporation (Incorporation by cono weeder, desiccation by 2, 4 - D spray @1.0kg ha-1 and Desiccation by Chlorimuron ethyl+ met sulfuron methyl spray @ 4.0 g ha-1 met sulfuron methyl spray @ 5 g ha-1) and two levels of nitrogen (100 and 75% of recommended N) and a control without daincha. Results indicated that concurrent growing of daincha can be successfully practiced in wet seeded rice with improved productivity. Incorporation of 30 days old daincha employing any of the three methods of incorporation was equally effective in increasing the productivity and profitability of wet seeded rice. Incorporation of daincha at 30 DAS could add about 14 t ha-1 of green matter with minimum investment and resulted in 70 per cent weed suppression. Concurrent growing of daincha receiving both 100 and 75 per cent of recommended N produced significantly higher yield than pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. Hence there was a saving of 25 per cent N without affecting the yield. The highest yield was obtained when 100 per cent of recommended N was applied to the system. The treatments for the experiment to study the residual effect of concurrent growing of daincha in wet seeded rice were similar to that of dry seeded rice. The results showed that concurrent growing of daincha and its incorporation at 30 DAS was effective in increasing the yield of succeeding rice and sustaining soil fertility status compared to pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. The highest yield of succeeding rice was achieved only when it received 100 per cent of the recommended N hence there was no savings of N fertilizer to the succeeding transplanted rice crop. Concurrent growing of daincha in wet seeded rice increased the profitability of the rice- rice cropping system. Concurrent growing of green manure crops in dry and wet seeded rice is a management alternative to reduce the production cost and to increase the yield of rice and is a practical model for sustainable rice production.ThesisItem Open Access Performance of summer crops in rice fallows and its effect on succeeding transplanted rice(Department of Agronomy, College of Agriculture, Vellayani, 2009) Shrikant P, Golabhavi; KAU; Latif, P HA field experiment entitled “Performance of summer crops in rice fallows and its effect on succeeding transplanted rice” was taken up at the Cropping systems research station, Karamana, Thiruvananthapuram during February 2008 to October 2008 that covered the summer (third crop) and virippu (the first crop) seasons of rice cultivation. The main objectives of the experiment was study the performance of different upland crops in the summer rice fallows of southern Kerala in terms of resource utilisation, yield, soil health and carry over effect on succeeding rice crop, and to arrive at a sound practice of summer rice fallow utilization. The experiment was laid out in a randomised block design with three replication and seven treatments (T1 - Control or summer rice fallow, T2 - Sweet potato, T3 - Pumpkin, T4 - Sesamum, T5 - Amaranthus, T6 – Cowpea and T7 - Daincha) which were followed by rice crop in the virippu season. Al the crops were raised as par the KAU package of practices recommendations. Results of the study revealed that there was a significant variation in the composition of weed flora of summer crops and the succeeding rice crop. The associated weed species of summer crop also varied significantly. Cowpea (T6) being grown on pandal had no weed separation effect and hence had the higher WDMP and SDR. Amaranthus (T5) recorded the highest economic yield and rice yield equivalent, water productivity, net profit and B:C ratio. However, sweet potato (T2) recorded the highest energy yield per unit area and highest nutrient uptake of macro and micro nutrients. The nutrient balance sheet showed a general negative balance for N and P except for sweet potato (T2) and Daincha (T7) where as K showed a negative balance for all treatments. The succeeding rice crop was not significantly influenced by the summer crops with respect to yield and yield attributes. The post rice soil was left less acidic by pumpkin-rice sequence, where as Daincha-rice significantly increased the soil acidity. The post rice soil significantly varied in the available P and K with the highest value noted in Amaranthus-rice (T5). Significantly higher quantity of Zn was recorded in Daincha-rice (T7).ThesisItem Open Access Standardisation of organic manures and effect of microbial inoculants on growth, yield and quality of kasthuri turmeric(Curcuma aromatica Salisb.)(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 2009) Nirmalatha, J D; KAU; Sulekha, G RThesisItem Open Access Ecofriendly management of weeds in rice(Department of Agronomy, College of Horticulture, Kerala Agricultural University, Vellanikkara, 2008) Sindhu, P V; KAU; George Thomas, C