Macro- and Micronutrient Uptake in Rice + Cowpea Production System as Influenced by Mineral Nitrogen and Crop Population

The study was aimed at evaluating macro- and micronutrient uptake of rice and cowpea when grown in sole and mixture populations under varying levels of density (5x 104, 10x 104 and 20 x104plants/ha) and nitrogen (0,15,30 and 45kgN/ha), using urea as nutrient source. Results obtained showed that uptake of nitrogen increased with increasing rates of nitrogen fertilizer in both crops used for the study. In both sole and mixture populations, 45kgN/ha (50000plants/ha) and 30kgN/ha (200000plants/ha) recorded the lowest nitrogen uptake value of 0.12 and 0.14mg/plant respectively. Mean P uptake in the second in the cropping was reduced by 35.3% over the first cropping. Medium density of 100000plants/ha gave the highest K value of 0.45mg/ha during the first cropping. Uptake of potassium, phosphorus, sodium, calcium and magnesium and microelements were generally higher in cowpea than rice. Values of zinc uptake in shoots of both rice and cowpea were very low ranging from 0.00002 to 0.000075mg/plant in rice and 0.00011 and 0.0017mg/plant in cowpea. Increasing plant population density generally depressed uptake of both macro- and microelements in both rice and cowpea. Results from this study indicate that the high plant densities reduce nutrient uptake of crops, hence farmers should select optimum densities that will maximize crop nutrition and consequently yield. Keywords: nutrient uptake, cowpea, rice, nitrogen fertilizer, plant populatio

Agro-Economic Returns from Rice + Cowpea Intercropping Under Varying Nitrogen Rates

Field experiments were conducted in the cropping seasons of 2009 and 2010 at the Teaching and Research Farm of the Delta State University, Abraka (latitude 50 46’ and longitude 60 5’) in the wet humid rainforest of Southern Nigeria. The main aim of the experiment was to evaluate the agro-economic returns obtainable from the intercrop involving rice (Oryza sativa L.) and cowpea (Vigna unguiculata L. Walp) at varying levels of nitrogen fertilizer (0, 15, 30 and 45 kgNha-1). The mean yield of rice grown under sole cropping was higher than that intercropped with cowpea. Maximum rice grain yield of 2340.82 kg ha-1 and 1960.59 kg ha-1 in sole and intercrop respectively, were achieved with 45 kgNha- 1. Rice-cowpea intercrops with 30 kgNha- 1 gave the highest net returns of $628.72, high benefit/cost ratio, land equivalent ratio and monetary advantage index. From this study, it is inferred that intercropping of rice with cowpea at 30 kgNha- 1 is most likely to give higher income, increased use efficiency and thus enhancing sustainability of crop production than sole cropping of each crop species. Hence it is recommended for farmers to intercrop rice and cowpea and apply nitrogen at 30 kgNha- 1 in other to achieve optimum economic crop yield in upland rice based ecosystems. Keywords Monetary advantage index, benefit/cost ratio, rice, cowpea, nitrogen fertilize

Fuel Briquettes from Water Hyacinth-Cow Dung Mixture as Alternative Energy for Domestic and Agro-Industrial Applications

The processing of agricultural wastes into biomass is a strategy towards the development of alternative energy sources. The study was undertaken to investigate the properties of fuel briquettes produced from a mixture of a water hyacinth and cow dung. Briquettes were manufactured with a manually-operated briquette press using four water hyacinth: cow dung mixing ratios (by weight), i.e., 100:0; 90: 10; 80: 20; and 70: 30. Results obtained showed that briquettes produced using 70:30 and 80:20 water hyacinth-cow dung ratios respectively exhibited the largest relaxed density on drying with values of 1157 and 1296 kg/m3 respectively. Equilibrium moisture content (e.m.c) of the briquettes ranged between 10.5 % and 15.1%, with a gradual increase in e.m.c with increase in cow dung content. A reciprocal relationship was observed between compressed/relaxed density and relaxation ratio of the briquettes. The durability rating of all the briquettes exceeded 85%. Flue gas temperature ranged from 60.5 to 74.5 0C.  Comparative water boiling tests indicated that water was brought to boiling within the range of 54 to 59 minutes. It was concluded that stable briquettes could be formed from water hyacinth mixed with cow dung and can be used as alternative energy source to kerosene and fuel wood. Keywords: water hyacinth, briquette, cow dung, durability rating, bulk densit

Nutritional Composition of Residues Available for Ruminants from Rice + Cowpea Intercrop During the Dry Season in Nigeria

Chemical analysis to assess the mineral status of two fodder crops (rice and cowpea) was carried out. The range of P, K, Na, Ca and Mg values in the rice and cowpea plants met the minimum requirements for beef and dairy cattle and sheep/goats in this area. In rice plants, the level of crude protein (CP) met the marginal requirement, while CP values of cowpea were within the recommended requirements for ruminants in the area of study. Values of Fe and Zn were below minimum requirements while over 50% of the rice and cowpea plants had adequate Cu. Mineral supplements are suggested for correction of deficiencies in feed of ruminants in the area of study. Keywords: crop residues, mineral supplements, macro elements, microelements, ruminant

Nutritional Composition of Residues Available for Ruminants from Rice + Cowpea Intercrop During the Dry Season in Nigeria

Chemical analysis to assess the mineral status of two fodder crops (rice and cowpea) was carried out. The range of P, K, Na, Ca and Mg values in the rice and cowpea plants met the minimum requirements for beef and dairy cattle and sheep/goats in this area. In rice plants, the level of crude protein (CP) met the marginal requirement, while CP values of cowpea were within the recommended requirements for ruminants in the area of study. Values of Fe and Zn were below minimum requirements while over 50% of the rice and cowpea plants had adequate Cu. Mineral supplements are suggested for correction of deficiencies in feed of ruminants in the area of study. Keywords: crop residues, mineral supplements, macro elements, microelements, ruminant