Water use and grain yield response of rainfed soybean to tillage-mulch practices in southeastern Nigeria

Despite the agronomic, economic and food values of soybean (Glycine max L. Merrill), there is still dearth of information on the tillage need and the implications of surface mulch for the crop in the eastern part of the forest-savanna transition zone of Nigeria. This study was therefore carried out on a sandy loam Ultisol at Nsukka with a sub-humid climate, during 2006 and 2007 cropping seasons. Our objective was to devise an appropriate tillage method for the crop from evaluated effects of no-till (NT), conventional tillage (CT) and mulch on selected key agronomic indices. Each of the NT and the CT was either unmulched (U) or mulched (M) in a split-plot, giving four treatments/tillage methods (NTU, NTM, CTU and CTM) randomized in four blocks. Rainfall was more favorable in the first than in the second season. The mean seasonal soil water storage (range, 99-109 mm) within 0.5-m soil layer differed among the treatments (NTU < CTU < NTM = CTM). However, for the first and second seasons, both water use (582-616 and 667-709 mm respectively) and grain yield (0.71-0.81 and 1.22-1.91 Mg ha-1 respectively) were not different. Mulch lowered the crop water use but had no influence on grain yield. Water use efficiency was enhanced with mulch only in the second season. Although either of the two mulch treatments (NTM/CTM) would be suitable for growing soybean especially in years of unfavorably distributed rainfall, NTM is a more rational choice than CTM. Rainfall adequacy at the critical reproductive stage of the crop showed to be a more important yield factor than the tested tillage methods

Phototrophic biofilms and their potential applications

Phototrophic biofilms occur on surfaces exposed to light in a range of terrestrial and aquatic environments. Oxygenic phototrophs like diatoms, green algae, and cyanobacteria are the major primary producers that generate energy and reduce carbon dioxide, providing the system with organic substrates and oxygen. Photosynthesis fuels processes and conversions in the total biofilm community, including the metabolism of heterotrophic organisms. A matrix of polymeric substances secreted by phototrophs and heterotrophs enhances the attachment of the biofilm community. This review discusses the actual and potential applications of phototrophic biofilms in wastewater treatment, bioremediation, fish-feed production, biohydrogen production, and soil improvement

Registration of ‘Choptank’ Wheat

‘Choptank’ (Reg. no. CV-976, PI 639724) is a soft red winter wheat (Triticum aestivum L.) that was jointly developed and released by the Maryland Agricultural Experiment Station, Department of Natural Resource Sciences and Landscape Architecture, and the Virginia Agricultural Experiment Station in 2004. Choptank is named after Maryland’s longest scenic river, which flows 70 miles from the western part of Delaware through Maryland and into the Chesapeake Bay, on Maryland’s Eastern Shore. Choptank has performed well in Maryland, Virginia, and Delaware and provides growers with a high-yielding cultivar with short stature, excellent powdery mildew [caused by Blumeria graminis (DC.) E.O. Speer f. sp. tritici Em. Marchal] resistance and early heading date. Choptank was derived from the cross ‘Coker 9803’ (PI 548845)/‘Freedom’ (PI 562382) that was made in 1990 at Virginia Polytechnic Institute and State University. The population was advanced from the F2 to F5 generation using a modified bulk breeding method. Wheat spikes were selected in Virginia from the population in each generation (F2–F5) based on the absence of obvious disease, early maturity, short straw, and desirable head shape and size. Selected spikes were threshed in bulk and the seed was planted the following fall of each selection year. Spikes selected from the F5:6 bulk block were threshed individually and planted in separate headrows in the fall of 1996 at Beltsville, MD. Choptank was derived as a bulk of one of these F6:7 headrows selected in 1997 and assigned the breeding line designation MD11–52. In addition to high grain yield, Choptank was selected on the basis of earliness of head emergence, short plant height, and resistance to powdery mildew. Choptank was evaluated in the Maryland Wheat Variety Test for 5 yr (from 2000–2004), in the Virginia and Delaware State Wheat Variety Tests for 3 yr, and in the USDA-ARS Uniform Eastern and Uniform Southern Soft Red Winter Wheat Nurseries in 2004. Coleoptiles of Choptank are white. Juvenile plants exhibit a semierect growth habit. Plant color at boot stage (Feekes growth stage 9–10) is blue green and a waxy bloom is present on the stem and flag leaf sheath. Anther color is yellow. Spikes are tapering, middense, and awnletted. Glumes are long and wide, with oblique shoulders and obtuse beaks. Kernels of Choptank are red, soft, and ovate with a crease of medium width and depth, rounded cheeks, and a long noncollared brush. Choptank carries the 1BL.1RS wheat–rye chromosomal translocation. Head emergence of Choptank in Maryland is similar to that of ‘Sisson’ and 2 d earlier than Pioneer brand ‘25R37’. In Maryland, average plant height of Choptank (77.5 cm) is 5 cm shorter than that of Sisson and 2 cm shorter than that of USG ‘3209’. Average straw strength (0.0 lodging score) of Choptank in Maryland is similar to that of Sisson (0.3)