No abstract

Cowpea (Vigna unguiculata [L.] Walp) is grown by resource poor farmers in Ghana using different tillage practices. Most of these farmers perform tillage operations without being aware of the effect of these operations on soil physical properties and crop responses. A field study was conducted during the 2009 and 2010 major crop growing seasons under rainfed conditions on sandy loam soil (Ferric Acrisol) to compare the effect of different tillage practices on some selected soil physical properties under Asontem cowpea variety. The experiment was arranged in a randomized complete block design with three replications. The treatments consisted of disc ploughing only, disc ploughing followed by disc harrowing, disc harrowing only and no tillage. Compared with the other treatments, the disc ploughing followed by disc harrowing treatment gave the most favourable soil conditions (i.e. lowest soil penetration resistance, lowest dry bulk density, highest soil moisture content, and highest total porosity). The no tillage plots produced the most unfavourable soil conditions (i.e. highest soil penetration resistance, highest dry bulk density, lowest soil moisture content, and lowest total porosity). Therefore, under the soil and weather conditions of the experiment, the best tillage practice identified for Asontem cowpea production is disc ploughing followed by disc harrowing.

An experiment was conducted to determine the effect of tillage practices on moisture retention and maize performance under rainfed conditions in Swaziland. The five treatments were based on structure of seedbed and seed planting method. They were ; zero tillage where jab planter was used to directly seed (JAB), tractor drawn planter to directly seed without ploughing (TDSS), tractor drawn cultivator to loosen soil followed by planting with tractor planter (TDRDS), planting basics made by using hand hoe (PLB) and conventional tillage (CNT) which was used as a control. The treatments were replicated three times. The data collected included weather data, germination counts, plant height, moisture retention, total dry matter and dry grain yield. The results displayed a significant difference in terms of moisture retention for the majority of the periods where measurements were done (p<0.05). Conventional tillage retained the least moisture while JAB retained the most moisture. In terms of seed emergence, TDRDS had the highest emergence during the first seven days compared to the other treatments. Conventional tillage had the tallest plants (268.5 cm) compared to the other treatments at 21 days after planting. Conventional tillage also had the highest total dry matter (16.2 tons/ha) and planting basins had the lowest dry matter (12.6 tons/ha). TDRDS had the highest grain yield (9.9 tons/ha), and JAB had the lowest grain yield (9.1 tons/ha). The difference in mean total dry matter and mean grain yield was not significant (p>0.05).

The objective of this study was to investigate the cause of black layer formation in maize (Zea mays L.). Four hybrids were field‐grown and defoliated at different stages of kernel maturity to determine the effect of assimilate supply reduction on black layer formation. Kernels from a fifth hybrid were cultured in vitro to determine the effect of temperature and scurose availability on black layer formation. Black layer formed in maize kernels independent of any specific environmental condition, and was not coincident with any particular physical state of the kernel. Black layer was observed in kernels ranging from 23 to 76% moisture. Kernel size at black layer ranged from 45 to 312 mg. Time from silking to black layer formation ranged from 29 to 78 days. Accumulated heat units from pollination to black layer ranged from 532 to 937. It appeared that a reduction in, or termination of, the supply of sucrose to the kernel induced black layer formation in maize. Premature formation of black layer following cold temperatures, drought or defoliation might all be explained on the basis of reduced sucrose availability.

An important objective of seeding for improved crop performance is putting seeds at a desired depth. Seeds should be sown at a depth that increases the likelihood of germination, emergence and improved growth. This study examined the effect of different sowing depths on the growth and dry matter yield of Anidaso soybean [Glycine max (L.) Merr.] on Ferric Acrisol (sandy loam soil) during the 2008 minor and 2009 major cropping seasons in Kumasi, Ghana under rainfed conditions. A randomised complete block design arrangement in three replications was used for the experiment. The treatments consisted of 2, 3, 5, 7 and 9 cm sowing depths. Analysis of variance showed significant effect of depth of sowing on Anidaso soybean variety performance. Sowing at a depth of 5 cm produced the tallest plant, biggest stem girth, highest number of leaves per plant, longest root and highest dry matter yield. The 9 cm sowing depth (i.e. the deepest sowing depth) gave the shortest plant, smallest stem girth, lowest number of leaves per plant, shortest root and smallest dry matter yield. The findings indicate that for improved growth and dry matter yield, Anidaso soybean variety should be sown at a depth of 5 cm.