Blue Ridge, Cape Fear, Georgiagem, and O Neal southern highbush blueberry cultivars were grown for 5 years on a fine sandy loam soil in a comparison of plants either mulched with uncomposted pine sawdust and woodchips or nonmulched. Other cultural practices were identical and all plants received the same amount of trickle irrigation. A significant mulch × cultivar interaction for yield and mulch × plant age interactions for yield, individual berry weight, and plant volume were found. Cape Fear was the highest-yielding mulched cultivar, followed by Blueridge, Georgiagem, and O Neal. Mulched plants had higher yields and produced larger plants. Average individual berry weight was greater for mulched plants in the first year of harvest, but not different among treatments in other years. The data reveal that these southern highbush cultivars performed similar to northern highbush (Vaccinicum corymbosum L.) in their need for mulching for adequate production on upland soils.
John R Clark and J.N. Moore
Michael L. Parker and John R. Meyer
Peach (Prunus persica L. Batsch. `Biscoe'/Lovell) trees were grown in a sandy loam soil under six orchard floor management systems, including five vegetative covers (continuous under the tree) and a vegetation-free control (bare ground). At the end of the fifth year, trees grown in bare ground and nimblewill grass (Muhlenbergia schreberi J.F. Gmel.) had a significantly larger trunk cross-sectional area (TCSA) than trees grown in weedy plots, centipedegrass [Eremochloa ophiuroides (Munro) Hack.], or bahiagrass (Paspalum notatum Flugge). Trees grown in brome (Bromus mollis L.) did not differ significantly in TCSA from any other treatment. Soil profile excavations of the root system revealed that trees grown in bare ground or with nimblewill had significantly higher root densities than those in the weedy plots or grown with bahiagrass. Vector analysis of root distribution indicated that trees grown in bare ground or nimblewill rooted deeper than trees in all other treatments. The greatest reduction in deep rooting occurred with bahiagrass.
James M. Spiers
In a field study, `Gulfcoast' southern highbush blueberry plants were subjected to irrigation [7.5 L (low) or 30 L per week (high)], mulching (none or 15 cm depth), row height (level or raised 15 cm), and soil-incorporated peatmoss (none or 15 L in each planting hole) treatments, in a factorial arrangement, at establishment. Plants were grown on a well-drained fine sandy loam soil that contained <1.0% organic matter. Plant volume and fruit yield were greater with mulching, high irrigation, incorporated peatmoss, and level beds. Plants grown with the combination of mulching, level beds, incorporated peatmoss, and high irrigation levels yielded 2.4 kg per plant or approximately eight times as much as plants grown without mulch, with raised beds, without peatmoss, and with the low rate of irrigation. Of the four establishment practices evaluated, mulching had the greatest influence on plant growth and fruiting.
Adán Fimbres Fontes, Raúl Leonel Grijalva Contreras and Manuel de Jesús Valenzuela Ruíz
The area of olives in the region of Caborca has been increasing in the last years to 4500 ha. Olives in other regions do not need the application of water, but at Caborca, evaporation is greater than rainfall. Because of this, an experiment was conducted in 1998 to determine the optimum water requirements for olives (table olives) in a sandy loam soil (flooded irrigation). The results indicated that the greatest yield (16.27 kg/tree) was with 90% and 80% depletion (15.8 kg/tree) of the available moisture (AM) in the soil (1-m depth) and the lowest yield (8.46 kg/tree) was with 100% depletion and 60% depletion of the available moisture in the soil. The total water applied with the 90% depletion of the AM was of 146.77 cm (1.467 m).
Kalala Mwamba, E.G. Rhoden, R.O. Ankumah and V. Khan
Amaranth (Amaranthus sp.) is a vegetable crop with grains and leaves high in protein, especially, lysine and the sulfur-containing amino acids which are limiting in many vegetables and grains. These nutritional qualities and the ease of growth make it a suitable alternate crop for limited resource farmers. A study was conducted to determine the effect of nitrogen sources and fertilization rates on amaranth production in Alabama and other Southeastern States. The experiment was set up as a complete randomized block design in Norfolk sandy loam (Fine silicoeus, thermic, Typic Paleudult). Four nitrogen sources (urea, sodium nitrate, ammonium sulfate, and ammonium nitrate) were used at three different levels (0, 40, and 80 Kg/ha) one week after transplanting. Sources of nitrogen did not have any significant effect on both fresh and dry vegetable yield (p 0.05). However, fertilization brought significant increases in both yield and total nitrogen content of vegetable amaranth (p 0.05).
D.C. Sanders, G.D. Hoyt, J.C. Gilsanz, J.M. Davis, J.T. Garrett, D.R. Decoteau, R.J. Dufault and K.D. Batal
`Jewel' sweetpotato was no-till planted into crimson clover, wheat, or winter fallow. Then N was applied at 0, 60, or 120 kg·ha–1 in three equal applications to a sandy loam soil. Each fall the cover crop and production crop residue were plowed into the soil, beds were formed, and cover crops were planted. Plant growth of sweetpotato and cover crops increased with N rate. For the first 2 years crimson clover did not provide enough N (90 kg·ha–1) to compensate for the need for inorganic N. By year 3, crimson clover did provide sufficient N to produce yields sufficient to compensate for crop production and organic matter decomposition. Soil samples were taken to a depth of 1 m at the time of planting of the cover crop and production crop. Cover crops retained the N and reduced N movement into the subsoil.
D.C. Sanders, J.C. Gilsanz, W.J. Snerry and G.D. Hoyt
A 3-year study of cover crops (rye + crimson clover or sudex) and vegetable rotation systems was conducted using a Norfolk sandy loam soil. Cash crops were planted on all plots each spring, and in the fall, crops were snap beans/squash, sudex, or fallow. Late incorporation of cover crops depleted soil water content, resulting in a need for irrigation before spring plantings. Sudex residue had a high C: N ratio, delaying the total mineralization of N. Potato yields were not affected by rotation treatments. Cover crops improved snap bean emergence and yield. Snap beans had a differential uptake of Fe, Al, and B with cover crops. Tomato growth and yield were reduced with winter cover crops. Fall squash yield was not influenced by rotations.
Nicolas Tremblay, Marie-Hélène Michaud, René Crête and André Gosselin
With the increase in popularity of natural medicine there is an ever growing market for the production of medicinal plants. In the last decade, screening trials of a number of species were conducted. The species currently under study are: angelica (Angelica archangelica; biennial, roots harvested), thyme (Thymus vulgaris; perennial, shoot harvested), German chamomilla (Matricaria recutita; annual, flowers harvested), horehound (Marrubium vulgare; perennial, shoot harvested) and dandelion (Taraxacum officinale; considered as a biennial, roots harvested). In 1990 the species were grown on three soil types (clay-loam, sandy loam and histosol) with different fertilization and irrigation practices. In 1991 two distinct trials were undertaken. The first considered herbicide efficiency and planting density. The second dealt with «organic» management strategies. Depending on the species, treatments of compost amendment, plastic mulch and implantation techniques were compared.
Doyle A. Smittle, Melvin R. Hall and Paul G. Thompson
Responses of sweet potato (Ipomoea batatas (L>) Lam) to irrigation rates were evaluated under line-source irrigation systems on Tifton loamy sand soil in Georgia and on a Bude silt loam soil in Mississippi. Total water (rainfall plus irrigation) rates ranged from about 55% to 160% of pan evaporation (Epan). Marketable yields increased with irrigation rate until total water was about 75% of Epan then decreased rapidly with greater irrigation rates. Sweet potato yields were more sensitive to excessive water rates when grown on a silt loam than on a sandy loam soil. Storage loss and quality of cooked 'Jewel' sweet potato roots also increased as the irrigation rate increased until total water was 75% to 95% of Epan then decreased rapidly at water rates of 135 to 160% of Epan.
Mack A. Wilson and Michael Aide
Four types of row covers were evaluated on 'Norchip' and 'Atlantis' potatoes at Charleston, Missouri on a Lilbourn sandy loam entisol. Row covers used were spun-bonded polyester, insolar slitted, clear slitted and VisPore. The row covers increased the mean afternoon soil temperature above the ambient afternoon air temperature from 3 to 25°F when potato plants were covered. The number of plants which emerged were significantly different among treatment for the cultivar 'Norchip'. Data for plant height was significantly different between the bare soil control and the row cover treatments. Yield (Kg/HA) were higher with the spunbonded polyester and insolar slitted row covers for both number and weight of grade A (47.6-82.6 mm) potatoes, and results were significantly different.