Effect of Hardening to drought Tolerance on the Moisture Content of Sunflower Plant. III. Moisture Percentage in Whole Plant

The study was conducted during spring seasons of 2000 and 2001.The aim was to study the changes in the moisture content of sunflower plants during growth stages under hardening conditions to drought tolerance .Agricultural practices were made according to recommendation. Asplit-split plots design was used with three replications. The main plots included irrigation treatments:irrigation to100%(full irrigation),75and50%of available water. The sub plots were the cultivars Euroflor and Flame.The sub-sub plots represented four seed soaking treatments: Control (unsoaked), soaking in water ,Paclobutrazol solution(250ppm),and Pix solution(500ppm). The soaking continued for 24 hours then seeds were dried at room temperature until they regained their original weight. Amount of water for each irrigation were calculated to satisfy water depletion in soil using a neutron meter. Results indicated that plant moisture content was not affected by irrigation treatments in both seasons and as a mean of seasons ,except after 72 days from planting in the season 2000.when stress 800 Kp caused a decreased in moisture content by 4.55and 5.18% compared with full irrigation and stress 600 Kp, respectively. Euroflor was superior over Flame after 30 days from planting by 13.64% in the season of 2000 and by 6.23% as a mean of seasons , and by 2.80% after 86 days from planting in the season of 2001.While Flame was superior by 2.75% after 58 days from planting in the season of 2001. Soaking in water , paclobutrazol and pix solutions increased plant moisture content by 4.56,3.92 and 3.82% after 86 days from planting in the season 2000 , soaking in water and paclobutrazol solution increased plant moisture content by 2.61 and 2.62% as amean of seasons compared with unsoaked treatment. In conclusion, soaking the seeds presowing in water or plant growth regulators could improve water relations of plants , and increase moisture content in plants tissues especially during flowering and seed filling , when the water requirements increased and associated with high temperature in spring season in Iraq.

Assessing ignition probability and moisture of extinction in a Mediterranean grass fuel

The objective of this study was the assessment of the probability of ignition and moisture of extinction of the annual herbaceous species Slender Oat (Avena barbata Pott. ex Link) in Greece. Multiple ignition tests were conducted in situ with a drip torch during two fire seasons, with simultaneous monitoring of the weather conditions. Stepwise logistic regression was applied to assess the probability of ignition based on plant moisture content and meteorological parameters. Fuel moisture content was determined to be the only statistically significant (P < 0.0001) parameter and, therefore, it was the only variable kept in the analysis. The logistic model correctly predicted fire ignition in 93.6% of the tests and 50% ignition probability was determined at 38.5% oven-dried weight (ODW) plant moisture content. Moisture of extinction (i.e. probability of ignition at 1%) was calculated at 55.5% ODW. Furthermore, classification tree analysis was applied to determine the independent variables that explain the variability in ignition probability. Wind speed was found to have an effect on ignition probability only at relatively high (>30% ODW) fuel moisture contents. Assessment of the ignition potential and moisture of extinction of grass fuels is a prerequisite for reliable fire danger prediction.

Effects of salt stress on growth, nodulation, and nitrogen and carbon fixation of ten genetically diverse lines of chickpea (Cicer arietinum L.)

Salinity is one of the major environmental constraints affecting agriculture in major regions of the world. It is known to depress greatly the growth and symbiotic performance of nodulated legumes. In the present study conducted over 2 rabi (dry) seasons, 2000–01 and 2001–02, 10 genetically diverse chickpea lines were compared for salt tolerance in terms of growth, nodulation, moisture content, and nodule nitrogen and carbon fixation. Chickpea lines were raised in an open-air chamber in soil supplied with 0, 50, 75, and 100 mm NaCl. The shoot, root, and the single-plant weight declined with increasing level of salt. Chickpea lines BG-1075 (desi type) and BGD-70 (Kabuli type) showed better plant growth than the former 2 lines but were poorer in nodulation under salt stress. An almost identical pattern of salt response was observed for nodule number, weight per nodule, nitrogen, and carbon fixation among the chickpea lines. No distinct relationship was found among root/shoot ratio, plant moisture content, and salt tolerance response of the chickpea. However, nodulation capacity (number and mass) under salt stress was related to salt tolerance response of chickpea lines. This trait could be used for improvement of salt tolerance of this legume species in order to increase its productivity and stability in saline soils.

CRITICAL TISSUE MOISTURE LEVELS NEEDED FOR MAINTENANCE OF ROSE PLANT VIABILITY.

Field grown `Mr. Lincoln' rose plants were dug and wrapped in plastic to reduce moisture loss during transport to the lab. Plants were then pruned, weighed, and returned to the plastic cover. After recording initial weights, plants were allowed to dry for 0, 1, 4, 7, or 24 hours at 16°C. Plants were then oven dried, potted, or soaked in water for 20 hours before potting for each drying time treatment. The potted plants were forced to first flower in a glasshouse at which time growth measurements were made. Undried plants had a moisture content of 48%. Seven hours drying reduced moisture content to 41%, but had no effect on growth or flowering. The 24 hour drying time resulted in a plant moisture content of 33%, a plant loss of 44%, and delayed growth initiation and flowering by up to 15 days compared to undried controls. Soaking after 24 hours drying increased plant survival from 38 to 75%. Plants that survived the excessive drying produced flowering growth comparable to plants with a moisture content of > 40%. A critical moisture level for rose plant survival was found to be between 33 and 41%.

EFFECT OF NITROGEN FERTILIZATION AND PLANT POPULATION ON THE VALUE OF CORN SILAGE FED TO BEEF STEERS

Corn was grown at 86 000 plants/ha and at 129 000 plants/ha and fertilized with nitrogen at rates of 150 and 200 kg/ha in order to determine the effect of population and N-fertilization on field production, silage preservation and animal performance. Silages from the four field treatments were offered ad libitum to Hereford steers during 112 days. Within each of the corn treatments, half of the animals were supplemented with 450 g of soybean meal (48% protein). Under field conditions characteristic of this trial, the higher plant populations and higher nitrogen levels failed to increase corn silage yields and resulted in lower ear production, later maturing plants and a higher plant moisture content at harvest. The trends were most noticeable in the high plant population treatments. The quality of the silage was not affected by the different treatments. No significant differences for total N, soluble N, NH3-N, lactic acid and acetic acid were noted among silages. Animal intake was increased with silages produced on high N-fertilization at 86 000 and 129 000 plants/ha. No significant differences in animal gain or feed efficiency were observed due to field treatments. The addition of soybean meal to the silages diluted the influence of field treatment on animal intake. However, within field treatments the supplement significantly improved dry matter intake, gain and feed efficiency. This study showed no advantage in increasing corn population over 86 000 plants/ha or N fertilization above 150 kg/ha. Key words: Corn silage, plant population, N-fertilization, steers

RELATIONSHIPS AMONG WHOLE-PLANT MOISTURE, GRAIN MOISTURE, DRY MATTER YIELD, AND QUALITY OF WHOLE-PLANT CORN SILAGE

Identical experiments were conducted at the Elora Research Station, near Guelph, Ontario in 1970 and 1971 with the objective of determining the relationships among whole-plant dry matter (DM) yield, whole-plant moisture content, and grain moisture content of corn (Zea mays L.) during the later part of the growing season. Each experiment involved eight commercial hybrids representative of the range in maturity, endosperm type, lodging resistance, and grain yield potential of corn hybrids grown commercially in central Ontario. The hybrids were sampled at weekly intervals over an 8-wk period beginning approximately 1 September; the sampled plants were divided into their leaf, stalk, husk, ear and grain components and oven-dried. Fresh and dry weights were used to calculate dry matter (DM) yields and "at harvest" moisture contents of the various components, and of the entire plant. Averaged across the eight hybrids, maximum DM yield was attained at whole-plant moisture content of 66–70%, and a grain moisture content of 45–50%. Among hybrids, 66% whole-plant moisture corresponded to a range in grain moisture content from 41 to 47%. Two additional experiments were grown also at Elora in 1970 and 1971 to evaluate the effects of harvest date on the DM yield and in vitro digestibility of corn plants and their component plant parts. Each experiment involved four representative commercial hybrids which were sampled at four equal time intervals during the month of September, and divided into grain, cob, husks (including shank) and stover (including leaves, leaf sheaths, stalks and tassels) for dry weight and in vitro digestibility measurement. Whole-plant DM digestibility was essentially constant over a range of whole-plant moisture from 76 to 56% in 1970, and from 76 to 64% in 1971. The consistency of whole-plant digestibility was the result of compensating changes in component yield and digestibility. A decrease in the digestibility of the stover, husks and cob with delayed harvest was compensated for by an increase in the proportion of grain in the whole-plant yield.