Afternoon Soil Temperatures Research Articles

Assessing the impact of agro-climatic factors on pod filling of grass pea

Field experiments were conducted for two successive years with grass pea (cv. ‘Prateek’) sown on nine dates at weekly interval at Instructional Farm (22°58´ N, 88°31´ E), Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India to investigate the impact of agroclimatic factors on pod filling of grass pea. Results showed that pod filling percentage (PFP) increased with delay in sowing dates, attaining the highest value (96.7 %) in crop sown on 30th November, beyond which it decreased gradually with further delay in sowing. Maximum and minimum temperatures, morning and afternoon soil temperatures, recorded at 5, 15 and 30 cm soil depths, morning and afternoon vapour pressure deficits at pre-flowering phase exhibited negative association and contrarily, when prevailing during reproductive and pod development phases, these parameters demonstrated positive correlation with PFP. Temperature range during reproductive phase increased with delay in sowing dates and it exhibited significant positive correlation with PFP. As demonstrated by stepwise regression analysis, Accumulated photothermal unit (APTU) prevailing at maturity phase alone accounted for 67.4 % of the total variation in PFP and together with temperature range it explained 91.3 % variation. APTU, temperature range, afternoon vapour pressure deficit and afternoon soil temperature seem to be the critical agroclimatic variables influencing the pod filling percentage significantly.

Effect of plastic low tunnel and mulch type on soil temperature, growth, earliness and yield of brinjal under net-house and open field in plains of North-Western India

A two-year study was conducted to compare the performance of brinjal hybrid BH-2 using paddy straw mulch @ 6 t ha-1, clear plastic mulch (25 μm), black plastic mulch (25 μm), plastic low tunnel and control (bare soil) under net-house and open field at Punjab Agricultural University, Ludhiana, India. The maximum increase in morning and afternoon soil temperature over bare soil was observed using black plastic mulch followed by clear plastic mulch in both net-house and open field whereas paddy straw mulch reduced the soil temperature over bare soil in open field. Under net house, black and clear plastic mulch were better than other treatments and recorded maximum plant height (50.8 cm and 43.7 cm), number of leaves/plant (64.8 and 64.3), early yield (7.1 and 6.6 t ha-1), number of fruits/plant (16.1 and 14.4) and total yield (57.4 and 55.7 t ha-1), respectively. In open field, plastic low tunnel was the best treatment and recorded maximum plant height (40.4 cm), number of leaves/plant (51.2), early yield (5.9 t ha-1), number of fruits/ plant (14.6) and total yield (58.5 t ha-1). The study offers the scope of enhancing brinjal production in spring and early summer which may be highly profitable for farmers.

Species Composition of Ants in Cashew Plantations and their Interrelationships with Cashew

In cashew plantations of south west Karnataka, India, foraging activity of 49 ants species belonging to 24 genera and 7 subfamilies were recorded. The study found that ants visited cashew trees regularly throughout the year. Myrmicinae ants were most dominant comprising 22 species followed by Formicinae with 13 species while, among Aenictinae and Dorylinae, only single species was found. Species richness was high in old cashew plantations recording 89.8 % of total species, while medium and young plantations recorded only 46.9 and 24.5 %. Dominance of different ant species was noticed on cashew canopy, trunk and soil in different aged cashew plantations. Old cashew plantations were characterized by Oecophylla smaragdina, followed by Anoplolepis gracillipes, while, Camponotus compressus and C. sericeus were dominant in young and medium aged plantations. Pit fall trap collection consisted mostly of Odontomachus haematodus, Lophomyrmex quadrispinosus, Technomyrmex albipes, Myrmicaria brunnea, Diacamma sp., C. compressus and C. sericeus. During flowering and fruiting period of cashew, foraging of up to 10 ant species was seen on the same tree at a time. Activities of most ant species were predominant during winter and summer which coincides with flowering and fruiting period of cashew (December–May), while during heavy down pour of south west monsoon, activities of only 10 species were seen. A significant positive correlation was found between number of ant species and maximum air temperature (0.842) and also with afternoon soil temperature (0.925).

Weather modification for off-season production of coriander (Coriandrum sativum L.) for leaf

Coriander is produced almost throughout the year for leaf purpose, however the demand for leaf during summer is high. The present investigation is under taken to study the weather modifications and their influence on production of coriander for leaf purpose during summer. Nine different production systems and their effect on micro-climate were studied. The study indicated that among the various weather factors studied, soil temperatures significantly influenced the germination, crop growth and yield. Soil temperature was significantly negatively correlated with number of leaves, leaf length, green biomass, shoot weight, leaf weight and yield. The mean afternoon (both ambient and soil) temperatures were also significantly negatively correlated with above growth parameters. The overall results of the experiment suggest that the soil temperatures are the most crucial factor in summer production of coriander. The afternoon soil temperature if ameliorated and maintained between 28. 0O C to 32.5O C, coriander production can be taken up successfully without any modification of other weather factors like air temperature and relative humidity. However, amelioration in ambient air temperature further improves the efficiency of the production system.

Effects of Three Mulch Types on the Growth and Yield of Tomato (<i>Lycopersicon esculentum</i> Mill.) and Weed Suppression in Ibadan, Rainforest-savanna Transition Zone of Nigeria

Field experiments were conducted in the 1998 and 2004 cropping seasons to assess the impacts of different mulching materials on weed control, soil temperature, soil moisture depletion and performance of tomato ( Lycopersicon esculentum Mill.) in Ibadan, a rainforest-savanna transition ecological zone of Nigeria. The crop growth and fruit yield were studied under plastic (grey-on-black), woodchip (Teak) and grass ( Pennisetum ) mulches, with handweeded and un-weeded as controls in a randomized complete block design with three replicates. Also assessed were weed dry matter and species spectrum, soil temperatures at 5-cm and 15-cm depths, and soil moisture depletion. Compared to unweeded control that had the least total fruit yield (2.7 t/ha in 1998 and 4.2 t/ha in 2004), mulch types and handweeded treatments increased the fruit yield by 152-237% in 1998 and 188-202% in 2004. Compared to mean pooled fruit yield from all mulched plots, unweeded treatment reduced tomato fruit yield by about 65% and 66% in 1998 and 2004, respectively. The weed control efficiencies of the mulches ranged between 91% and 100%. Dicotyledon weed species dominated the plots in the two years accounting for 81.8% in 1998 and 90% in 2004. The number of low-growing weed species enumerated on the plots was 11 in 1998 and 18 in 2004. After four weeks of no rainfall in 1998, moisture loss was least (1.68±0.10%) under plastic mulch and highest (13.96±0.08%) on the unweeded plot. The differences between morning and afternoon soil temperatures at 5 cm depth were low under grass mulch, woodchip mulch and unweeded control (5.0-5.9°C) but high under plastic mulch and handweeded control (8.7-8.9°C). Mulches are effective in weed control and conservation of soil moisture, and the plant-based mulches are most effective in reducing soil temperature. These improvements of crop growing environment resulted in increased tomato growth and fruit yield. Keywords : mulches; Lycopersicon ; weed control; moisture; temperature DOI: 10.4038/tare.v10i0.1871 Tropical Agricultural Research & Extension Vol.10 2007 53-60

Ecosystem and Restoration Consequences of Invasive Woody Species Removal in Hawaiian Lowland Wet Forest

A removal experiment was used to examine the restoration potential of a lowland wet forest in Hawaii, a remnant forest type that has been heavily invaded by non-native species and in which there is very little native species regeneration. All non-native woody and herbaceous biomass (approximately 45% of basal area) was removed in four 100-m 2 removal plots; plots were followed for a three-year period. Removal plots had a lower leaf area index, higher air temperatures, higher afternoon soil temperatures, and lower relative humidity than control plots. Removal plots had 40% less litterfall mass and similarly reduced nutrient inputs. Leaf litter decomposition rates were much slower in the removal plots, due more to site quality than litter quality. However, soil N and P were not different between treatments. Native species had a distinct suite of leaf traits (greater integrated water use efficiency, lower mass-based leaf nutrient concentrations, and lower specific leaf area). Despite major environmental changes in the removal plots, native species’ diameter growth and litterfall productivity were not significantly greater after removal, testifying to the slow response capabilities of native Hawaiian trees. Our results are consistent with the expectation that native species are conservative in regards to resource use and may not strongly respond to canopy removal, at least at the adult stage. Management strategies will have to incorporate the slow growth rate of Hawaiian species and the fact that weeding may be required to suppress expansion and nutrient inputs of introduced species.

Effects of Mulches on Soil Properties and Tomato Production I. Soil Temperature, Soil Moisture and Marketable Yield

ABSTRACT The effects of hay, compost, plastic and paper mulches on soil temperature, soil moisture and yield of paste tomato were evaluated on five farms in Virginia. Organic mulches reduced afternoon soil temperature and maintained higher soil moisture levels than other treatments. Black plastic mulch increased soil temperatures by 1–2°C, but sometimes resulted in lower soil moisture levels in early summer, probably by hindering penetration of rainfall. Both undyed kraft paper and black paper mulches reduced afternoon soil temperature slightly. Oiled paper initially increased afternoon soil temperature by 4°C, but this effect diminished over time. Paper mulches decomposed before the end of the season, allowing increased evaporative losses of soil moisture. Mulch treatments apparently affected early tomato yield by influencing soil temperature regime, but affected later yields by modifying soil moisture levels. Early yields were generally highest with black plastic mulch and lowest in organic mulches, with paper mulch intermediate. At sites not affected by late blight, total yields were generally: organic mulch ≥ plastic ≥ paper > unmulched. At sites affected by late blight, later-maturing fruit were lost, so that the delay in ripening in soil-cooling organic mulches resulted in a significant yield reduction compared to black plastic.

Root-zone soil temperature variation associated with microsite characteristics in high-elevation forest openings in the interior of British Columbia

Low soil temperatures have been suggested as a factor contributing to poor rooting of planted conifer seedlings and hence a cause for failure of some high-elevation reforestation efforts. Few studies have attempted to document soil temperature variation and its causal factors in post-logged, high-elevation openings during the growing season. A field survey of afternoon soil temperature (at a depth of −10 cm from the mineral soil surface) was conducted in six high-elevation clear-cuts located in the Engelmann Spruce-Subalpine Fir (ESSF) biogeoclimatic zone in central British Columbia, Canada. On a clear summer day, a difference of 8°C in afternoon soil temperatures was measured between the warmest microsites (bare mineral soil, 17.6 ± 2.5°C) and the coolest microsites (covered by forest floor and vegetation, 9.3 ± 0.7°C). Heavily covered microsites showed little diurnal or spot-to-spot (microsite) variation in soil temperature. Conversely, microsites with little surface cover exhibited the greatest spatial and temporal variability in soil temperature. Variation in afternoon root-zone soil temperature ( T) was most strongly associated with the combination of thickness of duff (forest floor) ( D), cumulative % vegetation cover ( C), and % soil moisture ( M). Comprised of these three microsite attributes, a multiple regression model, T = 24.06 − [1.05(ln( C) + 1.64(ln( D)) + 1.38(ln( M))] ( R 2 + 0.73) was created which predicts high-elevation afternoon soil temperatures to within ±2.0°C. Multiple regression models including relative surface irradiance (as a percentage of above canopy light), cumulative % vegetation height, micro-slope and micro-aspect were less predictive. The relationship between afternoon soil temperature and each microsite attribute generally showed a strongly negative curvilinear pattern, described by double exponential decay functions. Microsites associated with suboptimally low afternoon soil temperatures (< 12°C) during the growing season were widespread (70 to 80% of the sampled areas) in the surveyed high-elevation openings.

Some analytical aspects of cassava/maize/okra/ egusi-melon complex mixture: I. Soil temperature in relation to leaf-area variation

Afternoon soil temperature of about 39°C observed at 5 cm depth under sole cassava ( Manihot esculenta Crantz) early in the growing season was reduced by respectively 1.0, 1.3, 3.0 and 4.4°C by intercropping with maize ( Zea mays L.), maize/okra ( Abelmoschus esculentus Moench), maize/ egusi melon ( Citrullus lanatus Thunb.), and maize/okra/egusi melon. There was a negative but significant relationship between soil temperature and combined leaf area index ( L) of crops grown in mixture with sparse-canopy cassava ( r = −0.91 ∗∗ ) and with dense-canopy cassava ( r = −0.93 ∗∗ ). This work has shown that, for effective soil temperature reduction under cassava, associated intercrops must attain L of atleast 1.5 within the first eight weeks of growth. Since the L of cassava is below 0.5 during the first eight weeks of growth, intercrops such as egusi melon and maize would help in reducing supra-optimal temperatures under cassava.

INFLUENCE OF SEVERAL ROW COVERS ON YIELD OF BROCCOLI AND CABBAGE IN SOUTHEAST MISSOURI

Four row covers were evaluated on fall production of `Packman' broccoli and `Gourmet' cabbage at Cape Girardeau, Missouri. Row covers used were spunbonded polyester, insolar and clear slitted polyethylene and VisPore. The mean afternoon soil temperature for row covers were higher than the bare soil control. There were no significant differences among treatments with respect to head size, total numbers and yield of marketable broccoli. The number of broccoli heads per thousand between the bare soil control vs. row cover treatments were significantly different. Data for number of broccoli heads per thousand and marketable yield (Kg/Ha) were significant among row covers. Marketable yield (Kg/Ha) was significant among row covers for `Gourmet' cabbage.

EFFECT OF FOUR ROW COVER SYSTEMS ON PRODUCTION OF SOLANUM TUBEROSUM IN SOUTHEAST MISSOURI

`Norchip' and `Atlantic' potatoes grown at Blodgett and Dielstadt, Missouri on 2 sandy, well drained entisols were evaluated using four row covers. The row covers were spunbonded polyester, insolar slitted, clear slitted polyethylene and VisPore. Row covers increased the mean afternoon soil temperature from 62° to 108°. The mean plant heights were significantly different among treatments for the cultivar `Norchip' but were not different for `Atlantic'. Data for average and total plant heights were significantly different between the bare soil control and all row covers. The grade a marketable weights and numbers in Kg and nos/Ha of `Norchip' and `Atlantic' potatoes had a significant contrast at the 0.01 level of probability with cultivars.

DIFFERENTIAL RESPONSE OF SEVERAL ROW COVERS ON YIELD OF WHITE POTATOES IN MISSOURI

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.

Evaluation of Potential Herbivore Mediation of Plant Water Status in a North American Mixed-Grass Prairie

Xylem water potentials (ip) were monitored diurnally from June through August 1981 to ascertain the water status of plants of four species growing on a heavily grazed prairie dog (Cynomys ludovicianus) colony and an adjacent lightly grazed uncolonized site in southwestern South Dakota. Highest p values were observed in June and August after periods of relatively high precipitation. Lowest values occurred in July when soil moisture had been depleted. However, there were no large differences in V of grasses (Agropyron smithii, Andropogon gerardi, and A. scoparius) growing on and off the prairie dog colony, even though root biomass of plants on the colony was substantially lower. While midday leaf conductance was comparable for A. smithii tillers on and off the colony, conductance values for A. gerardi and A. scoparius tillers were generally higher (17 to 60%) on the heavily grazed site. Artemisia frigida plants had slightly higher Vp on the prairie dog town during periods of moderate or high water stress. Soil moisture content was slightly but significantly (P _ 0.05) higher on the heavily grazed prairie dog town, even though afternoon soil temperatures at the 15-cm depth averaged 2.7°C higher.

Susceptibility of Cyclocephala immaculata (Coleoptera: Scarabaeidae) Eggs and Immatures to Heat and Drought in Turf Grass

Eggs of the southern masked chafer, Cyclocephala immaculata Olivier, are laid under turf grass in the upper 3 cm of soil, where they are vulnerable to heat and desiccation. The ability of eggs to survive periods of drought was found to depend upon egg age, stress duration, and temperature. At 25°C, the minimum soil moisture level at which eggs developed was between 10.3 and 12.3%. Eggs surviving a stress period early in development required several days longer to hatch. In field tests, no eggs survived in desiccated turf, where afternoon soil temperatures exceeded 40°C and soil moisture dropped to <8%. Egg survival ranged from 55 to 73% in irrigated turf. Caged gravid females failed to lay eggs, and implanted 1st-instar grubs did not survive in desiccated turf.

The Effect of Fire on an Ungrazed Western Montana Grassland

On 28 June 1977 a hot wildfire burned part of a species-rich foothills grassland dominated by Festuca scabrella, F. idahoensis and Agropyron spicatum. We sampled plant species cover in paired stands, on and off the burn, during 1977 and 1978 to determine the initial impact of the fire, and during 1980 to document recovery after 3 years. Grass cover decreased on the burn due primarily to a sharp drop in the cover of the two dominant fescues. Forb cover increased. Moss and lichen cover dropped greatly. Much of the difference in species response was related to plant growth form and phenology. Large bunches of F. scabrella were more seriously damaged than small ones, indicating long intervals between fires are detrimental to the species when fire does return. At burned sites, afternoon soil temperatures were higher and near-surface soil moisture was lower. Three years after the fire, cover of most vascular species was similar in burned and unburned stands. Festuca idahoensis had recovered completely. Festuca scabrella had increased but was still well below unburned levels. Total moss cover on the burn was nearly that on unburned sites, but the species composition was greatly altered. Lichens were still reduced. The stability of the grassland in relation to fire is discussed.

The Effect of Rice-hull Mulch on Growth, Carbohydrate Content, and Nitrogen Fixation in Phaseolus vulgaris L.1

Abstract Mulching ‘Puebla 152’ beans with rice hulls to a depth of 4 cm reduced afternoon soil temperature, soil temperature fluctuation, and slowed the loss of soil moisture. These effects were greatest prior to canopy closure. Fresh weight of nodules, roots, stems, leaves, and total plant increased 50%, 38%, 49%, 24%, and 38%, respectively, with mulching, but pod and final seed weight were unaffected. Mulching had little effect on the concentration of soluble and insoluble carbohydrates. N2 fixation rates (C2H2 reduction) were low (≤ 0.6 µmole/plant per hr) but were as much as 3 times higher in mulched than unmulched plants.

Evaluation of Insecticides for the Control of Hippelates pusio in Soil1

In plot tests evaluated by emergence traps, excellent control of Hippelates pusio was obtained with aldrin at 1 or 2 pounds per acre, chlordane at 4 pounds per acre, and BHC at 2 ½ pounds of gamma isomer per acre. The continued effectiveness of the original BHC application against a second generation of gnats was demonstrated by a second test begun 40 days after the first. DDT was found to be of little or no benefit at rates up to 16 pounds per acre. When afternoon soil temperatures a t a depth of 6 inches aver-aged 83 and 78 degrees F., the development of H. pusio from oviposition to the peak of adult emergence took an estimated period of 21 and 26 days, respectively. In a test of emergence traps made where ants were abundant, the jars collected less than 25% of the adult gnats experimentally introduced. Another test indicated that relatively few gnats were removed from the collecting jars by scavengers. Means of improving the emergence trap are suggested.