Regular Harvests Research Articles

An Agronomic Approach to Pine Nut Production by Grafting Stone Pine on Two Rootstocks

Stone pine (Pinus pinea) grows in natural stands within the Mediterranean basin and its nut is highly appreciated for its nutritional profile. Nevertheless, a decline in this species due to biotic and abiotic damages is currently being clearly observed. This situation has led to its development as a nut crop, to try to save its production and obtain regular harvests over the years. Under this agronomic scenario, the aim of this work was to compare the behavior of the stone pine grafted onto two rootstocks, P. pinea (PP) and P. halepensis (PH), by evaluating cone productivity, tree growth response, mast seeding patterns and pine nut composition. The field test was composed of 14 PH and 14 PP, randomly distributed into groups of 4–5 trees/rootstock. Data were from seven productive growing seasons. The results show higher growth and ripe cone production on PP rather than PH, although the productivity (cones/m2 canopy) was similar. Any effect of rootstock was observed on the mast seeding pattern and weight of cones, while the pine nut composition showed differences in the fatty acids content. The global quality of production was similar in PH and PP.

Solar Irrigation System, Auto Fencing, Monitoring and Control using IOT

Agricultural strategies are changing quickly as a result of late advances in sustainable power innovation. The new headways in environmentally friendly power can be adequately utilized in the agribusiness area to decrease reliance on regular harvests water system procedures and petroleum derivatives. The Solar-Powered Smart Irrigation System intends to give an IoT arrangement in computerizing the watering interaction utilizing an Arduino-based microcontroller and sensors. It is an energy proficient and eco-accommodating framework that produces power from the photovoltaic cells to supply water to the plants from the water siphons. The watering cycle is driven by the dampness substance of the dirt utilizing sensors. Edge limit are set for soil dampness sensor to guarantee productive and viable utilization of water asset. The fundamental microcontroller unit controls the framework at whatever point the sensor is across limit esteem. Likewise, the framework has implicit temperature and dampness sensors to screen the environment condition on the particular climate. Another sensor is carried out to gauge the water tank level which fills in as capacity limit that provisions the water to the framework. With the incorporation of IoT, mechanized water system can be effectively access and distantly checked over the versatile application through a remote specialized gadget. With these shrewd water system procedures, it replaces the customary water system framework that helps decline the manual intercession and mix-ups

Effects of forest harvesting and biomass removal on soil carbon and nitrogen: Two complementary meta-analyses

Forest residues and logging slash from pre-commercial forest thinning and regeneration harvests are a potential feedstock for bioenergy production but there has been a concern about the impact of residue removal on forest soil C and N. This study aimed to address such by conducting two meta-analyses using the data available from published literature and an independent dataset compiled from the North American Long-Term Soil Productivity (LTSP) study.For the meta-analysis using literature, we categorized forest harvesting and biomass removal into i) no harvest control, ii) bole-only (BO, partial or clearcut) regular harvests, iii) BO with partial removal of logging slash and/or O horizon (BO+Removal), iv) whole tree harvests (WTH), and v) WTH with slash and O horizon removal (WTH+Removal). Accordingly, we compiled soil C and N data and key statistics (e.g., standard deviation) from 142 scientific articles published since 1979. We compared the results from this meta-analysis with data from 22 installations of the LTSP study where three levels of organic matter removal - BO, WTH, and WTH plus forest floor (+FF, O horizon) removal - as well as an additional vegetation control (+VC) were measured for two decades in either completely randomized or randomized block design.In the literature meta-analysis, BO+Removal (-19.2%), WTH (-15.4%) and WTH+Removal (-24.9%) contained significantly less soil C than no-harvest controls across combined soil depths, while BO had no difference. Within individual mineral soil horizons, only BO+Removal and WTH+Removal treatments contained significantly less carbon than controls. There was a high degree of heterogeneity in treatment response between studies in the literature. The analyses from the LTSP dataset showed no significant difference in combined soil depths for WTH or WTH+VC relative to BO harvest, but there was significantly less soil C in BO+VC (-3.6%), WTH+FF (-8.5%) and WTH+FF+VC (-15.3%). These treatment effects declined over time since harvest, particularly the most intensive treatments. Soil N results largely mirrored soil C in both meta-analyses with smaller estimated effects for most treatments at equivalent depths (except for WTH+Removal and WTH+FF+VC, which remain about the same). There were no significant differences in soil N for combined soil depths between WTH and no-harvest control (in the literature analysis) or BO harvest (for both analyses).Since the most severe losses of soil C and N involved FF removal, WTH that accounts for modest removals (<80%) of harvesting residues may provide a sustainable source of biomass for bioenergy production without additional soil impacts compared to BO harvesting practices.

Productive performance and economic evaluation of tilapia stocked in different times of the year

ABSTRACT This study aimed to determine production cycles based on the stocking period and the influence of the cycles on productive performance indices, production costs, and profitability. The present study was carried out on a fish farm located in Palmital – SP, Brazil, which consists of 2706 m3 of net cages with an annual production of 400 tons of tilapia and regular harvests throughout the year. Production data, investment and expenditures were obtained by using a semi-structured questionnaire to calculate [...]

Yielding to high yields? Critiquing food security definitions and policy implications for ethnic minority livelihoods in upland Vietnam

Agricultural intensification is at the core of the current agrarian transition in Southeast Asia. New crop varieties promise higher productive outputs, but depend on significant increases in chemical inputs. In the highlands of northern Vietnam, we find that adopting hybrid maize is inevitably associated with an increasing dependence on cash for direct and indirect inputs and investments. This reliance on the cash economy is a new reality for semi-subsistence ethnic minority Hmong households, and provides evidence of the advancing agrarian transition in Vietnam’s remote northern highlands. While livelihood outcomes of hybrid seed adoption include increased maize yields, local farmers highlight numerous drawbacks, including unstable input prices, limited storage periods, pest concerns, and the increased reliance on cash. Strong preferences for the taste of traditional local maize, as well as concerns over regular harvests, lead many households to resist the full adoption of new hybrid varieties and redirect hybrid maize to livestock feed and household alcohol production instead. Thus while state policies extoll the virtues of high-yielding hybrid maize for poverty reduction, we find that food availability is an overemphasized element of household food security and upland agricultural development policies. Food security interventions must move beyond conceptualizing food security as a result of food availability alone, and also incorporate cultural acceptability of food, better understandings of hybrid maize cultivation challenges, and respect the seed diversity on which local livelihoods and food security rely.

A method to evaluate the option of storing carbon in your forest

Managing the forest to store carbon is a relatively new concept. Various regional greenhouse gas initiatives and new Federal legislation are providing financial incentives for forest owners to manage for carbon in addition to other forest products. These incentives are intended for landowners who engage in activities that go beyond business as usual practices. Managing for carbon will likely involve foregoing other investment alternatives and increasing rotation lengths. The analysis approach demonstrated here provides a relatively simple method for an owner to compare traditional forest management and regular harvests with letting the trees grow to accumulate more carbon in the forest. Several financial decision statistics are considered and demonstrated with examples. A derivative of land expectation value, called rotation equivalent value, is shown to be a useful decision tool for comparing carbon storage with other management options having different rotation lengths.

Restocking and stock enhancement of coastal fisheries: Potential, problems and progress

The demand for fish is expected to rise substantially by 2020. Although aquaculture must provide much of the additional fish, it remains to be seen whether restored or enhanced capture fisheries can also help fill the projected gap in supply. The key challenges for capture fisheries involve reducing fishing effort, removing excess fishing capacity and building the institutional arrangements needed to restore spawning biomass to more productive levels, and to reverse degradation of the supporting habitats. Two interventions, based largely on hatchery technology, have the potential to reduce the time needed to rebuild some severely over-exploited fisheries, or improve the productivity of other ‘healthy’ fisheries. These interventions are ‘restocking’, which involves releasing cultured juveniles to restore spawning biomass to levels where the fishery can once again support regular harvests, and ‘stock enhancement’, which involves release of cultured juveniles to overcome recruitment limitation. However, despite the potential of these interventions, few restocking and stock enhancement programmes have met expectations. The main problems have been a pre-occupation with bio-technical research at the expense of objective analysis of the need for the intervention, and failure to integrate the technology within an appropriate management scheme that has the participation and understanding of the users. The papers presented at the Special Symposium on this subject at the Seventh Asian Fisheries Forum provide a series of valuable lessons to guide objective assessment of the potential for restocking and stock enhancement. They also show how to implement these interventions responsibly and effectively where they are deemed to add value to other forms of management. Above all, these studies demonstrate that restocking and stock enhancement programmes are applied in complex human–environment systems, involving dynamic interactions between the resource, the technical intervention and the people who use it.

Radiation-use efficiency and dry matter partitioning of a young olive (Olea europaea) orchard.

Radiation-use efficiency (RUE) relates biomass production to the photosynthetically active radiation (PAR) intercepted by a plant or crop. We determined RUE and biomass partitioning coefficients of young olive (Olea europaea) trees for use in a general growth model. In 1995, 1-year-old olive trees var. 'Picual' were planted at a density of either 0.5 or 2.0 trees m(-2) near Córdoba, Spain, at a site providing favorable growth conditions. During the experiment (1995-1997), both PAR interception by the canopy and plant area index (PAI) were measured with radiation sensors. Regular harvests were performed to determine leaf area and biomass accumulation in roots, wood (stem, branches and trunk) and leaves. Leaf, wood and root biomass partitioning coefficients were calculated. The leaf area partitioning coefficients were also estimated. Dry matter production was linearly related to cumulative intercepted PAR. Seasonal RUE, calculated as the slope of the regression of aboveground biomass and cumulative intercepted PAR, was 1.35 g (MJ PAR)(-1). Radiation-use efficiency appeared to respond to environmental conditions, but was independent of planting density and PAI. The young olive trees allocated 0.26 of their total biomass to roots. Partitioning of aboveground dry matter was 0.60 to wood and 0.37 to leaves. As competition increased, dry matter partitioning to wood increased to 0.70.

Effect of forms of nitrogen supply on mobilisation of phosphorus from a phosphate rock and acidification in the rhizosphere of tea

Nitrogen (N) is the main fertiliser input to tea plantations because of the large removal of this element with regular harvests of young shoots in the field. The form of N supply is known to influence the uptake of other plant nutrients, notably phosphorus (P), through its effect on soil pH in the rhizosphere. A glasshouse study was conducted to test the effect of N form (NH +4, NO-3 , or both) on the transformation of soil P in the rhizosphere and its availability to tea (Camellia sinensis L.) plants fertilised with sparingly soluble Eppawala phosphate rock (EPR). Four-month-old tea (TRI 2025) plants were grown in rhizosphere study containers containing an Ultisol from Sri Lanka (pH 4 ·5 in water) amended with EPR and KCl at 200 g P or K/g soil, and mixed with (NH4)2SO4 (100% NH+4 -N), NH4NO3 (50% NH+4 -N and 50% NO-3 -N), and Ca(NO3)2 (100% NO-3 -N) at the rate of 200 g N/g soil, with a control (no N fertiliser), as treatments. Rhizosphere pH decreased compared with the bulk soil when N was supplied as NH+4 or NH+4 +NO-3 forms, and increased when N was supplied as NO-3. The cation{anion balance estimations in the plants showed that the plants had taken up more NO-3 than NH+4 even in (NH4)2SO4 treated soil, suggesting high nitrification rates, especially in the rhizosphere, in spite of using a nitrification inhibitor. More EPR dissolved in the rhizosphere compared with that in the bulk soil, regardless of the N form applied. The (NH4)2SO4 treatment had the highest dissolution rate of EPR in the rhizosphere, whereas Ca(NO3)2 treatment had the lowest, reflecting the degree of acidification in the rhizosphere. Resin-P and NaOH-Pi (inorganic P) concentrations were lower and NaOH-Po (organic P) concentration was higher in the rhizosphere than in the bulk soil. Plant and possible microbial uptake of P is the main reason for the decrease in resin-P and NaOH-Pi. The increase in NaOH-Po concentration in the rhizosphere is believed to be due to transformation of Pi to Po by the high microbial activity in the rhizosphere. The (NH4)2SO4 treatment caused the highest depletion of resin-P but lowest depletion of NaOH-Pi, probably due to the fixation of P by the soils at the low pH in the rhizosphere. The study revealed that the use of the NH+4 form of fertiliser can increase acidification in tea rhizosphere compared with bulk soil and this can enhance the effectiveness of PR fertiliser utilisation by tea plants.

Radiation Interception and Productivity of Willow

(1) Stands of Salix viminalis L. (clone Bowles hybrid), growing near Edinburgh, were studied in two successive years. In 1984, the stands grew from coppiced stumps at 0 5 m spacing in the field. In 1985, the stands grew from cuttings in containers of compost, at 0 3 m spacing, supplied with trickle irrigation and nutrients. (2) Interception of total solar radiation by the canopies was measured using tube solarimeters. Regular harvests were made to determine above-ground dry matter in 1984 and both above-ground and root dry matter in 1985. Leaf area index (L) was also determined, and total stem surface area was estimated in 1985. (3) Accumulated dry matter was linearly related to accumulated intercepted radiation until heavy leaf fall. The slopes of the relationships for above-ground dry matter were 0 99 g MJ-I in 1984 and 1 38 g MJ-1 in 1985. This difference in light-use efficiency (rather than a difference in amounts of light intercepted) was primarily responsible for a difference between years in above-ground dry matter production (11 t ha-1y-I in 1984 and 14 t ha y1 in 1985). Greater efficiency in 1985 was attributed to better water and nutrient supplies and lower levels of incoming radiation. (4) L reached 2 4 in 1984 and 4 5 in 1985. The relationship between L and fractional interceptance (f) was:

Eichhornia crassipes: Production in repeated harvest systems on waste water in the Languedoc Region (France)

This study was carried out with a view to setting up Eichhornia crassipes systems, bringing together biomass production and water purification. The original method attempted allows the study of E. crassipes production (in terms of real harvest values) and the purification results (in terms of biomass removed) on a seasonal and annual basis, using five systems operating in parallel on waste water. These systems have different on-site biomass values, maintained by regular harvests; the harvest is adjusted each time according to system production. Production, conditioned by maximum temperatures greater than 15°C, went on for 6 months, 4/5 (production greater than 20 g m −2 day −1) being concentrated in the three summer months. In integrated harvest systems the mean varies between 40·5 to 47 t ha −1 year −1 DW (30·6–35·2 g DW m −2 day −1 for the whole of the production period). Purification thus corresponds to the removal of 1500–1900 g m −2 of C, 180–220 g m −2 of N and 35–43 g m −2 of P 2O 5. The best system (annual production of 69·5 t ha −1 year −1) in this cultivation mode had an on-site biomass of 13 kg WW m −2 at the beginning of the summer and 33 kg WW m −2 at the end of the summer (the production peak varied somewhat, due to the age and structure of the population, parameters which depend on the season and the harvesting methods). Production and purification of systems limited to a single harvest (at the end of the summer) were inferior by a factor of 3. The discussion concerns production analysis, with regard to different ecological parameters and bibliographical data, and comparison of Eichhornia systems with the other macrophyte systems tested on waste water in the region.

Radiation Inteception and the Growth of Soybeans Exposed to Ozone in Open- Top Field Chambers

SUMMARY (1) Soybeans (Glycine max (L.) Merr. 'Davis') were grown in the field in North Carolina, in open-top chambers which were ventilated with either charcoal-filtered air, or non-filtered air, or non-filtered air to which about 0.02, 0.04 or 0.06 ppm ozone (03) was added for 7 h day-' (10.00-17.00 h EDT). (2) Interception of total solar radiation by the canopy in each treatment was measured with tube solarimeters, integrating the signals electronically on a daily basis. (3) From regular harvests throughout the season, components of above-ground biomass and leaf area index (LAI) were determined., Non-destructive assessments of seed development were also made. (4) During vegetative growth (the first 9 weeks from emergence) the relation between dry matter and radiation intercepted from emergence was linear for all treatments. The slopes of the linear regressions consistently decreased as 03 concentration increased; in the highest 03 exposure the slope was about 30% less than that in filtered air. (5) As 03 concentration increased, the maximum radiation interception attained during the season decreased, and earlier senescence gave a shorter persistence of leaf cover. The seasonal mean value of the fraction of radiation intercepted decreased from 0.68 in filtered air to 0.65 in the highest 03 treatment. (6) Rates of seed growth were not significantly influenced by 03 but the duration of seed growth decreased with increased 03. Exposure to 03 reduced pod number per plant and mean seed weight, but the number of seeds per pod decreased only at the highest 03 concentration. (7) Seed yields in the highest 03 treatment were about 50% lower than in filtered air. Analysis of environmental and biological factors limiting seed yield showed that over the whole season the smaller light interception and shorter duration of growth (emergence to cessation of seed growth) each accounted for less than 7% of the yield loss. More important factors restricting yield were the action of 03 in lowering efficiencies of dry matter production early in the season and in altering seed and pod development. (8) The analysis showed that detailed studies of the interactions in the field between air

Effect of phosphate fertiliser and plant density on phosphate inflow into ryegrass roots in soil

Ryegrass plants were grown in pots of Horotiu sandy loam, either singly or as a dense sward, with a range of P fertiliser rates and regular harvests. Plants were non-mycorrhizal. P inflows into roots increased with P fertiliser rate. Sward plants absorbed up to 14.3% of the P fertiliser added, and single plants up to 7.6%. Sward plants absorbed most of the fertiliser P available to them within two weeks of germinating. After that, root growth ceased except at the highest P fertiliser rate used, and P inflow into roots decreased from 10−15 to 10−16 mole/cm/sec. Single plants, however, had continuous root growth and P uptake throughout the two month experiment, except for those at the two lowest fertiliser rates. Singly grown plants absorbed much more P than each plant in the dense swards. In single plants, root length/root weight ratio increased with increasing P fertiliser. Plant growth was dependant on continued P uptake by the roots, which only occurred if new roots were continally produced and new volumes of soil tapped for P. Non-growing root systems absorbed very little P. re]19760201

Growth and development of buffel grass (Cenchrus ciliaris)

Buffel grass (Cenchrus ciliaris), an important subtropical forage species, was grown under a range of environmental conditions; growth and development were followed by a series of regular harvests. The rates of plant growth and development increased with increasing levels of solar radiation up to the highest levels received (approximately 700 cal/cm2/day). The distribution of dry matter between the various plant organs was relatively unaffected by changes in temperature or mineral level ; differences in partitioning apparently occurred with respect to light intensity, root growth being restricted at the time of flower development at the lower intensities. The implications of the results are discussed with emphasis on possible differences between subtropical and temperate grass species.

Field infestation of cowpea (Vigna unguiculata) pods by beetles of the families Bruchidae and Curculionidae in Northern Nigeria

SummaryAn account is given of a study of infestation of cowpea pods in the field in Northern Nigeria by the weevil, Piezotrachelus varius (Wagn.), and the Bruchids, Bruchidius atrolineatus (Pic) and Callosobruchus maculatus (F.). Oviposition by Bruchids did not commence until the pods were fully formed and light green in colour, whilst infestation by P. varius originated in the young pods. Observations indicated that a high level of parasitism of Bruchid eggs occurred, but that the majority of Hymenopterous parasites emerging from within the pods were related to P. varius.When pods were harvested at regular intervals, large numbers of P. varius emerged from the early harvests only. B. atrolineatus was the predominant Bruchid species emerging, particularly from early harvests. In the case of a single final harvest of pods, large numbers of P. varius, and a higher level of infestation by B. atrolineatus than in pods collected at regular intervals, were recorded.Shelling of four batches of pods indicated a mean of 11 per cent, of seeds attacked by Bruchids in the case of single final harvests, and a mean of only 3·5 per cent, in the case of regular harvests as pods became dry. It is concluded that a considerable improvement in quality would result from an adoption of the latter method by farmers, provided that some method of control in respect of the harvested pods were introduced.From the observations made it is concluded that P. varius is a true field pest, B. atrolineatus primarily a field pest able to continue infestation in store to a very limited extent, and C. maculatus primarily a store pest able to commence its infestation in pods in the field and to build up in numbers rapidly during the immediate post-harvest storage period.The normal manner of cultivation precludes the use of field methods of control at oviposition peaks but observations suggest that elimination of secondary hosts of P. varius and B. atrolineatus might be worthwhile. A reduction in oviposition by C. maculatus by treatment of stored cowpeas in growing areas, and treatment of pods during the immediate post-harvest storage period, should considerably reduce the level of infestation by this species.