Growth studies with hemp (Cannabis sativa L.) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Horticultural Science at Massey University

The effect of latitude, sowing date and density on yield, height and growing time were studied by sowing two varieties of hemp for seed at three sites in New Zealand. Predation and poor germination hampered results. Latitude effects on height could not be confirmed but Anka, unlike Finola, suffered a reduction in height with later sowing. Anka was the larger plant with higher seed yield, but the dwarfed Finola gave a higher harvest index. Thus seed yield for later sowing is reduced for cv Anka, unchanged for cv Finola. Plant density data allowed estimated yields at 30, 60 and 90 plants.m-2 to be determined. At 30 plants.m-2, seed yield in both varieties was reduced with later sowing, and confirmed Anka with the greater gross yield against Finola having the higher harvest index. At 60 and 90 plt.m-2, the results confirmed only that Anka is the bigger plant. Earlier sowing than the 1st sowing in our trial (October) could be an advantage. Higher sowing rates than 40-50 plt.m-2 would be of little advantage for Anka, but rates higher than 90 plt.m-2 should be explored for Finola. The asymptotic yield maximum for Anka falls dramatically with later sowing, whereas Finola does not. This suggests double cropping might be explored, with an early sowing of Anka followed by Finola. Growing time data indicated the lower latitude site had longer growing times overall. Day length sensitivity (shorter growing time with later sowing) was confirmed for Anka, but Finola was unaffected. This suggests Finola is a day-length neutral plant. Leaf production in both varieties was higher at higher latitudes, and was reduced by later sowing date. A second experiment examined the nitrogen and phosphorus uptake of a fibre hemp cultivar (EIL1) with respect to three sowing dates and two latitudes. Harvests were taken monthly to establish growth trends. From biomass figures, equations were established for leaf/stem relationships. Uptake values (on a dry matter basis) tended to stabilize as the plant matured at: N(stem) 3.04%, N(leaf) 4.5%, p(stem) 0.26% and P(leaf) 0.45%. High initial concentration of both N and P fell rapidly. For maximum uptake seed should be sown early (October or earlier) and plants grown as long as possible (5 months or more)

Relationship between the timing of seedbed preparation and the efficacy of pre-emergence flaming

The field experiments were conducted in 1995 and 1996. Seedbed preparation was done with a rotary tiller to 15-20 cm depth either 5-7 days prior to sowing of carrot or at the day of sowing. In both cases, flaming was done 8 days after sowing

Sowing Organic Seeds

There is a growing realisation that only the adoption of ecological and sustainable farming practices can reverse the declining trend in farm productivity in the state of West Bengal, India. The paper is on how a small holding (3.8 acres) family farm in a remote dry land area in India demonstrates what can be achieved by way of love for land and nature, self-determination, innovation and hard work. The educated farm family has neatly woven traditional knowledge and modern improvements in agricultural science for developing their organic farm and sustenance of nature. The income from the farm meets their domestic and social needs. Their child goes to one of best private English medium school. There have been noticeable positive changes among the neighbouring farmers, soil and ecology

The effect of perennial ryegrass (Lolium perenne) sowing rates on weed establishment, after one year : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Plant Science at Massey University

Two trials were conducted to determine whether the weed control benefits of high sowing rates of perennial ryegrass (Lolium perenne) continued into the second year after sowing. Seeds of Scotch thistle (Cirsium vulgare), nodding thistle (Carduus nutans), ragwort (Senecio jacobaea) and hedge mustard (Sisymbrium officinale) were sown into established perennial ryegrass and white clover (Trifolium repens) swards both in trays and in the field, in late autumn. The emerging weed seedlings were mapped at intervals to enable their fate to be followed. In the trays, seedlings were mapped at four week intervals, and the experiment continued for four or five months, depending on the species. In the field, weed seedlings were mapped both before and after each grazing and the experiment continued for seven months. The trays with low ryegrass sowing rates had a higher density of white clover than those trays with high ryegrass sowing rates. In the field plots with low sowing rates, both the broad-leaved weed population and volunteer grasses were more abundant than in the high ryegrass sowing rate plots. This resulted in the different treatments having a similar competitive ability against the sown weed seeds, one year after the swards were sown. Both nodding thistle and Scotch thistle emergence was extremely low in the bare ground trays, probably relating to seed predation of these large seeds off bare soil. Scotch thistle and hedge mustard emergence were both reduced by high sowing rates of perennial ryegrass when compared to trays and field plots sown with white clover only. Nodding thistle and ragwort however provided some unusual results. Both of these species experienced an increase in total emergence as ryegrass sowing rate increased. With nodding thistle, this occurred in the field and with ragwort, in the trays. This obviously was unexpected but in reality the increases in emergence, although significant, were small and of little practical importance. The increases probably related to the similar competitive ability of the swards one year after pasture sowing. Emergence of ragwort in the field and nodding thistle in the trays was not affected by ryegrass sowing rate. For all species, in both the field and the trays, emergence was delayed as the sowing rate increased. There was very low mortality in the tray experiment. Mortality was much higher in the field due to the effects of grazing animals and also the longer time frame of the field experiment. All hedge mustard seedlings that emerged in the field were killed, and only one nodding thistle seedling survived to the end of the experiment. With both Scotch thistle and ragwort, seedlings seemed to have a higher chance of surviving in the high density ryegrass treatments, probably due to the physical protection from grazing animals provided by ryegrass. High mortality in the field experiment rendered seedling size data meaningless. In the trays, for all species, the heaviest seedlings were found in the treatments with either bare ground or where only clover was sown, indicating that competition from ryegrass had a serious negative effect on weed size. Weed size did not vary significantly as ryegrass sowing rate increased. In conclusion it would appear that most of the weed control advantages from higher sowing rates of perennial ryegrass are obtained in the first year after sowing, as all swards that contain perennial ryegrass appear to have a similar competitive ability against invading weeds in the second year after sowing

Sowing time affects the abundance of pests and weeds in winter rye

Selection of an appropriate sowing time for some winter rye (Secale cereale) cultivars could reduce the need for crop protection measures. In this study the occurrence and status of pests and weeds in relation to sowing time and growth habit of winter rye was studied in southern Finland. This was done using three sowing times and four rye varieties in field trials conducted at three locations in 1999–2001. The early sown rye was severely affected by pests (Oscinella frit, Mayetiola destructor) and weeds, whereas postponing sowing for two weeks after the recommended sowing time in late August resulted in considerably less damage and the optimal establishment of crop stands. The German hybrid varieties Picasso and Esprit produced more tillers m-2 in autumn than the Finnish varieties Anna and Bor 7068. However, the number of pests and weeds did not differ among rye varieties. Late sowing of rye should be considered to minimize the need for plant protection. If rye is sown at the recommended time it may still require insecticide treatments promptly in the autumn whereas herbicide treatment need not be determined until spring, after recording the winter mortality of weeds

Researches of pneumatic sowing machine with peripheral cells location and inertial superfluous seeds extraction

In the article we provide the new design of pneumatic sowing machine with peripheral cells on the seed disk and a passive device for removing extra seeds with inertia method for precise seeding of cultivated crops. A series of studies was proposed for sugar beet seeds sowing device, we defined the influence of dilution in a vacuum chamber of sowing device and angular velocity cell seed disk on the cells filling factor. The design of the new pneumatic sowing machine can significantly reduce the vacuum in the system having increased the angular speed in cell seed disk to the values of seeding device travelling speed, thus provide a constant point of seeds drop from the seed disc at the same trajectory of their flight to the furrows and the qualitative cells filling. To determine the rational parameters and modes of sowing device we used method of multifactor experiment planning. We determined the main levels and intervals of varying factors for sugar beet sowing along with determining the filling factor of cell seed disk. With application of package Statistica 6.0. for parameter optimization - cell seed disk filling factor was constructed response surface and line of even output

Impact of spring warming on sowing times of cereal, potato and sugar beet in Finland

Historical data were used to determine if the warm springs experienced in recent decades have influenced time of sowing of spring cereals (barley, wheat and oats), potato and sugar beet in Finland. The start of the thermal growing season was used to represent all climatic factors affecting sowing time. Regional anomalies in sowing and start of growing season were computed for the years 1965–2007. The start of the growing season was 2–2.8 days earlier per decade, with a steeper increase since 1980. Sugar beet sowing advanced 2.5 (since 1980 5.2) and potato planting 3.4 (since 1980 4.5) days per decade, more than expected solely due to earlier starts to the growing season. Sowing of spring cereals advanced 0.6, 0.7 and 1.7 days per decade in the east, north and west respectively (since 1980 1.0, 1.9 and 3.1), with statistically significant trend (p < 0.01) in the west. Earlier sowings can be largely explained by warmer springs, but the trend was not as steep as that for the growing season. This has however not led to increased temperatures during early vegetative phases and thus faster development and increased drought or pest risk, which would have reduced the positive effects of earlier sowing on yield potential. Earlier sowing detected in the west can be explained by changes in spring temperatures, but may also result from economic and technological development. Farmers seem to have adequately adjusted their field activities to the changes in spring temperatures

Effect of Different Dates of Dry Seeding and Staggered Nursery Sowing on Growth and Yield of Kharif Rice

A field experiment was conducted to study the effect of different dates of dry seeding and staggered nursery sowing on growth and yield of Kharif rice. The experiment was based on the difficulties faced by the farmers in the coastal areas of Andhra Pradesh and those who depend on canal irrigation and are located at the tail end areas. The experimental results have showed no difference among the methods of stand establishment in terms of yield. However, among the dates of sowing the delay in sowing beyond 30th July significantly reduced the grain yield and returns per rupee invested. It has been concluded that the rice crop may be established either by direct seeding or by transplanting nurseries but the sowing of the respective cultures should be done by the end of July for obtaining maximum yield and profits

Effect of Different Dates of Dry Seeding and Staggered Nursery Sowing on Growth and Yield of Kharif Rice

A field experiment was conducted to study the effect of different dates of dry seeding and staggered nursery sowing on growth and yield of Kharif rice. The experiment was based on the difficulties faced by the farmers in the coastal areas of Andhra Pradesh and those who depend on canal irrigation and are located at the tail end areas. The experimental results have showed no difference among the methods of stand establishment in terms of yield. However, among the dates of sowing the delay in sowing beyond 30th July significantly reduced the grain yield and returns per rupee invested. It has been concluded that the rice crop may be established either by direct seeding or by transplanting nurseries but the sowing of the respective cultures should be done by the end of July for obtaining maximum yield and profits