October Sowing Research Articles

The kill date as a management tool for cover cropping success.

Integrating cover crops (CC) in rotations provides multiple ecological services, but it must be ensured that management does not increase pre-emptive competition with the subsequent crop. This experiment was conducted to study the effect of kill date on: (i) CC growth and N content; (ii) the chemical composition of residues; (iii) soil inorganic N and potentially mineralizable N; and (iv) soil water content. Treatments were fallow and a CC mixture of barley (Hordeum vulgare L.) and vetch (Vicia sativa L.) sown in October and killed on two different dates in spring. Above-ground biomass and chemical composition of CC were determined at harvest, and ground cover was monitored based on digital image analysis. Soil mineral N was determined before sowing and after killing the CC, and potentially mineralizable N was measured by aerobic incubation at the end of the experiment. Soil water content was monitored daily to a depth of 1.1 m using capacitance sensors. Under the present conditions of high N availability, delaying kill date increased barley above-ground biomass and N uptake from deep soil layers; little differences were observed in vetch. Postponing kill date increased the C/N ratio and the fiber content of plant residues. Ground cover reached >80% by the first kill date (∼1250°C days). Kill date was a means to control soil inorganic N by balancing the N retained in the residue and soil, and showed promise for mitigating N losses. The early kill date decreased the risk of water and N pre-emptive competition by reducing soil depletion, preserving rain harvested between kill dates and allowing more time for N release in spring. The soil potentially mineralizable N was enhanced by the CC and kill date delay. Therefore kill date is a crucial management variable for maximizing the CC benefits in agricultural systems.

Influence of date of sowing and nutrient management practices on sustainable production of Indian mustard (Brassica juncea) under sub-temperate condition of eastern Himalaya

A field experiment was conducted during winter season of 2011–13 to study the influence of date of sowing and nutrient management practices for sustainable production of mustard under sub- temperate condition. The field experiment was conducted with split plot design with three replications, having 24 treatment combinations including four dates of sowing in main plot and six sub-plot treatments. Number of siliquae/plant, considerably maximum of 125.11 with 30 October sowing, and was at par with the 15 November (121.11) sowing. With respect of sub-plot treatments maximum of this parameter was found with the application of 125% RDF+PSB+Azotobacter (129.14), and showed parity with 100% RDF+PSB+Azotobacter (117.65) application. Seeds/siliqua were highest recorded with 30 October sowing, and significantly better than other sowing date except 15 November sowing. Sub-plot treatment revealed that more seeds/siliqua were registered with the use of 125% RDF+PSB+Azotobacter, and were statistically alike in response with the 125% RDF+vermicompost (@1.25 t/ha) and 100% RDF+PSB+Azotobacter. Significantly maximum seed yield of 1.21 t/ha was obtained under 30 October sowing, and was statistically at par with 15 November sowing date (1.11 t/ha). Amongst various fertility level treatments, highest seed yield was observed with the application of 100% RDF+PSB+Azotobacter (1.30 t/ha), and this was statistically comparable to 125% RDF+PSB+Azotobacter (1.26), 125% RDF+vermicompost (@1.25 t/ha) (1.15 t/ha) and 100% RDF+PSB+Azotobacter (1.04 t/ha). Economics revealed that 15 October sowing gave good returns (Rs. 20,036) and highest benefit: cost ratio (1.99). This was closely followed by 30 October sowing with benefit: cost ratio (1.98). Further, with sub-plot treatment highest net return (Rs. 30,256) were observed with the application of 100% RDF+PSB+Azotobacter with B: C ratio of 2.19.

Field Technique and Traits to Assess Reproductive Stage Cold Tolerance in Sorghum (Sorghum bicolor (L.) Moench

Post-rainy season sorghum (Sorghum bicolor (L.) Moench) yields are often constrained by cold stress. Cold tolerance is a prerequisite for adaptation to post-rainy season. A study was conducted to develop a field screening technique for cold tolerance, and to identify traits that discriminate genotypes to cold response. A set of rainy and post-rainy season adapted sorghum genotypes were sown in 2010 – 2011 and 2011 – 2012 in 3 dates of sowing in post-rainy seasons from third week of October to second week of November. The average minimum temperature during a 30-day period after the initial 40-day vegetative growth was lower in October sowing, moderate in November sowing and high in December sowing. The panicle harvest index (PHI) was found to be sensitive to low temperatures and was identified as a stable trait for genetic discrimination. Reduction in PHI can be indicative of failure to set seed or poor grain filling. The genotypes bred for rainy season ICSB 52, ICSR 149 and ICSR 93034 exhibited reduced PHI and lighter seed in cold-prone environments, indicating that their sensitivity is also well reflected in the yields of ICSB 52 and ICSR 149. However, the genotypes bred for post-rainy season, Dagadi solapur, SPV 1411 and M 35-1, were not affected by cold, as indicted by their higher PHI and relatively less reduction in seed weight. It was suggested that PHI and seed weight together can be used as proxies in selecting for reproductive stage cold tolerance in sorghum.

Standardization of sowing date and cultivars for seed production of garden pea (Pisum sativumvar.HortenseL.) under north western himalayas

An experiment was conducted during 2007-2008 and 2008-2009 to study the seed production of garden pea cultivars at variable sowing dates. The study was conducted in split plot design replicated thrice with sowing dates starting from 31st October in main plots and four varieties namely, ‘Azad P-1’, ‘Palam Priya’, ‘Arkel’ and ‘Pb-89’ in sub-plots. Different dates of sowing and varieties significantly influenced phenology and seed yield along with yield contributing traits. The early sowing on 31st October significantly increased the seed yield by 13% and 41% over 10th November and 21st November, respectively. Among the varieties, ‘Palam Priya’ out performed ‘Azad P-1’ and ‘Arkel’ for seed yield with an increase of 38 and 113 % while ‘Pb-89’ had an edge of 34 and 107% over these varieties. Interaction effects revealed that sowing beyond 31st October did not result in decline in seed yield in some cultivars. The highest seed yield was recorded in ‘Palam Priya’ on 31st October and 10th November and that of ‘Pb-89’on 31st October sowing dates over ‘Azad P-1’ and ‘Arkel’. Hence, sowing on end October in ‘Pb-89’ and that of ‘Palam Priya’ from end October to first quarter of November were the most ideal combinations to obtain higher seed yield in garden pea under sub-humid temperate environment.

Calibration of WAVE in Irrigated Maize: Fallow vs. Cover Crops

Nitrate leaching decreases crop available N and increases water contamination. Replacing fallow by cover crops (CC) is an alternative to reduce nitrate contamination, because it reduces overall drainage and soil mineral N accumulation. A study of the soil N and nitrate leaching was conducted during 5 years in a semi-arid irrigated agricultural area of Central Spain. Three treatments were studied during the intercropping period of maize (Zea mays L.): barley (Hordeum vulgare L.), vetch (Vicia villosa L.), and fallow. Cover crops, sown in October, were killed by glyphosate application in March, allowing direct seeding of maize in April. All treatments were irrigated and fertilised following the same procedure. Soil water content was measured using capacity probes. Soil Nmin accumulation was determined along the soil profile before sowing and after harvesting maize. Soil analysis was conducted at six depths every 0.20 m in each plot in samples from 0 to 1.2-m depth.The mechanistic water balance model WAVE [1] was applied in order to calculate drainage and plant growth of the different treatments, and apply them to the N balance. We evaluated the water balance of this model using the daily soil water content measurements of this field trial. A new Matlab version of the model was evaluated as well. In this new version improvements were made in the solute transport module and crop module. In addition, this new version is more compatible with external modules for data processing, inverse calibration and uncertainty analysis than the previous Fortran version.The model showed that drainage during the irrigated period was minimized in all treatments, because irrigation water was adjusted to crop needs, leading to nitrate accumulation on the upper layers after maize harvest. Then, during the intercrop period, most of the nitrate leaching occurred. Cover crops usually led to a shorter drainage period, lower drainage water amount and lower nitrate leaching than the treatment with fallow. These effects resulted in larger nitrate accumulation in the upper layers of the soil after CC treatments.

Effect of Time of Sowing and Plant Spacing on Broccoli Production

A field experiment was conducted at Agricultural Research Station, BARI, Thakurgaon during rabi season, 2009/10 to find out the optimum time of sowing and plant spacing on broccoli production. Three sowing time viz. (i) 1 October, (ii) 15 October and (iii) 30 October and three plant spacing viz. (i) 60 x 40cm, (ii) 60 x 50cm and (iii) 60 x 60cm were included in the study. Yield and yield contributing charac-ters were significantly influenced by the treatments. 1 October sowing produced the highest yield (21.39 t/ha) and 30 October sowing produced the lowest yield (13.6t/ha) of broccoli. On the other hand, closer spacing (60 x 40cm) produced the highest yield (18.8t/ha) which was statistically similar to 60 x 50cm (17.6t/ha) and lowest yield (16t/ha) was obtained from 60 x 60 cm spacing. 1 October sowing and 60 x 40cm plant spacing combination produced the highest yield (22.5t/ha) which was statistically similar to 1 October sowing and 60 x 50cm plant spacing (21.9t/ha) and the lowest yield (12.8t/ha) was produced from 30 October sowing and 60 x 60cm plant spacing combination. DOI: http://dx.doi.org/10.4038/tare.v14i4.4849 Tropical Agricultural Research & Extension 14(4): 2011 90-92

Effect of Sowing Dates and Varieties on the Severity of Alternaria Blight of Mustard

A study was carried out to find out the effect of sowing dates and varieties on the severity of Alternaria blight of mustard. Seeds of eight mustard varieties were sown on four different dates. Data on severity of the disease and seed yield were recorded. Disease severity differed significantly among the varieties. B. campestris varieties showed the higher disease severity compared to B. napus and B. juncea. The lowest disease severity was recorded in BARI Sarisha 11 which produced the highest seed yield. Percentages of leaf area diseased, leaf infection, siliqua infection, and spots per siliqua were found lowest under 21 October sowing, which were statistically lower than other sowing dates. The highest seed yield (1727 kg/ha) was recorded under 01 November sowing followed by 21 October sowing. Combination of sowing dates and varieties had a significant influence on disease severity and seed yield. Early sown (21 October and 1 November) BARI Sarisha 11 showed less disease severity and gave higher seed yield than other treatment combinations DOI: http://dx.doi.org/10.3329/bjar.v36i4.11746 Bangladesh J. Agril. Res. 36(4): 583-594, December 2011

Performance of two winter cover crops and their impacts on soil properties and two subsequent rice crops in Dongting Lake Plain, Hunan, China

Winter cover cropping is a common practice in paddy soils in southern China. This two year study (2008–2010) was undertaken to determine dry matter productivity and N uptake of two winter cover crops: ryegrass (Lolium multiflorum Lam.) and Chinese milkvetch (Astragalus sinicus L.) and their effects on soil properties as well as two subsequent rice (Oryza sativa L.) crops in Dongting Lake Plain in Hunan, China. Cover crops were broadcast sown in October, approximately 10d before the harvest of late rice. Ryegrass was first cut in March and finally harvested in April coincident with the plough of milkvetch. Two consecutive rice crops were grown following the cover crops without application of chemical N. Averaged over two years, ryegrass produced more aboveground dry matter and accumulated higher amounts of N than milkvetch (4.7Mgha−1 vs. 2.4Mgha−1, 128kgha−1 vs. 71kgha−1). Compared to CK (bare fallow without weed), both ryegrass (RG) and milkvetch (CMV) treated plots had lower soil bulk density at 0–15cm and 15–30cm depths. At the harvest of cover crops, CMV increased soil NH4+-N concentration at 0–10cm, 10–20cm and 20–30cm depths. In contrast, RG decreased soil NH4+-N and NO3−-N concentrations in the three depths. Averaged over four sampling dates in the double rice seasons in 2010, soil microbial biomass C was slightly different between RG (257mgkg−1) and CMV (249mgkg−1), and these were significantly higher than CK (218mgkg−1). Soil microbial biomass N was highest for CMV (15.4mgkg−1), followed by RG (11.3mgkg−1) and CK (6.1mgkg−1). Grain yield and total N yield of early rice were 0.6Mgha−1 and 11kgha−1 higher for CMV, respectively, and 1.0Mgha−1 and 20kgha−1 lower for RG as compared with CK averaged over years. Grain yield and total N yield of late rice were not significantly affected by cover crops.

Yield Response to Pea (Pisum sativum L.) Genotype, Population and Sowing Date

This research objective was to examine the effect of herbicide, genotype, population and sowing date on crop yield and weed growth in Pisum sativum. In 2007/08, cyanazine treated peas had a mean seed yield of 508 g m -2 , 19% more than in unsprayed plots. There was a significant sowing date by pea genotype interaction which showed that in the August sowing genotype had no effect on seed yield. However, in September Pro 7035 yielded 559 g m -2 , which was 40% more than Midichi. By the October sowing, it was 87% more. There was a distinct variation in weed spectrum, over time. It can be concluded that fully leafed peas and semi-leafless can be sown at similar plant populations and give similar yields under weed free conditions and that increased pea sowing rates increased total dry matter and seed yield in weedy environments. Fully leafed peas yielded more than semi-leafless peas when both were late sown. Increased pea sowing rate improved weed suppression.

Nitrogen and phosphorus leaching losses from potatoes with different harvest times and following crops

A 3-year field study (2007–2009) was conducted in separately tile-drained plots on a sandy soil in south-west Sweden to determine nitrogen (N) and phosphorus (P) leaching losses from potatoes to the drainage system. Different types of potatoes were grown and harvested at different times followed by different crops in order to identify the potato type/following crop system with the lowest risk of N and P leaching losses. Accumulated annual amounts of N and P lost to drainage between May (potato planting) and the following April varied between 13 and 72kgNha−1 and 0.04 and 0.24kgPha−1 depending on treatment and year. P leaching losses from this particular soil were low and differences between potato types not distinct, but there were significant differences between years. Abnormally high precipitation in summer 2007 led to significantly higher P leaching losses than in other years. N leaching losses were also higher in 2007, but differences between potato types were found in all years. Despite the high mineral soil nitrogen content (Nmin) after harvest in June, early potatoes (EP) with oilseed radish (oil) as catch crop showed the lowest N leaching losses of all potatoes. Potatoes harvested in August (table potato; TP) and September/October (late potato; LP) followed by triticale (tri) sown in October showed the highest leaching losses. Thus under current climate conditions in Sweden, oilseed radish after EP is a suitable catch crop for N, while triticale sown in October is ineffective in preventing N leaching after potatoes. The late harvest of starch potatoes (SP) did not allow establishment of a following crop. However, SP showed lower N leaching losses than TP+tri and LP+tri due to lower residual Nmin in deeper soil layers, low temperatures after harvest decreasing soil N mineralisation and higher C:N ratio of the potato haulm leading to lower N mineralisation potential. As a mean of all years, N leaching losses during and after EP+oil and SP were similar to those from the reference crop spring barley (SB), whereas TP+tri and LP+tri require countermeasures against N leaching.

Determination of Seed Quality Tests of Wheat Varieties under the Response of Different Sowing Dates and Nitrogen Fertilization

3 Abstract: A two years field study was conducted to determine seed quality tests of wheat varieties under the response of different sowing dates and nitrogen fertilization at New Developmental Farm of Khybe r Pakhtunkhawa Agricultural University, Peshawer, Pakistan under agro-climatic condition of Peshawar valley during 2008-09 and 2009-10. The experiment was laid out according to randomized complete block design having split plot arrangements with four repeats. Four planting dates (24th October, 13th November, 3rd December and 23rd December) with 20 days intervals allocated to main plots whole 4 levels of nitrogen (0, 100, 130 and 160 kg N/ha) along with two varieties (Pirsabak 2005 and Khyber-87) were allotted to sub plots. Wheat crop responded differently to sowing dates and nitrogen fertilization for various characters. Highest standard germination, field emergence, accelerated aging germination test and seedling dry weight were recorded under 24th October sowing but lowest values were obtained under delay seeded condition. Similarly these seed quality attributes of Khyber-87 significantly affected by nitrogen application. Early (Oct. 24th) seeding date in combination with 130 kg N/ha accelerated seed quality attributes of Khyber-87 whereas late seeded condition declined these parameters even using maximum dose of nitrogen.

Desempenho da cultura do milho implantada sobre resíduos culturais de leguminosas de verão em sistema plantio direto

The no-tillage system management is considered as an agricultural system very close to sustainability, since it causes less impact to the environment. The crops rotation, when well managed, includes the use of green manure; and leguminous are included in this system as they bring a number of benefits. This context, the study aimed tested leguminous as cover plants on soil with a no-tillage system regarding the growth, yield and maize seeds quality. This decision-making looks for alternatives that contribute for the agroecosystem sustainability, since they allow rational adoption of green manure in production units. The experiment was carried out in the field with leguminous species dwarf mucuna beans, dwarf pigeon pea and stylosanthes, sown in October 2007, in 4 x 5 m plots, with five replications. At 90 days after the cover crops sowing, the leguminous plants were grazed and corn plants were sown 15 days after grazing on waste. The plants heights were determined during the culture development. At the laboratory, after harvest, the productivity and physiological quality of seeds were determined. The experimental design was completely randomized and the averages were compared by the Scott-Knott test at 5% of significance. At 60 days after the maize crop sowing, the treatments with dwarf mucuna beans and dwarf pigeon pea showed higher heights. The other analyzed parameters did not differ among themselves, showing that the treatments not interfere on the maize crop. Actually, it is an alternative to the integrated management of species concerning the summer green manure and crop rotation in no-tillage system.

An investigation into the effects of sowing time, N and P fertilizers on seed yield, oil and protein production in Canola

Canola (Brassica napus L.) has been grown in Kerman province, Iran, for many years. However, little information is available on its response to sowing date, nitrogen (N) and phosphorous (P) fertilizers. Therefore, a field study was conducted in a research station located 17 km southwest of Kerman, investigating the effects of early and late October sowing, N and P fertilization in 2005 and 2006. The design used with split plot arrangement was randomized complete block design. Canola was sown after barley and alfalfa in the first and second year, respectively. At early October sowing 2005, 3.4 t seed ha−1 were obtained with fertilization of 300 kg N ha−1 and 50 kg P ha−1. In 2006, alfalfa had enriched soil with N. Consequently, at early October sowing 2006, 200 kg N ha−1 and 50 kg P ha−1 produced 3.9 t seed ha−1. N and P fertilizers had increased total dry matter accumulation and seed yield, while oil and protein production were increased as a result of seed yield increase. Delayed sowing reduced growth; therefore, seed, oil and protein production were decreased. It is concluded that sowing time and fertilizing according to soil test results cause optimum canola yields.

Achievements in breeding autumn-sown annual legumes for temperate regions with emphasis on the continental Balkans

Annual legumes represent one of the basic elements of the agriculture of Serbia. Until recently, only annual forage legumes such as pea or vetches were autumn-sown in Serbia and other neighbouring regions of the continental Balkan Peninsula. During the last decade, the first crucial steps in the development of autumn-sown grain legumes were made, with emphasis on dry pea, faba bean and dual-purpose vetches. The winter forage pea cultivars developed in Serbia are generally characterised by prominent winter hardiness and a rather extended growing season, usually beginning with sowing in early October and ending either by cutting for forage production in late May or harvesting seeds in mid-July. One of the strategic advantages of recently released cultivars of autumn-sown dry pea is their significantly improved earliness. The Serbian winter dry pea cultivar Mraz, newly registered in Serbia and developed from hybrids between French and Serbian autumn-hardy materials, is regularly at least a week earlier than winter barley, so many farmers will not have to choose between pea and cereals due to limited harvesting resources. The initial material for pre-breeding autumn-sown faba bean in the conditions of Serbia consisted of both collected local landraces of Serbia and populations from France and Germany. The preliminary results of their agronomic performance showed that they have a great potential for high grain yield in the conditions of Serbia. Promising results in breeding winter hardy cultivars were achieved with several vetch species, as well as with lentil and grass pea, and will be continued with more species including Medicago truncatula.

The impacts of different habitats on the development of Telekia speiosa (Schreb.) Baumg.

Telekia speiosa (Schreb.) Baumg. is a 100-150 cm high bushy perennial, which has yellow flowers and smells good. According to the descriptions (Farkas, 1999), it can be detected in two smaller areas within Hungary, namely in the Bükk hills and on the Szatmár-Bereg Plain. By the time of writing this paper, the population around Tiszabecs has already got extinct. Therefore, it is a protected relict species. It is named in honour of Sámuel Teleki, chancellor of Transylvania.Within the frame of the experiment, the Telekia speciosa (Schreb.) Baumg. was planted to places differently illuminated (sunny, semi shadow, shade), then the morphological changes brought about the various light conditions were investigated. The experiment was launched with a stock sown in October 2008. The seedlings were planted to three beds with diverse light conditions. The area of each bed was 1 m2, and ten seedlings were planted per m2. The parameters investigated are as follows: the length of leaf blade, the width of leaf blade, the length of petiole, the number of leaves per plant, and the alterations of leaves. As a result of our research, we can state that semi shadow is the optimal habitat for the plant. Under such ecological conditions the highest leaf production was observed, the leaves were species specific, healthy and big. The mean number of leaves per plant was 6.6, the mean length of blade was 16.6 cm, the mean width of blade was 13 cm, while the mean length of petiole was 14.2 cm. In the shade the plants grew poorly and the size of leaves were smaller. The mean number of leaves per plant was 4.1, the mean length of blade was 8.6 cm, the mean width of blade was 7.1 cm, and the mean length of petiole was 9.4 cm. In the sunny habitat a similarly high leaf production was observed as in the semi shadow; however, the leaves had brownish spots, they shriveled, feel rough, so they revealed a reduced aesthetical value. The mean number of leaves per plant was 6.6, the mean length of blade was 17.8 cm, the mean width of blade was 11.3 cm, and the mean length of petiole was 13.1 cm.

Crop growth and nitrogen turnover under increased temperatures and low autumn and winter light intensity

The rise in mean annual temperatures under the projected climate change will affect both soil organic matter turnover and cropping patterns in agriculture. Nitrogen (N) mineralization may be higher during autumn and winter and may increase the risk of nitrate leaching. Our study tested whether a soil cover of winter wheat or a ryegrass catch crop would be able to take up the extra N mineralized during autumn and winter under the low light conditions in Northern Europe, both at current average temperatures ( T 0) and at 4 °C ( T +4) and 8 °C ( T +8) above average. The crops were grown in pots in growth chambers from mid-September to February. Two sowing times were included for winter wheat, with an early sowing in September representing current practice and a late sowing in October to reflect possible future cropping conditions. Biomass yield and soil inorganic N were determined from replicate pots in November, December and February. Reference pots with bare soil were included. N mineralization clearly increased with higher temperatures with, respectively, 22% and 80% more N mineralized in bare soil at T +4 and T +8 than at T 0 after 136 days. The ryegrass catch crop emptied the soil of inorganic N very efficiently during both autumn and winter months at all temperatures. The early-sown wheat crop left negligible amounts of inorganic N in the soil at the last harvest in February at T +4 and T +8, whereas it was unable to take up all mineralized N at T 0. The prolonged period without a crop before the late sowing of wheat caused generally higher levels of inorganic N to accumulate in soil. Despite the higher mineralization under the raised temperatures, at T +8 the late-sown winter wheat was able to reduce soil inorganic N to a lower level than late-sown wheat at the two lower temperatures. The results indicate that even at the low light intensity during autumn and winter, accelerated N mineralization caused by raised temperatures can potentially be offset by crop N uptake. However, sowing should take place sufficiently early in the autumn to give the crop time to capture the additional N mineralized during autumn, and this may collide with the projected need for later sowing of winter cereals under a warmer climate.

Effect of the sowing date on the growth of hairy vetch (Vicia villosa) as a cover crop influenced the weed biomass and soil chemical properties in a subtropical region

Weeds emerge throughout the year in agricultural fields in subtropical regions. The weed suppression and improved soil fertility resulting from a living mulch of hairy vetch were investigated. Hairy vetch was sown in October and in December 2006. The fallow condition was without the sowing of hairy vetch, with the weeds allowed to grow naturally. The biomass of the top parts (BOT) of hairy vetch increased from February to April and then decreased in May on both sowing dates. The BOT of hairy vetch sown in October was significantly higher in February, March, and April than that sown in December. Hairy vetch sown in October and harvested from February to April varied from 372–403 × 10−3 kg m−2, with weed suppression percentages of 62.8% in comparison with the fallow plots. The fixed C, N, P, and mineral uptake of hairy vetch showed similar patterns to its biomass. The nitrate (NO3‐N) content increased from February to May for the soils in the October and December plots, in contrast to the fallow plots. Moreover, the NO3‐N and available N of the October and December soils sampled from February to May were higher than that of the fallow soils. In subtropical agriculture, hairy vetch should be sown in October in order to achieve a higher biomass for suppressing weeds effectively and improving the soil fertility, mainly N.

Growth, nitrogen fixation, and nutrient uptake of hairy vetch as a cover crop in a subtropical region

Hairy vetch (Vicia villosa), as a winter cover crop, can be used to suppress weeds in subtropical regions, as well as temperate regions. Information on the potential biomass growth of hairy vetch for weed control and nutrient accumulation is not available in subtropical regions. Hairy vetch was sown in November 2004, and October, November, and December 2005. The wide‐ranging cultivation period of hairy vetch indicated that it could be used in various cropping systems. It showed a higher biomass and nutrient accumulation when grown in subtropical Okinawa, Japan. Moreover, the biomass, and fixed carbon and magnesium (Mg) uptake in the above‐ground parts of hairy vetch were found to be the highest in late May, with the highest nitrogen (N), potassium, and calcium uptake in mid‐April and phosphorus (P) uptake in late March. Meanwhile, in the underground parts of the plant, they were highest in early May, except for the P and Mg uptake, which were highest in mid‐April. According to the sowing date, the biomass and nutrient uptake of hairy vetch that was harvested in February were higher when sown in October. Similarly, when harvested in March, the biomass and nutrient uptake were higher when sown in October or November. In April, they were higher when sown in November or December. Hairy vetch has the potential to effectively suppress weeds in the winter and the spring seasons related to its sufficient biomass during the growing seasons. However, both the sowing and harvesting times of hairy vetch should be considered with reference to the cropping system; the subsequent crop will be sown to meet the N requirement.

Evaluation of suitable tropical sugarbeet hybrids with optimum time of sowing

The investigation was carried out in tropical sugarbeet at Tamil Nadu Agricultural University, Coimbatore to evaluate optimum time of sowing with suitable hybrids. The experiment was conducted in strip plot design. The main plot consists of four times of sowing (15 days interval from 1st September to 15th October) and three tropical sugarbeet hybrids (Cauvery, Indus and Shubhra) in sub plot. Higher crop biometrics of tropical sugarbeet was recorded in October 1st sowing and was on par with 15th September and 15th October sowing. The yield characters and yield (72 and 88 tha−1 during 2005 and 2006 respectively) of tropical sugarbeet and brix reading were higher in 1st October sowing during both the experiments conducted during 2005–06 and 2006–07. With respect to tropical sugarbeet hybrids, Cauvery performed better in yield (76 and 92 t ha−1 during 2005 and 2006 respectively) and Shubhra recorded higher brix reading (20%). September second fortnight to October second fortnight sowing with Cauvery hybrid performed better for tropical sugarbeet emergence, establishment, yield and quality.

Estimativa do filocrono em calêndula

O objetivo deste trabalho foi estimar o filocrono em plantas de calêndula (Calendula officinalis L.) cultivadas em diferentes épocas de semeaduras. Realizaram-se três épocas de semeaduras: 06/04/2005, 23/06/2005 e 03/10/2006, no interior de uma estufa plástica com área de 240m2, instalada no campus da Universidade Federal de Santa Maria, UFSM. A semeadura foi realizada em vasos plásticos com capacidade volumétrica para cinco litros. O delineamento experimental foi inteiramente casualizado com 320 vasos em cada época, sendo distribuído em quatro fileiras de 80 vasos cada. Em uma planta de oito vasos de cada quatro fileiras, fez-se a contagem, semanalmente, do número de folhas emergidas da haste principal e na primeira haste lateral. Os dados do número de folhas foram correlacionados com a soma térmica diária acumulada, considerando-se uma temperatura base de 8°C. Constatou-se que o filocrono variou com a época de semeadura, sendo o menor valor igual 15,9°C dia folha-1, obtido na 2ª época de semeadura e o maior, igual a 24,5°C dia folha-1, na 1ª época na haste principal e 48,9°C dia folha-1 na semeadura de outubro na primeira haste lateral.