Fall Cultivation Research Articles

Nongrowing season soil nitrous oxide emissions as influenced by cover crops and fall tillage termination

Cropland soil is a major driver of global nitrous oxide (N2O) emissions. In cold climates, nongrowing season (NGS) emissions can be significant due to high fluxes during freeze–thaw (FT) cycles. Cover crops can alter key soil conditions that govern N2O-producing microbial processes, with multiple potential pathways to either increase or decrease N2O production during FT cycles. Cultivating cover crops in the fall to terminate may further disrupt these processes and the overall impact of cover crops on N2O emissions. Yet, few studies have touched on how termination practices of cover crops impact FT emissions over the NGS. Using the flux gradient method to continuously measure N2O emissions from a conventional corn–soybean rotation, we investigated the effects of summer-established cover crops (perennial ryegrass and crimson clover) (with cover crops, +CC; without cover crops, −CC) when terminated by fall cultivation (with fall cultivation, +FC; without fall cultivation, −FC) over a six-month NGS that was characterized by several freezing and thawing periods. Crimson clover cover crop was completely winterkilled, while the ryegrass survived on the +CC−FC field. Total NGS (Nov–Apr) emissions varied nearly 2.5-fold among treatments from 395.1 (−CC−FC) to 978.1 (+CC+FC) g N2O-N ha−1. Compared with the control treatment (−CC−FC), fall cultivation alone (−CC+FC) and cover crops alone (+CC−FC) increased total NGS N2O emissions, and fall cultivation with cover crops (+CC+FC) increased N2O fluxes even more. Careful CC species selection and management are important to avoid elevated NGS emissions.

The Physiological, Biochemical, and Molecular Modifications of Chickpea (Cicer arietinum L.) Seedlings Under Freezing Stress

Fall cultivation of field crops such as chickpea is prone to the risk of freezing stress. It is required to identify the mechanisms through which plants can tolerate low temperatures and provide conditions for fall cultivation of chickpea in the cold regions. To this, an experiment was carried out to evaluate the physiological, biochemical, and molecular alterations of chickpea genotypes (MCC797; cold-tolerant and MCC505; cold-sensitive) under freezing temperatures (− 3, − 6, − 9, and − 12 °C). Leaf malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EL) were increased due to freezing stress in both genotypes, with a greater increase in the cold-sensitive genotype. The plant survival was decreased 20% at − 12 °C in the cold-sensitive genotype, while it remained constant (100%) in the cold-tolerant genotype. The cold-tolerant maximum efficiency of PSII and the PSII operating efficiency recovered faster (24 h after freezing stress; AFS) compare to the cold-sensitive genotype (48 h AFS) during the recovery period. Proline and enzymatic antioxidants activity, including ascorbate peroxidase, catalase (cat), peroxidase (pod), and superoxide dismutase, were increased more rapidly in the cold-tolerant genotype. The relative gene expression of cat, pod, and proline were more stimulated in the cold-tolerant genotype. The cat, pod, and proline were over-expressed on average by 4, 3, and 6 folds, and 16, 13, and 16 folds, in the cold-sensitive and cold-tolerant genotype, respectively, exposed to freezing temperatures. The greater gene expression and the higher antioxidant content of leaves led to lower lipid peroxidation (MDA and H2O2 content) in the cold-tolerant genotype.

Performance study of exotic variety of potato (Solanum tuberosum L.) for processing industry under the agro-climatic condition of Lahore-Pakistan

Potato (Solanum tuberosum L.) crop is popular among the farming community for its high production per unit area and consequently high returns, therefore three crops of potato autumn, spring from plains and summer from high hills, are being grown in Pakistan. Its utilization as fast food and use for processing has further increased its importance among farmers, consumers and processors. With the aim in mind to enhance the farmer’s earnings by introducing new varieties of potato for processing and fresh market, current trial was performed to check the adaptability of exotic potato variety ‘Melanto’ (Cross: Impala × POS 97-1) in field trials, farms situated at Bedian Road, Lahore Cantt. Pakistan. This exotic varsity is better adapted specifically to summer, fall and spring cultivation districts of the Punjab, Pakistan. Big oval tubers produced with 17.5% dry matter content was ranked under cooking type A, i.e., no discoloration after cooking. ‘Melanto’ showed resistance to potato cyst nematodes Ro 1 and Ro 4 having relatively longer dormancy period than the control verity ‘Desiree’. The highest yield 30.46 t/ha (ton/hectare) was recorded for ‘Melanto’ followed by ‘Desiree’ 22.07 t/ha. But both varieties were found susceptible under high infection of late blight. Therefore, it can be concluded that the development and accessibility of new varieties of potato which are suitable for the processing is quite critical for sustaining the rise in processing industries of Pakistan. Moreover, the potato verities with more dry matter and less reducing sugars are required by potato processing industry to ensure high quality processed products. Enhancement in the production of potato is just due to the application of modern technologies and utilization of new seed varieties. White potatoes and the red potatoes are the major contributors in potato production by volume in Pakistan. Keywords: Adaptability test; Emergence percentage; Melanto; Solanum tuberosum L. http://dx.doi.org/10.19045/bspab.2019.80172

Effect of drought stress on qualitative characteristics of canola cultivars in winter cultivation

To determine the appropriate canola cultivars for winter cultivation under late-season drought stress conditions, a factorial split-plot test was conducted in a complete randomized blocks design with three replications for two cultivation years (2014–2016) in Karaj, Iran. In this work, cultivations at two levels included fall cultivation (Oct. 7) and winter cultivation (Feb. 4). The irrigation was conducted at three levels including routine irrigation (control), irrigation interruptions from flowering and pod formation stage in factorial status in main plots and five Brassica napus L. cultivars including Sarigol, Delgan, Jacomo, Jerumeh and Hyola 401 in subplots. The interaction effect of cultivation date × irrigation × cultivar on the features of palmitic acid, linolenic acid, linoleic acid, oleic acid, erucic acid, glucosinolate and oil yield was significant at the level of 1%. The results indicated that Delgan cultivar with the highest oil yield (1582 kg/ha) in the winter cultivation date and normal irrigation conditions as well as with standard levels of erucic acid and glucosinolate can be effective in canola cultivation in the new stage of winter cultivation. Moreover, in winter cultivation and in the late-season drought stress conditions, hybrids Hyola 401 with the highest seed yield, and standard oligosaccharide and glucosinolate can also be recommended in late-season drought stress conditions.

The effect of delay cultivation on dry matter accumulation and chickpea yield in dry land conditions

Plant yield as a result of the allocation of the photosynthesis material to economic organs is that was obtained through balanced relationships between source and the tank. Exact and correct of physiological processes understanding of controlling yield and proper use of them will be caused to increase crop plants yield. In this case the experiment was done in Islamic Azad University of Kermanshah in 2011. In this study, three cultivars of chickpea such as Flip93-93, 12-60-31 and Hashem in three planting dates such as fall, expended and spring (delay) were compared with complete random blocks factorial in 4 repetitions. Growth indicators such as: total dry matter (TDM), stem dry matter accumulation (SDM), leaf dry matter accumulation (LDM), pod dry matter accumulation (PDM) and grain dry matter accumulation (GDM) plant height, number of seeds per plant, 100seed weight, biological yield, harvest index and grain yield were evaluated. Flip93-93 cultivar in fall cultivation had the highest dry matter accumulation of leaf, stem and the whole plant. Meanwhile Hashem cultivar had the least dry matter accumulation in all of the indexes. Reducing the dry matter accumulation in total plant in delay cultivation (spring) rather than fall cultivation in Flip93-93, 12-60-31 and Hashem in order, were 145, 23, and 47%, which show that superiority of fall cultivation rather than spring cultivation. Finally Flip93-93 cultivar in fall cultivation (1002.1 Kg/ha) had the highest and 12-60-31 cultivar in delay cultivation (336.52 Kg/ha) had the least seed yield.

Effects of water shortage in late season on agronomic traits of rapeseed (Brassica napus L.)

Water deficit in the fall cultivation of Rapeseed occurs in cold and cool temperate regions, usually in the late period of growth, that is, the late spring and early summer. To examine the possibility of dealing with water deficit in the late season, appropriate experimental cultivars of the plant were cultivated in 2008 to 2009 and 2009 to 2010 cropping seasons at Karaj of Iran. An experiment was carried out in a split plot design based on RCBD with four replications over two years. Irrigation was the main factor in two levels including (irrigation after 80 mm evaporation from class A basin) and irrigation after flowering stage. The cultivar as the sub factor consisting of 34 new rapeseed cultivars at 34 levels was considered.The simple effects of irrigation and cultivar, as well as interaction of irrigation and cultivar on grain yield and oil yield were significant at 1% level. In normal irrigation conditions, Sunday cultivar had the highest grain and oil yield. In the conditions of stopping irrigation after flowering stage, ORW20-3002 cultivar had the highest grain yield and oil yield. Simple correlation between the experimental traits indicate that there was a highly significant positive relationship between grain yield and number of pod per plant, number of grain per pod, oil content, oil yield, biological yield and harvest index. Key words: Rapeseed, water deficit, grain yield, oil yield, biologic yield, harvest index.

Vineyard Weed Seedbank Composition Responds to Glyphosate and Cultivation after Three Years

This research compared effects of the weed control practice, soil cultivation, and the conventional practice, glyphosate application on weed seedbank, in a vineyard system. The experiment was conducted in a commercial wine-grape vineyard in the Napa Valley of northern California from 2003 to 2005. The annual treatments were “winter–spring glyphosate,” “spring cultivation,” “fall–spring cultivation,” and “fall cultivation–spring glyphosate,” and were applied “in-row,” under the vine. Composition of the weed seedbank collected in 2002 before treatment establishment did not differ among treatments. After 3 yr of weed treatments, detrended correspondence analysis indicated that the composition of spring cultivation and winter–spring glyphosate tended to differ from each other, but the remaining two treatments showed little differentiation. As determined by linear discriminant analysis, the specific weed species were associated with seedbanks of certain treatments. These were Carolina geranium, annual bluegrass, brome grasses, California burclover, and scarlet pimpernel, which do not pose problems with regard to physical aspects of grape production. Although ‘Zorro’ rattail fescue was ubiquitous among treatments, its distribution between depths in the cultivated treatments indicated that tillage provided some homogenization of seedbank along the vertical soil profile. The seedlings from the seedbank study were not congruent with those measured aboveground in the field, suggesting that both treatment and microclimatic effects in the field may have influenced germination, and thus, aboveground composition.

エンバク品種「たちいぶき」におけるミナミネグサレセンチュウの増殖性

Pratylenchus coffeae reproduction on Avena sativa cv. “Tachiibuki,” a root-knot nematode suppressive oat, was examined in phytotron and field conditions. In the phytotron experiment, 300 nematodes of four P. coffeae populations were inoculated on seedlings of “Tachiibuki,” A. strigosa (“Hay oats”), and cucumber at 25°C or 20°C. Eggs and nematodes inside roots were stained by acid-fuchsine and counted 40 days after inoculation. At 25°C, all populations reproduced on “Tachiibuki” with the final nematode number/initial nematode number (Pf/Pi) ranging from 1.2-2.8, significantly higher than in “Hay oats” (Pf/Pi = 0.3-0.7), but lower than in cucumber (Pf/Pi = 8.7-13.6). At 20°C, Pf/Pi on “Tachiibuki” ranged from 0.1-0.4, indicating low root invasion and reproductive activity of the nematode. In the field microplot experiment, fluctuation of soil nematode density during fall cultivation of “Tachiibuki” and successive sweet potato cultivation were compared with fall fallow and fall cultivation of “Hay oats.” The rate of nematode decrease in the “Tachiibuki” plot was slightly higher than in the fallow plot at successive planting of sweet potato, although the difference was not statistically significant. There was no significant difference in lesion ratings of sweet potato storage root among previous cultivation treatments. Although “Tachiibuki” supports multiplication of P. coffeae, the temperature range in fall cultivation seemed to be insufficient to affect soil nematode density.

Effects of Organic and Conventional Practices on Weed Control in a Perennial Cropping System

Vineyard weed communities were examined under the influence of an organic weed control practice, soil cultivation with a Clemens cultivator, and applications of the herbicide glyphosate. Experimental treatments (winter–spring glyphosate, spring cultivation, fall–spring cultivation, fall cultivation–spring glyphosate) were carried out in a California wine grape vineyard for 3 yr. Cultivation alone was not as effective as glyphosate, based on lower weed biomass in the glyphosate-only treatment in 2 of 3 yr. However, given that two passes with the Clemens cultivator decreased weed biomass relative to one pass, it is possible that additional passes could bring about further reductions. Pairing fall cultivation with glyphosate was as effective at reducing weed biomass as two glyphosate applications in 2 of 3 years, suggesting that substituting a glyphosate application with cultivation may be an effective method of reducing herbicide use in vineyards. Canonical correspondence analysis revealed significant treatment effects on community structure. Weed composition in the spring cultivation treatment was significantly different from that of all other treatments. Based on our findings of high relative abundance of field bindweed and sowthistle species, which are problematic vineyard weeds that grow into the vine canopy and disrupt canopy management practices, it is possible that either the presence of soil disturbance or the absence of herbicides favored these species.

Plant Mass and Yield of Broccoli as Affected by Soil Moisture

The effect of water supply on total mass and yield of broccoli (Brassica oleracea L. var. italica, `Emperor') was examined in an experiment carried out in a microplot field installation on three soil types: Gleyic Cambisol (sand) and Eutric Fluvisol (flood-plain loam) in spring and fall and on a Haplic Phaeosem (loessal loam) in fall. Soil moisture levels were established by irrigation under the following replacement protocols: 14 mm whenever the limit of 75% vol of the available soil water (ASW), 14 and 28 mm whenever the limit of 55% vol of ASW, and 14, 28, and 42 mm whenever the limit of 35% vol of ASW were reached. The highest total plant mass was achieved by irrigation at 75% vol of ASW on the sandy soil in spring cultivation, and at 55% vol of ASW (in doses of 28 mm) on the flood-plain loam in fall cultivation. The highest marketable yield (head mass) was obtained on the sandy soil at 55% vol of ASW (in doses of 14 mm) for both spring and fall production. The total plant mass and head mass was only significantly affected by reduced soil moisture at 35% vol of ASW in spring. At 75% vol of ASW, irrigation with 14 mm always resulted in reduced headmass. In fall, yield was not affected by soil moisture depletion or soil type. For the production of broccoli, it is recommended that irrigation be started when soil moisture falls below 55% vol of ASW, followed by a water application rates of either 14 or 28 mm.

Análise de crescimento de duas cultivares de amendoim (<em>Arachis hypogaea L.</em>)

The present work aims to evaluate the peanut Tatu and Botutatu cultivars growth rate through the study of the physiological parameters of the growth analysis and grain production. Two experiments were carried out under greenhouse conditions of the Department of Agriculture, Agronomic Sciences College, Botucatu, Sao Paulo, Brazil, in the fall cultivation (March to July 1998) and summer cultivation (November 1998 to March 1999) in Brazil. The experimental delineation of randomized blocks used four repetitions in a factorial scheme. The treatments consisted of two peanut cultivars, eight and six times sampling, for fall cultivation and summer cultivation in Brazil, respectively, covering the whole growth cycle. The results showed that in both cultivations, the LAR, NAR and RGR decreased with the plant development for Tatu and Botutatu cultivars. The grain production of Tatu and Botutatu cultivars did not present difference in both cultivations. In the fall cultivation the grain production was larger than that obtained in the summer cultivation.

Greenhouse Seed Production of Two Dwarf Green Bean Cultivars in Relation to the Duration of Irrigation

As good quality irrigation water becomes increasingly scarce in the Mediterranean region, especially in coastal areas where greenhouses are located, methods of economizing water consumption are essential. Therefore, the effect of the duration of irrigation on the quality and yield of seed of two cultivars of dwarf green bean (`Larma' and `Montano', Phaseolus vulgaris L.) was studied during fall and spring in Greece. Seeds were sown on 11 Sept. 2000 (fall crop) and 23 Feb. 2001 (spring crop) in peat compost and when the plants had two expanded leaves (11 and 20 days after sowing, respectively), they were transplanted to the soil of an unheated, plastic-covered greenhouse. The following irrigation treatments were applied: 1) irrigation for the entire duration (control), 2) irrigation until the first pods were dry, 3) irrigation until ≈50% of the pods had filled, and 4) irrigation till flowering. Fall cultivation was not suitable for seed production due to low yield and reduced seed quality. By contrast, the spring crop had a higher yield, seed size and good germination. Stopping irrigation of the spring crop at the drying of the first pods achieved an ≈20% saving in water without significantly affecting seed yield or quality. Earlier discontinuation of irrigation to achieve greater savings of water caused a reduction in yield, but did not affect seed quality.

아인산염을 이용한 감자 줄기기부썩음병 방제

감자 양액재배에서 발생하는 줄기기부썩음병을 방제하고자 아인산염을 시기별, 농도별로 양액에 처리한 결과 봄재배에서는 아인산염 200ppm 처리구는 90.5％, 100ppm 처리구는 50.5%의 방제가를 나타내었다. 가을재배에서는 200ppm 처리구는 100%, 100ppm 처리구는 69.9%로 아인산염 200ppm이 효과적이었다. 아인산염 200ppm 처리구는 10일 후 8.0%의 이병율을 나타냈으며, 100ppm 처리구는 5일 후 10.0％, 10일 후 20.0％, 무처리구는 5일후 56.7％, 10일 후에는 96.7%의 이병율을 나타내었다. Effect of potassium phosphonate on control of potato basal stem rot caused by Pythium myriotylum in hydroponics system was evaluated at spring and fall cultivation in Jeju island in 2001. Potassium phosphonate 200 ppm treatment, which was directly supplemented into the nutrient solution, showed 90.5%, and 100 ppm treatment showed 50.5% control value in spring cultivation. Fall cultivation, potassium phosphonate 200 ppm treatment showed 100%, and 100 ppm treatment showed 69.9% control value. Potassium phosphonate 200 ppm treatment, basal stem rot of potato started to develop 10 days ofter inoculation into the hydroponics system showed 8.0% in infection rate. Potassium phosphonate 100 ppm treatment, after 5 days showed 10.0%, and after 10 days showed 20.0% infection rate, but the non-treated was after 5 days showed 56.7%, and after 10 days showed 96.9% infection rate.

Persistence of Early-Season Treatments for Control of Colorado Potato Beetle,Leptinotarsa decemlineata(Say), Attacking Field Tomato

ABSTRACT The relative persistence of early-season treatments for control of Colorado potato beetle, Leptinotarsa decemlineata (Say) attacking field tomato, Lycopersicon esculentum, in southwestern Ontario, Canada, was compared by laboratory bioassay of field-collected foliage. Both mortality and feeding damage by introduced adult Colorado potato beetle (CPB) were recorded after 72 hours. Four methods of insecticide application (pre-plant foliar [PRF]); post-plant foliar [POF]; pre-plant drench [PRD]; and, planting water [PW]) were compared with commercial control programs. At an arbitrary acceptable threshold for percent mortality/damage reduction of 70%, the order of effectiveness in 1996 was: imidacloprid-PW > imidacloprid-PRD > imidacloprid-POF = cypermethrin-POF, Imidacloprid-PRF did not provide acceptable control of adult CPB. No residues of imidacloprid were detected in ripe tomato fruit following any application or in soil after fall cultivation following PRD-application. Relevance of results to po...

Effects of three tillage treatments on seasonal runoff and soil loss in the Peace River region

Three tillage treatments were evaluated over a 4-yr period for their effects on runoff and soil loss under natural precipitation on a Donnelly silt loam soil (Solonetzic Gray Luvisol) near Dawson Creek in the Peace River region of British Columbia. Conventional-tilled (CT) plots (spring or fall cultivation) received twice the amount of tillage as the reduced-tilled (RT) plots, while the zero-tilled (ZT) plots were only disturbed at seeding once a year. The plots were seeded to barley (Hordeum vulgare L.). Rainfall and snowmelt runoff were collected throughout the year to determine seasonal runoff and soil losses. The effects of the tillage treatments on runoff and soil loss depended on the season (whether caused by rainfall or snowmelt) and the crop year. Mean snowmelt runoff was ZT > CT > RT. Conventional tillage had significantly higher rainfall runoff and soil loss from snowmelt than the other two tillage treatments, with no significant differences between RT and ZT. Mean rainfall-induced soil loss was significantly different for each tillage treatment, with CT > RT > ZT. Soil losses from snowmelt were low, less than 30% of those from rainfall, since snowfall was 45% below normal. Soil losses from rainfall were consistently higher than from snowmelt for each tillage treatment in each of the four crop years and provided over 75% of the 4-yr total annual soil loss. Tillage effects were more pronounced in years with low runoff and soil loss than in years with high runoff and soil loss. Zero tillage and RT are effective in reducing average annual soil losses by 81 and 53%, respectively, of those observed under conventional tillage. Key words: Runoff, soil loss, erosion plots, seasons, tillage

Cultivation and weed control for aspen seedling establishment in the southern Rocky Mountains

Containerized aspen (Populustremuloides Michx.) seedlings were planted at high-elevation sites in southern (May 1982) and northern (July 1983) New Mexico. Each plantation compared fall cultivation (20 cm depth), prior to planting the following spring or summer, with cultivation at the time of planting. Subtreatments of the tests included applications of the postemergent herbicide dalapon and the preemergents linuron, trifluralin, or simazine applied 2 to 3 weeks before planting. First season survival exceeded 75% for the best treatment at each site. Cultivation, in general, effectively reduced weed cover and improved seedling success. Fall cultivation, in particular, improved seedling survival and growth only at the relatively dry southern site. Except for spring-cultivated plots in the south, some herbicide applications improved weed control and seedling performance over cultivation alone. The combination of fall cultivation plus trifluralin is considered the best site preparatory treatment tested.

Comparative Levels of Residues of Fensulfothion and Its Sulfone Absorbed by Carrots and Rutabagas from Treated Soil During Two Growing Seasons1

Four months after granular fensulfothion was banded at various rates 3 cm below the surface of a fine sandy loam soil, residues of the parent material (f) were ca. 2.5 times higher than those of its oxidation metabolite, fensulfothion sulfone (fs). The same relative concentrations of f and fs were present in mature carrots grown in the treated soil. However, in rutabagas, residues of fs were more than 3 times higher than the parent f. After fall cultivation by rototilling the rows 15 cm deep and mixing the insecticide into the soil, carrots and rutabagas were planted in the same treated soil the following year. Residues remaining in the soil (after 16 months) comprised ca. 3 times more fs than f. Carrots again contained the same relative ratios of residues as the treated soil, but totals of f and fs at all rates of application were higher in the 2nd year’s crop than in that grown the previous year. In the 2nd year’s rutabaga crop, low levels of fs and only traces of f were detected, even in plots where excessively high rates (up to 34 kg active/hal had been applied the previous year.

Fall Cultivation for Control of the Southwestern Corn Borer in Mississippi12

Journal Article Fall Cultivation for Control of the Southwestern Corn Borer in Mississippi Get access C. A. Henderson, C. A. Henderson Entomology Research Division, Agr. Res. Serv., USDA, State College, Mississippi Search for other works by this author on: Oxford Academic PubMed Google Scholar W. A. Douglas W. A. Douglas Entomology Research Division, Agr. Res. Serv., USDA, State College, Mississippi Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 60, Issue 2, 1 April 1967, Pages 602–603, https://doi.org/10.1093/jee/60.2.602 Published: 01 April 1967 Article history Accepted: 01 November 1966 Published: 01 April 1967

Studies on the absorption of nutrient elements in muskmelon. VII

1. To clarify the suitable application amounts of ureaform (Uf), a slowly available form of synthetic organic nitrogen, four plots which consisted of four levels of actual N (6, 8, 10, 12g per plant) were established. Furthermore, three plots whose plants received 8g of actual N with rape-seed cake (R), ammonium sulphate (A), and urea (U), respectively, were also made for comparison. Var. Earl′s Favourite for fall cultivation was used, and effects of these fertilizer treatments on the growth, the fruit weight and quality, and the concentration of various forms of nitrogen in the leaves of muskmelon were investigated.2. The fruit weight both in the plots of Uf-8 and Uf-10 was greater than that in the plot of Uf-12 as well as both in the plots of A and U. On the other hand, the external appearance of fruit in the plot of Uf-6 as well as in the plot of R, as measured by the net, and the days of post-ripening of the fruit, was superior to that in the plot of Uf-12 as well as both in the plots of A and U.3. With increasing the application amounts of ureaform from 6 to 10g per plant, the concentrations of NH4-N and NO3-N in the leaves, the electrical conductivity and NO3-N of the soil were increased.Judging from these results, especially, from the concentration of NO3-N in the leaves both in the plots of Uf-10 and Uf-12, the suitable application amounts of ureaform for muskmelon seemed to be 6 to 8g per plant as actual N.4. To clarify the trend of the mineralization of several nitrogen sources, the rates of ammonification and nitrification of ureaform, rape-seed cake, ammonium sulphate and urea incubated at the soil temperatures of 20°C and 30°C were measured.5. The ammonification rate of ureaform incubated at the soil temperature of 20°C increased up to 69% of the added nitrogen on the 28th day after incubation, and then gradually decreased down to 30% on the 63rd day after incubation. On the other hand, the nitrification rate of ureaform incubated at the same soil temperature increased up to 52% on the 63rd day after incubation.The ammonification rate of rape-seed cake incubated at the same soil temperature increased up to 60% on the 28th day after incubation, and then gradually decreased down to 27% on the 63rd day after incubation. On the other hand, the nitrification rate of rape-seed cake incubated at the same soil temperature increased up to 37% on the 63rd day after incubation.The trend of the nitrification rate of urea incubated at the same soil temperature was similar to that of ureaform.The nitrification rate of ammonium sulphate incubated at the same soil temperature only increased up to 10% on the 63rd day after incubation. This low nitrification rate seemed to be caused by the comparatively low soil pH brought by the added ammonium sulphate.6. Though the nitrification rates of ureaform and rape-seed cake incubated at the soil temperature of 30°C were much greater than those of the same nitrogen sources incubated at the soil temperature of 20°C, the nitrification rates of urea and ammonium sulphate incubated at the soil temperature of 30°C were slightly greater than those of the same nitrogen sources incubated at the soil temperature of 20°C.

Cropping, Cultivation, and Herbicides to Eliminate Leafy Spurge and Prevent Reinfestation

Cropping, Cultivation, and Herbicides to Eliminate Leafy Spurge and Prevent Reinfestation