Small Field Plots Research Articles

Effect of plant density and row spacing on maize (Zea mays L.) grain yield in different crop year

Nowadays the aim of crop production is to realize the highest possible yield per production area unit by the highest possible crop safety. One of the possible ways for this is to increase of plant density or to decrease row spacing. Therefore, the plant number per unit area can be increased and the potential yield loss of individual plants is compensated by the higher plant density. The development of yield amounts of eight different genotypes was investigated in a small-plot field experiment with four replications on a calcareous chernozem soil type at the Látókép Research Site of the University of Debrecen in the crop years 2013 and 2014. Row distances of 45 and 76 cm, just as plant densities of 50 000, 70 000 and 90 000 plants per ha were set. Significant differences were found between the yield amounts of the studied hybrids in both studied crop years, while the effect of plant density on yield amount showed different results. In the crop year of 2013 the hybrids resulted high yields in the treatment with a row distance of 45 cm and plant density of 90 000 plants per ha, however, in 2014 significant yield decrease was found in comparison with the previous year, that can be attributed to the weather conditions in the months April-May and June. Optimal plant densities of hybrids, just as the corresponding expectable yield amounts were determined with quadratic equations. Optimal plant densities of the hybrids were different in the two studied crop years: in 2013, regarding the treatments set with the row distance of 45 cm, increasing plant densities resulted in higher yields, while in 2014, the yield showed decreasing tendency parallel to the increasing plant densities, that is confirmed by the fact that plant densities of 50 000 and 65 000 plants ha-1 proved to be more favourable. Regarding the treatments with a row distance of 76 cm, hybrids obtained their yield maximums by 80 327 plants ha-1 in 2013, while in the vegetation of 2014, by higher plant density (85 845 plants ha-1).

Vliv různých formem dusíkatých hnojiv aplikovaných na konci odnožování na výnos a kvalitu zrna pšenice ozimé

In the years 1999 to 2001 in conditions of small-plot field experiments was carried out on loamy degraded chernozems at the Plant Breeding Station of Sládkovičovo-Nový Dvor to solve the problems of topdressing winter wheat (Triticum aestivum, L.), variety Astella, with different forms of nitrogenous fertilizers. Nitrogenous fertilizers were applied at the growth phase of the 6th leaf (Zadoks = 29). Four various forms of fertilizers were exemined: urea solution, DAM-390, DAM-390 + Dumag, DASA. Different weather conditions statistically highly significantly influenced grain yield in respective experimental years. Topdressing with nitrogen (30 kg N.ha–1) caused statistically highly significant increase of grain yield in all fertilized variants ranging from +0.29 t.ha–1 (applied of DAM-390) to +0.69 t.ha–1 (applied of DASA) according to respective treatments. Average grain yield in unfertilized control variant represented 7.23 t.ha–1. Nitrogen nutrition showed positive effect on the main macroelements offtake (N, P, K, Ca, Mg, S) by winter wheat grain in all fertilized variants. Nitrogen fertilizing positively influenced formation of wet gluten and crude protein with highest increment in variant with DASA and variant with DAM-390 + Dumag.

ADAPTABILITA VÝNOSU A MLYNÁŘSKÉ KVALITY ZRNA VYBRANÝCH ODRŮD PŠENICE OZIMÉ

Within the project of small-plot field trials we cultivated 10 varieties of winter wheat in 5 different trial stations of the Central Institute for Supervising and Testing in Agriculture in years 2001–2002. The yields achieved were assessed and the miller’s quality of the grain was defined. Wheat variety Contra reached the highest yields (10.226 t.ha–1) and Niagara wheat variety reached the lowest yields (8.516 t. ha–1) where the yields were conclusively lower (LSD, 95%) compared with the group C varieties. Apache and Ebi varieties achieved the most stable yields; the least plastic variety was Banquet. We marked high variability of volume capacity (682–840 g.1–1). The highest average volume capacity was proved by Niagara variety (802 g.1–1) while the lowest was provided by Windsor (736.9 g.1–1). The elite group wheat varieties (E) and the quality varieties (Niagara, Samanta) proved conclusively higher volume capacity than the group C varieties. The highest TGW, in comparison with the rest of varieties, was achieved by Niagara variety and the lowest TGW proved by Contra. The high proportion of grains on 2,5 mm sieve corresponded with TGW. In average, the highest proportion of grains on 2,5 mm sieve was achieved by Niagara variety (95.21%), the lowest by Contra. Higher TGW value achieved in 2001, in comparison with 2002, positively influenced the yield of flour. The highest yield were reached by the A class flour in 2001 and the elite wheat (E) in the following year. The highest content of ashes in flour T550 was found at Windsor variety (0.61%) contrary to the most positively evaluated Samanta (0.55%).

VLIV ÚROVNĚ DUSÍKATÉ VÝŽIVY A FUNGICIDNÍHO OŠETŘENÍ NA VÝNOS A VYBRANÉ UKAZATELE KVALITY ZRNA OZIMÉ PŠENICE

In 2001–2004 an influence of gradually increased portions of nitrogen (100–130–160 kg/N.ha–1) applied on the wheat variety Ebi in combination with the modified fungicidal protection in the yield and the selected quality grain parameters were observed within the small-plot field trials. Nitrogenous fertilizers according to the amount of nitrogen contained were applied in 2–4 terms during vegetation in regeneration (55kg/N.ha–1), 1st production (45kg/N.ha–1), 2nd production (30kg/N.ha–1) and qualitative portion (30kg/N.ha–1). The fungicidal protection was based on the equal treatment in the phase of BBCH 37 and with regard to the varieties different treatment in the phase of BBCH 55. The dependence on the year was proved at all observed parameters. Higher intensity of nitrogenous fertilization had no decisive impact on the yields. From the point of view of increased yields, the second production nitrogenous fertilization had the strongest impact; it increased the grain yields by 0.084–0.461 t./ha–1. Higher intensity of nitrogenous fertilization positively influenced the baker’s grain quality. The increased portions of nitrogen decisively increased the volume of N-substances in all trial years. The second production nitrogenous fertilization increased the N-substances volume from 0.1 to 0.8%. Qualitative additional fertilization increased their volume from 0.26 to 1.38%. Higher N portions increased sedimentation in most cases. The falling number was not considerably influenced. The mechanical grain qualities (volume weight, number full grains, and GTW) were relatively less influenced than the baker’s quality by the nitrogenous fertilization. The application of fungicides positively influenced not only the yields but also mechanical qualities of the grain, i.e. volume weight, thousand grains weight and portion of Full grains. On the contrary the baker’s quality was not decisively influenced. It was proved that the decisive fungicidal treatment is the one applied in the period of coming to ear (BBCH 55). Single fungicidal treatment in the early period of the flag leaves (BBCH 37) increased the yields only by 6% and the grain quality was not decisively influenced. Double treatment then increased the yields by 18.15% in average. The highest increases were reached at fungicidal varieties fertilized with the nitrogen portion (19.55%), the lowest after application of the N portion on the level of 100kg/ha–1. Here the grain yields were also in average 16.77% higher than the yields of the untreated varieties. The highest grain yields after the application of fungicide was reached in 2003 (26.16%) and the lowest in 2001 (14.16%). The differences in the yields at the varieties with the full fungicidal protection and different spectrum of fungicides used were not statistically evident in the trial duration. The increase in the yields contrary to untreated variety and the variety with the limited fungicidal protection (application of fungicides only in BBCH 37) was statistically evident in most cases. The least effective was the impact of the fungicide Caramba in the portion of 1 l/ha–1. On the contrary, the varieties containing the fungicides with the agent from the group of strobilurins including Charisma containing the agent of famoxate proved very good results. GTW was most influenced by the fungicidal protection. The relative increase of GTW was between 7.53–11.48%. This value was positively influenced by the application of Juwel followed by Amistar in full as well as reduced portion combined with azol contained in Caramba. With regard to the fact that these trends were reached in all years of the trial, we can say that strobilurins have the positive impact on the value of this parameter. In average of the trial duration as well as in particular years the positive impact of the double fungicidal treatment on the number of full grains (2.76–3.37% increase) was proved. On the contrary, the fungicidal protection decreased the value of the falling number by 1.52–10.23%.

VLIV APLIKACE FUNGICIDŮ NA FUSARIÓZY OZIMÉ PŠENICE A DALŠÍ PŮVODCE STÉBLOLAMU

From 1999 to 2004 the occurence of fungi: Pseudocercosporella herpotrichoides (Fron.) and Fusarium spp. was evaluated in small plot field trials on seven varieties of winter wheat. The efficacy of fungicide protection against stem base diseases and influence on yields was monitored in field conditions in Velká Bystřice near Olomouc.For diagnostic of casual fungi two methods were used: 1. Method of coloring mycelium in stems, 2. Method of cultivation of mycelim on agar.Results from detection of casual fungi are following: Pseudocercosporella herpotrichoides (Fron.), Fusarium culmorum (W. G. Sm.) Sacc. and Fusarium graminearum Schwabe.For high efficacy of protection against roots and stem base disease the following fungicide variants should be applied: Sportak Alpha 1.5 l . ha−1 (BBCH 30)/Cerelux Plus 0.7 l . ha−1 (BBCH 51), Sportak HF 1 l . ha−1 (BBCH 30)/Cerelux Plus 0.7 l . ha−1, Alert S 1.0 l . ha−1 (BBCH 30/Cerelux Plus 0.7 l . ha−1 (BBCH 51). The application of fungicides positively influenced yields. Yield increased at average by10–20 % after the aplication but the rise in yields was not in total correlation with the efficacy. These results can be possibly used in the system of integral control of winter wheat against stem base disease in wheat.

Vliv rychle fermentovaného prasečího hnoje na výnosové parametry brokolice a vybrané půdní parametry

The effect of Difert (a pig manure fermented by caddices of domestic flies produced on sawdust litter) on broccoli yield parameters and selected soil parameters were investigated on gleic fluvisol in a small-plot field trial localized at area of Slovak University of Agriculture in Nitra (48°18´ N, 18°05´ E).The results showed that Difert applied in doses of 250 kg N . ha−1 and 350 kg N . ha−1 acted positively on the yields of fresh primary broccoli roses. However, the results are not statistically significant. Also a positive effect on N, P, K, Ca, Mg contents in broccoli roses was recorded. Difert has a moderate alkalizing effect on soil and increases the content of Cox in the soil. Moreover Difert insignificantly decreased the content of vitamin C and significantly increased the content of nitrates in broccoli roses, but the worst qualitative effect on broccoli parameters was detected by applying mineral N fertilizers, which significantly increased the content of nitrates in broccoli roses and insignificantly decreased the vitamin C content. However, it resulted in the highest broccoli yields. The application of mineral N fertilizers had a negative effect on the total content of carbon in the soil as well.The effect of Difert on broccoli yield and soil parameters refers to the feasibility of reducing the maturing period of the manure from 6 months to 1 week, in order to decrease the manure storage capacities.

Effects of single and multiple applications of glyphosate or aminopyralid on simple constructed plant communities.

To determine effects of multiple applications of herbicides on small constructed plant communities, Prunella vulgaris L.var. lanceolata Fern, Festuca roemeri (Pavlick) Alexeev, Clarkia amoena (Lehm.) Nels., and Cynosurus echinatus L. were grown together in small field plots. Plants were treated with glyphosate at target concentrations of 0 × , 0.01 × , 0.1 × , and 0.2× a field application rate (FAR) of 1122 g ha(-1) active ingredient (a.i.) for 3 yr in 1 location, and for 2 yr in a second location. Plants also were treated with aminopyralid at 0 × , 0.037 × , 0.136 × , and 0.5× FAR of 123 g ha(-1) a.i. for 2 yr in 2 locations. Plants received 1, 2, or 3 applications of each herbicide each year. Species and community responses depended on herbicide concentration and number of applications. With glyphosate, plant volume (modified formula for a cone) tended to decrease for all species (especially C. echinatus), and the decreases generally became larger with more applications. Plant communities exposed to the 2 greatest concentrations initially differed from controls but then appeared to recover. With aminopyralid, C. amoena was essentially eliminated from the communities, especially at the 2 greatest FARs, whereas the other 3 species tended to have significant increases in volume, especially at the 2 smallest FARs. With aminopyralid, increasing numbers of applications produced variable results, and the plant community volume never tended to recover.

Soil organic carbon loss and selective transportation under field simulated rainfall events.

The study on the lateral movement of soil organic carbon (SOC) during soil erosion can improve the understanding of global carbon budget. Simulated rainfall experiments on small field plots were conducted to investigate the SOC lateral movement under different rainfall intensities and tillage practices. Two rainfall intensities (High intensity (HI) and Low intensity (LI)) and two tillage practices (No tillage (NT) and Conventional tillage (CT)) were maintained on three plots (2 m width × 5 m length): HI-NT, LI-NT and LI-CT. The rainfall lasted 60 minutes after the runoff generated, the sediment yield and runoff volume were measured and sampled at 6-min intervals. SOC concentration of sediment and runoff as well as the sediment particle size distribution were measured. The results showed that most of the eroded organic carbon (OC) was lost in form of sediment-bound organic carbon in all events. The amount of lost SOC in LI-NT event was 12.76 times greater than that in LI-CT event, whereas this measure in HI-NT event was 3.25 times greater than that in LI-NT event. These results suggest that conventional tillage as well as lower rainfall intensity can reduce the amount of lost SOC during short-term soil erosion. Meanwhile, the eroded sediment in all events was enriched in OC, and higher enrichment ratio of OC (ERoc) in sediment was observed in LI events than that in HI event, whereas similar ERoc curves were found in LI-CT and LI-NT events. Furthermore, significant correlations between ERoc and different size sediment particles were only observed in HI-NT event. This indicates that the enrichment of OC is dependent on the erosion process, and the specific enrichment mechanisms with respect to different erosion processes should be studied in future.

One gene versus two: a regional study on the efficacy of single gene versus pyramided resistance for soybean aphid management.

The soybean aphid (Aphis glycines Matsumura) is a threat to soybean production in the Midwestern United States. Varieties containing the Rag1 soybean aphid resistance gene have been released with limited success in reducing aphid populations. Furthermore, virulent biotypes occur within North America and challenge the durability of single-gene resistance. Pyramiding resistance genes has the potential to improve aphid population suppression and increase resistance gene durability. Our goal was to determine if a pyramid could provide improved aphid population suppression across awide range of environments. We conducted a small-plot field experiment across seven states and three years. We compared soybean near-isolines for the Rag1 or Rag2 gene, and a pyramid line containing both genes for their ability to decrease aphid pressure and protect yield compared with a susceptible line. These lines were evaluated both with and without a neonicitinoid seed treatment. All aphid-resistant lines significantly decreased aphid pressure at all locations but one. The pyramid line experienced lower aphid pressure than both single-gene lines at eight of 23 location-years. Soybean aphids significantly reduced soybean yield for the susceptible line by 14% and for both single-gene lines by 5%; however, no significant yield decrease was observed for the pyramid line. The neonicitinoid seed treatment reduced plant exposure to aphids across all soybean lines, but did not provide significant yield protection for any of the lines. These results demonstrate that pyramiding resistance genes can provide sufficient and consistent yield protection from soybean aphid in North America.

Ammonia emission from a permanent grassland on volcanic soil after the treatment with dairy slurry and urea

Ammonia (NH3) is an air pollutant largely emitted from agricultural activities including the application of livestock manures and fertilizers to grassland. This gas has been linked with important negative impacts on natural ecosystems. In southern Chile, the use of inorganic and organic fertilizers (e.g. slurries) has increased in cattle production systems over recent years, heightening the risk of N losses to the wider environment. The objectives of this study were to evaluate on permanent grasslands on a volcanic ash soil in southern Chile: 1) the N loss due to NH3 volatilization following surface application of dairy slurry and urea fertilizer; and 2) the effect of a urease inhibitor on NH3 emissions from urea fertilizer application. Small plot field experiments were conducted over spring, fall, winter and summer seasons, using a system of wind tunnels to measure ammonia emissions. Ammonia losses ranged from 1.8 (winter) to 26.0% (fall) and 3.1 (winter) to 20.5% (summer) of total N applied for urea and slurry, respectively. Based on the readily available N applied (ammoniacal N for dairy slurry and urea N for urea fertilizer), losses from dairy slurry were much greater, at 16.1 and 82.0%, for winter and summer, respectively. The use of a urease inhibitor proved to be an effective option to minimize the N loss due NH3 volatilization from urea fertilizer, with an average reduction of 71% across all seasons. The results of this and other recent studies regarding N losses suggest that ammonia volatilization is the main pathway of N loss from grassland systems in southern Chile on volcanic ash soils when urea and slurry are used as an N source. The use of good management practices, such as the inclusion of a urease inhibitor with urea fertilizer could have a beneficial impact on reducing N losses due NH3 volatilization and the environmental and economic impact of these emissions.

ЗАЩИТНОЕ ДЕЙСТВИЕ ПРАВАСТАТИНА ПРОТИВ ВОЗБУДИТЕЛЯ ГЕЛЬМИНТОСПОРИОЗА НА ЯРОВОМ ЯЧМЕНЕ

Use of natural compounds against phytopathogenic microorganisms instead of chemicals is regarded as the safer approach to protect environment, consumers and the staff. Previously in the laboratory tests, the Pravastatin, an inhibitor of sterol biosynthesis, was shown to prevent development of helminthosporium root rot, caused by Bipolaris sorokiniana, in spring barley seedlings. Further to this, we studied the protective effect of Pravastatin against B. sorokiniana in test field (Moscow Province). Before sowing, the spring barley (variety Zazerskii 85) seeds, naturally infected with B. sorokiniana, were treated with Pravastatin (0.05, 0.075 и 0.1 % for 24 hours). The pre-sowing examination of untreated naturally infected seeds showed the plant damage by helminthosporium root rot at 8.9 % and the disease severity at 36.8 %. Small-plot field trials showed that treatments of spring barley seeds with soaking in 0.075 or 0.1 % Pravastatin solutions for 24 hours before their sowing decreased the number of plans damaged by B. sorokiniana, as well as reduced the disease severity. The maximal protective effect was produced by Pravastatin at the concentration of 0.1 %. It was also found that seed treatments with Pravastatin at all tested concentrations did not influence negatively on the seed germinating capacity or density of planting at the tillering stage (phase 29). In addition, seed soaking in a 0.1 % Pravastatin solution resulted in increase of productive stem number at the stage of milky-wax ripeness (phase 83).

STUDYING THE ABILITY OF PRAVASTATIN TO PROTECT SPRING BARLEY PLANTS FROM THE HELMINTHOSPORIUM ROOT-ROT

Use of natural compounds against phytopathogenic microorganisms instead of chemicals is regarded as the safer approach to protect environment, consumers and the staff. Previously in the laboratory tests, the Pravastatin, an inhibitor of sterol biosynthesis, was shown to prevent development of helminthosporium root rot, caused by Bipolaris sorokiniana, in spring barley seedlings. Further to this, we studied the protective effect of Pravastatin against B. sorokiniana in test field (Moscow Province). Before sowing, the spring barley (variety Zazerskii 85) seeds, naturally infected with B. sorokiniana, were treated with Pravastatin (0.05, 0.075 e 0.1 % for 24 hours). The pre-sowing examination of untreated naturally infected seeds showed the plant damage by helminthospor ium root rot at 8.9 % and the disease severity at 36.8 %. Small-plot field trials showed that treatments of spring barley seeds with soaking in 0.075 or 0.1 % Pravastatin solutions for 24 hours before their sowing decreased the number of plans damaged by B. sorokiniana, as well as reduced the disease severity. The maximal protective effect was produced by Pravastatin at the concentration of 0.1 %. It Ðen. 3. Aeeia iaacaiiie e iiacaiiie ÷anoe (A) e eonoenoinou (A) o ðanoaiee y÷iaiy (Hordeum vulgare L.) niðoa Cacaðneee 85 â eiioa oacu eouaiey (oaca 29) iinea iðaaiinaâiie iaðaaioee naiyi ðanoâiðii iðaâanoaoeia â ðaciuo eiioaioðaoeyo: a — noaaee; a — eiðie (Iineiâneay iae., 2009 aia).

Biochar impact on Midwestern Mollisols and maize nutrient availability

Biochar applications have been shown to increase crop yields on acidic and low activity soils in the tropics but fewer positive yield responses have been reported for temperate soils. We hypothesized that even without a yield response, applying biochar to a Midwestern Mollisol could improve soil quality and plant nutrient availability because of the carbon it supplies and its conditioning effect. Eighteen small field plots (23.7m2) on a glacial-till derived soil were established by incorporating 0 to 96Mgha−1 of hardwood biochar to a depth of 30cm. Several soil quality indicators, plant nutrient availability, uptake, and yield of two consecutive maize (Zea mays L.) crops were monitored. Biochar application significantly increased soil pH, readily available water (RAW) content (defined as volumetric water available between −10kPa and −100kPa) and soil organic C (SOC). It decreased bulk density (BD), but had no consistent effect on soil infiltration rates, CEC, or nutrient uptake. Biochar application did increase grain yield during the first year by 11 to 55% following very high stover application rates (3.5× the typical amount), presumably because biochar mitigated adverse effects of allelochemicals released from the decomposing maize residue. There was no detectable biochar effect on maize yield during the second year when the crop was limited by severe drought.

SEED YIELD AS AFFECTED BY THE ECOLOGICAL STABILITY OF THE FIELD PEA (PISUM SATIVUM) CULTIVARS

A small–plot field trial was carried out from 2007 to 2009 including seven field pea (Pisum sativum L.) cultivars from the Ukraine and Bulgaria. The ecological stability in the tested pea cultivars was determined in relation to seed yield. Stability parameters were determined by the regression analysis according to the methods by Eberhart and Russell and Tai. The analysis of variance proved that the influence of the factors genotype, environment and genotype x environment and seed yield had a very high level of the probability. The cultivars Kerpo from Bulgaria and Usatii 90 from the Ukraine could be considered close to an ideal type (bi=1.04, λi=11.08; bi=1.05, λi= 1.12), suitable for growing in different environments. On the other hand, the Bulgarian Mir (bi=1.56, λi=49.41) and the Ukrainian Harkovskii Etalon (bi=1.28, λi=95.88) were identified as unstable (bi>1), but with good response that provide them with high seed yields in certain environments. The cultivars Vesela (bi=0.77, λi=6.77) from Bulgaria, Pleven 10 (bi=0.71, λi=59.49) from Bulgaria and Rezonator (bi=0.68, λi=35.07) from the Ukraine were assessed as stable (bi<1), but with a low adaptability except for Vesela. In conclusion, the cultivars Kerpo, Usatii 90 and Vesela may be regarded as suitable for including in the future hybridisation programmes and developing novel field pea lines with high and stable seed yields in contrasting environments.

Influence of precipitation amount during grain filling on nitrogen uptake and grain yield of spring barley fertilized by ammonium injection

The aim of this study was to observe the influence of the amount of precipitation during the grain filling period on nitrogen uptake and grain yield of spring barley fertilized by ammonium injection. Conventional nitrogen fertilization before sowing and CULTAN (Controlled Uptake Long Term Ammonium Nutrition) injection fertilization were compared during a 5-year small-plot field experiment under the conditions of Central Europe. In contrast to conventional nitrogen fertilization, with the CULTAN treatment there was observed no significantly negative effect of below-average precipitation during the grain filling period on post-heading (BBCH 51) nitrogen uptake from the soil with applications of 80 and 130 kg N.ha−1, grain yield, nitrogen uptake efficiency (NUpE) and thousand-grain weight with an application of 80 kg N.ha−1, nor there was a significantly positive effect on the contribution of nitrogen translocation to total nitrogen in the grain with an application of 130 kg N.ha−1. CULTANtreated plants achi...

Hydrological impacts of afforestation — A review of research in India

We review the current status of experimental studies in India to understand the linkages between afforestation and hydrology. This discipline deals with the use and management of water, social awareness of environmental problems, and ecosystem limitations on provision of watershed services by river basins in the mountain regions of India. Our review begins with examination of experimental works in tropical countries and proceeds to discussion of initiatives of Indian research institutes and Government organizations towards establishing experimental watersheds to understand the impacts of land cover changes on hydrologic regimes in the Indian sub-continent. This is followed by the review of the experimental work carried out by various authors to assess the impact of land cover changes on major water balance components such as, runoff, groundwater, evapotranspiration and sediment yield. The spatial scales of these experiments have been limited to small watersheds or field plots. This paper also describes impacts of human interventions (such as plantations of exotic forest species to restore degraded landscapes) on the water balance components in diverse hydro-geo-environmental conditions in the Indian sub-continent. We focus on identifying the research areas which require immediate attention to develop tools to assist planners and policy makers in assessing and managing the water resources in these complex environments. The review is largely based on research results reported during the last 20 to 30 years.

Effect of phosphoric fertilizer and starter rates of nitrogen fertilizers on the phosphatase activity in the rhizosphere soil and nonlignified soybean roots under drought conditions

In a smallplot field experiment, two soybean ( Glycine max L.) cultivars were grown on a calcare� ous chernozem under the drought conditions of 2012 with the preplanting application of simple superphos� phate (Ps) at 60 kg/ha, urea (Nu) at 10 and 20 kg/ha, and ammonium nitrate (Nan) at 20 kg/ha. The phos� phatase activity was measured in the rhizosphere soil (0� to 20�cm layer) and the fine nonlignified roots of soybean plants at the blossoming and podformation stages (the soil water content was 19 and 33% of the total water capacity, respectively). The maximum content of available phosphorus in the rhizosphere of both soy� bean cultivars (4.3-4.8 mg/100 g dry soil) was found at the simultaneous application of Ps and N u 20. Higher activities of the predominant phosphatases (alkaline phosphatase in the rhizosphere and acid phosphatase in the roots) were observed in the rootinhabited zone of the soil under the Indra cultivar compared to the Aura cultivar, which correlated with the lower content of available phosphorus in the rhizosphere soil (especially at the simultaneous application of Ps and N u 20) and the higher productivity of this cultivar in this treatment.

Vliv injektážní aplikace dusíku na příjem zinku a železa ozimou pšenicí a jarním ječmenem

Influence of CULTAN method (Controlled Uptake Long Term Ammonium Nutrition) on the iron and zinc uptake by winter wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.) was observed at four-year small-plot field experiments under conditions of the Czech Republic. No significant differences in iron and zinc concentration in grain of winter wheat as well as spring barley between conventional and CULTAN treatment were found. Neither increased supply of nitrogen fertilizer nor sulphur containing fertilizer resulted in significant differences in iron and zinc concentration in grain of winter wheat as well as spring barley at both nitrogen nutrition systems. No significant differences in sulphur concentration in aboveground biomass of winter wheat and spring barley between conventional and CULTAN treatment were recorded. Iron and zinc harvest index were not influenced by the CULTAN system. Because of no significant differences in iron and zinc concentration in grain of winter wheat as well as spring barley between conventional and CULTAN treatment, it can be assumed that nitrogen is taken up by CULTAN-treated plants in nitrate form.

Use of remote sensing to determine the relationship of early vigour to grain yield in canola (Brassica napus L.) germplasm

Early crop vigour in canola, as in other crops, is likely to result in greater competition with weeds, more rapid canopy closure, improved nutrient acquisition, improved water-use efficiency, and, potentially, greater final grain yield. Laborious measurements of crop biomass over time can be replaced with newer remote-sensing technology to aid data acquisition. Normalised difference vegetation index (NDVI) is a surrogate for biomass accumulation that can be recorded rapidly and repeatedly with inexpensive equipment. In seven small-plot field experiments conducted over a 4-year period with diverse canola germplasm (n = 105), we have shown that NDVI measures are well correlated with final grain yield. We found NDVI values were most correlated with yield (r &gt;0.7) if readings were taken when the crop had received 210–320 growing degree-days (usually the mid-vegetative phase of growth). It is suggested that canola breeders may use NDVI to objectively select for vigorous genotypes that are more likely to have higher grain yields.

The Influence of Fipronil on &lt;I&gt;Reticulitermes flavipes&lt;/I&gt; (Isoptera: Rhinotermitidae) Feeding Beyond Treated Plots

A small-plot field trial was conducted to examine the area of influence of fipronil at incremental distances away from treated plots on the Harrison Experimental Forest near Saucier, MS. Small treated (water and fipronil) plots were surrounded by untreated wooden boards in an eight-point radial pattern, and examined for evidence of termite feeding every 60 d for 1 yr after treatment. Circular areas of 0, 0.28, 1.13, 2.55, 4.52, 7.07, and 10.18 m2 around the treated plots were installed to evaluate feeding damage by termites on the boards. The relationship between feeding damage to boards and area for each time interval was examined by using an exponential increase model. For both treatments and controls in nearly all periods examined, feeding was suppressed in the boards nearest to the treated plots, but increased exponentially as the area increased. Beginning 4 mo after treatment, treatment plots had lower proportions of boards with termite feeding evidence than control plots. Reduction in feeding was the only influence of fipronil observed beyond the treated plots.