Effect of fertilization on flowering and seed crop in Scots pine seed orchards

Summary

Responses of yield and N use of spring sown crops to N fertilization, with special reference to the use of plant growth regulators

Selostus: Typpilannoituksen ja kasvunsääteiden vaikutukset kevätviljojen ja rypsin satoon sekä typen käyttöön

Relationship between potassium fertilization and panicle blast severity in upland rice

The influence of K2O (0, 40, 80, 120 kg ha-1) at varying rates of N application (0, 30, 60 kg ha-1) at planting, on panicle blast (Pyricularia grisea (Cooke) Sacc.) was studied in a field experiment conducted during three consecutive years with the upland rice cultivar Douradão. Panicle blast severity decreased with increasing rates of potassium in the absence of nitrogen (N0). The relationship between panicle blast and K rates was quadratic at 30 kg ha-1 of nitrogen. Significant response to K fertilization was not obtained at 60 kg ha-1 of nitrogen in relation to panicle blast severity.

Nitrogen fertilization impact on agronomic traits of maize hybrids released at different decades

Genetic selection of maize hybrids is often conducted using high N rates during the breeding cycle. This procedure may either lead to the release of genotypes that present nitrogen luxury consumption or require a stronger N input to accomplish their yield potential. This work was carried out to evaluate the effects of N rates on grain yield and N use efficiency of hybrids cultivated in different decades in Southern Brazil. The trial was performed in Lages, Santa Catarina State. A split plot design was used. Hybrids Ag 12, Ag 28, Ag 303 and Ag 9012, released during the 60's, 70's, 80's and 90's, respectively, were evaluated in the main plots. Nitrogen rates equivalent to 0, 50, 100 and 200 kg ha-1 were side-dressed in the split-plots when each hybrid had six fully expanded leaves. Modern-day hybrid Ag 9012 had higher grain yield than hybrids of earlier eras, regardless of N rates. Under high doses of N, the older hybrids Ag 12 and Ag 28 took up more N and presented higher values of shoot dry matter at flowering than Ag 9012. Nonetheless, they set less grains per ear which contributed to decrease their grain yield and N use efficiency.

Efficiency of split nitrogen fertilization with adjusted irrigation on potato

Selostus: Jaetun typpilannoituksen käyttömahdollisuudet perunalle

Harvesting strategy and N fertilization influence ¹³⁴Cs uptake by forage plants

Selostus: Korjuuaika ja typpilannoitus vaikuttavat rehukasvien radiocesiumpitoisuuteen

Potassium supply to cotton roots as affected by potassium fertilization and liming

Cotton (Gossypium hirsutum) is known to have a high requirement for K and to be very sensitive to low soil pH. Most of K reaches plant roots by diffusion in the soil. As K interacts with Ca and Mg, liming can interfere in K movement in the soil, affecting eventually the plant nutrition. The objective of this work was to study the effect of dolomitic lime and 0, 15, 30, 45 and 60 g kg-1 of K on the supply of K to cotton roots. Cotton plants were grown up to 40 days in 5 L pots containing a Dark Red Latosol (Typic Haplusthox) with 68% and 16% of sand and clay, respectively. There was an increase in dry matter yields and in K accumulation due to K fertilization. Root interception of soil K was also increased by K application, but was not affected by lime. Mass flow and diffusion increased linearly with K levels up to 60 mg kg-1, in pots with lime. In pots without lime the amount of K reaching the roots by diffusion increased up to 45 mg kg-1, but decreased at the highest K level. Accordingly, there was more K reaching the roots through mass flow at the highest K level. This happened because there were more fine roots in pots without lime, at the highest K level. As the roots grew closer, there was a stronger root competition leading to a decrease in the amount of K diffused to cotton roots.

Carbon and nitrogen partitioning during post-anthesis is conditioned by N fertilization and sink strength in three cereals

Further knowledge of the processes conditioning nitrogen use efficiency (NUE) is of great relevance to crop productivity. The aim of this paper was characterise C and N partitioning during grain filling and their implications for NUE. Cereals such as bread wheat (Triticum aestivum L. cv Califa sur), triticale (× Triticosecale Wittmack cv. Imperioso) and tritordeum (× Tritordeum Asch. & Graebn line HT 621) were grown under low (LN, 5 mm NH4NO3) and high (HN, 15 mm NH4NO3) N conditions. We conducted simultaneous double labelling (12CO2 and 15NH415NO3) in order to characterise C and N partitioning during grain filling. Although triticale plants showed the largest total and ear dry matter values in HN conditions, the large investment in shoot and root biomass negatively affected ear NUE. Tritordeum was the only genotype that increased NUE in both N treatments (NUEtotal), whereas in wheat, no significant effect was detected. N labelling revealed that N fertilisation during post-anthesis was more relevant for wheat and tritordeum grain filling than for triticale. The study also revealed that the investments of C and N in flag leaves and shoots, together with the"waste" of photoassimilates in respiration, conditioned the NUE of plants, and especially under LN. These results suggest that C and N use by these plants needs to be improved in order to increase ear C and N sinks, especially under LN. It is also remarkable that even though tritordeum shows the largest increase in NUE, the low yield of this cereal limits its agronomic value.

Pre-harvest soil acidification, liming or N fertilization did not significantly affect the survival and growth of young Norway spruce

Abstract

Boron, phosphorus and nitrogen fertilization in Norway spruce stands suffering from growth disturbances

Abstract

Production of annual winter forage sown before and after soybean harvest under different nitrogen fertilization levels

The objective of this work was to evaluate the effect on forage yield of sowing winter forage species before and after soybean harvest, at different nitrogen application levels. The experiment was set out in a randomized block design with a strip-split plot arrangement, and three replicates. Sowing methods (18 days before soybean harvest and six days after soybean harvest) were allocated in the main plots, and the combination among forage species (Avena strigosa cv. IAPAR 61 + Lolium multiflorum; A. strigosa cv. Comum + L. multiflorum; A. strigosa cv. Comum + L. multiflorum + Vicia villosa; A. strigosa cv. Comum + L. multiflorum + Raphanus sativus; and L. multiflorum) and nitrogen levels (0, 140, 280 and 420 kg ha-1) in the plots and subplots, respectively. Forage sowing before the soybean harvest made it possible to anticipate first grazing by 14 days, with satisfactory establishment of forage species without affecting forage production. This method permitted a longer grazing period, preventing the need for soil disking, besides allowing the use of no-tillage system. The mixture of forage species enables higher forage yield for pasture in relation to single species pastures, with response to nitrogen fertilization up to 360 kg ha-1.

Grazing intensities and poultry litter fertilization levels on corn and black oat yield

The objective of this work was to assess the effect of poultry litter fertilization levels on corn and black oat yield using different grazing intensities, poultry litter levels (mixture of manure and bedding material) and a chemical fertilization level. The experimental design was a randomized complete block in a split-plot arrangement with four replicates. Black oat + ryegrass grazing intensities, characterized by different pasture sward management, with animal entrance at 25, 30 and 35-cm heights and exit at 5.0, 10 and 15-cm heights, were established at the main plots. After the grazing period, corn was grown at the subplots with four levels of poultry litter (0, 4,953, 9,907 and 14,860 kg ha-1), aiming to supply 0, 100, 200 and 300 kg ha-1 of nitrogen, and a treatment with chemical fertilizer, according to soil analysis. Grazing intensities had no effect on corn yield. Corn yield was 7,493, 8,458, 9,188, 10,247 and 11,028 kg ha-1, respectively, for the treatments without and with 4,953, 9,907 and 14,860 kg ha-1 of poultry litter, and the treatment with chemical fertilization. Poultry litter levels have a residual effect on the production of black oat grown in succession to corn.