Nutrição do feijoeiro e intensidade da antracnose em função da aplicação de silício e cobre

The objective of this work was to evaluate the effect of calcium silicate and copper sulfate on anthracnose intensity and nutrition of bean plants. The experiment was conducted using an experimental design in randomized blocks following a 4 x 4 factorial arrangement, (four levels of calcium silicate and four levels of copper sulfate) and two additional treatments (plants without inoculation and plants sprinkled with Benomyl). Four evaluations of the incidence and severity of anthracnose were done, in addition to measuring total leaf area. At the end of the evaluations, incidence and severity data were integrated over time, obtaining the area under disease progress curve (AUDPC). Contents of N, P, K, Ca, Mg, B, Cu, Fe, Mn, Zn, Si and lignin were determined in the aerial part. A linear decrease of the intensity AUDPC was observed with the increase of the doses of calcium silicate. The severity AUDPC was influenced by the doses of copper, obtaining a reduction of 35% on the higher dosage. The supply of silicon and copper altered the content of the K, Mg, S, Zn, Ca and Si in the aerial part of the bean plants.

Estudo da influencia do potássio e do cálcio na reprodução do nematoide do cisto da soja

The objective of this work was to evaluate the reproduction of the soybean cyst nematode (SCN) in soybean plants in substract with different potassium (K) and calcium (Ca) doses. The experiment was conducted in a completely randomized block design, with 25 treatments and six replicates. A factorial scheme (5 x 5) was used with five K doses (0; 150; 300; 450; and 600 mg / dm3 ) and five Ca doses (0; 75; 150; 225; and 300 mg / dm3 ). Eighteen days after sowing, plants were inoculated with 4,000 H. glycines race 3 eggs. Thirty days after inoculation a total of three weekly evaluations were performed measuring plant height and stem diameter. Seventy days after inoculation, the following variables were analyzed: measurement of leaf blade, numbers of eggs / pot, cysts / pot, eggs / cyst, females and cysts / root system, eggs / female and the reproduction factor of H. glycines. Root and shoot dry matter were weighed. Then, K and Ca shoot contents of each sample was obtained. There was a significant interaction between K and Ca doses only for number of eggs / female. The K doses significatively influenced the numbers of cysts / pot, eggs / cyst, eggs / pot, females and cysts / root system and reproduction factor. The Ca doses did not influence significatively the nematologic variables analyzed. The K-Ca interaction affected all crop-related variables analyzed. A significative K-Ca interaction was observed for Ca contents in shoot dry matter. The K contents were only influenced by potassium doses amended to the soil.