Vanda Maria de Lira

Comparação de indicadores químicos do solo após o plantio da algaroba

A algaroba (Prosopis sp) foi trazida para o Semiarido Brasileiro como o objetivo de alimentar os rebanhos nos periodos mais secos do ano. Com o objetivo de avaliar parâmetros quimicos em solos cultivados com esta cultura, foi conduzido um experimento junto a area experimental do Departamento de Engenharia, UFCG, Universidade Federal de Campina Grande, Estado da Paraiba. No experimento foi utilizado um delineamento estatistico casualizado, com um esquema fatorial de 5 x 2, com 4 repeticoes, com 5 niveis de reposicao de agua (W1= 20% ate W5 = 100% da evapotranspiracao) e 2 tipos de solo. Em 92,5% dos lisimetros as analises mostraram que houve um aumento da fixacao no nivel de nitrogenio no solo. Ja com relacao ao teor de materia orgânica os resultados que foram encontrados no experimento, mostraram que 95% dos lisimetros apresentaram um acrescimo no valor da percentagem de materia orgânica, quando comparados com os resultados obtidos no inicio do experimento. Com os resultados obtidos ao final do experimento constatamos que a algaroba trouxe beneficios no tocante a melhoria na qualidade do solo.

Evaluation of the levels of nitrogen, organic matter and pH in sols cultivated with Prosopis

Prosopis crop was introduced in the Northeast region in Brazil with the objective to feed the livestock during the drier season. However, after 30 years, it was created a big polemic around it. Current the crop is considered as a plague. With the objective to evaluate the levels of nitrogen and organic matter and the content of pH in sols cultivated with Prosopis it was carried out an experiment between July 15th 2007 and September 30th 2008. The experimental design was in randomized block in a factorial scheme 5 x 2, with 4 repetitions, and five levels of soil available water at the irrigation management level (W1= 20% to W5 = 100% of the evapotranspiration rates) and two different soils. These when analyzed at the beginning of the experiment presented pH above 8,0, however at the end of the experiment when they were analyzed again, it was observed that in 65% of the lysimeters the pH was under 8,0 and reach a lower index of 7,1. In 92,5 of the lysimeters the level of nitrogen in the soil increased, which indexes at the begin was 0,04% and at the end of the experiment value of 0,06%, it increased in the rate that ranges from 33,3% to 66,6% respectively. In relation to the content of organic matter, it was observed that in 95% of the lysimeters there was an increase on it, when compared with the results that was found in the begin of the experiment. The values ranged from 0,86% to 2,19%, it means that there was an increase of 13,95% to the low value found and 66,21% to the bigger one. These results are according to other studies that in soil with prosopis crop there is an increase in the levels of organic matter, it is probably because of the leaves and branches that fall which protect the soil.