Jeane Cruz Portela

Chemical Attributes of an Oxisol Under Different Agricultural Uses in the Brazilian Semiarid Region

Different soil managements evidence soil properties, contributing positively or negatively to its quality. A study was conducted in the city of Martins, Rio Grande do Norte (RN) state, in four cultivated areas: corn intercropped with beans (CICB), cassava monocrop (CAMO), bean monocrop (BEMO) and native forest (NF, considered as the original soil condition). This study aimed to evaluate changes in the chemical properties of an Oxisol in function of different agricultural uses (N, P, K+, Ca2+, Mg2+, Na1+, Al3+, pH, EC, H+Al, BS, V, CEC, t, m, OM and ESP) and the distinction of environments using multivariate analysis. The sampling was performed up to 30 cm deep. Soil pH values were kept close to 5.5, except for the area with corn intercropped with beans, whose values were higher than 7.0. Corn intercropped with beans had the highest concentrations of K+, Na+ and Ca2+ on the soil, with a direct impact on base sum. Different uses modified soil chemical properties. Corn intercropped with beans differs from the other treatments due to the addition of solid waste to the soil. Principal component analyses showed pH and exchangeable bases are the most sensitive indicators of environment separation.

YIELD AND FORAGE QUALITY OF SALTBUSH IRRIGATED WITH REJECT BRINE FROM DESALINATION PLANT BY REVERSE OSMOSIS

Rural communities located in the Brazilian Northeast, especially in the semiarid zone, live with water shortages resulting from erratic rainfall. This work proposes the cultivation of saltbush (Atriplex nummularia) in the Rural Settlement Project of Boa Fé, Mossoró/RN as alternative to the disposal of reject brine from desalination plant on yield of forage. The statistical design was a split-plot design, being four treatments at the plots, related to irrigation with reject brine water, at different levels of soil moisture by moisture from Field Capacity (FC) (100, 85, 70 and 50% of FC) and in subplots and two levels of organic manure (without fertilized and fertilized) with four replications. The variables of yield and forage quality of saltbush were analyzed. It was observed that saltbush has a great production capacity in terms of fresh matter and drought for saltbush under a level of 85% soil moisture in relation to the field capacity of soil, presenting minimal loss of yield; however, this proved to be productive even with the dry soil. The total yield was satisfactory, showing its viability for forage production.

Topossequência de Neossolos na zona rural de Florânia, Rio Grande do Norte.

O estudo dos solos do semiarido e pouco explorado, embora seja importante para a sua sustentabilidade. Dessa forma, o objetivo deste trabalho foi estudar as relacoes solo-paisagem, a caracterizacao fisico-quimica e morfologica de solos em uma topossequencia em Florânia/RN, regiao do Serido no Semiarido brasileiro. A pesquisa foi realizada no Sitio Canacu, localizada em um vale, cortada pelo rio Garganta. Foram descritos, amostrados e georrefenciados cinco perfis de solos, em funcao dos horizontes pedogeneticos. Conclui-se que a variabilidade encontrada nos perfis reflete as condicoes impostas pelo clima e pela paisagem. Esses solos apresentam boa fertilidade oriunda do material de origem, porem, esta e comprometida pelo carater sodico. De modo geral, o silte predomina na maioria das profundidades e a relacao silte/argila caracterizam solos jovens e pouco intemperizados. As limitacoes quanto ao uso agricola desses solos encontram-se na deficiencia hidrica durante o ano, em limitacoes fisicas e nos elevados teores de sodio.