Níveis críticos para atributos do solo pela distribuição normal reduzida em culturas anuais de subsistência

Abstract

R E S U M OObjetivou-se, neste trabalho, propor níveis críticos para atributos químicos do solo utilizando-se a distribuição normal reduzida em áreas de agricultura familiar de subsistência cultivadas com milho e feijão-caupi, no semiárido brasileiro. Amostras de solo foram coletadas em propriedades de agricultores familiares do Sertão dos InhamunsCrateús. Para a obtenção de níveis críticos foi utilizada a distribuição normal reduzida que utiliza os dados de produtividade e a relação entre produtividade e o atributo químico do solo atribuindo o nível crítico para 90% da produtividade máxima. Os níveis críticos obtidos para as áreas cultivadas com milho e feijão caupi em região semiárida são: MO (g kg -1): 7,3 e 7,5; pH: 6,6 e 6,5; P (mg dm ): 11,2 e 9,9 e saturação por base (%): 73 e 71, respectivamente. O nível crítico pela distribuição normal reduzida pode ser utilizado com vista à obtenção de níveis críticos para atributos químicos do solo. Os atributos com maior frequência para o índice negativo em relação ao nível crítico estimado (NCRIz) são Ca > V > pH > Mg > K = MO > P e V > pH > P > MO > Mg > K > Ca para as áreas de milho e feijão, respectivamente.Critical levels for soil attributes by reduced normal distribution in annual crops of subsistence A B S T R A C TThis study aimed to propose critical levels for soil chemical properties using the reduced normal distribution in areas of family subsistence farming under maize and cowpea crops in the Brazilian semiarid. Soil samples were collected on family farms in the region of Inhamuns-Cratéus. To obtain the critical levels the reduced normal distribution was used which uses the productivity data and the relationship between productivity and soil chemical attributes and assigning the critical level for 90% of the maximum. Critical levels obtained for areas cultivated with maize and cowpea in the semiarid region are: OM (g kg -1 ): 7.3 and 7.5; pH: 6.6 and 6.5; P (mg dm ): 11.2 and 9.9; and base saturation (%): 73 and 71, respectively. The critical level for reduced normal distribution can be used to obtain critical levels for soil chemical properties. The attributes most frequently for negative index over estimated critical level (NCRIz) are Ca > V > pH > Mg > K = OM > P and V > pH > P > OM > Mg > K > Ca areas for corn and cowpea, respectively. Palavras-chave:Zea mays Vigna unguiculata fertilidade do solo semiárido sertão Inhamuns-Crateús

Use of Organic Compost Containing Waste from Small Ruminants in Corn Production

“…Furthermore, as shown in the tables on nutrient concentrations in the soil and plants and on yield results, the use of this organic compost based on wastes from slaughter of goats and sheep increased corn yields to a level above the average for the state of Ceará, which is especially important considering the crop yields of smallholders, who typically cannot afford commercial inputs to replace nutrients (Souza et al, 2014b). Hence, the use of this organic compost is an attractive alternative for reducing the need for waste treatment and for improving crop yields at the same time.…”

Critical levels for soil attributes in irrigated banana plantations in semiarid region

“…It should be pointed out that the soils in the region originated from calcareous rocks, naturally showing medium or weak acidity, Fe and Mn concretions and low P contents. Souza et al (2014), using the same method to calculate critical levels of some soil attributes in family farming areas under maize cultivation in the Sertão of Inhamuns-Crateús, obtained NCRIz of 6.6 for pH, 8.6 mg dm -3 for P and 2.8, 33.3 and 11.12 mmol c dm -3 for K, Ca and Mg, respectively. For beans, these values were 6.5 for pH, 8.2 mg dm -3 for P and 2.7, 22.4 and 9.9 mmol c dm -3 for K, Ca and Mg, respectively.…”

“…Good results were observed for coffee plants by the same authors and the method was also evaluated in other crops, such as grape (Tonin et al, 2009), orange (Camacho et al, 2012) and sugarcane (Santos et al, 2013). Although the NCRIz method was originally developed for leaf analysis, Souza et al (2014) used it to estimate the critical level of some soil chemical attributes in family farming areas cultivated with maize and cowpea, in the 'Sertão' of Inhamuns-Crateús. According to the results, it is possible to obtain critical levels for soil attributes, without the need for installation and conduction of field experiments.…”

Plant Components of Agroforestry System Have Different Contributions to Soil Fertility

“…These values of the element are explained by the pruning of leguminous species established in rows of the AFS and the deposition of this pruning residue along the maize planting rows. The application of manure and the cultivation in rows in agricultural areas constitute a good alternative to improve soil fertility, contributing to the increase in production, especially for family farmers (Souza et al, 2014).…”