Soil Properties and Crop Yields in Response to Mixed Paper Mill Sludges, Dairy Cattle Manure, and Inorganic Fertilizer Application

Abstract

Th e contribution of organic wastes to crop yields and soil fertility may be infl uenced by their composition and the soil type. Th is 6-yr study (2001)(2002)(2003)(2004)(2005)(2006) evaluated the eff ects of repeated additions of mineral fertilizers (MF), mixed paper mill sludges (PMS) (18, 36, and 54 Mg ha -1 ), dairy cattle manure (DCM) (36 Mg ha -1 ) alone or with reduced mineral fertilizer (60% NPK) (RMF) and a control, on soil properties and corn (Zea mays L.), barley (Hordeum vulgaris L.), and soybean (Glycine max L. Merr.) yields in a clay loam and sandy loam. Th e applications of PMS and DCM increased mostly N mineralization and crop yields in the sandy loam than in the clay loam. However, increases of soil C contents, water-stable aggregates and MWD following their application were higher in the clay loam than in the sandy loam. Th e DCM eff ects on the soil property changes were of less magnitude than those of PMS. Except in the fi rst year, the PMS applications at rates of 36 and 54 Mg ha -1 without NPK, and PMS applied at a rate of 18 Mg ha -1 with 60% NPK, produced highest crop yields in both soils and were comparable to those obtained with MF. Th e increase in yield following DCM additions (36 Mg ha -1 ) was lower than that obtained with PMS. Annual MF applications increased crop yields in both soil without signifi cant changes on soil properties. Th e benefi ts of PMS and DCM on soil properties and crop yields varied depending on organic wastes and soil type.

The Benefits of Crop Rotation Including Cereals and Green Manures on Potato Yield and Nitrogen Nutrition and Soil Properties

“…Our findings agree with others studies supporting that soil respiration, microbial biomass, and soil enzyme activities respond more quickly to changes in crop management than soil total C [35,48]. Increased soil respiration generally reflects an increase in soil microbial biomass [49] and, thereby, the greater respiration in soils previously cropped to cereals and GMs indicates that these preceding crops stimulated soil microbial growth and activity by supplying labile organic matter, as shown by soil WEOC ( Table 5).…”

“…The low soil organic matter and N accumulation observed in the present study indicates that the total quantities of organic residues (3 to 16 Mg ha -1 ) and C (1000 to 3800 kg C ha -1 ) incorporated in soils in 2008 and 2010 were not sufficient to induce an increase in soil organic matter. N'Dayegamiye [35] showed that three paper-mill sludges applications at 40 to 60 Mg ha -1 yr -1 significantly increased the soil C content. Moreover, GMs as used in the study also contain readily mineralizable organic materials as suggested by their low C/N ratios (Tables 3 and 4), and that they were likely mineralized more rapidly in the sandy soil of the present study than in the silt loam studied by N'Dayegamiye et Tran [12] and N'Dayegamiye [35].…”

“…N'Dayegamiye [35] showed that three paper-mill sludges applications at 40 to 60 Mg ha -1 yr -1 significantly increased the soil C content. Moreover, GMs as used in the study also contain readily mineralizable organic materials as suggested by their low C/N ratios (Tables 3 and 4), and that they were likely mineralized more rapidly in the sandy soil of the present study than in the silt loam studied by N'Dayegamiye et Tran [12] and N'Dayegamiye [35]. Soil water extractable C and N (WEOC, and WEON) concentrations varied from 110 to 140 mg C kg -1 , and from 15 to 24 mg N kg -1 , respectively (Table 5).…”

“…Organic mineralization rate is mainly controlled by their biochemical composition, such as C/N ratio and polyphenol, lignin, and nitrogen contents [34,35]. Fall GMs had lower C/N ratios than summer GMs (Tables 3 and 4), which suggests that they may decompose and release N more rapidly.…”

“…These results may be related to different conditions under which the experiments were conducted, including the use of different GMs species, different amounts and quality of green manure biomass returned to the soil, climatic conditions, and different soil types. It is well documented that clay soils retain more organic matter than sandy soils [39], because organic matter associated with clay minerals benefit more physical and chemical protection against decomposition than that associated with sand [35,40]. Potato is mostly cultivated on sandy soils and the decline of soil organic matter is of much concern.…”