Soil Properties and Nutrient Uptake of Corn-Legumes Intercropping Under Conservation Agriculture Practice Systems (CAPS) in a Sloping Upland Oxisol
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Journal of Multidisciplinary Studies Vol. 4, No. 1, pp. 25-49, August 2015 ISSNJournal 2350-7020 of Multidisciplinary (Print) Studies Vol. 4 No. 1, pp. 25-49, August 2015 ISSN 2362-94362350-7020 (Print)(Online) doi:ISSN http://dx.doi.org/10.7828/jmds.v4i1.860 2362-9436 (Online) doi: http://dx.doi.org/10.7828/jmds.v4i1.860 Soil Properties and Nutrient Uptake of Corn-legumes Intercropping Under Conservation Agriculture Practice Systems (CAPS) in a Sloping Upland Oxisol Apolinario B. Gonzaga, Jr. University of Science and Technology of Southern Philippines Claveria Campus, Misamis Oriental, 9004 Philippines Corresponding author: Apolinario B. Gonzaga, Jr., email: [email protected] Abstract Conservation Agriculture Practice Systems (CAPS) is new agronomic innovation anchored on three main pillars: minimal tillage, continuous mulching and diversified cropping all applied in a simultaneous manner in a cropping season and area. It is a global innovation adapted by major food production countries. However, it is not yet tested under local farming landscape more so in a sloping upland production area. Influence of CAPS on changes in soil properties, nutrient uptake, and soil moisture are critical factors in its long-term sustainability and adoption among local farmers. This study aimed to conduct a field experiment involving different corn-legumes intercropping (cropping system 1 or CS1, CS2, CS3, CS4) and monocrop corn (CS5, control) to evaluate the changes in soil properties, nutrient uptake, and soil moisture in an upland oxisol for two cropping seasons. Key edaphic parameters such as internal nitrogen (N) efficiency, organic matter (OM), organic carbon (OC) and soil moisture content were determined and evaluated. A notable increase in N efficiencies, OM, OC, and soil moisture content measured at different time intervals in corn-legumes systems (corn + Arachis pintoi, corn + Stylosanthes guianensis and corn-cowpea) compared with the control (corn-corn, CS5) was observed. Corn + S. guianensis (CS2) and corn + cowpea (CS3) appeared to have more efficient N absorption trend as compared to other cropping systems imposed. Key findings provided initial merits of adoption of CAPS within the context of productivity, profitability, and soil sustainability in local corn-based farms in sloping uplands. Keywords: edaphic, farming, nitrogen, productivity, sustainability 25 Journal of Multidisciplinary Studies Vol. 4, No. 1, pp. 25-49, August 2015 Soil Properties and Nutrient Uptake of Corn-legumes A. B. Gonzaga, Jr. Intercropping Under Conservation Agriculture Practice Systems (CAPS) in a Sloping Upland Oxisol Introduction Presently, agriculture needs to produce more from less land area through the most efficient use of natural resources with least possible negative impact on the environment to meet the demands of the growing population. This challenge has become more intense in recent years with the sharp rise in food cost, energy and production inputs, climate change, scarcity of water, degradation of ecosystem services and biodiversity, and financial crisis (Kassam et al., 2012). Dwindling land resources, declining soil fertility and climatic abnormalities attributed to the changing climate will be the main constraints to achieving a sustainable food production. Therefore, strategies must be developed to keep with the demand and overall productivity that is sustainable over the long-term. Conservation Agriculture (CA) refers to the system of raising crops with minimal disturbance to the soil while keeping crop residues on the surface. The Food and Agriculture Organization (FAO) characterized conservation agriculture as a system that maintains a permanent or semi-permanent organic soil cover that can be a growing crop or dead mulch. Its function is to protect the soil physically from sun, rain and wind, and to feed soil biota. It is a new agricultural management system that is gaining popularity in many parts of the world (Hobbs et al., 2008). Moreover, CA aims to conserve, improve and efficiently use more the natural resources such as the soil, water, and biological resources through an integrated management combined with external inputs. It contributes to environmental conservation, as well as to enhanced and sustained agricultural production. Similarly, it is one of the many practices that can sustain agricultural productivity (Hobbs et al., 2008; Derpsch, 2008; Kassam et al., 2012). The practice can also reduce soil erosion effectively (Scopel et al., 2005; Lal et al., 2007; Baldé et al., 2011). It is a system approach to sustainable soil and water conservation, high crop productivity and profitability. Therefore, CA is a system approach to sustainable agriculture (Li et al., 2011). This practice relies on continuous cropping rotation or cropping combination, minimum soil disturbance or tillage and continuous ground cover or 26 Soil Properties and Nutrient Uptake of Corn-legumes A. B. Gonzaga, Jr. Intercropping Under Conservation Agriculture Practice SystemsJournal of (CAPS) Multidisciplinary in a Sloping Studies Upland Vol. Oxisol 4 No. 1, pp. 25-49, August 2015 mulching. It spearheads an alternative no-till agroecological paradigm that is making an increasing contribution to sustainable production intensification (Hobbs et al., 2008; Pretty, 2008; Goddard et al., 2008). In Asia at present, there are still few adopters of CA despite gaining ground as an emerging alternative to conventional tillage-based agriculture worldwide. According to Ella et al. (2012), few countries like Cambodia, Vietnam, China and recently the Philippines conduct research on CA for future adoption. The same authors stated that in the Philippines, no research exists on the soil quality impacts of conservation agriculture in its strictest sense. In the Philippines, the last remaining frontiers for agricultural expansion are the sloping uplands. This ecosystem is fragile and vulnerable with the critical resource. Attributable to the topography, soil erosion is prevalent and excessive. At present, upland areas play a vital role as watersheds in the conservation of water resources and the maintenance of a stable agricultural ecosystem. Upland areas are also the potential expansion areas for agricultural production considering the shrinking agricultural areas due to other uses. The Philippine uplands, which constitute about 10 million hectares, are characterized by sloping and acidic soil in which about 50% of the area is less productive due to soil degradation (Mercado, 2011). Report of the Bureau of Agricultural Statistics showed that in 2014 the agricultural land area of the Philippines totalled to 9,671 million hectares divided into the arable land (4,936 M ha), permanent cropland (4,225 M ha), and forestland (0.7 M ha) (CountryStat Philippines, 2014). Cropping patterns in most sloping uplands are monocropping or multiple cropping of cereals (e.g. corn and rice), root crops (cassava and sweet potato) and vegetables (e.g. tomato, sweet pepper, cabbage, etc.) or combinations of these crops. Corn cultivation is both for food and feed while cassava production constitutes an important staple root crop in sloping farm areas. Both plants demand intensive tillage, heavy external fertilizer application, and other cultural management intensification measures. The challenge for CA for the adoption of local farmers is to evaluate the productivity of the two above-mentioned principal crops cultivated under its pillars. Similarly, CA in the country with its 27 Journal of Multidisciplinary Studies Vol. 4, No. 1, pp. 25-49, August 2015 Soil Properties and Nutrient Uptake of Corn-legumes A. B. Gonzaga, Jr. Intercropping Under Conservation Agriculture Practice Systems (CAPS) in a Sloping Upland Oxisol integrated components is a new development in crop production. Hence, testing for its adaptability and efficiency in local farming landscapes is essential. This step entails the formulation of CAPS, a tailor-fitted approach for successful adoption and implementation of CA to a particular location. The concept of CA that involves minimal soil disturbance, continuous retention of residue, mulching of soil surface, and diverse and rational use of crop rotations (Erenstein et al., 2008; Sustainable Agriculture and Natural Resource Management Collaborative Research Support Program [SANREM CRSP], 2009) constitute the basis of CAPS. The systems involve optimum seed integration or seedling establishment methods, implement farm selection, crop choice for rotation, suitability of germplasm, management of mulch and fodder, and demand to produce. The systems also involve profitability, nutrient management, farmer preferences and skills, local government policies, credit availability, production inputs, labor, gender, and other various concerns. Without appropriate soil conservation techniques, upland soils become prone to erosion, and could eventually become infertile as production intensifies. Hence, sustainability of the production system, concerning crop and soil productivity, is among the crucial considerations over the long-term. This study determined the changes of soil properties and nutrient uptake of corn-legumes intercropping systems under the CAPS in a sloping upland oxisol in Northern Mindanao. Specifically, the study aimed to evaluate the effect of different cropping systems on soil properties. The paper also determined the nutrient uptake and efficiencies and measured the moisture content of the soil as influenced by the various CAPS. This study also aimed to identify locally-viable