Root and Shoot Growth of Maize (Zea mays) as Affected by Incorporation of Crotalaria juncea and Tithonia diversifolia as Green Manures

Abstract

Crop establishment, determined by shoot and root growth during early growth is a vital component in procuring desired plant populations and high yields in rainfed tropical smallholder farming systems, where green manures help maintain soil fertility and sustainability. As green manure incorporation could affect early seedling growth, studies were conduced in a plant house using soils from fields, to evaluate the impact of incorporating two popular tropical green manures (Crotalaria juncea and Tithonia diversifolia) into soil under rainfed field conditions over 3 years, on selected physico-chemical properties of the soils and on establishment and early shoot and root growth of maize (Zea mays), with and without inorganic fertilizers. In a given year, green manure was grown in one season while maize was grown in the other. A soil that did not receive green manures but was left fallow during the period of green manure cultivation was used as the control treatment. The incorporation of green manures over the 3 years showed trends of increasing soil physical properties, and also the available nitrogen, phosphorus and potassium contents. Incorporation of Crotalaria, with its higher nitrogen content, promoted shoot growth, while Tithonia induced the development of an extended root system. The use of inorganic fertilizers stimulated the beneficial impact of the green manures in promoting shoot and root growth. The use of green manures, especially Tithonia, promoted the development of seminal and nodal roots of maize seedlings, both in the form of length and thickness (based on root surface area) and root length densities, which could assist in successful crop establishment and resource utilization, rather than primary roots. The benefits of using green manures, especially Tithonia, in promoting root growth and Crotalaria in shoot development of maize seedlings even without inorganic fertilizers is presented.

Performance of Acacia senegal (L.) Wild Seedlings Growth under some Tree Manures and NPK Fertilizers in Nursery Site

“…This observation is in agreement with works of many researchers (Önemli 2004;Sangakkara et al 2004;Bot and Benites 2005;Kung'u et al 2008) who found that different forms and compounds of organic matter (humic and fulvic substances, compost, rice straw and fresh Gliricidia spp.…”

“…Tree manure (biomass) can be incorporated into exploitable systems such as agroforestry, either naturally or artificially. It can be collected, transformed and transferred to other utilization practices such as farms, orchards and nurseries (Rao and Mathuva 2000;Mandal et al 2003;Schroth and Sinclair 2003;Sangakkara et al 2004). The choice for manure quality will depend on the utilization strategy, whether quick or slow decomposing substances is needed (Bot and Benites 2005;Mubarak et al 2008).…”

Utilization of Sunn Hemp for Cover Crops and Weed Control in Temperate Climates

“…With high fertilizer prices and sustainability concerns with synthetic soil amendments, the potential use of sunn hemp to provide nitrogen to crops such as cotton, corn, and rice has prompted research to determine N availability from a sunn hemp cover crop (Balkcom and Reeves 2005;Chung et al 2000;Sangakkara et al 2004;Schomberg et al 2007). Nitrogen production with sunn hemp varies depending on many factors; however, reported N values in sunn hemp range between 110 and 160 kg ha -1 (Balkcom and Reeves 2005;Mansoer et al 1997;Marshall et al 2001).…”

Yield Responses of Maize to Organic and Mineral Fertilizers at Different Inclinations in Tropical Smallholder Farming Systems

“…Repeated green manure applications can provide more long-term Kimaro et al, 2007;Makumba et al, 2007) or more short-term (Sangakkara et al, 2004;Reddy et al, 2008;Silva et al, 2008) benefits. However, there are not always positive effects (Pandey & Rai, 2007;Marin et al, 2007).…”