Effect of combined cattle manure and mineral nitrogen on maize N uptake and grain yield

TLDR: Combined application of manure with judicious use of N fertiliser can be positively exploited by smallholder farmers in Zimbabwe and other countries of sub-Saharan Africa, to increase yields through enhanced efficiency of use of scarce nutrient resources.

Abstract: The effectiveness in increasing N recovery by maize ( Zea mays L.) of N fertiliser (0, 60, 120 kg N ha-1 annum-1) and aerobically composted cattle manure (0, 12.5 Mg ha-1 annum-1 or 37.5 Mg ha-1 applied only in the first year) was determined when the two N sources were applied separately or in combination. A field experiment was established on a moderately leached sandy loam soil (Typic Kandiustalf) over three seasons, and N uptake was determined fortnightly from 4 weeks after planting (WAP) until harvest. Net N recovery during plant growth increased with N application rate (up to 90 kg N ha-1 in first season and up to 60 kg N ha-1 in second and third seasons). Net N recovery from manure during the growing period was relatively poor. There was no net recovery (up to 12 WAP) from annual application of manure during the first season and from first year application of the large rate of manure in the second season. Combined application of manure and N fertiliser increased net N recovery in all growing seasons (up to 120 kg N ha-1) above that achieved by separate applications of both N sources. There was a manure by N fertiliser interaction that enhanced N recovery, in two treatment combinations during the first season (low manure rate) and in the second season, and this was attributed to some non-N nutrient effects of the manure. Highest percentage increases in total N recovery at harvesting were observed when manure was combined with the low N fertiliser rate (60 kg N ha-1) (av. 58% in first season, 63% in third season) and limited further increases were recorded when the N fertiliser rate was doubled (120 kg N ha-1) (av. 15% in first season, 32% in third season). It was concluded that aerobically composted cattle manure from the smallholder farming areas of Zimbabwe was a poor source of N for maize growth in the short-term, even at high application rates. Combined application of manure with judicious use of N fertiliser can be positively exploited by smallholder farmers in Zimbabwe and other countries of sub-Saharan Africa, to increase yields through enhanced efficiency of use of scarce nutrient resources. Key Words: Aerobic composting, N mineralisation, N recovery, Zea mays RESUME L'efficacite dans l'augmentation de N du retablissement du ma?s ( Zea mays L.) de fertilisant N (0, 60, 120 kg N ha-1 annum-1) et le fumier de vache aerobicallement composte (0, 12,5 Mg ha-1 applique seulement en premiere annee) etait determinee quand les deux sources de N etaient appliquees separement ou en combinaison. Une experience sur le terrain etait etablie sur un filtre de terre de sol sable (Typic Kandiustalf) au dela de trois saisons, et la consommation de N etait determinee bimensuellement a partir de quatre semaines apres la plantation (WAP) jusqu'a la recolte. Le retablissement net de N pendant la croissance de la plante a augmente avec le taux d'application de N (jusqu'a 90 kg N ha-1 en premiere saison et jusqu'a 60 kg N ha-1 en seconde et troisieme saisons). Le retablissement net de N a partir du fumier durant la periode de croissance etait relativement pauvre. Il n'y avait pas retablissement (jusqu'a 12 WAP)a partir de l'application annuelle durant la premiere saison et a partir de la premiere annee d'application du large taux de fumier dans la seconde saison. L'application combinee du fumier et du fertilisant N a augmente le retablissement net dans toutes les saisons de croissance (jusqu'a 120 kg N ha-1) au dela de celui accomplit par les applications separees de deux sources de N. Il y avait un fumier par l'interaction du fertilisant N qui a ameliore le retablissement de N, dans deux combinaisons de traitement pendant la premiere saison (faible taux de fumier) et dans la seconde saison, et ceci etait attribue aux non effets des substances N du fumier. Les augmentations elevees du pourcentage dans le retablissement total de N a la recolte etaient observees quand le fumier etait combine avec le faible taux de fertilisant N (60 kg N ha-1) (av. 58% en premiere saison, 63% en troisieme saison) et davantage augmentations etaient enregistrees quand le taux de fertilisant etait double (120 kg N ha-1) (av. 15% en premiere saison, 32% en troisieme saison). Il etait conclu que le fumier de vache aerobicallement composte des fermiers des petites surfaces du Zimbabwe etait une pauvre source de N pour la croissance de ma?s a court terme, meme aux taux d'application eleves. L'application combinee du fumier avec un usage judicieux du fertilisant N peut etre positivement exploitee par les petits fermiers au Zimbabwe et autres pays de l'Afrique sub-Saharienne, pour augmenter les rendements a travers l'efficacite amelioree de l'usage des rares ressources des substances. Mots Cles : Compost aerobic, mineralisation de N, retablissement de N, Zea mays African Crop Science Journal Vol.11(4) 2003: 289-300