Carryover response of tillage depth, legume residue and nitrogenrates on maize yield and yield contributing traits

Abstract

Maize (Zea mays L.) after wheat (Triticum aestivum L.) is successfully grown in tropics and sub-topics where cereals grains contribute in staple food and their by-products as fodder. This study evaluated the carryover response of tillage depth (TD), crop residue (R) and fertilizer nitrogen rates (N) on maize in wheat-maize cropping system during summer 2010 and 2011. On dry matter (DM) basis, 5 tones ha-1 legume residue (LR) of cowpea and cereal residue (CR) from maize vs. no-residue (NR) were incorporated into the soil as main plot treatments. The soil was immediately plowed with moldboard for deep tillage (DT) and with cultivator for shallow tillage (ST) as main plot treatments. Different N-rates (0, 40, 80, 120 and 160 kg ha-1) were applied as subplot treatments. Results showed that DT increased grains yield by 2.27% than ST and ear number by 6%, grain number by 2.79% and thousand grains weight (1.02%). When compared with NR, the grain yield increased by 8.09% with incorporation of LR and 1.37% with CR with higher fractional contributions of ear and grain number than grain weight. Similarly, maize grain yield also increased by 44.91, 42.40, 29.81 and 6.64% by application of 160, 120, 80 and 40 kg N ha-1. Canopy radiation use efficiency (RUE) also increased in similar trend as for grain yield under given treatments. Interaction was significant (p < 0.05) for grain yield in 2011 and for two years average. Two years average data also showed markedly higher (p < 0.05) grain yield under LR than CR or NR treatments. Similarly, as compared to control and N-rate 40 kg ha-1, the 80 and 120 kg N ha-1 showed significantly marked changes in yield with highest in LR, followed by CR and lowest by NR. For interaction, the yield difference with treatments was mainly associated with ear number and to some extent in 1000 grain weight. The study suggests that 5 t ha-1 residue (legume > cereals > No residue) with 120 kg N ha-1 when incorporated deeply in soil has long lasting favorably positive response on crop yield and soil fertility in regularly cultivated cereal based rotation.