Assessment of Yield and Yield Attributing Characters of Hybrid Maize using Nutrient Expert® Maize Model in Eastern Terai of Nepal

Indiscriminate use of fertilizer and lack of site specific nutrient management technology is the main cause of low maize productivity in Nepal. Thus, field experiments on farmer's field were conducted on maize to assess the productivity at two sites of Jhapa district viz. Damak and Gauradaha using Nutrient Expert® Maize model from November 2015 to May 2016. The experiment was laid out in Randomized Completely Block Design consisting two treatments viz. NE (Nutrient Expert recommendation) and FFP (Farmer's Fertilizer Practice) with twenty replications. The result revealed significant differences in terms of grain yield, stover yield, biological yield, and yield attributing characters. NE based practices produced higher grain yield (9.22 t ha-1), which was 86.6 percent higher than FFP (4.94 t ha-1). Similarly, higher average cob number m 2 (8.2), average kernel rows cob-1 (14.2), average kernels number row-1 (589.9) and test weight (361.4 g) were recorded in NE based practice. Thus, NE based practice can be adopted for obtaining higher productivity in eastern terai region of Nepal.


I. INTRODUCTION
Maize (Zea mays L.) is the second most important cereal crop after rice in Nepal. It is used as food, feed, fodder and raw materials for industries. It is cultivated in 891,583 hectares of land with production and productivity of 2,231,517 tons and 2.5 t ha -1 , respectively (MoAD, 2017). It is the major food crop in the hills of Nepal and accounts about 71% of maize production of the country (MoAD, 2017). The demand of maize grain has increased, but the productivity in farm level is almost stagnant around 2-2.5 t ha -1 in last decade (MoAD, 2017). The farm level yield of maize (2.5 t ha -1 ) is not satisfactory as compared to attainable yield (5.7 t ha -1 ) in Nepal (MoAD, 2017;KC et al., 2015). Indiscriminate use of fertilizer and lack of site specific nutrient management technology is the main cause of low maize productivity in Nepal. Therefore, nutrient management is always the major concern in maize for increasing production in Nepal. Site specific nutrient management (SSNM) is a plant based approach for supplying crops with nutrients in right amount and time. It strives to enable farmers to adjust fertilizer use dynamically to make up the deficit in nutrients needs between that required by a high-yielding crop and nutrient supply from naturally occurring indigenous sources (i.e. soil, crop residues, manures and irrigation water) (Ghimire et al., 2015). Based on SSNM principles, a dynamic nutrient management tool, Nutrient Expert® (NE), was developed that can generate farmspecific fertilizer recommendation for maize (Majumdar et al., 2014). Many researches concerning about SSNM has been carried out around the globe. Similarly, Nutrient Expert has been tested earlier in India (Majumdar et al., 2014), Indonesia and Philippines  and found valid. But, In Nepal, limited research has been carried out concerning about SSNM and Nutrient Expert. Therefore, the present investigation is planned, executed and accomplished with the objective of assessing yield and yield attributing characters of maize using Nutrient Expert®-Maize.

II. MATERIALS AND METHODS
The study was carried out at two sites of Jhapa district viz. Damak and Gauradaha from November 2015 to May 2016. The experiment was laid out in single factorial Randomized Completely Block Design consisting two treatments viz. NE (Nutrient Expert recommendation) and FFP (Farmer's Fertilizer Practice) in twenty farmer's field, considering one farmer as one replication. The gross plot and net plot size for each treatment was maintained 100 m 2 and 10 m 2 , respectively. The NE plot consist the cultivation of maize under Nutrient Expert-Maize recommended spacing, seed rate, fertilizer dose and other factors of production. FFP plot consist of maize cultivation under farmer's own practice of spacing, seed rate, fertilizer dose and other factors of production. Data of observations on yield attributing characters, grain yield and stover yield were recorded from net plot. These recorded data were tabulated in MS-Excel which was subjected to ANOVA (Gomez and Gomez, 1984), after analysis through GENSTAT-C, computer based program at 5% significance level. The grain yield was adjusted at 14% moisture level.

III. RESULTS AND DISCUSSION 3.1 Grain yield
The grain yield of maize was highly influenced by nutrient management practices ( Table 1). The grain yield of maize under Nutrient Expert (NE) (9.22 t ha -1 ) was highly significant than grain yield of maize under farmer's fertilizer practice (FFP) (4.94 t ha -1 ). The significant increase in yield attributing characters under NE (Table 2)   The higher yields in NE may be ascribed to efficient adjustments in applying nutrients to accommodate field specific needs of the crops for supplementing plant nutrients (Pooniya et al., 2015). The increased availability of nutrients at critical physiological phases results in better translocation of photosynthates from source to sink, resulting better growth and yield attributing characters, and finally increasing the grain yield (Vikram et al., 2015).
Similarly, broadcasting of seed in FFP had caused patchy growth of crop, characterized by improper spacing. This led to increased incidence of insect, pest and diseases in FFP, which also led to reduced grain yield.

Stover and biological yields
The stover yield was highly influenced by nutrient management practices ( Table 1). The stover yield under NE was found to be 12.7 t ha -1 , which was highly significant than stover yield under farmer's practice (

Yield attributing characters
The result showed that yield attributing characters viz. average plant number per m 2 , average cob number per m 2 , average kernel row per cob, average kernel number per row, average kernel number per cob and test weight were highly influenced by nutrient management practices (  IV. CONCLUSION Indiscriminate use of fertilizer and lack of site specific nutrient management technology is the main cause of low maize productivity in Nepal. Therefore, nutrient management is always the major concern in maize for increasing production in Nepal. The productivity of maize was increased under NE based nutrient management practice. Thus, NE based practice can be adopted for obtaining higher productivity in eastern terai region and similar agro-climatic condition of Nepal.