Spring wheat response to nitrogen, tillage and cropping system under rainfed condition

Abstract

The objective of this research work was to assess the existing summer fallow elimination by growing short duration leguminous crop (mungbean) and reduction in number of plows could be a good substitute in recent shift of rainfall pattern. The traditional tillage frequencies (exceeding 4–5 plow + 2 harrows) of the summer fallow land without the addition of commercial fertilizers to wheat are the century-old practices in the project area. The rainfall efficiency is very low and is certainly related to the low and marginal fertility status. The existing wheat–fallow–wheat (W–F–W) where field remains without crop for five–six months in summer was compared with the proposed wheat–mungbean–wheat (W–Mb–W) cropping system by eliminating the summer fallow. Four tillage systems, i.e. no tillage (NT), conventional tillage (CT), reduced tillage (RT), and maximum tillage (MT), were employed before wheat sowing. Wheat (Triticum aestivum L., cv. Tatara) was sown at the residual moisture of the monsoon rainfall and four levels of N (0, 25, 50, and 75 kg ha⁻¹) were added at the time of wheat sowing. Results show that the wetter year (second year) of the experiment had higher soil water (26.35%), grain yield (2,561 kg ha⁻¹), harvest index (43.5%), and water use efficiency (WUE) (6.1 kg ha⁻¹ mm⁻¹). The existing W–F–W cropping system had more soil water (17%), grain yield (17%), harvest index (1%), WUE (9%), and grain N (23%) than W–Mb–W. CT system had more soil water (13%), grain yield (5%), WUE (2%), harvest index (3%), and grain N (5%) as compared with NT. CT also had more soil water contents (5%), grain yield (3%), WUE (10%),), and harvest index (3%) than MT. Nitrogen application had increased grain yield (33%), WUE (25%), harvest Index (3%), and grain N (7%) compared with the control (no N application). The present study does not suggest the replacement of summer fallow with mungbean crop as for as the grain yield and WUE is concerned. Apparently no negative impact of CT was recorded on grain yield and other parameters; however, to be on the safe side, RT with application of 75 kg N ha⁻¹ is recommended for areas with similar rainfall pattern and soil fertility status.

Keywords:

• wheat
• dryland
• water use efficiency
• grain N
• grain yield
• harvest index
• cropping system
• tillage and nitrogen

Public Interest Statement

Wheat–fallow–wheat or wheat–millet/sorghum–wheat is the dominant cereal-based cropping system in the project area. Since ages, application of farm yard manure is the sole source of plant nutrients. Wheat is sown on the residual moisture of the monsoon rainfall preferably in the last week of October, while millet/sorghum is grown during the current rainfall of the rainy season (July–August). With the recent introduction of farm machinery, reliance on the animal power has drastically reduced. Therefore, the reduction in numbers of livestock and farm yard manure declined the soil fertility in the study area. Two approaches to increase the soil fertility with introduction of legumes in summer gap instead of fallow and application of reasonable amount of inorganic fertilizers keeping in view the financial conditions of the farmers and expected yield based on the past experience were adopted.

Competing interests

The authors declare no competing interest.

Acknowledgments

Financial support provided by the Higher Education Commission Islamabad, Pakistan, through The University of Agriculture Peshawar is greatly acknowledged.

Additional information

Funding

Financial support was provided by the Higher Education Commission Islamabad, Pakistan, through The University of Agriculture Peshawar.

Notes on contributors

Amanullah

The principal author and his family have a very long association as inhabitants as well as working farmers of the area and growing of cereal crops, exceptionally legume crops in the area. A numbers of adoptive trails on the farmer’s field have already been conducted from the last 20–25 years involving bachelor’s and master’s students. With climatic change and in the improvement of livelihood of the community, cereal-based cropping system is not feasible any more. Instead, attention should be focused on the combined use both sources of fertilizers (organic and inorganic) and inclusion of legume crops for sustainable crop production in dryland is necessary. This minimum intervention is also socially acceptable for the farmers of the area.