Submitted to: Better Crops
Publication Type: Other
Publication Acceptance Date: 9/9/1995
Publication Date: N/A
Interpretive Summary: Fertilizer use is essential for producing adequate crop yield in many semi-arid regions because diversified crop rotation that includes legumes is not practical. But efficient use of fertilizer is a prerequisite to attaining optimum yield while preventing adverse environmental impact. We determined the need for nitrogen, phosphorus, and sulfur in a semi-arid environment cropped to wheat either conventionally (plowed) or grown without tillage (no-till). We grew wheat both annually (one crop each year) or after fallow (one crop every two years). Fertilizer increased crop yield from less than 1000 kilograms per hectare (1120 pounds per acre) without fertilizer to over 4000 with optimum amounts applied. Wheat did not grow well when nitrogen was applied without phosphorus and sulfur; all three elements were needed to grow normally. This was especially true when wheat was grown without tillage (no- till) rather than tilled aggressively (plowed and cultivated). The need for fertilizer was also much greater when cereals were grown every year. Cereal production in semi-arid regions to meet food needs is possible, but judicious cropping must be accompanied by appropriate application of essential nutrients to maintain adequate fertility in soil.
Technical Abstract: Efficient fertilizer use is a prerequisite for achieving optimum crop yield while avoiding adverse environmental impacts. We measured wheat grain yield response to nitrogen (N), phosphorus (P), and sulfur (S) for six years in a semi- arid region. WE compared conventional- with no-tillage and a wheat/fallow rotation with annual cereal production. All fertilizer elements increased wheat yield significantly; yield ranged from 1000 kg per ha without fertilizer to more than 4000 where fertilized with N, P, and S. Both N and S were more deficient in no-till than conventional-till, and where cropped annually rather than following fallow. Phosphorus needs were minimally affected by cropping intensity and tillage. Adequate P and S application were essential to achieving optimum response to N fertilizer.