Growing Cotton Under Sprinkler Irrigation

Cotton grown under Centre Pivot and Lateral Move (CPLM) irrigation systems employing traditional full tillage raised bed cotton farming systems will give poor yield and water use efficiency results.

Ground cover, in the form of specialised cover crops or previous year’s cereal stubble, is crucial to achieving high yielding, highly water efficient cotton crops. Ground cover material must have enough lignin and cellulose to resist decomposition until after row closure in the cotton crop. Planting cotton into fields with high ground cover residue loads is possible, but requires specialised equipment and separate farming systems to traditional, full tillage, raised bed cotton systems. Principles widely adopted in dryland cropping systems can be adapted to growing cotton under CPLM machines with specialist tools and correct planter set up. Zerotill cotton, grown on the flat can be achieved utilising new Bollgard 3 genetics, however tillage may still be required to control ratoon cotton.

Sprinkler selection is very important in delivering water to the soil efficiently. Sprinkler selection will have the greatest influence in machine performance, for minimal cost. Irrigation scheduling is very different to traditional cotton farming systems. However, the same decision-making tools are relevant for furrow and sprinkler irrigated crops. Machine maintenance is of the highest importance because, if the machine breaks down, there is zero capacity to irrigate the crop. Preventative pre-season maintenance can minimise down-time during the season and help prevent severe water stress.

Strip tilling is a new technique to Australian farming systems that has delivered significant yield increases in corn crops in the United States. Strip tilling is a precision agriculture tool and beneficial in a cotton system under CPLM, because it rips directly below the plant line, applies fertilizer at depth directly below the roots, prepares a seed bed, and moves trash out of the plant line in one pass, while retaining full ground cover between rows.