Points to con­sid­er – Cri­te­ria for using stub­ble cul­ti­va­tion in practice

As soon as har­vest­ing is over, the foun­da­tions start to be laid for the next farm­ing year. Even at this ear­ly stage, deci­sions are made that not only have an impact on yield but also on soil qual­i­ty. Var­i­ous fac­tors come into play when choos­ing the best method for stub­ble cul­ti­va­tion and seedbed prepa­ra­tion. Phy­tosan­i­tary rea­sons are one exam­ple. Oth­er crit­i­cal fac­tors include the site con­di­tions and planned rota­tion crop. Stub­ble cul­ti­va­tion is used to encour­age vol­un­teer cere­als and weed seeds to ger­mi­nate, as well as to pro­mote rot­ting in straw and oth­er plant residues.

The aim of seedbed prepa­ra­tion is to ensure the opti­mum con­di­tions for sow­ing and cul­ti­vat­ing the sub­se­quent crop, so that it can estab­lish itself well enough to pro­duce a good yield. Soil prop­er­ties such as gen­er­al char­ac­ter­is­tics and expo­sure – along with their asso­ci­at­ed ero­sion and drought risks – play an impor­tant role in this. Site con­di­tions also include the chang­ing envi­ron­men­tal con­di­tions and antic­i­pat­ed weath­er con­di­tions. Com­mer­cial con­sid­er­a­tions, and para­me­ters such as the lev­el of mech­a­ni­sa­tion, antic­i­pat­ed yield, pro­vi­sion of labour and dif­fer­ences in fuel con­sump­tion also weigh into the assessment.

The cho­sen method and tim­ing of stub­ble cul­ti­va­tion has a direct impact on the soil prop­er­ties and water bal­ance of arable fields. Increas­ing­ly fre­quent heavy rains and dry spells are also chang­ing the require­ments pro­file for arable farm­ing sys­tems. As a con­se­quence, boost­ing the infil­tra­tion, stor­age and drainage capac­i­ties of soil is becom­ing ever more impor­tant. The best way to achieve this is through low-impact mulching at a shal­low depth. The exact meth­ods and means for achiev­ing opti­mum results will depend on your indi­vid­ual farm and its spe­cif­ic circumstances.

To make it eas­i­er to come to a deci­sion, the soil prop­er­ties can be record­ed using farm man­age­ment soft­ware. By com­bin­ing this data with data gath­ered dur­ing cul­ti­va­tion work, farm man­age­ment soft­ware can high­light the impact of the cho­sen stub­ble cul­ti­va­tion method. To ben­e­fit from the pos­i­tive effects of “plough­less” cul­ti­va­tion, it should be imple­ment­ed over the longer term.

The rec­i­p­ro­cal impact of stub­ble cul­ti­va­tion on site con­di­tions and vice versa

Crop cul­ti­va­tion meth­ods incor­po­rate a range of high to low lev­els of trac­tive pow­er and deep to ultra-shal­low lev­els of soil cul­ti­va­tion. In fact, the direct seed­ing method does­n’t require stub­ble cul­ti­va­tion at all. Plough­ing is the most wide­ly used method of prepar­ing the ground for sow­ing. This method inter­feres heav­i­ly with the soil struc­ture. It does have its advan­tages, how­ev­er: it cre­ates a clean sweep, which is great for seed drills and reduces pres­sure from weeds and pests, espe­cial­ly when the crop rota­tion is tight. The phy­tosan­i­tary rea­sons for plough­ing are extreme­ly rel­e­vant because self-seed­ed plants, root-prop­a­gat­ed weeds and heavy pest infes­ta­tions can be a huge prob­lem. In order to com­bat pest infes­ta­tions in par­tic­u­lar, crop residues need to be chopped, spread and neat­ly incor­po­rat­ed into the soil. Effec­tive stub­ble cul­ti­va­tion removes unwant­ed plants, thus enabling mechan­i­cal weed con­trol. If the soil is cul­ti­vat­ed at a deep­er lev­el, it needs to be recon­sol­i­dat­ed in order to safe­guard the plants’ water supply.

Nev­er­the­less, there are also dis­ad­van­tages in terms of soil prop­er­ties. Con­ven­tion­al cul­ti­va­tion using a plough is the main cause of soil silt­ing, which pre­vents it from being infil­trat­ed and encour­ages runoff and ero­sion. Inad­e­quate aer­a­tion caus­es prob­lems such as a lack of oxy­gen in the crust, insuf­fi­cient soil warm­ing, poor root for­ma­tion in the main crop and poor crop devel­op­ment as a result. Stale sur­face water leads to water ero­sion because nutri­ents and soil par­ti­cles drift away on top of the soil sur­face. As a result, so-called “min-till” farm­ing meth­ods (cul­ti­va­tion with­out using a plough) are gain­ing in importance.

Long-term tri­als are already pro­duc­ing valid data in sup­port of these meth­ods. As a gen­er­al rule, the choice of method depends on the site con­di­tions. That said, just because some­thing is tech­ni­cal­ly pos­si­ble does not mean it is ben­e­fi­cial from a crop cul­ti­va­tion stand­point. Accord­ing­ly, soil that is too wet should not be tilled if it con­tains high lev­els of clay. Oth­er­wise, there is a dan­ger of soil com­pres­sion which can be detri­men­tal to the soil prop­er­ties. Using high­er lev­els of chem­i­cal plant pro­tec­tion to improve weed erad­i­ca­tion can cause even greater destruc­tion to soil fau­na and have a neg­a­tive impact on the soil. In a worst-case sce­nario, poor cul­ti­va­tion can lead to irre­versible soil loss and inten­si­fied soil dam­age. Exam­ples of min-till arable farm­ing meth­ods are described in the fol­low­ing section.

Stub­ble cul­ti­va­tion options

There are sev­er­al approach­es to assess­ing min-till meth­ods and mak­ing the most of their advan­tages. Deal­ing with the resid­ual organ­ic mat­ter from pre­ced­ing crops can be a chal­lenge, not least due to the mechan­i­cal and phy­tosan­i­tary prob­lems it cre­ates. An ever-chang­ing crop rota­tion with fre­quent catch crops is the best way to deal with unwant­ed plants and a build-up of pests. Chang­ing sum­mer and win­ter crops fre­quent­ly and incor­po­rat­ing under­sown crops are just two exam­ples of this. Sprout­ing vol­un­teer cere­als can be large­ly sup­pressed by the grow­ing com­pe­ti­tion and shade gen­er­at­ed by a catch crop. The growth from the catch crop can then be used as green manure for the main crop. Main­tain­ing cov­er­age of the soil in gen­er­al not only helps to avoid unwant­ed crops. It can also sig­nif­i­cant­ly reduce soil ero­sion. The amount of organ­ic mat­ter that remains on the soil sur­face until crop cov­er­age is crit­i­cal for pre­vent­ing ero­sion. Pests can also be reduced by mechan­i­cal­ly destroy­ing their win­ter habi­tats used for hibernation.

There is no short­age of equip­ment avail­able for min-till cul­ti­va­tion. Some cul­ti­va­tion imple­ments work at a shal­low depth to thor­ough­ly shred crop residues and incor­po­rate them into the soil. Direct seed drills enable grains to be deposit­ed effec­tive­ly and achieve a clean result despite the pres­ence of organ­ic mat­ter on the sur­face. This method allows cul­ti­va­tion and sow­ing to be car­ried out in one pass. Strip-till vari­ants only loosen up the soil where the crop is intend­ed to ger­mi­nate. This means a min­i­mal amount of soil is turned over, thus pre­serv­ing the all-impor­tant soil struc­ture for pre­vent­ing ero­sion. When crops are sown using the strip-till method, fer­tilis­er is deposit­ed direct­ly below the plants to ensure an effi­cient sup­ply of nutrients.

Sup­ple­men­tal pay­ments are avail­able through the direct pay­ment reg­u­la­tion for min-till farm­ing meth­ods to com­pen­sate finan­cial­ly for any poten­tial loss­es in yield. Dig­i­tal farm­ing tools can prove use­ful for pro­vid­ing evi­dence of activ­i­ties and com­pli­ance with leg­isla­tive frame­works such as “cross com­pli­ance”. Deci­sions on which meth­ods are suit­able and whether min-till farm­ing makes sense for you should be based on an analy­sis of your spe­cif­ic farm struc­ture. We rec­om­mend analysing the impact of these meth­ods in advance by tri­alling them on sub­sec­tions of your fields. To doc­u­ment your activ­i­ties and be able to pro­vide evi­dence of their impact, we also rec­om­mend using dig­i­tal farm­ing tools and farm man­age­ment software.