Dig­ging deep into an

NZ Lifestyle Block - - Down On The Farm -

A pad­dock of two halves. This view looks down down the north­ern, bet­ter half. The poorer-per­form­ing area is at the back, to the right. The other half. In both pic­tures the dry stalks are re­mains of pars­ley drop­wort flow­ers, which needed to be mown off. When the cows first come into this pad­dock they do seem to pre­fer the bet­ter half, although that may be be­cause of quan­tity of feed avail­able, as much as qual­ity or type.

of good pro­duc­tion if man­aged well.

But it is easy to see a chang­ing gra­di­ent of ‘good­ness' across these flats, from pad­docks which grow grass very well to ar­eas ob­vi­ously much less fer­tile. That fer­til­ity seems re­lated to its height above and dis­tance from the largest stream, although that may be co­in­ci­den­tal.

Com­pli­cat­ing that ob­ser­va­tion is that some of the strug­gling ar­eas were used for potato crop­ping for a few years, which dis­rupted the soil pro­file and pre­sum­ably de­pleted some nu­tri­ents.

There are a few pad­docks where the dif­fer­ences are very no­tice­able. Parts of those pad­docks grow an ex­cel­lent, dense sward of the chang­ing sea­sonal grasses I ex­pect to be there, but in other ar­eas there is a much re­duced vari­a­tion in pas­ture species and far less

growth in the plants. There is usu­ally also a greater num­ber of var­i­ous weeds.

I've tried to ad­dress what I as­sumed was go­ing on in the poorer ar­eas, putting on heav­ier dress­ings of lime and fer­tiliser in those places. They have grad­u­ally im­proved to some ex­tent, but progress has been slow.

On a small prop­erty one tends to do a soil test on an ‘av­er­age' area that gen­er­ally rep­re­sents the land­scape, and then ex­trap­o­late from that for fer­tiliser ap­pli­ca­tion. Some ar­eas have re­sponded very well to the cho­sen treat­ments, but not uni­ver­sally achieved my de­sired aim.

I re­alised if I was go­ing to get a bet­ter un­der­stand­ing I would have to dig a lit­tle deeper and find out what was go­ing on and how best I might ad­dress the prob­lems. I de­cided to 'do some science'

on the most

In very dry con­di­tions ground cover be­comes sparse in this area. Where kikuyu is present, the ground re­mains thickly cov­ered even in the mid­dle of a drought.

var­ied pad­dock to see if I could iden­tify the prob­lem. Half of that pad­dock is al­right and most of the other half is poor. The 'av­er­age' ap­proach to fer­tiliser in that area hasn't worked well enough, so it was time to find out what it specif­i­cally needs.

I spoke to my most reg­u­lar soil fer­til­ity con­sul­tant, from whom I haven't ac­tu­ally bought much prod­uct, but Steve Pol­glase from Agrifert is the most in­ter­ested and in­ter­est­ing con­sul­tant I've had con­tact with. He came up late one af­ter­noon and the two of us walked around the pad­dock, ex­am­in­ing the pas­ture com­po­si­tion and tak­ing soil plugs for later test­ing. I sug­gested that I wanted to take three lots of sam­ples, in three strips, down each side of this pad­dock and (with per­mis­sion) one lot from the neigh­bour­ing prop­erty as well, which was once part of the same pad­dock but has had no fer­tiliser nor lime for nearly 30 years. I thought the three tests might pro­vide some use­ful com­par­a­tive in­for­ma­tion. Steve was ini­tially doubt­ful but as we walked around he agreed there were quite ob­vi­ous dif­fer­ences be­tween one side of the pad­dock and the other.

In the first strip the grass is dom­i­nated by kikuyu, grow­ing well, with quite a bit of white clover amongst it, along with

some rye and pas­palum (since it was still late sum­mer), a bit of left-over pars­ley drop­wort, some self-heal and so on, all nice stuff for cows to eat.

On the other side of the pad­dock the pas­ture has gen­er­ally been quite poor. Even the kikuyu doesn't grow well there, or even at all in some places. I've long been sus­pi­cious that it was the fer­til­ity of the soil to blame, although Steve and I dis­cussed the pos­si­bil­ity that soil type could also be play­ing a part.

Many peo­ple think kikuyu is a dread­ful pas­ture grass, but it grows well in our cli­mate so if it isn't in a par­tic­u­lar lo­ca­tion, I want to find out why. Sum­mer 2014-2015 was quite dry early on, but we had good amounts of rain in au­tumn and such con­di­tions are ex­actly those to make kikuyu grow well. In my ex­pe­ri­ence, if it doesn't there's some­thing pretty wrong un­der­neath it.

The pre­dom­i­nant species on this poor side of the pad­dock is Ax­ono­pus fis­si­folius or nar­row-leaved car­pet grass, with its cute lit­tle seed-head which looks a bit like a bird's foot with two toes and a lower ‘thumb'. It's a grass the cat­tle quite like eat­ing (and I re­mem­ber lik­ing it in my lawn be­cause it was easy to cut with a hand-mower), but its nu­tri­tive value is The roots of the

grasses in the poorer area were deeper than we ex­pected to see and there were

earth­worms, de­spite the dry

con­di­tions. ap­par­ently not high. It has al­ways been an in­di­ca­tor of lower fer­til­ity, or lower ph in our pas­tures, par­tic­u­larly where it has be­come the pri­mary species in an area. It also grows in the higher-fer­til­ity ar­eas quite well, but pre­sum­ably ends up where the other plants can't com­pete as strongly. It's also pos­si­ble there are fer­til­ity or acid­ity is­sues in those spots too.

Over the fence in the neigh­bour's place things were far worse, with only very small bits of kikuyu grow­ing weakly in some places. The dom­i­nant species was the car­pet grass, with a bit of pas­palum thrown in. While well-fer­tilised ar­eas of our place were cur­rently grow­ing a lot of kikuyu and clover quite quickly, this pas­ture was puny and dry-look­ing.

Back on my side of the bound­ary, Steve dug up a spade-width of soil in the good and poor ar­eas of the pad­dock for us to look at the com­po­si­tion of the top­soil. He pointed out, among other things: • an or­ange strip of iron ox­i­da­tion which in­di­cates wet­ness, not sur­pris­ing where 1900mm of rain falls each year and the soils are wet for sev­eral months over win­ter and spring; • that the plants' roots were toughly re­sis­tant to stretch­ing, which he said in­di­cates a lack of ab­sorp­tion of cal­cium; • that the roots of the plants in the poor area were, sur­pris­ingly, deeper into the soil than those in the good part of the pad­dock, although that may have been a func­tion of the plant species since kikuyu tends to run across the top of the soil to a large ex­tent; • a fair num­ber of earth­worms, a good sign con­sid­er­ing the time of year.

Steve went on his way with my soil and pas­ture sam­ples and we'll talk again be­fore I write next month's col­umn. I hope the soil test re­sults will show suf­fi­cient dif­fer­ences to ex­plain our ob­ser­va­tions.

There seems to have been a ris­ing level of in­ter­est amongst farm­ers in the last cou­ple

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